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We analyze the BCS-BEC crossover for a Fermi gas made of neutral atoms in three hyperfine states with a SU(3) invariant attractive interaction. By solving the extended BCS equations for the total number of particles and the pairing gap, we…

Quantum Gases · Physics 2012-11-27 Luca Salasnich

We elucidate the role of the effective range in the Bose-Einstein-condensate (BEC) to Bardeen-Cooper-Schrieffer (BCS) crossover regime of two-component fermions in three dimensions. In contrast to ultracold Fermi gases near the broad…

Quantum Gases · Physics 2023-05-01 Hiroyuki Tajima , Haozhao Liang

We theoretically investigate strong-coupling properties of an ultracold Fermi gas in the BCS-BEC crossover regime in the non-equilibrium steady state, being coupled with two fermion baths. By developing a non-equilibrium strong-coupling…

Quantum Gases · Physics 2020-01-09 Taira Kawamura , Ryo Hanai , Daichi Kagamihara , Daisuke Inotani , Yoji Ohashi

Phase transitions are ubiquitous in our three-dimensional world. By contrast most conventional transitions do not occur in infinite uniform two-dimensional systems because of the increased role of thermal fluctuations. Here we explore the…

We investigate the macroscopic quantum tunneling of fermionic superfluids in the two-dimensional BCS-BEC crossover by using an effective tunneling energy which explicitly depends on the condensate fraction and the chemical potential of the…

Quantum Gases · Physics 2020-08-21 Filippo Pascucci , Luca Salasnich

We investigate the crossover from Bardeen-Cooper-Schrieffer (BCS) superfluidity to Bose-Einstein condensation (BEC) in a two-dimensional Fermi gas at T=0 using the fixed-node diffusion Monte Carlo method. We calculate the equation of state…

Quantum Gases · Physics 2015-03-17 G. Bertaina , S. Giorgini

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…

We study pseudogap behaviors of ultracold Fermi gases in the BCS-BEC crossover region. We calculate the density of states (DOS), as well as the single-particle spectral weight, above the superfluid transition temperature $T_{\rm c}$…

Quantum Gases · Physics 2015-05-13 S. Tsuchiya , R. Watanabe , Y. Ohashi

We study a rotating atomic Fermi gas near a narrow s-wave Feshbach resonance in a uniaxial harmonic trap with frequencies $\Omega_\perp$, $\Omega_z$. Our primary prediction is the upper-critical angular velocity, $\omega_{c2} (\delta,T)$,…

Superconductivity · Physics 2007-05-23 Martin Y. Veillette , Daniel E. Sheehy , Leo Radzihovsky , Victor Gurarie

In this paper, we study the effect of population imbalance and its interplay with pairing strength and lattice effect in atomic Fermi gases in a one-dimensional optical lattice. We compute various phase diagrams as the system undergoes…

Quantum Gases · Physics 2020-05-20 Jibiao Wang , Lin Sun , Qiang Zhang , Leifeng Zhang , Yi Yu , Chaohong Lee , Qijin Chen

We theoretically investigate a Bose-condensed exciton gas out of equilibrium. Within the framework of the combined BCS-Leggett strong-coupling theory with the non-equilibrium Keldysh formalism, we show how the Bose-Einstein condensation…

Strongly Correlated Electrons · Physics 2016-03-29 Ryo Hanai , Peter B. Littlewood , Yoji Ohashi

We investigate pairing in a strongly interacting two-component Fermi gas with positive scattering length. In this regime, pairing occurs at temperatures above the superfluid critical temperature; unbound fermions and pairs coexist in…

We show that two new intra-species P-wave superfluid phases appear in two-component asymmetric Fermi systems with short-range S-wave interactions. In the BEC limit, phonons of the molecular BEC induce P-wave superfluidity in the excess…

Other Condensed Matter · Physics 2007-05-23 Aurel Bulgac , Michael McNeil Forbes , Achim Schwenk

We investigate the ground state properties of a disordered superfluid Fermi gas across the BCS-BEC (Bose Einstein condensate) crossover. We show that, for weak disorder, both the depletion of the condensate fraction of pairs and the normal…

Superconductivity · Physics 2009-11-13 G. Orso

We study the expansion of a dilute ultracold sample of fermions initially trapped in a anisotropic harmonic trap. The expansion of the cloud provides valuable information about the state of the system and the role of interactions. In…

Soft Condensed Matter · Physics 2009-11-07 C. Menotti , P. Pedri , S. Stringari

In a trapped atomic Fermi gas, one can tune continuously via a Feshbach resonance the effective pairing interaction between fermionic atoms from very weak to very strong. As a consequence, the low temperature superfluidity evolves…

Quantum Gases · Physics 2011-01-17 Yi Yu , Qijin Chen

We present a theory of a degenerate atomic Fermi gas, interacting through a narrow Feshbach resonance, whose position and therefore strength can be tuned experimentally, as demonstrated recently in ultracold trapped atomic gases. The…

Superconductivity · Physics 2007-05-23 V. Gurarie , L. Radzihovsky

The splitting instability of a doubly-quantized vortex in the BEC-BCS crossover of a superfluid Fermi gas is investigated by means of a low-energy effective field theory. Our linear stability analysis and non-equilibrium numerical…

Quantum Gases · Physics 2023-11-21 Wout Van Alphen , Hiromitsu Takeuchi , Jacques Tempere

The critical properties of the phase transition from a normal gas to a BEC (superfluid) of a harmonically confined Bose gas are addressed with the knowledge of an equation of state of the underlying homogeneous Bose fluid. It is shown that…

Quantum Gases · Physics 2017-08-02 I. Reyes-Ayala , F. J. Poveda-Cuevas , J. A. Seman , V. Romero-Rochín

The physics of quantum degenerate Fermi gases in uniform as well as in harmonically trapped configurations is reviewed from a theoretical perspective. Emphasis is given to the effect of interactions which play a crucial role, bringing the…

Other Condensed Matter · Physics 2009-11-13 Stefano Giorgini , Lev P. Pitaevskii , Sandro Stringari