The equation of state of a low-temperature Fermi gas with tunable interactions.
Interacting fermions are ubiquitous in nature, and understanding their thermodynamics is an important problem. We measured the equation of state of a two-component ultracold Fermi gas for a wide range of interaction strengths at low temperature. A detailed comparison with theories including Monte-Carlo calculations and the Lee-Huang-Yang corrections for low-density bosonic and fermionic superfluids is presented. The low-temperature phase diagram of the spin-imbalanced gas reveals Fermi liquid behavior of the partially polarized normal phase for all but the weakest interactions. Our results provide a benchmark for many-body theories and are relevant to other fermionic systems such as the crust of neutron stars.
Navon
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Laboratoire Kastler Brossel, CNRS, Université Pierre et Marie Curie, Ecole Normale Supérieure, 24 rue Lhomond, 75231 Paris, France. navon@ens.fr
Nascimbène
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Chevy
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Salomon
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