Quantum dynamics in symmetry-breaking states of correlated electrons: Antiferromagnetic phase

Fuente: arXiv
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Hauptverfasser: Janiš, Václav, Khanore, Mukesh, Klíč, Antonín
Format: Preprint
Veröffentlicht: 2024
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author Janiš, Václav
Khanore, Mukesh
Klíč, Antonín
author_facet Janiš, Václav
Khanore, Mukesh
Klíč, Antonín
contents Symmetry-breaking phases in many-fermion systems are characterized by anomalous functions that represent transient processes during which some properties of free particles, such as spin or charge, are not conserved. Connecting the low-temperature symmetry-breaking phase with the high-temperature one within the Baym-Kadanoff scheme, beyond the static mean-field approximation, remains an unresolved, long-standing challenge. We identify the reason why approximations with critical dynamical fluctuations in the Schwinger-Dyson equation lead to a mismatch in the transition temperatures calculated from the high- and low-temperature phases. We propose a solution to this generic problem by excluding anomalous contributions to response functions that do not obey conservation of excitations in their interactions. We illustrate this behavior using the example of an antiferromagnetic state. We reveal that the spectral function in the antiferromagnetic phase exhibits a double-gap structure at zero temperature when the anomalous self-energy is frequency-dependent.
format Preprint
id arxiv_https___arxiv_org_abs_2410_06831
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Quantum dynamics in symmetry-breaking states of correlated electrons: Antiferromagnetic phase
Janiš, Václav
Khanore, Mukesh
Klíč, Antonín
Strongly Correlated Electrons
Superconductivity
Symmetry-breaking phases in many-fermion systems are characterized by anomalous functions that represent transient processes during which some properties of free particles, such as spin or charge, are not conserved. Connecting the low-temperature symmetry-breaking phase with the high-temperature one within the Baym-Kadanoff scheme, beyond the static mean-field approximation, remains an unresolved, long-standing challenge. We identify the reason why approximations with critical dynamical fluctuations in the Schwinger-Dyson equation lead to a mismatch in the transition temperatures calculated from the high- and low-temperature phases. We propose a solution to this generic problem by excluding anomalous contributions to response functions that do not obey conservation of excitations in their interactions. We illustrate this behavior using the example of an antiferromagnetic state. We reveal that the spectral function in the antiferromagnetic phase exhibits a double-gap structure at zero temperature when the anomalous self-energy is frequency-dependent.
title Quantum dynamics in symmetry-breaking states of correlated electrons: Antiferromagnetic phase
topic Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/2410.06831