BCS BEC crossover: From high temperature superconductors to ultracold superfluids

By Qijin Chen, J. Stajic, Shina Tan, K. Levin. 2004

580 citations recorded by the source corpus.

Abstract We review the BCS to Bose–Einstein condensation (BEC) crossover scenario which is based on the well known crossover generalization of the BCS ground state wavefunction Ψ 0 . While this ground state has been summarized extensively in the literature, this Review is devoted to less widely discussed issues: understanding the effects of finite temperature, primarily below T c , in a manner consistent with Ψ 0 . Our emphasis is on the intersection of two important problems: high T c superconductivity and superfluidity in ultracold fermionic atomic gases. We address the “pseudogap state” in the copper oxide superconductors from the vantage point of a BCS–BEC crossover scenario, although there is no consensus on the applicability of this scheme to high T c . We argue that it also provides a useful basis for studying atomic gases near the unitary scattering regime; they are most likely in the counterpart pseudogap phase. That is, superconductivity takes place out of a non-Fermi liquid state where preformed, metastable fermion pairs are present at the onset of their Bose condensation. As a microscopic basis for this work, we summarize a variety of T-matrix approaches, and assess their theoretical consistency. A close connection with conventional superconducting fluctuation theories is emphasized and exploited.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics, Electronic, Optical and Magnetic Materials

View Paper: https://www.semanticscholar.org/paper/18e339b9fcafa9ef932582e064af8ab09d6bd013

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Citations in the corpus

Strongly correlated quantum fluids: ultracold quantum gases, quantum chromodynamic plasmas and holographic duality (2012, background): “The upper curve on the figure depicts the pair formation temperature Tpair, which in general is distinct from the critical temperature for superfluidity, Tc [35].”
The phase diagram of dense QCD (2010, background): “the high-temperature superconductivity and in the BEC regime of ultracold fermionic atoms [44].”
The BCS–BEC crossover: From ultra-cold Fermi gases to nuclear systems (2018, background): “(56) is replaced by a full G [156, 157, 158, 54]; (ii) The extended t-matrix approximation (ETMA), where the propagator G0 closing the loop in Σ [cf.”
Feshbach resonances in ultracold gases (2008, background): “This BEC-BCS crossover has attracted considerable attention in many-body quantum physics for more than two decades, and has recently reviewed in (Chen et al., 2005; Giorgini et al., 2008; Inguscio et al., 2008).”
Evolution of cosmological perturbations in Bose–Einstein condensate dark matter (2011, methodology): “…of laser and evaporative cooling techniques, opening several new lines of research, at the border of atomic, statistical and condensed matter physics (Dalfovo et al. 1999; Cornell & Wieman 2002; Ketterle 2002; Pitaevskii & Stringari 2003; Duine & Stoof 2004; Chen et al. 2005; Pethick & Smith 2008).”
Theory of ultracold atomic Fermi gases (2007, methodology): “…original treatment by Nozières and Schmitt-Rink (1985) to the brokensymmetry phase below Tc (Pieri, Pisani and Strinati, 2004) as well as to improve on it by including higher order diagrams (Haussmann, 1993 and 1994; Chen et al., 2005; Combescot, Leyronas and Kagan, 2006; Haussmann et al., 2006).”
Comparing and contrasting nuclei and cold atomic gases (2013, background): “(20) provide gap, ∆, and chemical potential, µ (Eagles 1969, Leggett 1980, Engelbrecht et al. 1997, Papenbrock & Bertsch 1999, Chen et al. 2005a).”