Photoemission spectrum and effect of inhomogeneous pairing fluctuations in the BCS-BEC crossover regime of an ultracold Fermi gas
- Department of Physics, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)
We investigate the photoemission-type spectrum in a cold Fermi gas which was recently measured by the JILA group [Stewart et al., Nature (London) 454, 744 (2008)]. This quantity gives us very useful information about single-particle properties in the BCS-BEC crossover. In this paper, including pairing fluctuations within a T-matrix theory, as well as effects of a harmonic trap within the local density approximation, we show that spatially inhomogeneous pairing fluctuations due to the trap potential are an important key to understanding the observed spectrum. In the crossover region, while strong pairing fluctuations lead to the so-called pseudogap phenomenon in the trap center, such strong-coupling effects are found to be weak around the edge of the gas. Our results including this effect are shown to agree well with the recent photoemission data of the JILA group.
- OSTI ID:
- 21456964
- Journal Information:
- Physical Review. A, Vol. 82, Issue 3; Other Information: DOI: 10.1103/PhysRevA.82.033629; (c) 2010 The American Physical Society; ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
74 ATOMIC AND MOLECULAR PHYSICS
APPROXIMATIONS
ATOMS
BCS THEORY
BOSE-EINSTEIN CONDENSATION
COUPLING
DENSITY
EMISSION SPECTRA
ENERGY GAP
FERMI GAS
FLUCTUATIONS
PHOTOEMISSION
POTENTIALS
S MATRIX
TRAPS
CALCULATION METHODS
EMISSION
MATRICES
PHYSICAL PROPERTIES
SECONDARY EMISSION
SPECTRA
VARIATIONS