Entanglement, information and non-equilibrium phase transitions in long-range open quantum Ising chains

Fuente: arXiv
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Main Authors: Paz, Daniel A., Maves, Benjamin E., Kamar, Naushad A., Safavi-Naini, Arghavan, Maghrebi, Mohammad
Format: Preprint
Published: 2024
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author Paz, Daniel A.
Maves, Benjamin E.
Kamar, Naushad A.
Safavi-Naini, Arghavan
Maghrebi, Mohammad
author_facet Paz, Daniel A.
Maves, Benjamin E.
Kamar, Naushad A.
Safavi-Naini, Arghavan
Maghrebi, Mohammad
contents Non-equilibrium phase transitions of open quantum systems generically exhibit diverging classical but not quantum correlations. Still entanglement -- characterizing the latter correlations -- can be sensitive to the phase transition. Furthermore, mutual information, bounding the total correlations, should exhibit critical scaling at the transition. In this work, we study these quantities in the steady state of open quantum Ising chains with power-law interactions (with the exponent $0\le α\le 3$) where spins are subject to spontaneous emission. The bulk of this paper is dedicated to a detailed analytical as well as numerical analysis of the infinite-range model ($α=0$), a model that is closely related to the paradigmatic open Dicke model. Our main findings are that the entanglement, while being finite, peaks, exhibits a kink and takes a universal value at the transition, while the mutual information exhibits critical scaling not only at the transition but well into the ordered phase, underscoring a hidden criticality that is not captured by (two-point) correlations. We consider three distinct entanglement measures: logarithmic negativity; quantum Fisher information; and, spin squeezing. Specifically, we show that the collective spin operator that maximizes the quantum Fisher information can be identified with the \textit{gapless} mode of the phase transition, while the squeezed direction is that of the \textit{gapped} mode. Finally, we investigate power-law interacting models using matrix product states where we find comparable bounds on squeezing even when no phase transition is expected (for larger $α$), thus the connection to the phase transition does not appear to hold for shorter-range interactions.
format Preprint
id arxiv_https___arxiv_org_abs_2410_05370
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Entanglement, information and non-equilibrium phase transitions in long-range open quantum Ising chains
Paz, Daniel A.
Maves, Benjamin E.
Kamar, Naushad A.
Safavi-Naini, Arghavan
Maghrebi, Mohammad
Quantum Gases
Quantum Physics
Non-equilibrium phase transitions of open quantum systems generically exhibit diverging classical but not quantum correlations. Still entanglement -- characterizing the latter correlations -- can be sensitive to the phase transition. Furthermore, mutual information, bounding the total correlations, should exhibit critical scaling at the transition. In this work, we study these quantities in the steady state of open quantum Ising chains with power-law interactions (with the exponent $0\le α\le 3$) where spins are subject to spontaneous emission. The bulk of this paper is dedicated to a detailed analytical as well as numerical analysis of the infinite-range model ($α=0$), a model that is closely related to the paradigmatic open Dicke model. Our main findings are that the entanglement, while being finite, peaks, exhibits a kink and takes a universal value at the transition, while the mutual information exhibits critical scaling not only at the transition but well into the ordered phase, underscoring a hidden criticality that is not captured by (two-point) correlations. We consider three distinct entanglement measures: logarithmic negativity; quantum Fisher information; and, spin squeezing. Specifically, we show that the collective spin operator that maximizes the quantum Fisher information can be identified with the \textit{gapless} mode of the phase transition, while the squeezed direction is that of the \textit{gapped} mode. Finally, we investigate power-law interacting models using matrix product states where we find comparable bounds on squeezing even when no phase transition is expected (for larger $α$), thus the connection to the phase transition does not appear to hold for shorter-range interactions.
title Entanglement, information and non-equilibrium phase transitions in long-range open quantum Ising chains
topic Quantum Gases
Quantum Physics
url https://arxiv.org/abs/2410.05370