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We study the macroscopic quantum tunneling of two weakly-linked superfluids made of interacting fermionic atoms. We derive atomic Josephson junction equations and find that zero-mode and pi-mode frequencies of coherent atomic oscillations…

Statistical Mechanics · Physics 2008-04-09 L. Salasnich , N. Manini , F. Toigo

We present an exact theory of the BEC-BCS crossover in the BEC regime, which treats explicitely dimers as made of two fermions. We apply our framework, at zero temperature, to the calculation of the equation of state. We find that, when…

Statistical Mechanics · Physics 2009-11-13 X. Leyronas , R. Combescot

We present a pairing fluctuation theory which self-consistently incorporates finite momentum pair excitations in the context of BCS--Bose-Einstein condensation (BEC) crossover, and we apply this theory to high $T_c$ superconductors and…

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

We show how to describe the $T \neq 0$ behavior associated with the usual BCS- Bose Einstein condensation (BEC) crossover ground state. We confine our attention here to the BEC and near-BEC regime where analytical calculations are possible.…

Soft Condensed Matter · Physics 2011-09-13 Jelena Stajic , Qijin Chen , K. Levin

We investigate the superfluid phase transition and effects of mass imbalance in the BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein condensation) crossover regime of an cold Fermi gas. We point out that the Gaussian fluctuation theory…

Quantum Gases · Physics 2013-07-11 Ryo Hanai , Takashi Kashimura , Ryota Watanabe , Daisuke Inotani , Yoji Ohashi

Preparation of molecular quantum gas promises novel applications including quantum control of chemical reactions, precision measurements, quantum simulation and quantum information processing. Experimental preparation of colder and denser…

Atomic Physics · Physics 2021-04-29 Zhendong Zhang , Liangchao Chen , Kaixuan Yao , Cheng Chin

We investigate the equilibrium properties of a quasi-two-dimensional degenerate boson-fermion mixture (DBFM) with a bosonic vortex-antivortex superposed state (VAVSS) using a quantum-hydrodynamic model. We show that, depending on the choice…

Quantum Gases · Physics 2010-11-02 Linghua Wen , Yongping Zhang , Jian Feng

Fermionic many-body systems provide an unrivaled arena to investigate how interactions drive the emergence of collective quantum behavior, such as macroscopic coherence and superfluidity. Central to these phenomena is the formation of…

We present a description of the behavior of a superfluid gas of fermions in the presence of a Feshbach resonance over the complete range of magnetic field detunings. Starting from a resonance Hamiltonian, we exploit a functional method to…

Soft Condensed Matter · Physics 2009-02-05 J. N. Milstein , S. J. J. M. F. Kokkelmans , M. J. Holland

The simulation of strongly correlated fermionic systems remains one of the most significant challenges in computational physics due to the exponential growth of the Hilbert space and the fermionic sign problem. In this work, we present a…

Quantum Physics · Physics 2026-02-18 Hugo Catala , Ezequiel Valero , German Rodrigo

The Josephson current-phase characteristics, that arise when a supercurrent flows across two fermionic superfluids separated by a potential barrier, can be controlled by varying either the inter-particle coupling or the temperature. While…

Superconductivity · Physics 2020-10-21 Verdiana Piselli , Stefano Simonucci , Giancarlo Calvanese Strinati

We demonstrate that the well-known $(k\uparrow, -k\downarrow)$ Bardeen-Cooper-Schrieffer interaction, when considered in real space, is equivalent to an infinite-range Penson-Kolb pairing mechanism coexisting with an attractive Hubbard…

Superconductivity · Physics 2024-04-17 Francesco Romeo , Alfonso Maiellaro

We investigate strong coupling effects on the superfluid phase transition in a gas of Fermi atoms with a Feshbach resonance. The Feshbach resonance describes a composite quasi-Boson, which can give rise to an additional pairing interaction…

Soft Condensed Matter · Physics 2016-08-31 Y. Ohashi , A. Griffin

We investigate the relation between Bose-Einstein condensation (BEC) and superfluidity in the ground state of a one-dimensional model of interacting Bosons in a strong random potential. We prove rigorously that in a certain parameter regime…

Quantum Gases · Physics 2015-06-22 M. Könenberg , T. Moser , R. Seiringer , J. Yngvason

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 present a theory for a superfluid Fermi gas near the BCS-BEC crossover, including pairing fluctuation contributions to the free energy similar to that considered by Nozieres and Schmitt-Rink for the normal phase. In the strong coupling…

Superconductivity · Physics 2007-05-23 Hui Hu , Xia-Ji Liu , Peter D. Drummond

We study two models realized by two-component Fermi gases loaded in optical lattices. We clarify that multi-band effects inevitably caused by the optical lattices generate a rich structure, when the systems crossover from the region of…

Quantum Gases · Physics 2015-05-14 Ryota Watanabe , Masatoshi Imada

Motivated by the prospect of Bardeen-Cooper-Schrieffer (BCS) pairing in cold fermionic gases we analyze the superfluid phase of 3 fermionic flavors in the attractive Hubbard model. We show that there are several low--lying collective…

Superconductivity · Physics 2007-05-23 Carsten Honerkamp , Walter Hofstetter

We experimentally investigate the first-order correlation function of a trapped Fermi gas in the two-dimensional BEC-BCS crossover. We observe a transition to a low-temperature superfluid phase with algebraically decaying correlations. We…

Quantum Gases · Physics 2015-07-03 P. A. Murthy , I. Boettcher , L. Bayha , M. Holzmann , D. Kedar , M. Neidig , M. G. Ries , A. N. Wenz , G. Zürn , S. Jochim

A debated issue in the physics of the BCS-BEC crossover with trapped Fermi atoms is to identify characteristic properties of the superfluid phase. Recently, a condensate fraction was measured on the BCS side of the crossover by sweeping the…

Superconductivity · Physics 2007-05-23 A. Perali , P. Pieri , G. C. Strinati