The strongly correlated regime of the crossover from Bardeen-Cooper-Schrieffer pairing to Bose-Einstein condensation 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 determinant Monte Carlo method and determine the universal curve Tc/epsilonF for the transition temperature between the normal and the superfluid states as a function of the scattering length with the maximum on the Bose-Einstein condensation side. At unitarity, we confirm that Tc/epsilonF=0.152(7).The strongly correlated regime of the crossover from Bardeen-Cooper-Schrieffer pairing to Bose-Einstein condensation 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 determinant Monte Carlo method and determine the universal curve Tc/epsilonF for the transition temperature between the normal and the superfluid states as a function of the scattering length with the maximum on the Bose-Einstein condensation side. At unitarity, we confirm that Tc/epsilonF=0.152(7).

arXiv:0805.3047Physical Review LettersAug 27, 200898 citations

Temperatura critica nel crossover BCS-BEC con accoppiamento spin-orbitale

Stefano Grava

The thesis analyze thermodynamic properties of a system of Fermions with a spin-orbit coupling, whose strength can be tuned continuously in a crossover from BCS theory of superconductivity to a Bose-Einstein condensate (BEC). Below the critical temperature $T_{c}$ both system are characterized by an order parameter. Generally a mean field approximation cannot reproduce the correct behavior of the critical temperature $T_{c}$ over the whole crossover; this happen instead if inclusions of quantum Gaussian fluctuations are considered. So the aim of the thesis is to study Gaussian fluctuations beyond mean field and to find the $T_{c}$ over the whole crossover also in the presence of a spin-orbit coupling.The thesis analyze thermodynamic properties of a system of Fermions with a spin-orbit coupling, whose strength can be tuned continuously in a crossover from BCS theory of superconductivity to a Bose-Einstein condensate (BEC). Below the critical temperature $T_{c}$ both system are characterized by an order parameter. Generally a mean field approximation cannot reproduce the correct behavior of the critical temperature $T_{c}$ over the whole crossover; this happen instead if inclusions of quantum Gaussian fluctuations are considered. So the aim of the thesis is to study Gaussian fluctuations beyond mean field and to find the $T_{c}$ over the whole crossover also in the presence of a spin-orbit coupling.

Apr 1, 20160 citations

The critical velocity in the BEC-BCS crossover

Jonas Siegl, Wolf Weimer, Kai Morgener +3 more

Bulletin of the American Physical SocietyJun 3, 20140 citations

T_{c}

both system are characterized by an order parameter. Generally a mean field approximation cannot reproduce the correct behavior of the critical temperature

T_{c}

over the whole crossover; this happen instead if inclusions of quantum Gaussian fluctuations are considered. So the aim of the thesis is to study Gaussian fluctuations beyond mean field and to find the

T_{c}

over the whole crossover also in the presence of a spin-orbit coupling.