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We explore the zero temperature phase behavior of a two-dimensional two-component atomic Fermi gas with population and mass imbalance in the regime of the BEC-BCS crossover. Working in the mean-field approximation, we show that the normal…

Strongly Correlated Electrons · Physics 2009-01-16 G. J. Conduit , P. H. Conlon , B. D. Simons

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

The shear viscosity has been shown to be equal to the product of pressure and relaxation time in normal scale-invariant fluids, but the presence of superfluidity at low temperatures can alter the relation. By using the mean-field…

Quantum Gases · Physics 2017-04-03 Hao Guo , Weimin Cai , Yan He , Chih-Chun Chien

The strongly attractive Fermi gas in the BCS-BEC crossover is efficiently described in terms of coupled fermions and fermion pairs, or molecules. We compute the spectral functions of both fermions and pairs in the normal state near the…

Quantum Gases · Physics 2024-03-01 Tilman Enss

We investigate the effects of quantum fluctuations on the low-energy collective modes of two-dimensional (2D) $s$-wave Fermi superfluids from the BCS to the Bose limit. We compare our results to recent Bragg scattering experiments in 2D box…

Quantum Gases · Physics 2023-09-19 Senne Van Loon , Carlos A. R. Sá de Melo

We present an overview of our recent measurements on the crossover from a Bose-Einstein condensate of molecules to a Bardeen-Cooper-Schrieffer superfluid. The experiments are performed on a two-component spin-mixture of $^6$Li atoms, where…

Other Condensed Matter · Physics 2009-11-10 M. Bartenstein , A. Altmeyer , S. Riedl , S. Jochim , R. Geursen , C. Chin , J. Hecker Denschlag , R. Grimm

Taking inspiration from the state-of-the art knowledge of the Bose-Hubbard (BH) model and recent methodological developments in its fermionic counterpart, this work deals with the study of the collective dynamics of a lattice Bose gas…

Quantum Gases · Physics 2022-11-15 Fabio Caleffi

We theoretically investigate the uniform spin susceptibility $\chi$ in the superfluid phase of an ultracold Fermi gas in the BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein condensation) crossover region. In our previous paper [H.…

Quantum Gases · Physics 2016-01-20 H. Tajima , R. Hanai , Y. Ohashi

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

We study the T=0 crossover from the BCS superconductivity to Bose-Einstein condensation in the attractive Hubbard Model within dynamical mean field theory(DMFT) in order to examine the validity of Hartree-Fock-Bogoliubov (HFB) mean field…

Superconductivity · Physics 2009-11-11 Arti Garg , H. R. Krishnamurthy , Mohit Randeria

This article reviews the current status of precursor superconducting phase fluctuations as a possible mechanism for pseudogap formation in high-temperature superconductors. In particular we compare this approach which relies on the…

Superconductivity · Physics 2007-05-23 Vadim M. Loktev , Rachel M. Quick , Sergei G. Sharapov

We present a theory of a two-component atomic Fermi gas with tunable attractive contact interactions on a spherical shell going through the Bardeen-Cooper-Schrieffer (BCS) - Bose Einstein condensation (BEC) crossover, inspired by the…

Quantum Gases · Physics 2022-04-01 Yan He , Hao Guo , Chih-Chun Chien

Bardeen-Schrieffer-Cooper (BCS) and Bose-Einstein condensation (BEC) occur at opposite limits of a continuum of pairing interaction strength between fermions. A crossover between these limits is readily observed in a cold atomic Fermi gas.…

Superconductivity · Physics 2022-07-13 N. Harrison , M. K. Chan

We report on the observation of the Josephson effect between two strongly interacting fermionic superfluids coupled through a thin tunneling barrier. We prove that the relative population and phase are canonically conjugate dynamical…

Based on an equations--of--motion approach for time--dependent pair correlations in strongly interacting Fermi liquids, we have developed a theory for describing the excitation spectrum of these systems. Compared to the known ``correlated''…

Other Condensed Matter · Physics 2009-11-11 Helga M. Böhm , Eckhard Krotscheck , Martin Panholzer

We investigate the fluctuation contribution to the specific heat of a two-dimensional superconductor with a non-Fermi normal state described by a Anderson Green's function $G(k,i\omega)=\omega_c^{-\alpha}/(i\omega-\epsilon_k)^{1-\alpha}$.…

Superconductivity · Physics 2007-05-23 I. Tifrea , I. Grosu , M. Crisan

We investigate theoretically the momentum-dependent frequency and damping of low-lying collective excitations of superconductors and charged superfluids in the BCS-BEC crossover regime. The study is based on the Gaussian pair-and-density…

Superconductivity · Physics 2023-06-26 S. N. Klimin , J. Tempere , H. Kurkjian

We investigate the system of a heavy impurity embedded in a paired two-component Fermi gas at the crossover from a Bose-Einstein condensate (BEC) to a Bardeen--Cooper--Schrieffer (BCS) superfluid via an extension of the functional…

Quantum Gases · Physics 2022-07-22 Jia Wang , Xia-Ji Liu , Hui Hu

In this paper we compare Bose transport in normal phase atomic gases with its counterpart in Fermi gases, illustrating the non-universality of two dimensional bosonic transport associated with different dissipation mechanisms. Near the…

Quantum Gases · Physics 2014-12-01 A. Rancon , Cheng Chin , K. Levin

We calculate the pair correlation function and the order parameter correlation function, which probe, respectively, the intra-pair and inter-pair correlations of a Fermi gas with attractive inter-particle interaction, in terms of a…

Superconductivity · Physics 2014-06-18 F. Palestini , G. C. Strinati