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We consider a polarized Fermi gas in the BCS-BEC crossover region above the critical temperature within a T matrix formalism. By treating the mean-field like shift of the quasiparticle energies in a self-consistent manner, we avoid the…

Quantum Gases · Physics 2014-11-27 Pierre-Alexandre Pantel , Dany Davesne , Michael Urban

The BCS-BEC crossover and phase diagram for asymmetric nuclear superfluid with pairings in isospin I = 0 and I = 1 channels are investigated at mean field level, by using a density dependent nucleon-nucleon potential. Induced by the…

Nuclear Theory · Physics 2009-11-12 Shijun Mao , Xuguang Huang , Pengfei Zhuang

We consider the problem of the crossover from BCS superconductivity to Bose-Einstein condensation in three dimensions for a system of fermions with an attractive interaction, for which we adopt the simplifying assumption of a suitably…

Superconductivity · Physics 2009-10-31 P. Pieri , G. C. Strinati

The superfluid density is a fundamental quantity describing the response to a rotation as well as in two-fluid collisional hydrodynamics. We present extensive calculations of the superfluid density \rho_s in the BCS-BEC crossover regime of…

Materials Science · Physics 2012-05-10 N. Fukushima , Y. Ohashi , E. Taylor , A. Griffin

We have demonstrated that it is possible to access a crossover scenario starting with a weak coupling (BCS) d-wave superconductor to a strongly coupled Bose-Einstein condensate (BEC) phase as the exchange interaction is tuned in a two…

Strongly Correlated Electrons · Physics 2015-06-15 Subrat Kumar Das , Ayan Khan , Saurabh Basu

Experiments with ultracold atoms provide a highly controllable laboratory setting with many unique opportunities for precision exploration of quantum many-body phenomena. The nature of such systems, with strong interaction and quantum…

Quantum Gases · Physics 2017-12-13 Ettore Vitali , Hao Shi , Mingpu Qin , Shiwei Zhang

The BCS-BEC crossover is studied in a systematic way in the broken-symmetry phase between zero temperature and the critical temperature. This study bridges two regimes where quantum and thermal fluctuations are, respectively, important. The…

Superconductivity · Physics 2007-05-23 P. Pieri , L. Pisani , G. C. Strinati

Cooper pairing in two dimensions is analyzed with a set of renormalized equations to determine its binding energy for any fermion number density and all coupling assuming a generic pairwise residual interfermion interaction. \ Also…

Superconductivity · Physics 2016-08-15 S. K. Adhikari , M. Casas , A. Puente , A. Rigo , M. Fortes , M. A. Solís , M. de Llano , A. A. Valladares , O. Rojo

A consistent microscopic theory of pseudogap phenomena and novel Bose-liquid superconductivity (superfluidity) is presented, based on the fact that in high-$T_c$ cuprates and related systems the energy $\varepsilon_A$ of the effective…

Superconductivity · Physics 2020-01-22 S. Dzhumanov

We theoretically investigate the shear viscosity $\eta$ in the BCS-BEC crossover regime of an ultracold Fermi gas with a Feshbach resonance. Within the framework of the strong-coupling self-consistent $T$-matrix approximation, we examine…

Quantum Gases · Physics 2019-10-17 Daichi Kagamihara , Daisuke Inotani , Yoji Ohashi

We investigate pseudogap phenomena in the unitarity limit of a trapped superfluid Fermi gas. Including effect of strong pairing fluctuations within a $T$-matrix approximation, as well as effects of a harmonic trap within the local density…

Quantum Gases · Physics 2015-05-28 Ryota Watanabe , Shunji Tsuchiya , Yoji Ohashi

The BCS-BEC crossover realized experimentally with ultra-cold Fermi gases may be considered as one of the important scientific achievements occurred during the last several years. The flexibility for operating on these systems on the…

Quantum Gases · Physics 2024-03-20 Giancarlo Calvanese Strinati

We investigate Bardeen-Cooper-Schrieffer (BCS)- Bose-Einstein condensation (BEC) crossover in a two-band superfluid Fermi gas with an energy shift between the bands. When the intraband coupling in the cold (first) band is fixed as weak, we…

Superconductivity · Physics 2019-10-09 Yuriy Yerin , Hiroyuki Tajima , Pierbiagio Pieri , Andrea Perali

We study the finite temperature $T$ behavior of trapped Fermi gases as they undergo BCS-Bose Einstein condensation (BEC) crossover, in the presence of a population imbalance. Our results, in qualitative agreement with recent experiments,…

Strongly Correlated Electrons · Physics 2011-09-13 Chih-Chun Chien , Qijin Chen , Yan He , K. Levin

One of the most remarkable properties of the high-temperature superconductors is a pseudogap regime appearing in the underdoped cuprates above the superconducting transition temperature T_c. The pseudogap continously develops out of the…

Superconductivity · Physics 2009-11-10 T. Eckl , W. Hanke , S. V. Borisenko , A. A. Kordyuk , T. Kim , A. Koitzsch , M. Knupfer , J. Fink

We determine the effects of quantum fluctuations about the T=0 mean field solution of the BCS-BEC crossover in a dilute Fermi gas using the functional integral method. These fluctuations are described in terms of the zero point motion of…

Other Condensed Matter · Physics 2008-03-20 Roberto B. Diener , Rajdeep Sensarma , Mohit Randeria

We theoretically investigate the recent photoemission-type experiment on $^{40}$K Fermi gases done by JILA group. Including pairing fluctuations within a strong-coupling $T$-matrix theory, as well as effects of a harmonic trap within the…

Quantum Gases · Physics 2016-11-18 Ryota Watanabe , Shunji Tsuchiya , Yoji Ohashi

We study the crossover of a quasi-two-dimensional Fermi gas trapped in the radial plane from the Bardeen-Cooper-Schrieffer (BCS) regime to the Bose-Einstein condensation (BEC) regime by crossing a wide Feshbach resonance. We consider two…

Strongly Correlated Electrons · Physics 2008-08-06 Wei Zhang , G. -D. Lin , L. -M. Duan

Quantum confinement is known to influence fermionic condensates, resulting in quantum-size oscillations of superfluid/superconducting properties. Here we show that the impact of quantum-size effects is even more dramatic. Under realistic…

Quantum Gases · Physics 2011-10-24 A. A. Shanenko , M. D. Croitoru , A. V. Vagov , V. M. Axt , A. Perali , F. M. Peeters

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