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Main Authors: Janiš, Václav, Yan, Jiawei
Format: Preprint
Published: 2021
Subjects:
Online Access:https://arxiv.org/abs/2112.10397
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author Janiš, Václav
Yan, Jiawei
author_facet Janiš, Václav
Yan, Jiawei
contents The zero-temperature physics of interacting quantum dots attached to superconducting leads is now well understood. The overall qualitative picture is obtained from the static mean-field approximation. The situation drastically changes at non-zero temperatures. No reliable solutions apart from numerical simulations exist there. We show that any static mean-field approximation fails at non-zero temperatures since magnetic fluctuations induce dynamical corrections that lead to broadening of the in-gap state energies to energy bands. Spin-symmetric equilibrium state at non-zero temperatures is unstable with respect to magnetic fluctuations and the zero magnetic field can be reached only as a weak limit of the spin-polarized solution like in a magnetically ordered phase.
format Preprint
id arxiv_https___arxiv_org_abs_2112_10397
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Failure of the mean-field description of magnetic fluctuations in the superconducting quantum dot
Janiš, Václav
Yan, Jiawei
Strongly Correlated Electrons
Superconductivity
The zero-temperature physics of interacting quantum dots attached to superconducting leads is now well understood. The overall qualitative picture is obtained from the static mean-field approximation. The situation drastically changes at non-zero temperatures. No reliable solutions apart from numerical simulations exist there. We show that any static mean-field approximation fails at non-zero temperatures since magnetic fluctuations induce dynamical corrections that lead to broadening of the in-gap state energies to energy bands. Spin-symmetric equilibrium state at non-zero temperatures is unstable with respect to magnetic fluctuations and the zero magnetic field can be reached only as a weak limit of the spin-polarized solution like in a magnetically ordered phase.
title Failure of the mean-field description of magnetic fluctuations in the superconducting quantum dot
topic Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/2112.10397