Dynamics of entanglement after exceptional quantum quench

Abstract

We investigate a quantum quench from a critical to an exceptional point. The initial state, prepared in the ground state of a critical hermitian system, is time evolved with a non-hermitian SSH model, tuned to its exceptional point. The single particle density matrix exhibits supersonic modes and multiple light cones, characteristic to non-hermitian time evolution. These propagate with integer multiples of the original Fermi velocity. In the long time limit, the fermionic Green's function decays spatially as $1/x^2$, in sharp contrast to the usual $1/x$ decay of non-interacting fermions. The entanglement entropy is understood as if all these supersonic modes arise from independent quasiparticles (though they do not), traveling with the corresponding supersonic light cone velocity. The entropy production rate decreases with time and develops plateaus during the time evolution, signaling the distinct velocities in the propagation of non-local quantum correlations. At late times, the entanglement entropy saturates to a finite value, satisfying a volume law.

10 pages, 5 figures

References in corpus (7)

• The physics of exceptional points
• Many body localization in Heisenberg XXZ magnet in a random field
• Quantum trajectories and open many-body quantum systems
• Topological phases in the non-Hermitian Su-Schrieffer-Heeger model
• Evolution of entanglement entropy following a quantum quench: Analytic results for the XY chain in a transverse magnetic field
• Mean-field dynamics of a non-Hermitian Bose-Hubbard dimer
• Quantum quench dynamics of the sine-Gordon model in some solvable limits

Cited by in corpus (2)

• Quantum Entanglement of Non-Hermitian Quasicrystals
• Entanglement phase transitions in non-Hermitian Kitaev chains