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Pauli Blocking of Collisions in a Quantum Degenerate Atomic Fermi Gas

B. DeMarco·S. B. Papp·D. S. Jin
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Abstract

We have produced an interacting quantum degenerate Fermi gas of atoms composed of two spin-states of magnetically trapped $^{40}$K. The relative Fermi energies are adjusted by controlling the population in each spin-state. Measurements of the thermodynamics reveal the resulting imbalance in the mean energy per particle between the two species, which is as large as a factor of 1.4 at our lowest temperature. This imbalance of energy comes from a suppression of collisions between atoms in the gas due to the Pauli exclusion principle. Through measurements of the thermal relaxation rate we have directly observed this Pauli blocking as a factor of two reduction in the effective collision cross-section in the quantum degenerate regime.

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B. DeMarco, S. B. Papp, D. S. Jin. 2001-02-07. Pauli Blocking of Collisions in a Quantum Degenerate Atomic Fermi Gas. https://doi.org/10.1103/physrevlett.86.5409

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