Extracting the condensate density from projection experiments with Fermi gases

A. Perali; P. Pieri; G. C. Strinati

doi:10.1103/physrevlett.95.010407

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Extracting the condensate density from projection experiments with Fermi gases

A. Perali·P. Pieri·G. C. Strinati

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Abstract

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 system in a fast (nonadiabatic) way from the BCS to the BEC sides, thus ``projecting'' the initial many-body state onto a molecular condensate. We analyze here the theoretical implications of these projection experiments, by identifying the appropriate quantum-mechanical operator associated with the measured quantities and relating them to the many-body correlations occurring in the BCS-BEC crossover. Calculations are presented over wide temperature and coupling ranges, by including pairing fluctuations on top of mean field.

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A. Perali, P. Pieri, G. C. Strinati. 2005-04-21. Extracting the condensate density from projection experiments with Fermi gases. https://doi.org/10.1103/physrevlett.95.010407

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