Entanglement in a fermion chain under continuous monitoring

• DOI: 10.21468/scipostphys.7.2.024
• Publication Date: 2019-08-23T02:26:27Z
• Authors: Xiangyu Cao; Antoine Tilloy; Andrea De Luca
• Keywords: Quantum Physics; Statistical Mechanics (cond-mat.stat-mech); Quantum Gases (cond-mat.quant-gas); Physics; QC1-999; 0103 physical sciences; FOS: Physical sciences; Condensed Matter - Quantum Gases; Quantum Physics (quant-ph); 01 natural sciences; Condensed Matter - Statistical Mechanics

We study the entanglement entropy of the quantum trajectories of a free fermion chain under continuous monitoring of local occupation numbers. We propose a simple theory for entanglement entropy evolution from disentangled and highly excited initial states. It is based on generalized hydrodynamics and the quasi-particle pair approach to entanglement in integrable systems. We test several quantitative predictions of the theory against extensive numerics and find good agreement. In particular, the volume law entanglement is destroyed by the presence of arbitrarily weak measurement.