Signature of quantum phase transition manifested in quantum fidelity at finite temperature

Fuente: arXiv
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Autores principales: Nandi, Protyush, Bhattacharyya, Sirshendu, Dasgupta, Subinay
Formato: Preprint
Publicado: 2023
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author Nandi, Protyush
Bhattacharyya, Sirshendu
Dasgupta, Subinay
author_facet Nandi, Protyush
Bhattacharyya, Sirshendu
Dasgupta, Subinay
contents The signature of quantum phase transition is generally wiped out at finite temperature. A few quantities that have been observed to carry this signature through a nonanalytic behavior are also limited to low temperatures only. With an aim to identify a suitable dynamical quantity at a high temperature, we have recently constructed a function from quantum fidelity, which has the potential to bear a nonanalytic signature at the quantum critical point beyond low temperature regime. In this paper, we elaborate our earlier work and demonstrate the behavior of the corresponding rate function and the robustness of the nonanalyticity for a number of many-body Hamiltonians in different dimensions. We have also shown that our rate function reduces to that used in the demonstration of the dynamical quantum phase transition (DQPT) at zero temperature. It has been further observed that, unlike DQPT, the long time limit of the rate function can faithfully detect the equilibrium quantum phase transition as well.
format Preprint
id arxiv_https___arxiv_org_abs_2302_01795
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Signature of quantum phase transition manifested in quantum fidelity at finite temperature
Nandi, Protyush
Bhattacharyya, Sirshendu
Dasgupta, Subinay
Statistical Mechanics
Quantum Physics
The signature of quantum phase transition is generally wiped out at finite temperature. A few quantities that have been observed to carry this signature through a nonanalytic behavior are also limited to low temperatures only. With an aim to identify a suitable dynamical quantity at a high temperature, we have recently constructed a function from quantum fidelity, which has the potential to bear a nonanalytic signature at the quantum critical point beyond low temperature regime. In this paper, we elaborate our earlier work and demonstrate the behavior of the corresponding rate function and the robustness of the nonanalyticity for a number of many-body Hamiltonians in different dimensions. We have also shown that our rate function reduces to that used in the demonstration of the dynamical quantum phase transition (DQPT) at zero temperature. It has been further observed that, unlike DQPT, the long time limit of the rate function can faithfully detect the equilibrium quantum phase transition as well.
title Signature of quantum phase transition manifested in quantum fidelity at finite temperature
topic Statistical Mechanics
Quantum Physics
url https://arxiv.org/abs/2302.01795