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We study the time evolution of a system of fermions with pairing interactions at a finite temperature. The dynamics is triggered by an abrupt increase of the BCS coupling constant. We show that if initially the fermions are in a normal…

Superconductivity · Physics 2021-07-20 Emil A. Yuzbashyan , Oleksandr Tsyplyatyev

We present a systematic theoretical study of the BCS-BEC crossover problem in three-dimensional atomic Fermi gases at zero temperature with a spherical spin-orbit coupling which can be generated by a synthetic non-Abelian gauge field…

Quantum Gases · Physics 2012-07-13 Lianyi He , Xu-Guang Huang

We analyze a mean-field model of electrons on a square lattice with two types of interaction: forward scattering favoring a d-wave Pomeranchuk instability and a BCS pairing interaction driving d-wave superconductivity. Tuning the…

Superconductivity · Physics 2009-11-13 Hiroyuki Yamase , Walter Metzner

Mesoscopic interacting Bose-Einstein condensates confined in a few traps display phase transitions that cannot be explained with a mean field theory. By describing each trap as an effective site of a Bose-Hubbard model and using the…

Quantum Gases · Physics 2018-09-07 A. Gallemí , M. Guilleumas , R. Mayol , A. Sanpera

We develop an explicit description of a time-dependent response of fermionic condensates to perturbations. The dynamics of Cooper pairs at times shorter than the energy relaxation time can be described by the BCS model. We obtain a general…

Superconductivity · Physics 2009-11-10 Emil A. Yuzbashyan , Boris L. Altshuler , Vadim B. Kuznetsov , Victor Z. Enolskii

In this work, we explore two-dimensional attractive Fermi gases at the microscopic level by probing spatial charge and spin correlations in situ. Using atom-resolved continuum quantum gas microscopy, we directly observe fermion pairing and…

Possible superconductivity of electrons with the Dirac spectrum is analyzed using the BCS model. We calculate the critical temperature, the superconducting energy gap, and supercurrent as functions of the doping level and of the pairing…

Superconductivity · Physics 2019-10-04 N. B. Kopnin , E. B. Sonin

Superconducting state is achieved through quantum condensation of Cooper pairs which are new types of charge carriers other than single electrons in normal metals. The theory established by Bardeen-Cooper-Schrieffer (BCS) in 1957 can…

Superconductivity · Physics 2025-02-20 Hai-Hu Wen

The existence of a normal state spectral gap in underdoped cuprates raises important questions about the associated superconducting phase. For example, how does this pseudogap evolve into its below Tc counterpart? In this paper we…

Superconductivity · Physics 2007-05-23 Ioan Kosztin , Qijin Chen , Boldizsar Janko , K. Levin

This paper presents a comparison of two finite-temperature BCS-Bose Einstein condensation (BEC) crossover theories above the transition temperature: Nozieres Schmitt-Rink (NSR) theory and finite $T$-extended BCS-Leggett theory. The…

Quantum Gases · Physics 2013-05-29 Chih-Chun Chien , Hao Guo , Yan He , K. Levin

We model fermions with an attractive interaction in an optical lattice with a single-band Hubbard model away from half-filling with on-site attraction $U$ and nearest neighbor hopping $t$. Our goal is to understand the crossover from BCS…

Superconductivity · Physics 2011-07-20 Parag Ghosh

A two-dimensional (2D) assembly of noninteracting, temperature-dependent, composite-boson Cooper pairs (CPs) in chemical and thermal equilibrium with unpaired fermions is examined in a binary boson-fermion statistical model as the…

Superconductivity · Physics 2016-08-15 M. Casas , N. J. Davidson , M. de Llano , T. A. Mamedov , A. Puente , R. M. Quick , A. Rigo , M. A. Solís

We consider a BCS-type model in the spin formalism and argue that the structure of the interaction provides a mechanism for control over directions of the spin $\vect S$ other than $S_z$, which is being controlled via the conventional…

High Energy Physics - Theory · Physics 2007-06-13 Nevena Ilieva , Walter Thirring

A two-dimensional (2D) assembly of noninteracting, temperature-dependent, composite-boson Cooper pairs (CPs) in chemical and thermal equilibrium with unpaired fermions is examined in a binary boson-fermion statistical model as the…

Superconductivity · Physics 2016-08-16 M. Casas , N. J. Davidson , M. de Llano , T. A. Mamedov , A. Puente , R. M. Quick , A. Rigo , M. A. Solís

A mean field spin system consisting two interacting groups each with homogeneous interaction coefficients is introduced and studied. Existence of the thermodynamic limit is shown by an asymptotic sub-addittivity method and factorization of…

Statistical Mechanics · Physics 2007-10-12 Ignacio Gallo , Pierluigi Contucci

We analyze the reduced BCS model with an imaginary magnetic field in a large domain of the temperature and the imaginary magnetic field. The magnitude of the attractive reduced BCS interaction is fixed to be small but independent of the…

Mathematical Physics · Physics 2021-04-21 Yohei Kashima

The pseudogap phenomenon is a hallmark of strongly interacting Fermi systems, from high-temperature superconductors to ultracold atomic gases, yet its precise origin remains debated. Here we calculate the spectral function and rf spectra of…

Quantum Gases · Physics 2026-04-08 Chuping Li , Lin Sun , Kaichao Zhang , Junru Wu , Yuxuan Wu , Dingli Yuan , Pengyi Chen , Qijin Chen

A gas of interacting ultracold fermions can be tuned into a strongly interacting regime using a Feshbach resonance. Here we theoretically study quasiparticle transport in a system of two reservoirs of interacting ultracold fermions on the…

Quantum Gases · Physics 2016-09-19 Tibor Sekera , Christoph Bruder , Wolfgang Belzig

Superconducting electron systems of solids hosting flat bands are studied, with a view to improved understanding of the fundamental physics giving rise to high-temperature superconductivity. We present a modified form of the set of Gor'kov…

Strongly Correlated Electrons · Physics 2017-02-03 V. A. Khodel , J. W. Clark , M. V. Zverev

We examine distinct measures of fermionic entanglement in the exact ground state of a finite superconducting system. It is first shown that global measures such as the one-body entanglement entropy, which represents the minimum relative…

Quantum Physics · Physics 2018-06-20 M. Di Tullio , N. Gigena , R. Rossignoli