Failure of the mean-field description of magnetic fluctuations in the superconducting quantum dot
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arXiv
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| Autori principali: | , |
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| Natura: | Preprint |
| Pubblicazione: |
2021
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| _version_ | 1866913385321332736 |
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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 |