Interferometric and Bipartite OTOC for Non-Markovian Open Quantum Spin-Chains and Lipkin-Meshkov-Glick Model

TL;DR

This paper investigates information scrambling in open quantum spin chains and LMG models using interferometric and bipartite OTOC methods, revealing phase-dependent quantum chaos and ballistic information spreading.

Contribution

It introduces interferometric and bipartite OTOC techniques to analyze scrambling in open quantum systems, highlighting phase-specific chaos and information dynamics in LMG and spin-chain models.

Findings

Quantum chaos appears only in the symmetry-broken phase of LMG.

Ballistic information spreading observed via light cones in OTOC profiles.

Bipartite OTOC behavior varies with system parameters, providing insights into scrambling mechanisms.

Abstract

The information scrambling phenomena in an open quantum system modeled by Ising spin chains coupled to Lipkin-Meshkov-Glick (LMG) baths are observed via an interferometric method for obtaining out-of-time-ordered correlators ($\mathcal{F}-$OTOC). We also use an anisotropic bath connecting to a system of tilted field Ising spin chain in order to confirm that such situations are suitable for the emergence of ballistic spreading of information manifested in the light cones in the $\mathcal{F}-$OTOC profiles. Bipartite OTOC is also calculated for a bipartite open system, and its behavior is compared with that of the $\mathcal{F}-$OTOC of a two-spin open system to get a picture of what these measures reveal about the nature of scrambling in different parameter regimes. Additionally, the presence of distinct phases in the LMG model motivated an independent analysis of its scrambling properties, where $\mathcal{F}-$OTOC diagnostics revealed that quantum chaos emerges exclusively in the symmetry-broken phase.