Entanglement entropy distinguishes PT-symmetry and topological phases in
a class of non-unitary quantum walks
- URL: http://arxiv.org/abs/2212.07453v1
- Date: Wed, 14 Dec 2022 19:01:15 GMT
- Title: Entanglement entropy distinguishes PT-symmetry and topological phases in
a class of non-unitary quantum walks
- Authors: Gene M. M. Itable and Francis N. C. Paraan
- Abstract summary: We calculate the hybrid entanglement entropy between coin and walker degrees of freedom in a non-unitary quantum walk.
An analysis at long times reveals that the quantum walk can indefinitely sustain hybrid entanglement in the unbroken symmetry phase even when gain and loss mechanisms are present.
- Score: 0.0
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: We calculate the hybrid entanglement entropy between coin and walker degrees
of freedom in a non-unitary quantum walk. The model possesses a joint parity
and time-reversal symmetry or PT-symmetry and supports topological phases when
this symmetry is unbroken by its eigenstates. An asymptotic analysis at long
times reveals that the quantum walk can indefinitely sustain hybrid
entanglement in the unbroken symmetry phase even when gain and loss mechanisms
are present. However, when the gain-loss strength is too large, the PT-symmetry
of the model is spontaneously broken and entanglement vanishes. The
entanglement entropy is therefore an effective and robust parameter for
constructing PT-symmetry and topological phase diagrams in this non-unitary
dynamical system.
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