Critical Zeeman splitting of a unitary Fermi superfluid

Article

关键词: PHASE-SEPARATION;    CRITICAL FIELD;    SUPERCONDUCTIVITY;    THERMODYNAMICS;    CONDENSATION;    TEMPERATURE;    CROSSOVER;    EQUATION;    DIAGRAM;    MATTER;   

DOI  :  10.1103/PhysRevB.83.174504

来源: SCIE

【 摘 要 】

We determine the critical Zeeman energy splitting of a homogeneous Fermi superfluid at unitary in terms of the Fermi energy epsilon(F) according to recent experimental results in Laboratoire Kastler Brossel ( LKB)-Lhomond. Based on the universal equations of state for the superfluid and normal phases, we show that there exist two critical fields H-c1 and H-c2, between which a superfluid-normal mixed phase is energetically favored. Universal formulas for the critical fields and the critical population imbalance P-c are derived. We have found a universal relation between the critical fields and the critical imbalances: H-c1 = gamma xi epsilon(F) and H-c2 = ( 1 + gamma P-c)H-2/3(c1), where xi is the universal constant and gamma is the critical value of the chemical potential imbalance in the grand canonical ensemble. Since xi, gamma, and P-c have been measured in the experiments, we can determine the critical Zeeman fields without the detailed information of the equation of state for the polarized normal phase. Using the experimental data from LKB-Lhomond, we have found H-c1 similar or equal to 0.37 epsilon(F) and H-c2 similar or equal to 0.44 epsilon(F). Our result of the polarization P as a function of the Zeeman field H/epsilon(F) is in good agreement with the data extracted from the experiments. We also give an estimation of the critical magnetic field for dilute neutron matter at which the matter gets spin polarized, assuming the properties of the dilute neutron matter are close to those of the unitary Fermi gas.

【 授权许可】

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