Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum phase transition in few-layer NbSe$_2$ probed through quantized
  conductance fluctuations   We present the first observation of dynamically modulated quantum phase
transition (QPT) between two distinct charge density wave (CDW) phases in
2-dimensional 2H-NbSe$_2$. There is recent spectroscopic evidence for the
presence of these two quantum phases, but its evidence in bulk measurements
remained elusive. We studied suspended, ultra-thin \nbse devices fabricated on
piezoelectric substrates - with tunable flakes thickness, disorder level and
strain. We find a surprising evolution of the conductance fluctuation spectra
across the CDW temperature: the conductance fluctuates between two precise
values, separated by a quantum of conductance. These quantized fluctuations
disappear for disordered and on-substrate devices. With the help of mean-field
calculations, these observations can be explained as to arise from dynamical
phase transition between the two CDW states. To affirm this idea, we vary the
lateral strain across the device via piezoelectric medium and map out the phase
diagram near the quantum critical point (QCP). The results resolve a
long-standing mystery of the anomalously large spectroscopic gap in NbSe$_2$.

36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat