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Related papers: Pairing in spin polarized two-species fermionic mi…

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We investigate pairing fluctuation effects in a two band fermionic system, where a shallow band in the Bardeen--Cooper--Schrieffer--Bose--Einstein condensation (BCS-BEC) crossover regime is coupled with a weakly interacting deep band.…

Superconductivity · Physics 2020-01-23 Hiroyuki Tajima , Andrea Perali , Pierbiagio Pieri

The crossover from weak coupling Bardeen-Cooper-Schrieffer (BCS) pairing to a Bose-Einstein condensate (BEC) of tightly bound pairs, as a function of the attractive interaction in Fermi systems, has long been of interest to theoretical…

Quantum Gases · Physics 2014-04-09 Mohit Randeria , Edward Taylor

We measure excitation spectra of an ultracold gas of fermionic $^{40}$K atoms in the BCS-BEC crossover regime. The measurements are performed with a novel spectroscopy that employs a small modulation of the B-field close to a Feshbach…

Statistical Mechanics · Physics 2011-08-12 Markus Greiner , Cindy A. Regal , Deborah S. Jin

The BCS-to-BEC crossover, as well as the nature of Cooper pairs, in a superconducting and Fermi superfluid medium is studied from the exact ground state wavefunction of the reduced BCS Hamiltonian. As the strength of the interaction…

Superconductivity · Physics 2009-11-11 Gerardo Ortiz , Jorge Dukelsky

We obtain the phase diagram of spin-imbalanced interacting Fermi gases from measurements of density profiles of $^6$Li atoms in a harmonic trap. These results agree with, and extend, previous experimental measurements. Measurements of the…

Atomic Physics · Physics 2015-12-16 Ben A. Olsen , Melissa C. Revelle , Jacob A. Fry , Daniel E. Sheehy , Randall G. Hulet

Grassmann Phase Space Theory (GSPT) is applied to the BEC/BCS crossover in cold fermionic atomic gases and used to determine the evolution (over either time or temperature) of the Quantum Correlation Functions (QCF) that specify: (a) the…

Quantum Gases · Physics 2023-02-07 B. J. Dalton , N. M. Kidwani

We study a two-component Fermi system with attractive interactions and different populations of the two species in a cubic lattice. For an intermediate coupling we find a uniformly polarized superfluid which is stable down to very low…

Superconductivity · Physics 2008-12-08 Tung-Lam Dao , Michel Ferrero , Antoine Georges , Massimo Capone , Olivier Parcollet

We study quantum degenerate ultra-cold Fermi gases in the presence of artificial spin-orbit coupling and crossed Zeeman fields. We emphasize the case where parity is violated in the excitation spectrum and compare it with the simpler…

Quantum Gases · Physics 2012-11-22 Kangjun Seo , Li Han , C. A. R. Sá de Melo

We investigate the crossover from Bardeen-Cooper-Schrieffer (BCS) pairing to a Bose-Einstein condensate (BEC) in a relativistic superfluid within a boson-fermion model. The model includes, besides the fermions, separate bosonic degrees of…

Nuclear Theory · Physics 2008-11-26 Jian Deng , Andreas Schmitt , Qun Wang

We consider the two-dimensional Fermi gas at finite temperature with attractive short-range interactions. Using the virial expansion, which provides a controlled approach at high temperatures, we determine the spectral function and contact…

Quantum Gases · Physics 2014-01-08 V. Ngampruetikorn , J. Levinsen , Meera M. Parish

We present a theoretical interpretation of radio-frequency (RF) pairing gap experiments in trapped atomic Fermi gases, over the entire range of the BCS-BEC crossover, for temperatures above and below $T_c$. Our calculated RF excitation…

Soft Condensed Matter · Physics 2011-09-13 Yan He , Qijin Chen , K. Levin

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

The superfluidity and pairing phenomena in ultracold atomic Fermi gases have been of great interest in recent years, with multiple tunable parameters. Here we study the BCS-BEC crossover behavior of balanced two-component Fermi gases in a…

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

This chapter presents the crossover from the Bardeen-Cooper-Schrieffer (BCS) state of weakly-correlated pairs of fermions to the Bose-Einstein condensation (BEC) of diatomic molecules in the atomic Fermi gas. Our aim is to provide a…

Quantum Gases · Physics 2017-08-23 Meera M. Parish

We derive upper and lower bounds on the critical temperature $T_c$ and the energy gap $\Xi$ (at zero temperature) for the BCS gap equation, describing spin 1/2 fermions interacting via a local two-body interaction potential $\lambda V(x)$.…

Superconductivity · Physics 2009-11-13 Christian Hainzl , Robert Seiringer

We study a trapped system of fermions with a zero-range two-body interaction using the shell-model Monte Carlo method, providing {\em ab initio} results for the low particle number limit where mean-field theory is not applicable. We present…

Superconductivity · Physics 2009-09-22 N. T. Zinner , K. Mølmer , C. Özen , D. J. Dean , K. Langanke

By adopting a $T$-matrix based method within $G_0G$ approximation for the pair susceptibility, we studied the effects of pairing fluctuation on the BCS-BEC crossover in symmetric nuclear matter. The pairing fluctuation induces a pseudogap…

Nuclear Theory · Physics 2015-03-13 Xu-Guang Huang

Ultracold atomic gases and low-density neutron matter are unique in that they exhibit pairing gaps comparable to the Fermi energy which in this sense are the largest in the laboratory and in nature, respectively. This strong pairing regime,…

Nuclear Theory · Physics 2017-08-23 J. Carlson , S. Gandolfi , A. Gezerlis

We have examined the role of the BCS pairing mechanism in the formation of the magnetic moment and henceforth a spin glass (SG) phase by studying a fermionic Sherrington-Kirkpatrick model with a local BCS coupling between the fermions. This…

Statistical Mechanics · Physics 2016-08-31 S. G. Magalhaes , Alba Theumann

The pairing of interacting fermions leading to superfluidity has two limiting regimes: the Bardeen-Cooper-Schrieffer (BCS) scheme for weakly interacting degenerate fermions and the Bose-Einstein condensation (BEC) of bosonic pairs of…

Superconductivity · Physics 2022-01-27 Y. Suzuki , K. Wakamatsu , J. Ibuka , H. Oike , T. Fujii , K. Miyagawa , H. Taniguchi , K. Kanoda