Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ab-initio low-energy dynamics of superfluid and solid 4He   We have extracted information about real time dynamics of 4He systems from
noisy imaginary time correlation functions f(tau) computed via Quantum Monte
Carlo (QMC): production and falsification of model spectral functions s(omega)
are obtained via a survival-to-compatibility with f(tau) evolutionary process,
based on Genetic Algorithms. Statistical uncertainty in f(tau) is promoted to
be an asset via a sampling of equivalent f(tau) within the noise, which give
rise to independent evolutionary processes. In the case of pure superfluid 4He
we have recovered from exact QMC simulations sharp quasi-particle excitations
with spectral functions displaying also the multiphonon branch. As further
applications, we have studied the impuriton branch of one 3He atom in liquid
4He and the vacancy-wave excitations in hcp solid 4He finding a novel roton
like feature.

31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ