BCS to Bose crossover: Broken-symmetry state

Journal Article · Sun Jun 01 04:00:00 EDT 1997 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.55.15153· OSTI ID:530169

Engelbrecht, J R ^[1]; Randeria, M ^[2]; Sa de Melo, C A ^[2]

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1. Los Alamos National Laboratory, CMS MS-K765, Los Alamos, New Mexico 87545 (United States)
2. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

A functional integral formulation, used previously to calculate T{sub c} and describe normal state properties of the BCS-Bose crossover, is extended to T{lt}T{sub c}. The saddle point approximation is shown to be qualitatively correct for T{lt}T{sub c} for {ital all} couplings, in contrast to the situation above T{sub c}. Several features of the crossover are described. The difference between the T=0 {open_quotes}pair size{close_quotes} and the (prefactor of the T dependent) Ginzburg-Landau coherence length is pointed out: the two quantities are the same only in the BCS limit. The evolution of the collective modes from the BCS to the Bose regime is discussed together with the mixing of the amplitude and phase in the absence of a particle-hole symmetry. {copyright} {ital 1997} {ital The American Physical Society}

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 530169
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 22 Vol. 55; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BCS THEORY
BOSE-EINSTEIN CONDENSATION
BOSE-EINSTEIN GAS
COHERENCE LENGTH
COLLECTIVE EXCITATIONS
COOPER PAIRS
FERMI GAS
GINZBURG-LANDAU THEORY
SUPERCONDUCTIVITY
SYMMETRY BREAKING
TEMPERATURE DEPENDENCE
TRANSITION TEMPERATURE
WAVE FUNCTIONS