Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Correlations at PT-symmetric quantum critical point   We consider a PT-symmetric Fermi gas with an exceptional point, representing
the critical point between PT-symmetric and symmetry broken phases. The low
energy spectrum remains linear in momentum and is identical to that of a
hermitian Fermi gas. The fermionic Green's function decays in a power law
fashion for large distances, as expected from gapless excitations, albeit the
exponent is reduced from $-1$ due to the quantum Zeno effect. In spite of the
gapless nature of the excitations, the ground state entanglement entropy
saturates to a finite value, independent of the subsystem size due to the
non-hermitian correlation length intrinsic to the system. Attractive or
repulsive interaction drives the system into the PT-symmetry broken regime or
opens up a gap and protects PT-symmetry, respectively. Our results challenge
the concept of universality in non-hermitian systems, where quantum criticality
can be masked due to non-hermiticity.

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The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci