Many-body perturbation theory for the superconducting quantum dot: Fundamental role of the magnetic field

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378271%3A_____%2F21%3A00553383" target="_blank" >RIV/68378271:_____/21:00553383 - isvavai.cz</a>
Result on the web
<a href="https://doi.org/10.1103/PhysRevB.103.235163" target="_blank" >https://doi.org/10.1103/PhysRevB.103.235163</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1103/PhysRevB.103.235163" target="_blank" >10.1103/PhysRevB.103.235163</a>

Result language
angličtina
Original language name
Many-body perturbation theory for the superconducting quantum dot: Fundamental role of the magnetic field
Original language description
We develop the general many-body perturbation theory for a superconducting quantum dot represented by a single-impurity Anderson model attached to superconducting leads. We build our approach on a thermodynamically consistent mean-field approximation with a two-particle self-consistency of the parquet type. The two-particle self-consistency leading to a screening of the bare interaction proves substantial for suppressing the spurious transitions of the Hartree-Fock solution. We demonstrate that the magnetic field plays a fundamental role in the extension of the perturbation theory beyond the weakly correlated 0 phase. It controls the critical behavior of the 0-pi quantum transition and lifts the degeneracy in the pi phase, where the limits to zero temperature and zero magnetic field do not commute. The response to the magnetic field is quite different in 0 and pi phases. While the magnetic susceptibility vanishes in the 0 phase it becomes divergent in the pi phase at zero temperature.
Czech name
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Czech description
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Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Project
Result was created during the realization of more than one project. More information in the Projects tab.
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year
2021
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

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