Operator content of entanglement spectra after global quenches in the transverse field Ising chain

TL;DR

This paper investigates how the entanglement spectrum gaps evolve over time after sudden magnetic field quenches in the transverse field Ising chain, revealing universal features linked to boundary conformal field theory at criticality.

Contribution

It demonstrates that the ratios of entanglement spectrum gaps encode universal conformal data during quenches at or across the quantum critical point.

Findings

Universal behavior of entanglement spectrum gap ratios at criticality

Connection between entanglement spectrum and boundary conformal field theory

Numerical evidence supporting conformal spectrum encoding

Abstract

We consider the time evolution of the gaps of the entanglement spectrum for a block of consecutive sites in finite transverse field Ising chains after sudden quenches of the magnetic field. We provide numerical evidence that, whenever we quench at or across the quantum critical point, the time evolution of the ratios of these gaps allows to obtain universal information. They encode the low-lying gaps of the conformal spectrum of the Ising boundary conformal field theory describing the spatial bipartition within the imaginary time path integral approach to global quenches at the quantum critical point.