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We study the superfluid behavior of ultracold atomic Fermi gases with a short range attractive interaction in a two-dimensional optical lattice (2DOL) using a pairing fluctuation theory, within the context of BCS-BEC crossover. We find that…

Quantum Gases · Physics 2022-03-01 Lin Sun , Jibiao Wang , Xiang Chu , Qijin Chen

We in this paper investigate the phase diagram associated with the BCS-BEC crossover of a three-component ultracold superfluid-Fermi-gas of different chemical-potentials and equal masses in two dimensions. The gap order parameter and number…

Quantum Gases · Physics 2015-06-04 Jiajia Du , Junjun Liang , J. -Q. Liang

We investigate the non-universal behavior of the BCS-BEC crossover model at the normal to superfluid transition. By using a finite temperature quantum field theoretical approach due to Nozieres and Schmitt-Rink and by making the effective…

Superconductivity · Physics 2007-05-23 L. M. Jensen

We show that the long-distance behavior of the two-body density correlation functions and the Cooper-pair probability density of a balanced mixture of a two-component Fermi gas at $T = 0$, is universal along the BEC-BCS crossover. Our…

In a recent paper [Phys. Rev. A 99, 053617 (2019)], the total number of fermion pairs in a spin-balanced two-component Fermi gas of $^6$Li atoms was experimentally probed in the normal phase above the superfluid critical temperature, in…

Quantum Gases · Physics 2020-08-27 M. Pini , P. Pieri , M. Jäger , J. Hecker Denschlag , G. Calvanese Strinati

The (mean field based) BCS theory is considered one of the most successful theories in condensed matter physics. It is justified in ordinary metal superconductors the coherence length $\xi$ is large, with two important features: the order…

Superconductivity · Physics 2018-01-22 Qijin Chen

A Fermi liquid with weak attractive interaction undergoes a BCS transition to a superconductor with reducing temperature. With increasing interaction strength, the thermal transition is progressively modified as the high temperature…

Strongly Correlated Electrons · Physics 2011-05-06 Sabyasachi Tarat , Pinaki Majumdar

Superconductors at temperatures below the critical temperature $T_c$ can be modeled as a mixture of Fermi and Bose gases, where the Fermi gas consists of conduction electrons and the Bose gas comprises Cooper pairs. This simple model…

Superconductivity · Physics 2024-11-14 Mi-Ra Hwang , Eylee Jung , MuSeong Kim , DaeKil Park

Most theoretical treatments of inhomogeneous superconductivity/fermionic superfluidity have been based on the Bogoliubov-deGennes equations (or, else, on their various simplified forms), which implement a standard mean-field decoupling in…

Superconductivity · Physics 2024-03-25 Leonardo Pisani , Verdiana Piselli , Giancarlo Calvanese Strinati

By selectively probing the center of a trapped gas, we measure the local, or homogeneous, contact of a unitary Fermi gas as a function of temperature. Tan's contact, C, is proportional to the derivative of the energy with respect to the…

Quantum Gases · Physics 2012-11-29 Yoav Sagi , Tara E. Drake , Rabin Paudel , Deborah S. Jin

Studying the collective pairing phenomena in a two-component Fermi gas, we predict the appearance near the transition temperature $T_c$ of a well-resolved collective mode of quadratic dispersion. The mode is visible both above and below…

Quantum Gases · Physics 2021-05-12 S. N. Klimin , J. Tempere , H. Kurkjian

We consider the evolution of superfluid properties of a three dimensional p-wave Fermi gas from weak (BCS) to strong (BEC) coupling as a function of scattering volume. We analyse the order parameter, quasi-particle excitation spectrum,…

Other Condensed Matter · Physics 2009-11-11 M. Iskin , C. A. R. Sá de Melo

This paper addresses the transition from the normal to the superfluid state in strongly correlated two dimensional fermionic superconductors and Fermi gases. We arrive at the Berezinskii-Kosterlitz-Thouless (BKT) temperature…

Superconductivity · Physics 2020-07-13 Xiaoyu Wang , Qijin Chen , K. Levin

A realistic description of the Josephson effect at finite temperature with ultra-cold Fermi gases embedded in nontrivial geometrical constraints (typically, a trap plus a barrier) requires appropriate consideration of pairing fluctuations…

Superconductivity · Physics 2024-03-25 Verdiana Piselli , Leonardo Pisani , Giancarlo Calvanese Strinati

By using a well established 'ab initio' theoretical approach developed in the past to quantitatively study the superconductivity of condensed matter systems, which is based on the Kohn-Sham Density Functional theory, I study the superfluid…

Quantum Gases · Physics 2016-06-01 Francesco Ancilotto

The interplay between dimensionality, coherence and interaction in superfluid Fermi gases is analyzed by the phase correlation function of the field of fermionic pairs. We calculate this phase correlation function for a two-dimensional…

Quantum Gases · Physics 2015-06-22 J. Tempere , S. N. Klimin

The unitarity regime of the BCS-BEC crossover can be realized by diluting a system of two-component lattice fermions with an on-site attractive interaction. We perform a systematic-error-free finite-temperature simulations of this system by…

Statistical Mechanics · Physics 2007-05-23 Evgeni Burovski , Nikolay Prokof'ev , Boris Svistunov , Matthias Troyer

We study the crossover from the Bardeen-Cooper-Shrieffer (BCS) regime to the Bose-Einstein-condensation (BEC) regime in a quasi-two-dimensional quantum gas of ultracold fermionic atoms. Using an effective two-dimensional Hamiltonian with…

Quantum Gases · Physics 2023-08-16 Jing Zhou , Tingting Shi , Xia-Ji Liu , Hui Hu , Wei Zhang

Twodimensional spin-orbit-coupled Fermi gases subject to s-wave pairing can be driven into a topological phase by increasing the Zeeman spin splitting beyond a critical value. In the topological phase, the system exhibits the hallmarks of…

Quantum Gases · Physics 2020-01-15 K. Thompson , J. Brand , U. Zülicke

A model of charged hole-pair bosons, with long range Coulomb interactions and very weak interlayer coupling, is used to calculate the order parameter -Phi- of underdoped cuprates. Model parameters are extracted from experimental superfluid…

Superconductivity · Physics 2010-01-12 Alexander Mihlin , Assa Auerbach