id
stringlengths 9
16
| title
stringlengths 4
335
| abstract
stringlengths 18
3.51k
| categories
listlengths 1
4
| creation_date
timestamp[ns, tz=UTC] |
|---|---|---|---|---|
2304.14547
|
On the structure-to-property relationship of polyanilines. A modern quantum chemistry perspective
|
We employ state-of-the-art quantum chemistry methods to study the structure-to-property relationship in polyanilines (PANIs) of different lengths and oxidation states. Specifically, we focus on leucoemeraldine, emeraldine, and pernigraniline in their tetramer and octamer forms. We scrutinize their structural properties, HOMO and LUMO energies, HOMO-LUMO gaps, and vibrational and electronic spectroscopy using various Density Functional Approximations (DFAs). Furthermore, the accuracy of DFAs is assessed by comparing them to experimental and wavefunction-based reference data. For that purpose, we performed large-scale orbital-optimized pair-Coupled Cluster Doubles (oo-pCCD) calculations for ground and electronically excited states and conventional Configuration Interaction Singles (CIS) calculations for electronically excited states in all investigated systems. Furthermore, we augment our study with a quantum informational analysis of orbital correlations in various forms of PANIs. Our study highlights the growing multi-reference nature of PANIs with the length of the polymer. While structural and vibrational features of the investigated PANIs, regardless of their oxidation states, are adequately modeled in the tetramer forms, the length of the PANI chain profoundly affects electronic spectra. Specifically, polymer elongation changes the character of the leading transitions in the lowest-lying excited states in all investigated PANIs.
|
[
"Physics Archive->physics->physics.chem-ph"
] | 2023-04-27T21:55:39Z |
0909.4623
|
Quantum Simulation of Markov Chains
|
The possibility of simulating a stochastic process by the intrinsic randomness of quantum system is investigated. Two simulations of Markov Chains by the measurements of quantum systems are proposed.
|
[
"Mathematics Archive->math.MP",
"Physics Archive->math-ph",
"Physics Archive->quant-ph"
] | 2009-09-25T06:56:59Z |
1009.2306
|
Linear amplification and quantum cloning for non-Gaussian continuous variables
|
We investigate phase-insensitive linear amplification at the quantum limit for single- and two-mode states and show that there exists a broad class of non-Gaussian states whose nonclassicality survives even at an arbitrarily large gain. We identify the corresponding observable nonclassical effects and find that they include, remarkably, two-mode entanglement. The implications of our results for quantum cloning outside the Gaussian regime are also addressed.
|
[
"Physics Archive->quant-ph"
] | 2010-09-13T06:37:40Z |
2204.00964
|
AdaFace: Quality Adaptive Margin for Face Recognition
|
Recognition in low quality face datasets is challenging because facial attributes are obscured and degraded. Advances in margin-based loss functions have resulted in enhanced discriminability of faces in the embedding space. Further, previous studies have studied the effect of adaptive losses to assign more importance to misclassified (hard) examples. In this work, we introduce another aspect of adaptiveness in the loss function, namely the image quality. We argue that the strategy to emphasize misclassified samples should be adjusted according to their image quality. Specifically, the relative importance of easy or hard samples should be based on the sample's image quality. We propose a new loss function that emphasizes samples of different difficulties based on their image quality. Our method achieves this in the form of an adaptive margin function by approximating the image quality with feature norms. Extensive experiments show that our method, AdaFace, improves the face recognition performance over the state-of-the-art (SoTA) on four datasets (IJB-B, IJB-C, IJB-S and TinyFace). Code and models are released in https://github.com/mk-minchul/AdaFace.
|
[
"Computer Science Archive->cs.CV"
] | 2022-04-03T01:23:41Z |
1104.0783
|
Lectures on localization and matrix models in supersymmetric Chern-Simons-matter theories
|
In these lectures I give a pedagogical presentation of some of the recent progress in supersymmetric Chern-Simons-matter theories, coming from the use of localization and matrix model techniques. The goal is to provide a simple derivation of the exact interpolating function for the free energy of ABJM theory on the three-sphere, which implies in particular the N^{3/2} behavior at strong coupling. I explain in detail part of the background needed to understand this derivation, like holographic renormalization, localization of path integrals, and large N techniques in matrix models
|
[
"Physics Archive->hep->hep-th"
] | 2011-04-05T09:20:14Z |
hep-ex/0505017
|
Charge Asymmetry of Same-Sign Dileptons in $B^0$-$\bar{B}^0$ Mixing
|
We report a measurement of the charge asymmetry for same-sign dileptons in $B^0$-$\bar{B}^0$ mixing, $A_{\rm sl}$. The data were collected with the Belle detector at KEKB. Using a data sample of 78 fb$^{-1}$ recorded at the $\Upsilon(4S)$ resonance and 9 fb$^{-1}$ recorded at an energy 60 MeV below the resonance, we measure $A_{\rm sl} = (-1.1 \pm 7.9(\text{stat}) \pm 7.0(\text{sys}))\times 10^{-3}$.
|
[
"Physics Archive->hep->hep-ex"
] | 2005-05-09T16:52:52Z |
0901.1216
|
Measurement of B(Ds+ -->ell+ nu) and the Decay Constant fDs From 600/pb of e+e- Annihilation Data Near 4170 MeV
|
We examine e+e- --> Ds^-D_s^{*+} and Ds^{*-}Ds^{+} interactions at 4170 MeV using the CLEO-c detector in order to measure the decay constant fDs with good precision. Previously our measurements were substantially higher than the most precise lattice based QCD calculation of (241 +/- 3) MeV. Here we use the D_s^+ --> ell^+ nu channel, where the ell^+ designates either a mu^+ or a tau^+, when the tau^+ --> pi^+ anti-nu. Analyzing both modes independently, we determine B(D_s^+ --> mu^+ nu)= 0.565 +/- 0.045 +/- 0.017)%, and B(D_s^+ --> mu^+ nu)= (6.42 +/- 0.81 +/- 0.18)%. We also analyze them simultaneously to find an effective value of B^{eff}(D_s^+ --> mu^+ nu)= (0.591 +/- 0.037 +/- 0.018)% and fDs=(263.3 +/- 8.2 +/- 3.9) MeV. Combining with the CLEO-c value determined independently using D_s^+ --> tau^+ nu, tau^+ --> e^+ nu anti-nu decays, we extract fDs=(259.5 +/- 6.6 +/- 3.1) MeV. Combining with our previous determination of B(D^+ --> mu^+ nu), we extract the ratio fDs/fD+=1.26 +/- 0.06 +/- 0.02. No evidence is found for a CP asymmetry between Gamma(D_s^+ --> mu^+\nu) and \Gamma(D_s^- --> mu^- nu); specifically the fractional difference in rates is measured to be (4.8 +/- 6.1)%. Finally, we find B(D_s^+ --> e^+ nu) < 1.2x10^{-4} at 90% confidence level.
|
[
"Physics Archive->hep->hep-ex"
] | 2009-01-09T16:48:10Z |
1312.5401
|
Fan-extensions in fragile matroids
|
If S is a set of matroids, then the matroid M is S-fragile if, for every element e in E(M), either M\e or M/e has no minor isomorphic to a member of S. Excluded-minor characterizations often depend, implicitly or explicitly, on understanding classes of fragile matroids. In certain cases, when F is a minor-closed class of S-fragile matroids, and N is in F, the only members of F that contain N as a minor are obtained from N by increasing the length of fans. We prove that if this is the case, then we can certify it with a finite case-analysis. The analysis involves examining matroids that are at most two elements larger than N.
|
[
"Mathematics Archive->math.CO"
] | 2013-12-19T04:12:53Z |
2209.09796
|
400 kHz repetition rate THz-TDS with 24 mW of average power driven by a compact industrial Yb-laser
|
We demonstrate a high average power terahertz time-domain (THZ-TDS) spectrometer based on optical rectification in the tilted-pulse front geometry in lithium niobate at room temperature, driven by a commercial, industrial femtosecond-laser operating with flexible repetition rate between 40 kHz - 400 kHz. The driving laser provides a pulse energy of 41 uJ for all repetition rates, at a pulse duration of 310 fs, allowing us to explore repetition rate dependent effects in our TDS. At the maximum repetition rate of 400 kHz, up to 16.5 W of average power are available to drive our THz source, resulting in a maximum of 24 mW of THz average power with a conversion efficiency of ~ 0.15 % and electric field strength of several tens of kV/cm. At the other available lower repetition rates, we show that the pulse strength and bandwidth of our TDS is unchanged, showing that the THz generation is not affected by thermal effects in this average power region of several tens of watts. The resulting combination of high electric field strength with flexible and high repetition rate is very attractive for spectroscopy, in particular since the system is driven by an industrial, compact laser without the need for external compressors or other specialized pulse manipulation.
|
[
"Physics Archive->physics->physics.optics"
] | 2022-09-20T15:30:37Z |
2311.02530
|
One-to-Many Simultaneous Secure Quantum Information Transmission
|
This paper presents a new quantum protocol designed to simultaneously transmit information from one source to many recipients. The proposed protocol, which is based on the phenomenon of entanglement, is completely distributed and is provably information-theoretically secure. Numerous existing quantum protocols guarantee secure information communication between two parties but are not amenable to generalization in situations where the source must transmit information to two or more parties, so they must be applied sequentially two or more times in such a setting. The main novelty of the new protocol is its extensibility and generality to situations involving one party that must simultaneously communicate different, in general, messages to an arbitrary number of spatially distributed parties. This is achieved by the special way employed to encode the transmitted information in the entangled state of the system, one of the distinguishing features compared to previous protocols. This protocol can prove expedient whenever an information broker, say, Alice, must communicate distinct secret messages to her agents, all in different geographical locations, in one go. Due to its relative complexity, compared to similar cryptographic protocols, as it involves communication among $n$ parties, and relies on $GHZ_{n}$ tuples, we provide an extensive and detailed security analysis so as to prove that it is information-theoretically secure. Finally, in terms of its implementation, the prevalent characteristic of the proposed protocol is its uniformity and simplicity because it only requires CNOT and Hadamard gates, and the local quantum circuits are identical for all information recipients.
|
[
"Physics Archive->quant-ph"
] | 2023-11-05T00:41:55Z |
2311.07541
|
mlscorecheck: Testing the consistency of reported performance scores and experiments in machine learning
|
Addressing the reproducibility crisis in artificial intelligence through the validation of reported experimental results is a challenging task. It necessitates either the reimplementation of techniques or a meticulous assessment of papers for deviations from the scientific method and best statistical practices. To facilitate the validation of reported results, we have developed numerical techniques capable of identifying inconsistencies between reported performance scores and various experimental setups in machine learning problems, including binary/multiclass classification and regression. These consistency tests are integrated into the open-source package mlscorecheck, which also provides specific test bundles designed to detect systematically recurring flaws in various fields, such as retina image processing and synthetic minority oversampling.
|
[
"Computer Science Archive->cs.LG"
] | 2023-11-13T18:31:48Z |
1709.07495
|
A Symbolic Approach to Safety LTL Synthesis
|
Temporal synthesis is the automated design of a system that interacts with an environment, using the declarative specification of the system's behavior. A popular language for providing such a specification is Linear Temporal Logic, or LTL. LTL synthesis in the general case has remained, however, a hard problem to solve in practice. Because of this, many works have focused on developing synthesis procedures for specific fragments of LTL, with an easier synthesis problem. In this work, we focus on Safety LTL, defined here to be the Until-free fragment of LTL in Negation Normal Form~(NNF), and shown to express a fragment of safe LTL formulas. The intrinsic motivation for this fragment is the observation that in many cases it is not enough to say that something "good" will eventually happen, we need to say by when it will happen. We show here that Safety LTL synthesis is significantly simpler algorithmically than LTL synthesis. We exploit this simplicity in two ways, first by describing an explicit approach based on a reduction to Horn-SAT, which can be solved in linear time in the size of the game graph, and then through an efficient symbolic construction, allowing a BDD-based symbolic approach which significantly outperforms extant LTL-synthesis tools.
|
[
"Computer Science Archive->cs.LO"
] | 2017-09-21T19:02:57Z |
0901.1824
|
A Highly Nonlinear Differentially 4 Uniform Power Mapping That Permutes Fields of Even Degree
|
Functions with low differential uniformity can be used as the s-boxes of symmetric cryptosystems as they have good resistance to differential attacks. The AES (Advanced Encryption Standard) uses a differentially-4 uniform function called the inverse function. Any function used in a symmetric cryptosystem should be a permutation. Also, it is required that the function is highly nonlinear so that it is resistant to Matsui's linear attack. In this article we demonstrate that a highly nonlinear permutation discovered by Hans Dobbertin has differential uniformity of four and hence, with respect to differential and linear cryptanalysis, is just as suitable for use in a symmetric cryptosystem as the inverse function.
|
[
"Computer Science Archive->cs.IT",
"Mathematics Archive->math.IT"
] | 2009-01-13T16:37:17Z |
0805.2816
|
Connexions affines et projectives sur les surfaces complexes compactes
|
We prove that holomorphic normal projective connections on compact complex surfaces are flat. We show that a holomorphic torsion-free affine connection $\nabla$ on a compact complex surface is locally modelled on a translations-invariant affine connection on $\C^2$, except if $\nabla$ is a generic connection on a principal elliptic bundle over a Riemann surface of genus $g \geq 2$, with odd first Betti number. In the last case, the local Killing Lie algebra is of dimension one, generated by the fundamental vector field of the principal fibration.
|
[
"Mathematics Archive->math.CV",
"Mathematics Archive->math.DG"
] | 2008-05-19T09:10:10Z |
2312.05138
|
M\"obius function and primes: an identity factory with applications
|
We study the sums $\sum_{n\le X, (n,q)=1}\frac{\mu(n)}{n^s}\log^k\left(\frac{X}{n}\right)$, where $k\in\{0,1\}$, $s\in\mathbb{C}$, $\Re s>0$ and give asymptotic estimations in an explicit manner. In order to do so, we produce a large family of arithmetical identities and derive several applications. Along similar ideas, we present an appendix showing the inequality $\sum_{n\le X}\Lambda(n)/n\le \log X$, valid for any $X\geq 1$.
|
[
"Mathematics Archive->math.NT"
] | 2023-12-08T16:16:56Z |
hep-th/0210097
|
Renormalization as a functor on bialgebras
|
The Hopf algebra of renormalization in quantum field theory is described at a general level. The products of fields at a point are assumed to form a bialgebra B and renormalization endows T(T(B)^+), the double tensor algebra of B, with the structure of a noncommutative bialgebra. When the bialgebra B is commutative, renormalization turns S(S(B)^+), the double symmetric algebra of B, into a commutative bialgebra. The usual Hopf algebra of renormalization is recovered when the elements of B are not renormalised, i.e. when Feynman diagrams containing one single vertex are not renormalised. When B is the Hopf algebra of a commutative group, a homomorphism is established between the bialgebra S(S(B)^+) and the Faa di Bruno bialgebra of composition of series. The relation with the Connes-Moscovici Hopf algebra of diffeomorphisms is given. Finally, the bialgebra S(S(B)^+) is shown to give the same results as the standard renormalisation procedure for the scalar field.
|
[
"Physics Archive->hep->hep-th"
] | 2002-10-10T13:56:54Z |
1604.00410
|
Multiband Effects and the Bose-Hubbard Model in One-Dimensional Lattices
|
We study phase diagrams of one-dimensional bosons with contact interactions in the presence of a lattice. We use the worm algorithm in continuous space and focus on the incommensurate superfluid Mott-insulator transition. Our results are compared to those from the one-band Bose-Hubbard model. When Wannier states are used to determine the Bose-Hubbard model parameters, the comparison unveils an apparent breakdown of the one-band description for strong interactions, even for the Mott-insulating state with an average of one particle per site ($n=1$) in deep lattices. We introduce an inverse confined scattering analysis to obtain the ratio $U/J$, with which the Bose-Hubbard model provides correct results for strong interactions, deep lattices, and $n=1$.
|
[
"Physics Archive->cond-mat->cond-mat.quant-gas"
] | 2016-04-01T21:07:50Z |
1206.5178
|
Full support of the Kasteleyn operator associated with a bipartite toroidal graph
|
A perfect matching in a bipartite graph embedded on a torus defines a height function on the graph's faces and an associated height change vector in $\Z^2$. These matchings are enumerated by a combination of four evaluations of a bivariate Laurent polynomial, called Kasteleyn operator, whose coefficient of bidegree (i,j) is, up to the sign, the number of perfect matchings with height change (i,j). Therefore the Newton polygon of the Kasteleyn operator is the convex hull of the height change vectors. In this article, we prove that any point with integer coordinates in that polygon is realized by a perfect matching.
|
[
"Mathematics Archive->math.CO"
] | 2012-06-22T15:34:53Z |
1812.04124
|
The Planet Formation Potential Around a 45 Myr old Accreting M Dwarf
|
Debris disk detections around M dwarfs are rare, and so far no gas emission has been detected from an M dwarf debris disk. This makes the 45 Myr old M dwarf WISEJ080822.18-644357.3 a bit of a curiosity; it has a strong infrared excess at an age beyond the lifetime of a typical planet-forming disk, and also exhibits broad H$\alpha$ emission consistent with active accretion from a gaseous disk. To better understand the cold gas and dust properties of this system, we obtained ALMA observations of the 1.3mm continuum and the CO/$^{13}$CO/C$^{18}$O J=2-1 emission lines. No cold CO gas is detected from this system, ruling out a gas-rich protoplanetary disk. Unresolved dust continuum emission is detected at a flux of 198$\pm$15 $\mu$Jy, consistent with 0.057$\pm$0.006 M$_{\oplus}$ worth of optically thin dust, and consistent with being generated through a collisional cascade induced by large bodies at radii $<$16 au. With a sufficiently strong stellar wind, dust grains released in the outer disk can migrate inwards via PR drag, potentially serving as a source of grains for the strong infrared excess.
|
[
"Physics Archive->astro-ph->astro-ph.SR"
] | 2018-12-10T22:01:53Z |
1411.1445
|
The Gamma Ray Opacity of the Universe -- Indirect Measurements of the Extragalactic Background Light
|
Indirect constraints on the intensity of the Extragalactic Background Light (EBL) were provided by recent studies of extragalactic sources emitting sub-TeV to multi-TeV photons. These constraints are provided thanks to the absorption of gamma rays by soft photons from the EBL (UV/optical/IR) via pair production by gamma - gamma interactions. This paper provides an overview of recent results that have led to substantially reduced uncertainties on the EBL intensity over a wide range of wavelengths from 0.1 to 15 micron.
|
[
"Physics Archive->astro-ph->astro-ph.CO",
"Physics Archive->astro-ph->astro-ph.HE"
] | 2014-11-05T23:13:28Z |
2009.02724
|
MeerKAT's discovery of a radio relic in the bimodal merging cluster A2384
|
We present the discovery of a single radio relic located at the edge of the galaxy cluster A2384, using the MeerKAT radio telescope. A2384 is a nearby ($z$ = 0.092), low mass, complex bimodal, merging galaxy cluster that displays a dense X-ray filament ($\sim$ 700 kpc in length) between A2384(N) (Northern cluster) and A2384(S) (Southern cluster). The origin of the radio relic is puzzling. By using the MeerKAT observation of A2384, we estimate that the physical size of the radio relic is 824 $\times$ 264 kpc$^{2}$ and that it is a steep spectrum source. The radio power of the relic is $P_{1.4\mathrm{GHz}}$ $\sim$ (3.87 $\pm$ 0.40) $\times$ 10$^{23}$ W Hz$^{-1}$. This radio relic could be the result of shock wave propagation during the passage of the low-mass A2384(S) cluster through the massive A2384(N) cluster, creating a trail appearing as a hot X-ray filament. In the previous GMRT 325 MHz observation we detected a peculiar FR I radio galaxy interacting with the hot X-ray filament of A2384, but the extended radio relic was not detected; it was confused with the southern lobe of the FR I galaxy. This newly detected radio relic is elongated and perpendicular to the merger axis, as seen in other relic clusters. In addition to the relic, we notice a candidate radio ridge in the hot X-ray filament. The physical size of the radio ridge source is $\sim$ 182 $\times$ 129 kpc$^{2}$. Detection of the diffuse radio sources in the X-ray filament is a rare phenomenon, and could be a new class of radio source found between the two merging clusters of A2384(N) and A2384(S).
|
[
"Physics Archive->astro-ph->astro-ph.GA"
] | 2020-09-06T12:59:19Z |
astro-ph/0605470
|
Parametric Strong Gravitational Lensing Analysis of Abell 1689
|
(Abridged) We measure the mass distribution of galaxy cluster Abell 1689 within 0.3 Mpc/h_70 of the cluster centre using its strong lensing effect on 32 background galaxies. The multiple images are based on those of Broadhurst et al. 2005 with some modifications. The cluster profile is explored further out to ~2.5 Mpc/h_70 with weak lensing shear measurements from Broadhurst et al. 2005b. The masses of ~200 cluster galaxies are measured with Fundamental Plane in order to accurately model the small scale mass structure in the cluster. The galaxies are modelled as elliptical truncated isothermal spheres. The dark matter component of the cluster is described by either non-singular isothermal ellipsoids (NSIE) or elliptical versions of the universal dark matter profile (ENFW). We use two dark matter haloes to model the smooth DM in the cluster. The total mass profile is well described by either an NSIS profile with sigma=1514+-18 km/s and core radius of r_c=71+-5kpc/h_70, or an NFW profile with C=6.0+-0.5 and r_200=2.82+-0.11 Mpc/h_70. The errors are assumed to be due to the error in assigning masses to the individual galaxies in the galaxy component. The derived total mass is in good agreement with the mass profile of Broadhurst et al. 05. Using also weak lensing we can constrain the profile further out to r~2.5 Mpc/h_70. The best fit parameters are then sigma=1499+-15 km/s and r_c=66+-5 kpc/h_70 for the NSIS profile and C=7.6+-0.5 and r_200=2.55+-0.07 Mpc/h_70 for the NFW profile. Using the same image configuration as Broadhurst et al. 2005 we obtain a strong lensing model that is superior to that of Broadhurst et al. 2005 (rms of 2.7'' compared to 3.2'').
|
[
"Physics Archive->astro-ph"
] | 2006-05-19T09:32:49Z |
2112.04883
|
On the index of the critical M\"obius band in $\mathbb B^4$
|
In this paper we prove that the Morse index of the critical M\"obius band in the $4-$dimensional Euclidean ball $\mathbb B^4$ equals 5. It is conjectured that this is the only embedded non-orientable free boundary minimal surface of index 5 in $\mathbb B^4$. One of the ingredients in the proof is a comparison theorem between the spectral index of the Steklov problem and the energy index. The latter also enables us to give another proof of the well-known result that the index of the critical catenoid in $\mathbb B^3$ equals 4.
|
[
"Mathematics Archive->math.DG"
] | 2021-12-09T13:11:12Z |
2108.00376
|
The Aging Effect in Evolving Scientific Citation Networks
|
The study of citation networks is of interest to the scientific community. However, the underlying mechanism driving individual citation behavior remains imperfectly understood, despite the recent proliferation of quantitative research methods. Traditional network models normally use graph theory to consider articles as nodes and citations as pairwise relationships between them. In this paper, we propose an alternative evolutionary model based on hypergraph theory in which one hyperedge can have an arbitrary number of nodes, combined with an aging effect to reflect the temporal dynamics of scientific citation behavior. Both theoretical approximate solution and simulation analysis of the model are developed and validated using two benchmark datasets from different disciplines, i.e. publications of the American Physical Society (APS) and the Digital Bibliography & Library Project (DBLP). Further analysis indicates that the attraction of early publications will decay exponentially. Moreover, the experimental results show that the aging effect indeed has a significant influence on the description of collective citation patterns. Shedding light on the complex dynamics driving these mechanisms facilitates the understanding of the laws governing scientific evolution and the quantitative evaluation of scientific outputs.
|
[
"Computer Science Archive->cs.SI",
"Physics Archive->physics->physics.soc-ph"
] | 2021-08-01T06:45:27Z |
1506.07859
|
Area-Delay-Energy Tradeoffs of Strain-Mediated Multiferroic Devices
|
Multiferroic devices hold profound promise for ultra-low energy computing in beyond Moore's law era. The magnetization of a magnetostrictive shape-anisotropic single-domain nanomagnet strain-coupled with a piezoelectric layer in a multiferroic composite structure can be switched between its two stable states (separated by an energy barrier) with a tiny amount of voltage via converse magnetoelectric effect. With appropriate choice of materials, the magnetization can be switched with a few tens of millivolts of voltages in sub-nanosecond switching delay while spending a miniscule amount of energy of ~1 attojoule at room-temperature. Here, we analyze the area-delay-energy trade-offs of these multiferroic devices by solving stochastic Landau-Lifshitz-Gilbert equation in the presence of room-temperature thermal fluctuations. We particularly put attention on scaling down the lateral area of the magnetostrictive nanomagnet that can increase the device density on a chip. We show that the vertical thickness of the nanomagnet can be increased while scaling down the lateral area and keeping the assumption of single-domain limit valid. This has important consequence since it helps to some extent preventing the deterioration of the induced stress-anisotropy energy in the magnetostrictive nanomagnet, which is proportional to the nanomagnet's volume. The results show that if we scale down the lateral area, the switching delay increases while energy dissipation decreases. Avenues available to decrease the switching delay while still reducing the energy dissipation are discussed.
|
[
"Physics Archive->cond-mat->cond-mat.mes-hall"
] | 2015-06-18T18:11:00Z |
1807.09863
|
Metastability of the contact process on fast evolving scale-free networks
|
We study the contact process in the regime of small infection rates on finite scale-free networks with stationary dynamics based on simultaneous updating of all connections of a vertex. We allow the update rates of individual vertices to increase with the strength of a vertex, leading to a fast evolution of the network. We first develop an approach for inhomogeneous networks with general kernel and then focus on two canonical cases, the factor kernel and the preferential attachment kernel. For these specific networks we identify and analyse four possible strategies how the infection can survive for a long time. We show that there is fast extinction of the infection when neither of the strategies is successful, otherwise there is slow extinction and the most successful strategy determines the asymptotics of the metastable density as the infection rate goes to zero. We identify the domains in which these strategies dominate in terms of phase diagrams for the exponent describing the decay of the metastable density.
|
[
"Mathematics Archive->math.CO",
"Mathematics Archive->math.PR"
] | 2018-07-25T21:11:26Z |
2110.06660
|
An introduction to Geometric Manin's conjecture
|
This is a survey paper on Geometric Manin's conjecture which was proposed by Brian Lehmann and the author. We introduce Geometric Manin's conjecture (GMC) and review some recent progress on this conjecture.
|
[
"Mathematics Archive->math.AG"
] | 2021-10-13T11:51:29Z |
2211.05322
|
On Optimizing the Communication of Model Parallelism
|
We study a novel and important communication pattern in large-scale model-parallel deep learning (DL), which we call cross-mesh resharding. This pattern emerges when the two paradigms of model parallelism - intra-operator and inter-operator parallelism - are combined to support large models on large clusters. In cross-mesh resharding, a sharded tensor needs to be sent from a source device mesh to a destination device mesh, on which the tensor may be distributed with the same or different layouts. We formalize this as a many-to-many multicast communication problem, and show that existing approaches either are sub-optimal or do not generalize to different network topologies or tensor layouts, which result from different model architectures and parallelism strategies. We then propose two contributions to address cross-mesh resharding: an efficient broadcast-based communication system, and an "overlapping-friendly" pipeline schedule. On microbenchmarks, our overall system outperforms existing ones by up to 10x across various tensor and mesh layouts. On end-to-end training of two large models, GPT-3 and U-Transformer, we improve throughput by 10% and 50%, respectively.
|
[
"Computer Science Archive->cs.DC",
"Computer Science Archive->cs.LG"
] | 2022-11-10T03:56:48Z |
1805.04719
|
Lie Groups with flat Gauduchon connections
|
We pursuit the research line proposed in \cite{YZ-Gflat} about the classification of Hermitian manifolds whose $s$-Gauduchon connection $\nabla^s =(1-\frac{s}{2})\nabla^c + \frac{s}{2}\nabla^b$ is flat, where $s \in \mathbb{R}$ and $\nabla^c$ and $\nabla^b$ are the Chern and the Bismut connections, respectively. We focus on Lie groups equipped with a left invariant Hermitian structure. Such spaces provide an important class of Hermitian manifolds in various contexts and are often a valuable vehicle for testing new phenomena in complex and Hermitian geometry. More precisely, we consider a connected $2n$-dimensional Lie group $G$ equipped with a left-invariant complex structure $J$ and a left-invariant compatible metric $g$ and we assume that its connection $\nabla^s$ is flat. Our main result states that if either $n$=2 or there exits a $\nabla^s$-parallel left invariant frame on $G$, then $g$ must be K\"ahler. This result demonstrates rigidity properties of some complete Hermitian manifolds with $\nabla^s$-flat Hermitian metrics.
|
[
"Mathematics Archive->math.DG"
] | 2018-05-12T13:23:04Z |
2102.04734
|
Phase-space interpretation of spatial stationarity for coherence holography
|
We extend the wide-sense spatial stationarity concept of coherence holography in the regime of phase-space using the wigner distribution function. We focus mainly on the incoherent light source and the Fourier and Fresnel propagation kernels for the optical-field transformation rule (inputoutput relation) and derive the same analogy in WDF. We further show that in phase-space the WDF obtained from the ensemble-averaged and space-averaged coherence functions are the same. Finally, we interpret behaviour of these results through numerical simulations.
|
[
"Physics Archive->physics->physics.optics"
] | 2021-02-09T09:58:29Z |
0808.1504
|
Open and hidden charm in proton-nucleus and heavy-ion collisions
|
We review the collectivity and the suppression pattern of charmed mesons - produced in proton-nucleus and nucleus-nucleus collisions at SPS (158 AGeV) and RHIC energies (21 ATeV) - in comparison to dynamical and thermal models. In particular, we examine the charmonium `melting' and the `comover dissociation' scenarios - implemented in a microscopic transport approach - in comparison to the available data from the SPS and RHIC. The analysis shows that the dynamics of c, c-bar quarks at RHIC are dominated by partonic or `pre-hadronic' interactions in the strongly coupled plasma stage. Both the `charmonium melting' and the hadronic `comover absorption and recreation model' are found, however, to be compatible with the experimental observation at SPS energies; the experimental ratio of Psi'/J/Psi versus centrality clearly favors the `hadronic comover' scenario. We find that the collective flow of charm in the purely hadronic Hadron-String Dynamics (HSD) transport appears compatible with the data at SPS energies, but substantially underestimates the data at top RHIC energies. Thus, the large elliptic flow v2 of D-mesons and the low R_AA(p_T) of J/Psi seen experimentally have to be attributed to early interactions of non-hadronic degrees of freedom. Simultaneously, we observe that non-hadronic interactions are mandatory in order to describe the narrowing of the J/Psi rapidity distribution from pp to central Au+Au collisions at the top RHIC energy. We demonstrate additionally that the strong quenching of low-pT J/Psi's in central Au+Au collisions indicates that a large fraction of final J/Psi mesons is created by a coalescence mechanism close to the phase boundary. Throughout this review we, furthermore, provide predictions for charm observables from Au+Au collisions at FAIR energies of 25-35 AGeV.
|
[
"Physics Archive->nucl->nucl-th"
] | 2008-08-11T13:01:35Z |
nucl-th/9508040
|
Transverse Momentum Dependence of Hanbury-Brown/Twiss Correlation Radii
|
The transverse momentum dependence of Hanbury-Brown/Twiss (HBT) interferometry radii for 2-body correlation functions provides experimental access to the collective dynamics in heavy-ion collisions. We present an analytical approximation scheme for these HBT radii which combines the recently derived model-independent expressions with an approximate determination of the saddle point of the emission function. The method is illustrated for a longitudinally boost-invariant hydrodynamical model of a heavy ion collision with freeze-out on a sharp hypersurface. The analytical approximation converges rapidly to the width of the numerically computed correlation function and reproduces correctly its exact transverse momentum dependence. However, higher order corrections within our approximation scheme are essential, and the previously published lowest order results with simple $m_{\perp}$ scaling behaviour are quantitatively and qualitatively unreliable.
|
[
"Physics Archive->nucl->nucl-th"
] | 1995-08-24T07:38:40Z |
2112.12376
|
Revisiting and Advancing Fast Adversarial Training Through The Lens of Bi-Level Optimization
|
Adversarial training (AT) is a widely recognized defense mechanism to gain the robustness of deep neural networks against adversarial attacks. It is built on min-max optimization (MMO), where the minimizer (i.e., defender) seeks a robust model to minimize the worst-case training loss in the presence of adversarial examples crafted by the maximizer (i.e., attacker). However, the conventional MMO method makes AT hard to scale. Thus, Fast-AT (Wong et al., 2020) and other recent algorithms attempt to simplify MMO by replacing its maximization step with the single gradient sign-based attack generation step. Although easy to implement, Fast-AT lacks theoretical guarantees, and its empirical performance is unsatisfactory due to the issue of robust catastrophic overfitting when training with strong adversaries. In this paper, we advance Fast-AT from the fresh perspective of bi-level optimization (BLO). We first show that the commonly-used Fast-AT is equivalent to using a stochastic gradient algorithm to solve a linearized BLO problem involving a sign operation. However, the discrete nature of the sign operation makes it difficult to understand the algorithm performance. Inspired by BLO, we design and analyze a new set of robust training algorithms termed Fast Bi-level AT (Fast-BAT), which effectively defends sign-based projected gradient descent (PGD) attacks without using any gradient sign method or explicit robust regularization. In practice, we show our method yields substantial robustness improvements over baselines across multiple models and datasets. Codes are available at https://github.com/OPTML-Group/Fast-BAT.
|
[
"Computer Science Archive->cs.LG"
] | 2021-12-23T06:25:36Z |
2105.11844
|
CI-dataset and DetDSCI methodology for detecting too small and too large critical infrastructures in satellite images: Airports and electrical substations as case study
|
The detection of critical infrastructures in large territories represented by aerial and satellite images is of high importance in several fields such as in security, anomaly detection, land use planning and land use change detection. However, the detection of such infrastructures is complex as they have highly variable shapes and sizes, i.e., some infrastructures, such as electrical substations, are too small while others, such as airports, are too large. Besides, airports can have a surface area either small or too large with completely different shapes, which makes its correct detection challenging. As far as we know, these limitations have not been tackled yet in previous works. This paper presents (1) a smart Critical Infrastructure dataset, named CI-dataset, organised into two scales, small and large scales critical infrastructures and (2) a two-level resolution-independent critical infrastructure detection (DetDSCI) methodology that first determines the spatial resolution of the input image using a classification model, then analyses the image using the appropriate detector for that spatial resolution. The present study targets two representative classes, airports and electrical substations. Our experiments show that DetDSCI methodology achieves up to 37,53% F1 improvement with respect to Faster R-CNN, one of the most influential detection models.
|
[
"Computer Science Archive->cs.AI",
"Computer Science Archive->cs.CV",
"Computer Science Archive->cs.LG"
] | 2021-05-25T11:38:15Z |
hep-th/9607161
|
Dictionary on Lie Superalgebras
|
The main definitions and properties of Lie superalgebras are proposed a la facon de a short dictionary, the different items following the alphabetical order. The main topics deal with the structure of simple Lie superalgebras and their finite dimensional representations; rather naturally, a few pages are devoted to supersymmetry. This modest booklet has two ambitious goals: to be elementary and easy to use. The beginner is supposed to find out here the main concepts on superalgebras, while a more experimented theorist should recognize the necessary tools and informations for a specific use.
|
[
"Physics Archive->hep->hep-th"
] | 1996-07-18T18:38:46Z |
hep-ph/0405233
|
NNLO Corrections to the Polarized Drell-Yan Coefficient Function
|
We present the full next-to-next-to-leading order (NNLO) corrections to the coefficient function for the polarized cross section $d \Delta\sigma/d Q$ of the Drell-Yan process. We study the effect of these corrections on the process $p+p\to l^+l^-+`X'$ at an C.M. energy $\sqrt{S}=200 GeV$. All QCD partonic subprocesses have been included provided the lepton pair is created by a virtual photon, which is a valid approximation for a lepton pair invariant mass $Q<50 GeV$. For this reaction the dominant subprocess is given by $q+\bar q\to \gamma^*+`X'$ and its higher order corrections so that it provides us with an excellent tool to measure the polarized sea-quark densities.
|
[
"Physics Archive->hep->hep-ph"
] | 2004-05-24T15:14:48Z |
2102.07082
|
Heavy quark transport in an anisotropic hot QCD medium: Collisional and Radiative processes
|
The impact of momentum anisotropy on the heavy quark transport coefficients due to collisional and radiative processes in the QCD medium has been studied within the ambit of kinetic theory. Anisotropic aspects (momentum) are incorporated into the heavy quark dynamics through the non-equilibrium momentum distribution function of quarks, antiquarks, and gluons. These non-equilibrium distribution functions that encode the physics of momentum anisotropy and turbulent chromo-fields have been obtained by solving the ensemble-averaged diffusive Vlasov-Boltzmann equation. The momentum dependence of heavy quark transport coefficients in the medium is seen to be sensitive to the strength of the anisotropy for both collisional and radiative processes. In addition, the collisional and radiative energy loss of the heavy quark in the anisotropic hot QCD medium have been analyzed. The effects of anisotropy on the drag and diffusion coefficients are observed to have a visible impact on the nuclear suppression factor both at the RHIC and LHC.
|
[
"Physics Archive->hep->hep-ph",
"Physics Archive->nucl->nucl-th"
] | 2021-02-14T06:29:35Z |
1102.0392
|
Theoretical uncertainty in sin 2beta: An update
|
The source of theoretical uncertainty in the extraction of sin 2beta from the measurement of the golden channel Bd -> J/psi K0 is briefly reviewed. An updated estimate of this uncertainty based on SU(3) flavour symmetry and the measurement of the decay Bd -> J/psi pi0 is also presented.
|
[
"Physics Archive->hep->hep-ph"
] | 2011-02-02T09:53:57Z |
1412.0241
|
Status of some P-wave baryon resonances and importance of inelastic channels
|
We analyze the current status of three P-wave baryon states $N(1710){1/ 2}^+$, $N(1900){3/2}^+$, and $\Delta(1600){3/2}^+$ as given in the Review of Particles Physics (RPP). Since the evidence for a particle's existence is linked to its RPP "star" rating, we discuss its subjective present definition. We also present the accumulating evidence supporting these states and give our new "star" rating recommendations.
|
[
"Physics Archive->nucl->nucl-ex",
"Physics Archive->nucl->nucl-th"
] | 2014-11-30T16:40:29Z |
1411.0023
|
Validation of Matching
|
We introduce a technique to compute probably approximately correct (PAC) bounds on precision and recall for matching algorithms. The bounds require some verified matches, but those matches may be used to develop the algorithms. The bounds can be applied to network reconciliation or entity resolution algorithms, which identify nodes in different networks or values in a data set that correspond to the same entity. For network reconciliation, the bounds do not require knowledge of the network generation process.
|
[
"Computer Science Archive->cs.LG",
"Statistics Archive->stat.ML"
] | 2014-10-31T20:46:44Z |
2108.13549
|
Laminar natural double diffusive convection in a square cavity containing a square hot obstacle and filled with various types of Nanofluids: Benchmark
|
This article represents a set of results numerically studied in the framework of laminar double diffusive natural convection. We have investigated the thermophysical comportment of Water-based incompressible nanofluids circulating, due to buoyancy forces, inside a two-dimensional enclosed rectangular cavity for two comparable cases of considering or not a centered isothermal block. Results of this investigation are mainly built on parametric study of the most analytical variables that govern the flow. The buoyancy ratio ranged from -5 to 100, while Rayleigh number ranged from 103 to 106, and Lewis number ranged from 0 to 200. Four types of nanoparticles were considered: Copper, Alumina, Carbon-nanotubes and Titania which had a concentration range from 0 to 0.1.The flow is characterized by the isotherms, isoconcentrations and streamlines, and results were discussed in term of Nusselt and Sherwood average numbers, Streamlines maximum average values and Kinetic energy as function to the various aforementioned governing parameters.
|
[
"Physics Archive->physics->physics.flu-dyn"
] | 2021-08-30T23:19:35Z |
astro-ph/0512102
|
Slitless spectroscopy with the Advanced Camera for Surveys
|
The Advanced Camera for Surveys (ACS) enables low resolution slitless spectroscopic imaging in the three channels. The most-used modes are grism imaging with the WFC and the HRC at a resolution of 40 and 24 A/pixel, respectively. In the far UV there are two prisms for the SBC and a prism for the HRC in the near-UV. An overview of the slitless spectroscopic modes of the ACS is presented together with the advantages of slitless spectroscopy from space. The methods and strategies developed to establish and maintain the wavelength and flux calibration for the different channels are outlined. Since many slitless spectra are recorded on one deep exposure, pipeline science quality extraction of spectra is a necessity. To reduce ACS slitless data, the aXe spectral extraction software has been developed at the ST-ECF. aXe was designed to extract large numbers of ACS slitless spectra in an unsupervised way based on an input catalogue derived from a companion direct image. In order to handle dithered slitless spectra, drizzle, well-known in the imaging domain, has been applied. For ACS grism images, the aXedrizzle technique resamples 2D spectra from individual images to deep, rectified images before extracting the 1D spectra. aXe also provides tools for visual assessment of the extracted spectra and examples are presented.
|
[
"Physics Archive->astro-ph"
] | 2005-12-05T13:06:40Z |
1211.3694
|
On-Orbit Sensitivity Evolution of the EUV Imaging Spectrometer on Hinode
|
Since its launch on 22 September 2006, the EUV Imaging Spectrometer onboard the Hinode satellite has exhibited a gradual decay in sensitivity. Using spectroheliograms taken in the Fe VIII 185.21 Angstrom and Si VII 275.35 Angstrom emission lines in quiet regions near Sun center we characterize that decay. For the period from December 2006 to March 2012, the decline in the sensitivity can be characterized as an exponential decay with an average time constant of 7358 +/- 1030 days (20.2 +/- 2.8 years). Emission lines formed at temperatures >10^6.1 K in the quiet-Sun data exhibit solar-cycle effects.
|
[
"Physics Archive->astro-ph->astro-ph.SR"
] | 2012-11-15T18:47:00Z |
2107.03208
|
Compactification and decompactification by weights on Bergman spaces
|
We characterize the symbols $\Phi$ for which there exists a weight w such that the weighted composition operator M w C $\Phi$ is compact on the weighted Bergman space B 2 $\alpha$. We also characterize the symbols for which there exists a weight w such that M w C $\Phi$ is bounded but not compact. We also investigate when there exists w such that M w C $\Phi$ is Hilbert-Schmidt on B 2 $\alpha$.
|
[
"Mathematics Archive->math.FA"
] | 2021-07-07T13:32:42Z |
1008.3879
|
A formalism for causal explanations with an Answer Set Programming translation
|
We examine the practicality for a user of using Answer Set Programming (ASP) for representing logical formalisms. Our example is a formalism aiming at capturing causal explanations from causal information. We show the naturalness and relative efficiency of this translation job. We are interested in the ease for writing an ASP program. Limitations of the earlier systems made that in practice, the ``declarative aspect'' was more theoretical than practical. We show how recent improvements in working ASP systems facilitate the translation.
|
[
"Computer Science Archive->cs.AI"
] | 2010-08-23T18:38:23Z |
1502.03520
|
A Latent Variable Model Approach to PMI-based Word Embeddings
|
Semantic word embeddings represent the meaning of a word via a vector, and are created by diverse methods. Many use nonlinear operations on co-occurrence statistics, and have hand-tuned hyperparameters and reweighting methods. This paper proposes a new generative model, a dynamic version of the log-linear topic model of~\citet{mnih2007three}. The methodological novelty is to use the prior to compute closed form expressions for word statistics. This provides a theoretical justification for nonlinear models like PMI, word2vec, and GloVe, as well as some hyperparameter choices. It also helps explain why low-dimensional semantic embeddings contain linear algebraic structure that allows solution of word analogies, as shown by~\citet{mikolov2013efficient} and many subsequent papers. Experimental support is provided for the generative model assumptions, the most important of which is that latent word vectors are fairly uniformly dispersed in space.
|
[
"Computer Science Archive->cs.CL",
"Computer Science Archive->cs.LG",
"Statistics Archive->stat.ML"
] | 2015-02-12T02:50:08Z |
1909.12788
|
Comment on "Gapless spin liquid ground state of the spin-$\frac{1}{2}$ $J_1$-$J_2$ Heisenberg model on square lattices"
|
Liu et al. [Phys.Rev.B 98, 241109 (2018)] used Monte Carlo sampling of the physical degrees of freedom of a Projected Entangled Pair State (PEPS) type wave function for the $S=1/2$ frustrated $J_1$-$J_2$ Heisenberg model on the square lattice and found a non-magnetic state argued to be a gapless spin liquid when the coupling ratio $g=J_2/J_1$ is in the range $g \in [0.42,0.6]$. Here we show that their definition of the order parameter for another candidate ground state within this coupling window---a spontaneously dimerized state---is problematic. The order parameter as defined will not detect dimer order when lattice symmeties are broken due to open boundaries or asymmetries originating from the calculation itself. Thus, a dimerized phase for some range of $g$ cannot be excluded (and is likely based on several other recent works).
|
[
"Physics Archive->cond-mat->cond-mat.str-el"
] | 2019-09-27T16:41:37Z |
1710.08176
|
On the transmission-based graph topological indices
|
The distance $d(u,v)$ between the vertices $u$ and $v$ of a connected graph $G$ is defined as the number of edges in a minimal path connecting them. The \emph{transmission} of a vertex $v$ of $G$ is defined by $\sigma(v)=\sum\limits_{u\in V(G)}{d(v,u)}$. In this article we aim to define some transmission-based topological indices. We obtain lower and upper bounds on these indices and characterize graphs for which these bounds are best possible. Finally, we find these indices for various graphs using the group of automorphisms of $G$. This is an efficient method of finding these indices especially when the automorphism group of $G$ has a few orbits on $V(G)$ or $E(G)$.
|
[
"Mathematics Archive->math.CO"
] | 2017-10-23T10:05:28Z |
1810.08982
|
Evaluation of Dynamical Properties of Open Quantum Systems Using the Driven Liouville-von Neumann Approach: Methodological Considerations
|
Methodological aspects of using the driven Liouville-von Neumann (DLvN) approach for simulating dynamical properties of molecular junctions are discussed. As a model system we consider a non-interacting resonant level uniformly coupled to a single Fermionic bath. We demonstrate how a finite system can mimic the depopulation dynamics of the dot into an infinite band bath of continuous and uniform density of states. We further show how the effects of spurious energy resolved currents, appearing due to the approximate nature of the equilibrium state obtained in DLvN calculations, can be avoided. Several ways to approach the wide band limit that is often adopted in analytical treatments, using a finite numerical model system are discussed including brute-force increase of the lead model bandwidth as well as efficient cancellation or direct subtraction of finite-bandwidth effect. These methodological considerations may be relevant also for other numerical schemes that aim to study non-equilibrium thermodynamics via simulations of open quantum systems.
|
[
"Physics Archive->cond-mat->cond-mat.mes-hall"
] | 2018-10-21T15:57:16Z |
2203.16350
|
Density Matrix Renormalization Group Algorithm For Mixed Quantum States
|
Density Matrix Renormalization Group (DMRG) algorithm has been extremely successful for computing the ground states of one-dimensional quantum many-body systems. For problems concerned with mixed quantum states, however, it is less successful in that either such an algorithm does not exist yet or that it may return unphysical solutions. Here we propose a positive matrix product ansatz for mixed quantum states which preserves positivity by construction. More importantly, it allows to build a DMRG algorithm which, the same as the standard DMRG for ground states, iteratively reduces the global optimization problem to local ones of the same type, with the energy converging monotonically in principle. This algorithm is applied for computing both the equilibrium states and the non-equilibrium steady states, and its advantages are numerically demonstrated.
|
[
"Physics Archive->cond-mat->cond-mat.str-el",
"Physics Archive->quant-ph"
] | 2022-03-30T14:29:31Z |
1201.4660
|
Simulation study of a highly efficient, high resolution X-ry sensor based on self-organizing aluminum oxide
|
State of the art X-ray imaging sensors comprise a trade-off between the achievable efficiency and the spatial resolution. To overcome such limitations, the use of structured and scintillator filled aluminum oxide (AlOx) matrices has been investigated. We used Monte-Carlo (MC) X-ray simulations to determine the X-ray imaging quality of these AlOx matrices. Important factors which influence the behavior of the matrices are: filling factor (surface ratio between channels and 'closed' AlOx), channel diameter, aspect ratio, filling material etc. Therefore we modeled the porous AlOx matrix in several different ways with the MC X-ray simulation tool ROSI [1] and evaluated its properties to investigate the achievable performance at different X-ray spectra, with different filling materials (i.e. scintillators) and varying channel height and pixel readout. In this paper we focus on the quantum efficiency, the spatial resolution and image homogeneity.
|
[
"Physics Archive->physics->physics.ins-det"
] | 2012-01-23T10:05:29Z |
2307.07721
|
Non-Gaussian fluctuations of a probe coupled to a Gaussian field
|
The motion of a colloidal probe in a complex fluid, such as a micellar solution, is usually described by the generalized Langevin equation, which is linear. However, recent numerical simulations and experiments have shown that this linear model fails when the probe is confined, and that the intrinsic dynamics of the probe is actually non-linear. Noting that the kurtosis of the displacement of the probe may reveal the non-linearity of its dynamics also in the absence confinement, we compute it for a probe coupled to a Gaussian field and possibly trapped by a harmonic potential. We show that the excess kurtosis increases from zero at short times, reaches a maximum, and then decays algebraically at long times, with an exponent which depends on the spatial dimensionality and on the features and correlations of the dynamics of the field. Our analytical predictions are confirmed by numerical simulations of the stochastic dynamics of the probe and the field where the latter is represented by a finite number of modes.
|
[
"Physics Archive->cond-mat->cond-mat.soft",
"Physics Archive->cond-mat->cond-mat.stat-mech"
] | 2023-07-15T05:56:52Z |
1003.3959
|
Compactly presented groups
|
This survey purports to be an elementary introduction to compactly presented groups, which are the analogue of finitely presented groups in the broader realm of locally compact groups. In particular, compact presentation is interpreted as a coarse simple connectedness condition on the Cayley graph, and in particular is a quasi-isometry invariant. In the appendix, an example of a Lie group, not quasi-isometric to any homogeneous graph, is given; the short argument relies on results of Trofimov and Pansu, anterior to~1990.
|
[
"Mathematics Archive->math.GR"
] | 2010-03-21T00:51:16Z |
0812.2115
|
Performance of a greedy algorithm for edge covering by cliques in interval graphs
|
In this paper a greedy algorithm to detect conflict cliques in interval graphs and circular-arc graphs is analyzed. In a graph, a stable set requires that at most one vertex is chosen for each edge. It is equivalent to requiring that at most one vertex for each maximal clique is chosen. We show that this algorithm finds all maximal cliques for interval graphs, i.e. it can compute the convex hull of the stable set polytope. In case of circular-arc graphs, the algorithm is not able to detect all maximal cliques, yet remaining correct. This problem occurs in the context of railway scheduling. A train requests the allocation of a railway infrastructure resource for a specific time interval. As one is looking for conflict-free train schedules, the used resource allocation intervals in a schedule must not overlap. The conflict-free choices of used intervals for each resource correspond to stable sets in the interval graph associated to the allocation time intervals.
|
[
"Computer Science Archive->cs.DM",
"Computer Science Archive->cs.DS"
] | 2008-12-11T15:35:45Z |
0809.4520
|
Rescaled Lotka-Volterra Models Converge to Super Stable Processes
|
Recently, it has been shown that stochastic spatial Lotka-Volterra models when suitably rescaled can converge to a super Brownian motion. We show that the limit process could be a super stable process if the kernel of the underlying motion is in the domain of attraction of a stable law. The corresponding results in Brownian setting were proved by Cox and Perkins (2005, 2008). As applications of the convergence theorems, some new results on the asymptotics of the voter model started from single 1 at the origin are obtained which improve the results by Bramson and Griffeath (1980).
|
[
"Mathematics Archive->math.PR"
] | 2008-09-26T02:13:46Z |
2011.02447
|
Epitaxial integration of improper ferroelectric h-YMnO$_3$ thin films in heterostructures
|
We report on multiple fundamental qualitative improvements in the growth of improper ferroelectric hexagonal YMnO$_3$ (YMO) thin films and heterostructures by pulsed laser deposition (PLD). By a combination of pre-growth substrate annealing and low-energy-fluence PLD, we obtain a two-dimensional growth mode of the YMO films on yttria-stabilized zirconia (YSZ) with ultralow roughness and devoid of misoriented nanocrystalline inclusions. By inserting a sacrificial manganite layer capped with conducting indium-tin oxide between the substrate and the final film, the latter is grown in a fully lattice-relaxed mode and, thus, without any misfit dislocations while maintaining the extraordinary flatness of the films grown directly on pre-annealed YSZ. This provides a template for the fabrication of heterostructures based on hexagonal manganites as promising class of multiferroics with improper room-temperature ferroelectricity and the implementation of these into technologically relevant epitaxial metal|ferroelectric-type multilayers.
|
[
"Physics Archive->cond-mat->cond-mat.mtrl-sci"
] | 2020-11-04T17:58:38Z |
gr-qc/0110098
|
The Affine Quantum Gravity Program
|
The central principle of affine quantum gravity is securing and maintaining the strict positivity of the matrix $\{\hg_{ab}(x)\}$ composed of the spatial components of the local metric operator. On spectral grounds, canonical commutation relations are incompatible with this principle, and they must be replaced by noncanonical, affine commutation relations. Due to the partial second-class nature of the quantum gravitational constraints, it is advantageous to use the recently developed projection operator method, which treats all quantum constraints on an equal footing. Using this method, enforcement of regularized versions of the gravitational operator constraints is formulated quite naturally by means of a novel and relatively well-defined functional integral involving only the same set of variables that appears in the usual classical formulation. It is anticipated that skills and insight to study this formulation can be developed by studying special, reduced-variable models that still retain some basic characteristics of gravity, specifically a partial second-class constraint operator structure. Although perturbatively nonrenormalizable, gravity may possibly be understood nonperturbatively from a hard-core perspective that has proved valuable for specialized models. Finally, developing a procedure to pass to the genuine physical Hilbert space involves several interconnected steps that require careful coordination.
|
[
"Physics Archive->gr-qc",
"Physics Archive->hep->hep-th"
] | 2001-10-23T14:32:36Z |
2209.13935
|
Search for direct pair production of sleptons and charginos decaying to two leptons and neutralinos with mass splittings near the $W$-boson mass in ${\sqrt{s}=13\,}$TeV $pp$ collisions with the ATLAS detector
|
A search for the electroweak production of pairs of charged sleptons or charginos decaying into two-lepton final states with missing transverse momentum is presented. Two simplified models of $R$-parity-conserving supersymmetry are considered: direct pair-production of sleptons ($\tilde{\ell}\tilde{\ell}$), with each decaying into a charged lepton and a $\tilde{\chi}_1^0$ neutralino, and direct pair-production of the lightest charginos $(\tilde{\chi}_1^\pm\tilde{\chi}_1^\mp)$, with each decaying into a $W$-boson and a $\tilde{\chi}_1^0$. The lightest neutralino ($\tilde{\chi}_1^0$) is assumed to be the lightest supersymmetric particle (LSP). The analyses target the experimentally challenging mass regions where $m(\tilde{\ell})-m(\tilde{\chi}_1^0)$ and $m(\tilde{\chi}_1^\pm)-m(\tilde{\chi}_1^0)$ are close to the $W$-boson mass (`moderately compressed' regions). The search uses 139 fb$^{-1}$ of $\sqrt{s}=13$ TeV proton-proton collisions recorded by the ATLAS detector at the Large Hadron Collider. No significant excesses over the expected background are observed. Exclusion limits on the simplified models under study are reported in the ($\tilde{\ell},\tilde{\chi}_1^0$) and ($\tilde{\chi}_1^\pm,\tilde{\chi}_1^0$) mass planes at 95% confidence level (CL). Sleptons with masses up to 150 GeV are excluded at 95% CL for the case of a mass-splitting between sleptons and the LSP of 50 GeV. Chargino masses up to 140 GeV are excluded at 95% CL for the case of a mass-splitting between the chargino and the LSP down to about 100 GeV.
|
[
"Physics Archive->hep->hep-ex"
] | 2022-09-28T09:11:54Z |
1604.04701
|
Pure Gravitational Dark Matter, Its Mass and Signatures
|
In this study, we investigate a scenario that dark matter (DM) has only gravitational interaction. In the framework of effective field theory of gravity, we find that DM is still stable at tree level even if there is no symmetry to protect its longevity, but could decay into standard model particles due to gravitational loop corrections. The radiative corrections can lead to both higher- and lower-dimensional effective operators. We also first explore how DM can be produced in the early universe. Through gravitational interaction at high temperature, DM is then found to have mass around TeV $\lesssim m_X \lesssim 10^{11}$GeV to get the right relic abundance. When DM decays, it mostly decays into gravitons, which could be tested by current and future CMB experiments. We also estimate the resulting fluxes for cosmic rays, gamma-ray and neutrino.
|
[
"Physics Archive->astro-ph->astro-ph.CO",
"Physics Archive->hep->hep-ph"
] | 2016-04-16T06:45:22Z |
1105.1312
|
GRB 090426: Discovery of a jet break in a short burst afterglow
|
Context: The link between the duration of GRBs and the nature of their progenitors remains disputed. Short bursts (with durations of less than ~2 s) are less frequently observed, technically more difficult to localize, and exhibit significantly fainter afterglows. Aims: It is of critical importance to establish whether the burst duration can reliably distinguish the different GRB population models of collapsars and compact stellar mergers. The Swift GRB 090426 provides an unique opportunity to address this question. Its duration (T_90=1.28 s) places GRB 090426 firmly in the short burst population, while the high redshift (z=2.609), host galaxy properties, and prompt emission spectral characteristics are more similar to those of long-duration GRBs. Methods: On the basis of data obtained with the Tautenburg 2m telescope (Germany) and the 7-channel imager GROND (La Silla, Chile), we compiled the most finely sampled light curve available for a short burst optical/NIR afterglow. The light curve was then analysed in a standard fashion. GROND and XRT data were used to determine the broad-band spectral energy distribution of the afterglow across more than three orders of magnitude. Results: Our data show that a light curve break exists at 0.4 days, which is followed by a steep decay. This light curve decay is achromatic in the optical/NIR bands, and interpreted as a post-jet break phase. The X-ray data do not disagree with this interpretation. Conclusions: The half-opening angle of the suspected jet as well as the luminosity of the optical afterglow provide additional evidence that GRB 090426 is probably linked to the death of a massive star rather than to the merger of two compact objects.
|
[
"Physics Archive->astro-ph->astro-ph.CO"
] | 2011-05-06T15:46:50Z |
2102.08488
|
On the Capture of Interstellar Objects by our Solar System
|
Motivated by recent visits from interstellar comets, along with continuing discoveries of minor bodies in orbit of the Sun, this paper studies the capture of objects on initially hyperbolic orbits by our solar system. Using an ensemble of $\sim500$ million numerical experiments, this work generalizes previous treatments by calculating the capture cross section as a function of asymptotic speed. The resulting velocity-dependent cross section can then be convolved with any distribution of relative speeds to determine the capture rate for incoming bodies. This convolution is carried out for the usual Maxwellian distribution, as well as the velocity distribution expected for rocky debris ejected from planetary systems. We also construct an analytic description of the capture process that provides an explanation for the functional form of the capture cross section in both the high velocity and low velocity limits.
|
[
"Physics Archive->astro-ph->astro-ph.EP"
] | 2021-02-16T23:06:29Z |
1803.10781
|
Keck/Palomar Cosmic Web Imagers (KCWI/PCWI) Reveal an Enormous Ly$\alpha$ Nebula in an Extremely Overdense QSO Pair Field at $z=2.45$
|
Enormous Ly$\alpha$ nebulae (ELANe) represent the extrema of Ly$\alpha$ nebulosities. They have detected extents of $>200$ kpc in Ly$\alpha$ and Ly$\alpha$ luminosities $>10^{44}$ erg s$^{-1}$. The ELAN population is an ideal laboratory to study the interactions between galaxies and the intergalactic/circumgalactic medium (IGM/CGM) given their brightness and sizes. The current sample size of ELANe is still very small, and the few $z\approx2$ ELANe discovered to date are all associated with local overdensities of active galactic nuclei (AGNs). Inspired by these results, we have initiated a survey of ELANe associated with QSO pairs using the Palomar and Keck Cosmic Web Imagers (PCWI/KCWI). In this letter, we present our first result: the discovery of ELAN0101+0201 associated with a QSO pair at $z=2.45$. Our PCWI discovery data shows that, above a 2-$\sigma$ surface brightness of $1.2\times10^{-17}$ \sbunit, the end-to-end size of ELAN0101+0201 is $\gtrsim 232$ kpc. We have conducted follow-up observations using KCWI, resolving multiple Ly$\alpha$ emitting sources within the rectangular field-of-view of $\approx 130\times165$ projected kpc$^2$, and obtaining their emission line profiles at high signal-to-noise ratios. Combining both KCWI and PCWI, our observations confirm that ELAN0101+0201 resides in an extremely overdense environment. Our observations further support that a large amount of cool ($T\sim10^4$K) gas could exist in massive halos (M$\gtrsim10^{13}$M$_\odot$) at $z\approx2$. Future observations on a larger sample of similar systems will provide statistics of how cool gas is distributed in massive overdensities at high-redshift and strongly constrain the evolution of the intracluster medium (ICM).
|
[
"Physics Archive->astro-ph->astro-ph.GA"
] | 2018-03-28T18:00:03Z |
quant-ph/0512148
|
Quantum teleportation between nanomechanical modes
|
We study a quantum teleportation scheme between two nanomechanical modes without local interaction. The nanomechanical modes are linearly coupled to and connected by the continuous variable modes of a superconducting circuit consisting of a transmission line and Josephson junctions. We calculate the fidelity of transferring Gaussian states at finite temperature and non-unit detector efficiency. For coherent state, a fidelity above the classical limit of 1/2 can be achieved for a large range of parameters.
|
[
"Physics Archive->quant-ph"
] | 2005-12-19T00:30:09Z |
1902.06068
|
Deep Learning for Image Super-resolution: A Survey
|
Image Super-Resolution (SR) is an important class of image processing techniques to enhance the resolution of images and videos in computer vision. Recent years have witnessed remarkable progress of image super-resolution using deep learning techniques. This article aims to provide a comprehensive survey on recent advances of image super-resolution using deep learning approaches. In general, we can roughly group the existing studies of SR techniques into three major categories: supervised SR, unsupervised SR, and domain-specific SR. In addition, we also cover some other important issues, such as publicly available benchmark datasets and performance evaluation metrics. Finally, we conclude this survey by highlighting several future directions and open issues which should be further addressed by the community in the future.
|
[
"Computer Science Archive->cs.CV"
] | 2019-02-16T08:39:36Z |
0805.1115
|
Neutral Higgs bosons in the MNMSSM with explicit CP violation
|
Within the framework of the minimal non-minimal supersymmetric standard model (MNMSSM) with tadpole terms, CP violation effects in the Higgs sector are investigated at the one-loop level, where the radiative corrections from the loops of the quark and squarks of the third generation are taken into account. Assuming that the squark masses are not degenerate, the radiative corrections due to the stop and sbottom quarks give rise to CP phases, which trigger the CP violation explicitly in the Higgs sector of the MNMSSM. The masses, the branching ratios for dominant decay channels, and the total decay widths of the five neutral Higgs bosons in the MNMSSM are calculated in the presence of the explicit CP violation. The dependence of these quantities on the CP phases is quite recognizable, for given parameter values.
|
[
"Physics Archive->hep->hep-ph"
] | 2008-05-08T07:26:19Z |
0807.4756
|
Restricted Wiedemann-Franz law and vanishing thermoelectric power in one-dimensional conductors
|
In one-dimensional (1D) conductors with linear E-k dispersion (Dirac systems) intrabranch thermalization is favored by elastic electron-electron interaction in contrast to electron systems with a nonlinear (parabolic) dispersion. We show that under external electric fields or thermal gradients the carrier populations of different branches, treated as Fermi gases, have different temperatures as a consequence of self-consistent carrier-heat transport. Specifically, in the presence of elastic phonon scattering, the Wiedemann-Franz law is restricted to each branch with its specific temperature and is characterized by twice the Lorenz number. In addition thermoelectric power vanishes due to electron-hole symmetry, which is validated by experiment.
|
[
"Physics Archive->cond-mat->cond-mat.mes-hall"
] | 2008-07-29T22:48:38Z |
2004.06341
|
Stochastic batch size for adaptive regularization in deep network optimization
|
We propose a first-order stochastic optimization algorithm incorporating adaptive regularization applicable to machine learning problems in deep learning framework. The adaptive regularization is imposed by stochastic process in determining batch size for each model parameter at each optimization iteration. The stochastic batch size is determined by the update probability of each parameter following a distribution of gradient norms in consideration of their local and global properties in the neural network architecture where the range of gradient norms may vary within and across layers. We empirically demonstrate the effectiveness of our algorithm using an image classification task based on conventional network models applied to commonly used benchmark datasets. The quantitative evaluation indicates that our algorithm outperforms the state-of-the-art optimization algorithms in generalization while providing less sensitivity to the selection of batch size which often plays a critical role in optimization, thus achieving more robustness to the selection of regularity.
|
[
"Computer Science Archive->cs.CV",
"Computer Science Archive->cs.LG",
"Statistics Archive->stat.ML"
] | 2020-04-14T07:54:53Z |
1405.5510
|
Anisotropy results from 193 GeV U+U collisions at RHIC
|
We report the measurement of azimuthal anisotropy $v_{n}$ for n = 1-5 as a function of transverse momentum $p_{T}$ and centrality in U+U collisions at $\sqrt{s_{NN}}$ = 193 GeV, recorded with the STAR detector at RHIC. We also present results on $v_{2}$ and azimuthal correlator related to charge separation across the reaction plane due to local parity violation(LPV) in the ultra-central collisions.
|
[
"Physics Archive->nucl->nucl-ex"
] | 2014-05-21T18:30:46Z |
1101.3096
|
Status and Prospects of Fermi LAT Pulsar Blind Searches
|
Blind Searches of Fermi Large Area Telescope (LAT) data have resulted in the discovery of 24 gamma-ray pulsars in the first year of survey operations, most of which remain undetected in radio, despite deep radio follow-up searches. I summarize the latest Fermi LAT blind search efforts and results, including the discovery of a new Geminga-like pulsar, PSR J0734-1559. Finally, I discuss some of the challenges faced in carrying out these searches into the future, as well as the prospects for finding additional pulsars among the large number of LAT unassociated sources.
|
[
"Physics Archive->astro-ph->astro-ph.GA",
"Physics Archive->astro-ph->astro-ph.HE"
] | 2011-01-16T21:51:28Z |
1409.5473
|
Diffraction, forward physics and soft QCD results from CMS
|
We report on the recent CMS measurements of soft hadron-hadron production, including the measurements of inclusive single- and double-diffractive cross sections, as well as the measurement of pseudorapidity distributions, and of the leading charged particle and leading jet cross sections. We present the cross sections for low-pT forward jets production, and production of dijets with large rapidity separation (central-forward, and forward-backward jets). Studies of double parton scattering using four-jet and W+2-jet events, and the cross sections for Drell-Yan with associated jet production are discussed as well. The results, corresponding to the proton-proton center-of-mass energy of 7 or 8 TeV, are compared to predictions of various Monte Carlo models.
|
[
"Physics Archive->hep->hep-ex"
] | 2014-09-18T21:57:30Z |
1412.4824
|
Congruence Function Fields with Class Number One
|
We prove that there exists, up to isomorphism, exactly one function field over the finite field of two elements of class number one and genus four. This result, together with the ones of MacRae, Madan, Leitzel, Queen and Stirpe, establishes that there exist eight non-isomorphic congruence function fields of genus larger than zero and class number one.
|
[
"Mathematics Archive->math.NT"
] | 2014-12-15T22:16:55Z |
0712.1895
|
Unoriented D-brane Instantons vs Heterotic worldsheet Instantons
|
We discuss Fermi interactions of four hyperini generated by ``stringy'' instantons in a Type I / Heterotic dual pair on T^4/Z_2.
|
[
"Physics Archive->hep->hep-th"
] | 2007-12-12T10:10:51Z |
hep-ex/0008008
|
Spin Observables in Antilambda-Lambda Production from Antiproton-Proton Annihilation with a Transverse Inital State Polarization
|
The formalism describing the scattering of two spin-1/2 objects is reviewed for the case of antilambda-lambda production from antiproton-proton annihilation. It is shown that an experiment utilizing a transverse target polarization can, in principle, completely determine the spin structure of the reaction. Additional measurements, even those using both beam and target polarizations, would not be sensitive to any additional spin dynamics. Thus, the transverse target polarization allows access to the complete set of spin observables, not just the subset upon which the literature has previously focused. This discussion is especially relevant in light of the data collected by PS185/3 at LEAR.
|
[
"Physics Archive->hep->hep-ex"
] | 2000-08-04T17:54:52Z |
hep-ph/9505213
|
Accidental $\xi$-scaling as a Signature of Nuclear Effects at $x>1$
|
We propose an interpretation of the $\xi$-scaling behavior of nuclear structure functions observed at Bjorken $x>1$ and $Q^2 \lesssim 4 \, {\rm (GeV/c)^2}$. We show that at $\xi \gtrsim 1$, $\xi$-scaling might arise accidentally because of the approximate cancellation of two different $Q^2$-dependent effects, namely Final State Interactions and the effects implicit in the choice of the scaling variable $\xi$. We provide a new convolution formula for the nuclear structure function in terms of $\xi$ and make predictions for the kinematical regions where Final State Interactions are expected to be small and the suggested balancing of scaling violations is expected to break down. Our analysis is aimed at the final goal of clarifying the range of applicability of local duality ideas in nuclei.
|
[
"Physics Archive->hep->hep-ph"
] | 1995-05-02T14:01:28Z |
hep-lat/0407041
|
The finite temperature transition for 3-flavour lattice QCD at finite isospin density
|
We simulate 3-flavour lattice QCD with a small chemical potential $\mu_I$ for isospin, at temperatures close to the finite temperature transition. Using quark masses just above the critical mass for zero chemical potential, we determine the position of the transition from hadronic matter to a quark-gluon plasma as a function of $\mu_I$. We see evidence for a critical endpoint where the transition changes from a crossover to a first-order transition as $\mu_I$ is increased. We argue that QCD at finite $\mu_I$ and QCD at finite quark-numberchemical potential $\mu$ should behave similarly in this region.
|
[
"Physics Archive->hep->hep-lat"
] | 2004-07-30T16:05:04Z |
2203.04631
|
Unusual phase formation in reactively sputtered La-Co-O perovskite thin films
|
La-based perovskites are a versatile class of materials that are of interest for solid oxide fuel cells and electrocatalytic water splitting. During fabrication of composition spread materials libraries of La-Co-based oxide systems for the discovery of new catalytic materials, an unusual phase formation phenomenon was observed: instead of the expected continuous composition gradient, regions with homogeneous composition and single-phase structure (La2O3 or stoichiometric La-perovskite) form. This phenomenon occurs during reactive co-sputtering and is dependent on O2-flux and substrate temperature, investigated from room temperature up to 700 C and is independent of the used substrate. It can be described as a self-organized growth, where excess transition metal cannot be incorporated into the growing film and the forming single-phase regions. It is hypothesized that due to the high reactivity of La and the significantly low formation energies of La2O3 and La-perovskites, the reactive sputter deposition of La-based oxide films can turn, regarding film growth, into a partial CVD-like process which results in the unusual self-organized growth of single-phase regions. This phenomenon can be leveraged for the exploration of multinary perovskite thin film libraries, where the B-site atoms of La-perovskites are systematically substituted.
|
[
"Physics Archive->cond-mat->cond-mat.mtrl-sci"
] | 2022-03-09T10:35:30Z |
2106.00689
|
Mellin amplitudes for 1$d$ CFT
|
We define a Mellin amplitude for CFT$_1$ four-point functions. Its analytical properties are inferred from physical requirements on the correlator. We discuss the analytic continuation that is necessary for a fully nonperturbative definition of the Mellin transform. The resulting bounded, meromorphic function of a single complex variable is used to derive an infinite set of nonperturbative sum rules for CFT data of exchanged operators, which we test on known examples. We then consider the perturbative setup produced by quartic interactions with an arbitrary number of derivatives in a bulk AdS$_2$ field theory. With our formalism, we obtain a closed-form expression for the Mellin transform of tree-level contact interactions and for the first correction to the scaling dimension of "two-particle" operators exchanged in the generalized free field theory correlator.
|
[
"Physics Archive->hep->hep-th"
] | 2021-06-01T18:00:03Z |
2103.04925
|
On wall crossing for K-stability
|
In this paper, we explore the wall crossing phenomenon for K-stability, and apply it to explain the wall crossing for K-moduli stacks and K-moduli spaces.
|
[
"Mathematics Archive->math.AG"
] | 2021-03-08T17:37:03Z |
2208.09795
|
Stop&Hop: Early Classification of Irregular Time Series
|
Early classification algorithms help users react faster to their machine learning model's predictions. Early warning systems in hospitals, for example, let clinicians improve their patients' outcomes by accurately predicting infections. While early classification systems are advancing rapidly, a major gap remains: existing systems do not consider irregular time series, which have uneven and often-long gaps between their observations. Such series are notoriously pervasive in impactful domains like healthcare. We bridge this gap and study early classification of irregular time series, a new setting for early classifiers that opens doors to more real-world problems. Our solution, Stop&Hop, uses a continuous-time recurrent network to model ongoing irregular time series in real time, while an irregularity-aware halting policy, trained with reinforcement learning, predicts when to stop and classify the streaming series. By taking real-valued step sizes, the halting policy flexibly decides exactly when to stop ongoing series in real time. This way, Stop&Hop seamlessly integrates information contained in the timing of observations, a new and vital source for early classification in this setting, with the time series values to provide early classifications for irregular time series. Using four synthetic and three real-world datasets, we demonstrate that Stop&Hop consistently makes earlier and more-accurate predictions than state-of-the-art alternatives adapted to this new problem. Our code is publicly available at https://github.com/thartvigsen/StopAndHop.
|
[
"Computer Science Archive->cs.LG"
] | 2022-08-21T03:41:19Z |
0802.3024
|
Chaotic synchronizations of spatially extended systems as non-equilibrium phase transitions
|
Two replicas of spatially extended chaotic systems synchronize to a common spatio-temporal chaotic state when coupled above a critical strength. As a prototype of each single spatio-temporal chaotic system a lattice of maps interacting via power-law coupling is considered. The synchronization transition is studied as a non-equilibrium phase transition, and its critical properties are analyzed at varying the spatial interaction range as well as the nonlinearity of the dynamical units composing each system. In particular, continuous and discontinuous local maps are considered. In both cases the transitions are of the second order with critical indexes varying with the exponent characterizing the interaction range. For discontinuous maps it is numerically shown that the transition belongs to the {\it anomalous directed percolation} (ADP) family of universality classes, previously identified for L{\'e}vy-flight spreading of epidemic processes. For continuous maps, the critical exponents are different from those characterizing ADP, but apart from the nearest-neighbor case, the identification of the corresponding universality classes remains an open problem. Finally, to test the influence of deterministic correlations for the studied synchronization transitions, the chaotic dynamical evolutions are substituted by suitable stochastic models. In this framework and for the discontinuous case, it is possible to derive an effective Langevin description that corresponds to that proposed for ADP.
|
[
"Physics Archive->nlin->nlin.CD"
] | 2008-02-21T11:43:11Z |
1212.3358
|
Stabilization of a linear nanomechanical oscillator to its ultimate thermodynamic limit
|
The rapid development of micro- and nanooscillators in the past decade has led to the emergence of novel sensors that are opening new frontiers in both applied and fundamental science. The potential of these novel devices is, however, strongly limited by their increased sensitivity to external perturbations. We report a non-invasive optomechanical nano-stabilization technique and apply the method to stabilize a linear nanomechanical beam at its ultimate thermodynamic limit at room temperature. The reported ability to stabilize a mechanical oscillator to the thermodynamic limit can be extended to a variety of systems and increases the sensitivity range of nanosensors in both fundamental and applied studies.
|
[
"Physics Archive->cond-mat->cond-mat.mes-hall",
"Physics Archive->physics->physics.optics"
] | 2012-12-13T22:21:24Z |
cond-mat/0701717
|
Magnetic Anisotropy, Spin Pinning and Exchange Constants of (Ga,Mn)As films
|
We present a detailed investigation of exchange-dominated nonpropagating spin-wave modes in a series of 100 nm Ga$_{1 - x}$Mn$_{x}$As films with Mn concentrations $x$ ranging from 0.02 to 0.08. The angular and Mn concentration dependences of spin wave resonance modes have been studied for both as-grown and annealed samples. Our results indicate that the magnetic anisotropy terms of Ga$_{1 - x}$Mn$_{x}$As depend on the Mn concentration $x$, but are also strongly affected by sample growth conditions; moreover, the magnetic anisotropy of Ga$_{1 - x}$Mn$_{x}$As films is found to be clearly linked to the Curie temperature. The spin wave resonance spectra consist of a series of well resolved standing spin-wave modes. The observed mode patterns are consistent with the Portis volume-inhomogeneity model, in which a spatially nonuniform anisotropy field acts on the Mn spins. The analysis of these exchange-dominated spin wave modes, including their angular dependences, allows us to establish the exchange stiffness constants for Ga$_{1 - x}$Mn$_{x}$As films.
|
[
"Physics Archive->cond-mat->cond-mat.mtrl-sci"
] | 2007-01-29T16:44:32Z |
2006.00936
|
Rosenthal's space revisited
|
Let $E$ be a rearrangement invariant (r.i.) function space on $[0,1]$, and let $Z_E$ consist of all measurable functions $f$ on $(0,\infty)$ such that $f^*\chi_{[0,1]}\in E$ and $f^*\chi_{[1,\infty)}\in L^2$. We reveal close connections between properties of the generalized Rosenthal's space, corresponding to the space $Z_E$, and the behaviour of independent symmetrically distributed random variables in $E$. The results obtained are applied to consider the problem of the existence of isomorphisms between r.i.\ spaces on $[0,1]$ and $(0,\infty)$. Exploiting particular properties of disjoint sequences, we identify a rather wide new class of r.i.\ spaces on $[0,1]$ ``close'' to $L^\infty$, which fail to be isomorphic to r.i.\ spaces on $(0,\infty)$. In particular, this property is shared by the Lorentz spaces $\Lambda_2(\log^{-\alpha}(e/u))$, with $0<\alpha\le 1$.
|
[
"Mathematics Archive->math.FA"
] | 2020-06-01T13:31:34Z |
1107.4459
|
Ultra High Energy Particles
|
We revisit considerations of temporal order in relativistic effects, taking into account Heisenberg's Uncertainty Principle. We then use a formulation of relativistic Quantum Mechanical equations given by Feshbach and Villars to exhibit novel particle antiparticle effects.
|
[
"Physics Archive->physics->physics.gen-ph"
] | 2011-07-22T09:17:52Z |
2002.03653
|
Divergence of finitely presented groups
|
We construct families of finitely presented groups exhibiting new divergence behavior; we obtain divergence functions of the form $r^\alpha$ for a dense set of exponents $\alpha \in [2,\infty)$ and $r^n\log(r)$ for integers $n \geq 2$. The same construction also yields examples of finitely presented groups which contain Morse elements that are not contracting.
|
[
"Mathematics Archive->math.GR"
] | 2020-02-10T11:02:14Z |
hep-ex/9503005
|
First Measurement of the Deep--Inelastic Structure of Proton Diffraction
|
A measurement is presented, using data taken with the H1 detector at HERA, of the contribution of diffractive interactions to deep-inelastic electron-proton scattering. The diffractive contribution to the proton structure function is evaluated as a function of the appropriate deep-inelastic scattering variables using a class of deep-inelastic ep scattering events with no hadronic energy flow in an interval of pseudo-rapidity adjacent to the proton beam direction. The dependence of this contribution on x-pomeron is consistent with both a diffractive interpretation and a factorisable ep diffractive cross section. A first measurement of the deep-inelastic structure of the pomeron in the form of a factorised structure function is presented. This structure function is observed to be consistent with scale invariance.
|
[
"Physics Archive->hep->hep-ex"
] | 1995-03-06T10:10:30Z |
nlin/0611023
|
Vibrational and stochastic resonances in two coupled overdamped anharmonic oscillators
|
We study the overdamped version of two coupled anharmonic oscillators under the influence of both low- and high-frequency forces respectively and a Gaussian noise term added to one of the two state variables of the system. The dynamics of the system is first studied in the presence of both forces separately without noise. In the presence of only one of the forces, no resonance behaviour is observed, however, hysteresis happens there. Then the influence of the high-frequency force in the presence of a low-frequency, i.e. biharmonic forcing, is studied. Vibrational resonance is found to occur when the amplitude of the high-frequency force is varied. The resonance curve resembles a stochastic resonance-like curve. It is maximum at the value of $g$ at which the orbit lies in one well during one half of the drive cycle of the low-frequency force and in the other for the remaining half cycle. Vibrational resonance is characterized using the response amplitude and mean residence time. We show the occurrence of stochastic resonance behaviour in the overdamped system by replacing the high-frequency force by Gaussian noise. Similarities and differences between both types of resonance are presented.
|
[
"Physics Archive->nlin->nlin.CD"
] | 2006-11-10T13:55:34Z |
1107.5458
|
Observable estimation of entanglement of formation and quantum discord for bipartite mixed quantum states
|
We present observable lower and upper bounds for the entanglement of formation (EOF) and quantum discord (QD), which facilitates estimates of EOF and QD for arbitrary experimental unknown states in finite-dimensional bipartite systems. These bounds can be easily obtained by a few experimental measurements on a twofold copy $\varrho\otimes\varrho$ of the mixed states. Based on our results, we use the experimental measurement data of the real experiment given by Schmid \textit{et al.} [Phys. Rev. Lett. \textbf{101}, 260505 (2008)] to obtain the lower and upper bounds of EOF and QD for the experimental unknown state.
|
[
"Physics Archive->quant-ph"
] | 2011-07-27T12:42:56Z |
2205.15433
|
The NEWS-G detector at SNOLAB
|
The New Experiments With Spheres-Gas (NEWS-G) collaboration intends to achieve $\mathrm{sub-GeV/c^{2}}$ Weakly Interacting Massive Particles (WIMPs) detection using Spherical Proportional Counters (SPCs). SPCs are gaseous detectors relying on ionization with a single ionization electron energy threshold. The latest generation of SPC for direct dark matter searches has been installed at SNOLAB in Canada in 2021. This article details the different processes involved in the fabrication of the NEWS-G experiment. Also outlined in this paper are the mitigation strategies, measurements of radioactivity of the different components, and estimations of induced background event rates that were used to quantify and address detector backgrounds.
|
[
"Physics Archive->physics->physics.ins-det"
] | 2022-05-30T21:19:40Z |
1810.03077
|
DeepGeo: Photo Localization with Deep Neural Network
|
In this paper we address the task of determining the geographical location of an image, a pertinent problem in learning and computer vision. This research was inspired from playing GeoGuessr, a game that tests a humans' ability to localize themselves using just images of their surroundings. In particular, we wish to investigate how geographical, ecological and man-made features generalize for random location prediction. This is framed as a classification problem: given images sampled from the USA, the most-probable state among 50 is predicted. Previous work uses models extensively trained on large, unfiltered online datasets that are primed towards specific locations. To this end, we create (and open-source) the 50States10K dataset - with 0.5 million Google Street View images of the country. A deep neural network based on the ResNet architecture is trained, and four different strategies of incorporating low-level cardinality information are presented. This model achieves an accuracy 20 times better than chance on a test dataset, which rises to 71.87% when taking the best of top-5 guesses. The network also beats human subjects in 4 out of 5 rounds of GeoGuessr.
|
[
"Computer Science Archive->cs.CV",
"Computer Science Archive->cs.LG"
] | 2018-10-07T03:10:57Z |
astro-ph/9502077
|
Element Abundances at High Redshifts: The N/O Ratio in a Primeval Galaxy
|
The damped Lyman alpha systems seen in the spectra of high redshift QSOs offer the means to determine element abundances in galaxies observed while still at an early stage of evolution. Such measurements, which have only recently come within reach, complement and extend the data provided by studies of different stellar populations in our Galaxy and of extragalactic H~II regions which have up to now formed the basis of galactic chemical evolution models. In this paper we demonstrate the potential of this new approach with high-resolution echelle observations of several elements in the z(abs) = 2.27936 absorption system in the bright z(em) = 2.940 QSO 2348-147. The absorbing galaxy appears to be chemically unevolved, with heavy element abundances only 1/100 of solar; if it is the progenitor of a spiral galaxy like our own, it is unlikely to have collapsed to form a thin disk by z = 2.3 (corresponding to a look-back time of approximately 13 Gyr for H_0 = 50 km/s/Mpc and q_0 = 0.01). Our data allow us to measure the nitrogen-to-oxygen ratio at a metallicity lower than those of the most metal-poor dwarf galaxies known. We find that, relative to the solar scale, N is more underabundant than O by at least a factor of 15. This result is broadly in line with current ideas on the relative importance of primary and secondary production of N; future measurements in several damped Lyman alpha systems will permit more stringent tests of models for the evolution of the N/O ratio with time. Oxygen and other alpha-elements are overabundant relative to Fe by no more than the factor of about 3 typical of metal-poor stars in the disk and halo of the Milky Way.
|
[
"Physics Archive->astro-ph"
] | 1995-02-16T12:16:37Z |
hep-th/0106164
|
Classical string propagation in gravitational fields
|
The motion of a string in curved spacetime is discussed in detail. The basic formalism for string motion in Minkowski spacetime and in curved spacetime is presented. The description applies to cosmic strings as well as to fundamental strings. Major ansatze for solving the string equations of motion are reviewed. In particular, the ``null string ansatz'', which is relevant to strings in strong gravitational fields, is emphasised. The formalism is applied to the motion of strings in 5-dimensional Kaluza-Klein black hole backgrounds with electric and magnetic charge. Such background spacetimes have been of interest lately, particularly from the point of view of fundamental string theory. It is shown that interesting results, relating to the extra dimension as seen by the string, are obtained even at the classical level.
|
[
"Physics Archive->gr-qc",
"Physics Archive->hep->hep-th"
] | 2001-06-19T04:22:05Z |
hep-ex/0409037
|
A Study of Strange Particles Produced in Neutrino Neutral Current Interactions in the NOMAD Experiment
|
Results of a detailed study of strange particle production in neutrino neutral current interactions are presented using the data from the NOMAD experiment. Integral yields of neutral strange particles (K0s, Lambda, Lambda-bar) have been measured. Decays of resonances and heavy hyperons with an identified K0s or Lambda in the final state have been analyzed. Clear signals corresponding to K* and Sigma(1385) have been observed. First results on the measurements of the Lambda polarization in neutral current interactions have been obtained.
|
[
"Physics Archive->hep->hep-ex"
] | 2004-09-14T14:09:06Z |
1510.07783
|
Baryon properties from light-front holographic QCD
|
We investigate the properties of octet and decuplet baryons in a light-front holographic model. By taking into account the effect of nonvanishing quark mass, we obtain the modified light-front wave functions which are applicable at both low and high energy scales. We calculate the spectra, form factors, magnetic moments and electromagnetic radii of octet and decuplet baryons with the results all matching the experiments well. The axial charge, which describes the contribution of quark helicity to the proton spin in the quark-parton model at the high energy scale, is also consistent with the experimental value. Therefore, the light-front holographic method is successful in studying hadronic physics at all energy scales, and the nonzero quark mass is essential to understand the spin structures together with other low energy properties.
|
[
"Physics Archive->hep->hep-ph"
] | 2015-10-27T06:35:19Z |
2201.03729
|
Design, fabrication, and spectral characterization of temperature-dependent liquid crystal-based metamaterial to tune dielectric metasurface resonances
|
Tunable dielectric meta-surface nanostructures offer incredible performance in optical application due to their extraordinary tunability of the polarization and engineering the dispersion of light with low loss in infrared range. In this article, we designed and experimentally measured the tunability of all-dielectric subwavelength silicon nanoparticles with the help of the temperature-based refractive index of the liquid crystal in the telecom regime. The proposed structure composed of high dielectric nanodisk surrounded by nematic liquid crystal (NLC) is simulated with numerical software, assembled with pre-alignment material, and optically measured by Fourier-transform infrared (FTIR) spectroscopy. The simulated result is compatible with the practical measurements, shows that the tunability of 30nm is achieved. Electric and magnetic resonance modes of the high dielectric nanodisks are tailored in different rates by anisotropic temperature dependent NLC. The phase switching of anisotropic to isotropic nematic liquid crystal enables spectral tunning of the two modes of all dielectric metasurface and modifies the symmetry of the optical response of the metamaterial structure.
|
[
"Physics Archive->physics->physics.app-ph",
"Physics Archive->physics->physics.optics"
] | 2022-01-11T00:59:42Z |
2111.13307
|
Self-supervised Correlation Mining Network for Person Image Generation
|
Person image generation aims to perform non-rigid deformation on source images, which generally requires unaligned data pairs for training. Recently, self-supervised methods express great prospects in this task by merging the disentangled representations for self-reconstruction. However, such methods fail to exploit the spatial correlation between the disentangled features. In this paper, we propose a Self-supervised Correlation Mining Network (SCM-Net) to rearrange the source images in the feature space, in which two collaborative modules are integrated, Decomposed Style Encoder (DSE) and Correlation Mining Module (CMM). Specifically, the DSE first creates unaligned pairs at the feature level. Then, the CMM establishes the spatial correlation field for feature rearrangement. Eventually, a translation module transforms the rearranged features to realistic results. Meanwhile, for improving the fidelity of cross-scale pose transformation, we propose a graph based Body Structure Retaining Loss (BSR Loss) to preserve reasonable body structures on half body to full body generation. Extensive experiments conducted on DeepFashion dataset demonstrate the superiority of our method compared with other supervised and unsupervised approaches. Furthermore, satisfactory results on face generation show the versatility of our method in other deformation tasks.
|
[
"Computer Science Archive->cs.CV"
] | 2021-11-26T03:57:46Z |
2002.02005
|
On hybric order dimensions
|
The notion of interval order was introduced by Norbert Wiener \cite{wie} in order to clarify the relation between the notion of an instant of time and that of a period of time. This was a problem on which Bertrand Russell \cite{rus} worked at the time. Interval orders play an important role in many areas of pure and applied mathematics, graph theory, computer science and engineering. Special cases of interval order are the semiorder and linear order. All of these notions are especially important in the study of linear-interval and linear-semiorder dimension of a binary relation. This kind of dimension, which we call {\it hybric order dimension}, gives a common generalization of linear order and interval order (semiorder) dimension and is arguably the most important measure of ordered set complexity. In this paper, we give three main results of the theory of hybric order dimension. More precicely, we obtain necessary and sufficient conditions for a binary relation to have an interval order (resp. linear-interval order, linear-simiorder) extension as well as a realizer of interval orders (resp. linear-interval orders, linear-simiorders). We also obtain a characterization of the interval order (resp. linear-interval order, linear-simiorder) dimension. Since the hybric order dimension of a binary relation is less than its (linear) order dimension, these results will be able to improve known results in graph theory and computer science by finding more efficient algorithms.
|
[
"Mathematics Archive->math.CO"
] | 2020-02-04T15:40:11Z |
1707.08049
|
Enriched $\infty$-operads
|
In this paper we initiate the study of enriched $\infty$-operads. We introduce several models for these objects, including enriched versions of Barwick's Segal operads and the dendroidal Segal spaces of Cisinski and Moerdijk, and show these are equivalent. Our main results are a version of Rezk's completion theorem for enriched $\infty$-operads: localization at the fully faithful and essentially surjective morphisms is given by the full subcategory of complete objects, and a rectification theorem: the homotopy theory of $\infty$-operads enriched in the $\infty$-category arising from a nice symmetric monoidal model category is equivalent to the homotopy theory of strictly enriched operads.
|
[
"Mathematics Archive->math.AT",
"Mathematics Archive->math.CT"
] | 2017-07-25T15:34:16Z |
2211.03641
|
Ultracool dwarfs in Gaia DR3
|
Aims. In this work we use the Gaia DR3 set of ultracool dwarf candidates and complement the Gaia spectrophotometry with additional photometry in order to characterise its global properties. This includes the inference of the distances, their locus in the Gaia colour-absolute magnitude diagram and the (biased through selection) luminosity function in the faint end of the Main Sequence. We study the overall changes in the Gaia RP spectra as a function of spectral type. We study the UCDs in binary systems, attempt to identify low-mass members of nearby young associations, star forming regions and clusters, and analyse their variability properties. Results. We detect 57 young, kinematically homogeneous groups some of which are identified as well known star forming regions, associations and clusters of different ages. We find that the primary members of 880 binary systems with a UCD belong mainly to the thin and thick disk components of the Milky Way. We identify 1109 variable UCDs using the variability tables in the Gaia archive, 728 of which belong to the star forming regions defined by HMAC. We define two groups of variable UCDs with extreme bright or faint outliers. Conclusions. The set of sources identified as UCDs in the Gaia archive contains a wealth of information that will require focused follow-up studies and observations. It will help to advance our understanding of the nature of the faint end of the Main Sequence and the stellar/substellar transition.
|
[
"Physics Archive->astro-ph->astro-ph.EP",
"Physics Archive->astro-ph->astro-ph.GA",
"Physics Archive->astro-ph->astro-ph.SR"
] | 2022-11-07T15:52:54Z |
1406.4122
|
(Pseudo)Generalized Kaluza-Klein G-Spaces and Einstein Equations
|
Introducing the Lie algebroid generalized tangent bundle of a Kaluza-Klein bundle, we develop the theory of general distinguished linear connections for this space. In particular, using the Lie algebroid generalized tangent bundle of the Kaluza-Klein vector bundle, we present the $\left( g,h\right) $-lift of a curve on the base $M$ and we characterize the horizontal and vertical parallelism of the $\left( g,h\right) $-lift of accelerations with respect to a distinguished linear $\left( \rho ,\eta \right) $-connection. Moreover, we study the torsion, curvature and Ricci tensor field associated to a distinguished linear $\left( \rho ,\eta \right) $-connection and we obtain the identities of Cartan and Bianchi type in the general framework of the Lie algebroid generalized tangent bundle of a Kaluza-Klein bundle. Finally, we introduce the theory of (pseudo) generalized Kaluza-Klein G-spaces and we develop the Einstein equations in this general framework.
|
[
"Mathematics Archive->math.MP",
"Physics Archive->math-ph"
] | 2014-06-14T09:26:22Z |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.