Southwest Quantum Information and Technology

Eigenstate entanglement in integrable collective spin models

Presenting Author: Meenu Kumari, Perimeter Institute
Contributing Author(s): Álvaro M. Alhambra

The average entanglement entropy (EE) of the energy eigenstates in non-vanishing partitions has been recently proposed as a diagnostic of integrability in quantum many-body systems. We examine this diagnostic in the class of collective spin models characterized by permutation symmetry in the spins. The well-known Lipkin-Meshov-Glick (LMG) model is a paradigmatic integrable system in this class. We calculate analytically the average EE of the Dicke basis in any non-vanishing bipartition, and show that in the thermodynamic limit, it converges to 1/2 of the maximal EE in the corresponding bipartition. Using finite-size scaling, we numerically demonstrate that the aforementioned average EE in the thermodynamic limit is universal for all parameter values of the LMG model. Our analysis illustrates how the value of the average EE in the thermodynamic limit may be a robust criteria for identifying integrability.

Read this article online: https://arxiv.org/abs/2108.09866

(Session 5 : Thursday from 12:00pm-2:00 pm)