Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fidelity and Uhlmann connection analysis of topological phase
  transitions in two dimensions   We study the behaviour of the fidelity and the Uhlmann connection in
two-dimensional systems of free fermions that exhibit non-trivial topological
behavior. In particular, we use the fidelity and a quantity closely related to
the Uhlmann factor in order to detect phase transitions at zero and finite
temperature for topological insulators and superconductors. We show that at
zero temperature both quantities predict quantum phase transitions: a sudden
drop of fidelity indicates an abrupt change of the spectrum of the state, while
the behavior of the Uhlmann connection signals equally rapid change in its
eigenbasis. At finite temperature, the topological features are gradually
smeared out, indicating the absence of finite-temperature phase transitions,
which we further confirm by performing a detailed analysis of the edge states.
Moreover, we performed both analytical and numerical analysis of the fidelity
susceptibility in the thermodynamic limit, providing an explicit quantitative
criterion for the existence of phase transitions. The critical behaviour at
zero temperature is further analysed through the numerical computation of
critical exponents.

15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
2
The categories of this paper are: math
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics