Spin squeezing in open Heisenberg spin chains

TL;DR

This paper analyzes how changing boundary conditions from periodic to open in Heisenberg spin chains affects spin squeezing dynamics, revealing new regimes and confirming findings through numerical simulations.

Contribution

It provides an analytical and numerical study of boundary condition effects on spin squeezing in open Heisenberg spin chains, expanding the understanding of entanglement generation.

Findings

Boundary conditions significantly alter spin squeezing dynamics.

Open chains can simulate various twisting models, including one- and two-axis twisting.

Numerical simulations confirm analytical predictions.

Abstract

Spin squeezing protocols successfully generate entangled many-body quantum states, the key pillars of the second quantum revolution. In our recent work [Phys. Rev. Lett. 129, 090403 (2022)] we showed that spin squeezing described by the one-axis twisting model could be generated in the Heisenberg spin-1/2 chain with periodic boundary conditions when accompanied by a position-dependent spin-flip coupling induced by a single laser field. This work shows analytically that the change of boundary conditions from the periodic to the open ones significantly modifies spin squeezing dynamics. A broad family of twisting models can be simulated by the system in the weak coupling regime, including the one- and two-axis twisting under specific conditions, providing the Heisenberg level of squeezing and acceleration of the dynamics. Full numerical simulations confirm our analytical findings.