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Normal state of a polarized Fermi gas at unitarity

C. Lobo·A. Recati·S. Giorgini·S. Stringari
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Abstract

We study the Fermi gas at unitarity and at T=0 by assuming that, at high polarizations, it is a normal Fermi liquid composed of weakly interacting quasiparticles associated with the minority spin atoms. With a quantum Monte Carlo approach we calculate their effective mass and binding energy, as well as the full equation of state of the normal phase as a function of the concentration x=n_\down/n_\up of minority atoms. We predict a first order phase transition from normal to superfluid at x_c=0.44 corresponding, in the presence of harmonic trapping, to a critical polarization P_c=(N_\up-N_\down)/ (N_\up+N_\down)=77%. We calculate the radii and the density profiles in the trap and predict that the frequency of the spin dipole mode will be increased by a factor of 1.23 due to interactions.

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C. Lobo, A. Recati, S. Giorgini, S. Stringari. 2006-07-27. Normal state of a polarized Fermi gas at unitarity. https://doi.org/10.1103/physrevlett.97.200403

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