Quantum entanglement of nonHermitian quasicrystals
Abstract
As a hallmark of a pure quantum effect, quantum entanglement has provided unconventional routes to characterize condensed matter systems. Here, from the perspective of quantum entanglement, we disclose exotic quantum physics in nonHermitian quasicrystals. We study a class of experimentally realizable models for nonHermitian quasicrystal chains, in which asymmetric hopping and complex potential coexist. We diagnose the global phase diagram by means of entanglement from both the realspace and momentumspace partitions. By measuring the entanglement entropy, we numerically determine the metalinsulator transition point. We combine realspace and momentumspace entanglement spectra to complementarily characterize the delocalization phase and the localization phase. Inspired by the entanglement spectrum, we further analytically prove that a duality exists between the two phase regions. The transition point is selfdual and exact, further validating the numerical result from diagonalizing nonHermitian matrices. Finally, we identify the mobility edge by means of entanglement.
 Publication:

Physical Review B
 Pub Date:
 March 2022
 DOI:
 10.1103/PhysRevB.105.L121115
 arXiv:
 arXiv:2112.13411
 Bibcode:
 2022PhRvB.105l1115C
 Keywords:

 Condensed Matter  Mesoscale and Nanoscale Physics;
 Condensed Matter  Quantum Gases;
 Physics  Optics;
 Quantum Physics
 EPrint:
 Accepted by Phys. Rev. B (Letter). New data in SM added, references updated