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Based on previous works, analytical calculational procedures for dealing with the strongly interacting fermions ground state are further developed through a medium dependent potential in terms of the Bethe-Peierls contact interaction model.…

Statistical Mechanics · Physics 2008-11-26 Ji-sheng Chen , Chuan-ming Cheng , Jia-rong Li , Yan-ping Wang

We study the superfluid critical temperature in a two-band attractive Fermi system with strong pairing fluctuations associated with both interband and intraband couplings. We focus specifically on a configuration where the intraband…

Quantum Gases · Physics 2019-06-05 Hiroyuki Tajima , Yuriy Yerin , Andrea Perali , Pierbiagio Pieri

We present a numerical study of the interaction quench dynamics in a superfluid ultracold Fermi gas confined in a three-dimensional cigar-shaped harmonic trap. In the present paper we investigate the amplitude mode of the superfluid order…

Quantum Gases · Physics 2018-11-14 S. Hannibal , P. Kettmann , M. D. Croitoru , V. M. Axt , T. Kuhn

We investigate the Bose-Einstein condensation of fermionic pairs in a two-dimensional uniform two-component Fermi superfluid obtaining an explicit formula for the condensate density as a function of the chemical potential and the energy…

Statistical Mechanics · Physics 2009-11-13 Luca Salasnich

In this article we study the two-dimensional (2D) ultracold Fermi gas with weak impurity in the framework of mean-field theory where the impurity is introduced through Gaussian fluctuations. We have investigated the role of the impurity by…

Quantum Gases · Physics 2020-07-31 Ayan Khan , B. Tanatar

The strongly-correlated regime of the BCS-BEC crossover can be realized by diluting a system of two-component fermions with a short-range attractive interaction. We investigate this system via a novel continuous-space-time diagrammatic…

Strongly Correlated Electrons · Physics 2009-11-13 Evgeni Burovski , Evgeny Kozik , Nikolay Prokof'ev , Boris Svistunov , Matthias Troyer

We investigate the collective oscillations in the BCS-BEC crossover region of a trapped Fermi superfluid at T=0. We explicitly include the effect of a Feshbach resonance, which leads to a tunable pairing interaction adjusted by the…

Other Condensed Matter · Physics 2007-05-23 Yoji Ohashi , Allan Griffin

We present a manifestly gauge invariant linear response theory for ultra-cold Fermi gases undergoing BCS-Bose-Einstein Condensation (BEC) crossover with pair fluctuation effect included, especially in the superfluid phase, by introducing an…

Quantum Gases · Physics 2018-07-25 Yan He , Hao Guo

We use the standard fermionic and boson-fermion Hamiltonians to study the BCS-BEC cross-over near the 202 G resonance in a two-component mixture of fermionic 40K atoms employed in the experiment of C.A. Regal et al., Phys. Rev. Lett. 92,…

Superconductivity · Physics 2009-02-05 Marzena H. Szymanska , Krzysztof Goral , Thorsten Koehler , Keith Burnett

In this letter, we investigate the fluctuation effects on the transport properties of unitary Fermi gases in the vicinity of the superfluid transition temperature $T_c$. Based on the time-dependent Ginzburg-Landau formalism of the BEC-BCS…

Quantum Gases · Physics 2014-12-17 Boyang Liu , Hui Zhai , Shizhong Zhang

In this work, we present a theoretical study for the collective oscillation modes, i.e. quadrupole, radial and axial mode, of a mixture of Bose and Fermi superfluids in the crossover from a Bardeen-Cooper-Schrieffer (BCS) superfluid to a…

Quantum Gases · Physics 2019-10-03 Wen Wen , Ying Wang , Jianyong Wang

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

Dynamic critical behavior in superfluid systems is considered in a presence of external stirring and advecting processes. The latter are generated by means of the Gaussian random velocity ensemble with white-noise character in time variable…

Statistical Mechanics · Physics 2020-08-19 Michal Dančo , Michal Hnatič , Tomáš Lučivjanský , Lukáš Mižišin

We present a truly canonical theory of superconductivity in ultrasmall metallic grains by variationally optimizing fixed-N projected BCS wave-functions, which yields the first full description of the entire crossover from the bulk BCS…

Superconductivity · Physics 2009-10-31 Fabian Braun , Jan von Delft

We study the BCS-Bose Einstein Condensation (BEC) crossover of a three dimensional spin polarized Fermi gas with Rashba spin-orbital-coupling (SOC). At finite temperature, the effects of non-condensed pairs due to the thermal excitation are…

Quantum Gases · Physics 2016-06-24 Chang-Yan Wang , Yan He

We investigate the strong out-of-equilibrium dynamics occurring when a harmonically trapped ultracold bosonic gas is evaporatively cooled across the Bose--Einstein condensation transition. By imaging the cloud after free expansion, we study…

Quantum Gases · Physics 2022-03-29 Wolswijk L. , Mordini C. , Farolfi A. , Trypogeorgos D. , Dalfovo F. , Zenesini A. , Ferrari G. , Lamporesi G

Effects of superconducting fluctuation (SCF) on thermodynamic properties of electron systems in the so-called BCS-BEC-crossover regime are studied. As the attractive interaction between electrons becomes stronger upon approaching the…

Superconductivity · Physics 2017-11-15 Kyosuke Adachi , Ryusuke Ikeda

The application of the exact renormalisation group to a many-fermion system with a short-range attractive force is studied. We assume a simple ansatz for the effective action with effective bosons, describing pairing effects and derive a…

Nuclear Theory · Physics 2014-11-18 Boris Krippa

We briefly discuss recent experiments on the BCS-BEC crossover with ultracold alkali-metal atoms both in three-dimensional configurations and two-dimensional ones. Then we analyze the quantum-field-theory formalism used to describe an…

Quantum Gases · Physics 2016-02-26 L. Salasnich

We calculate the single particle spectral density of a normal (non-superfluid) two component gas of fermions in the BCS-BEC crossover within a T-matrix approximation. We review how non-condensed pairs lead to a spectral density reminiscent…

Quantum Gases · Physics 2015-05-20 Erich J. Mueller