Critical Zeeman Splitting of a Unitary Fermi Superfluid

Abstract

We determine the critical Zeeman energy splitting of a homogeneous Fermi superfluid at unitary in terms of the Fermi energy ${\epsilon }_{\text{F}}$ according to recent experimental results in 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 formulae 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: $H_{c1}=\gamma \xi {\epsilon }_{\text{F}}$ and $H_{c2}=(1+\gamma P_c{)}^{2/3}{H}_{c1}$ 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 detail information of the equation of state for the polarized normal phase. Using the experimental data from LKB-Lhomond, we have found $H_{c1}\simeq 0.37{\epsilon }_{\text{F}}$ and $H_{c2}\simeq 0.44{\epsilon }_{\text{F}}$. Our result of the polarization $P$ as a function of the Zeeman field $H/{\epsilon }_{\text{F}}$ 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.

arXiv commentVersion to appear in Physical Review B

References in corpus (43)

• Vortices and Superfluidity in a Strongly Interacting Fermi Gas
• Pairing and Phase Separation in a Polarized Fermi Gas
• Fermionic Superfluidity with Imbalanced Spin Populations and the Quantum Phase Transition to the Normal State
• Exploring the Thermodynamics of a Universal Fermi Gas
• Superfluid Fermi Gases with Large Scattering Length
• Universal Thermodynamics of Degenerate Quantum Gases in the Unitarity Limit
• Universal phase diagram of a strongly interacting Fermi gas with unbalanced spin populations
• Interior Gap Superfluidity
• The Equation of State of Neutron-Star Matter in Strong Magnetic Fields
• Phase diagram of a two-component Fermi gas with resonant interactions
• BEC-BCS crossover in "magnetized" Feshbach-resonantly paired superfluids
• Phase separation in asymmetrical fermion superfluids
• Asymmetric Two-component Fermion Systems in Strong Coupling
• Normal state of highly polarized Fermi gases: simple many-body approaches
• Normal state of a polarized Fermi gas at unitarity
• Gapless two-flavor color superconductor
• Quantum Monte Carlo Studies of Superfluid Fermi Gases
• Low-density neutron matter
• Strongly paired fermions: Cold atoms and neutron matter
• Finite temperature phase diagram of a polarised Fermi condensate
• BEC-BCS crossover, phase transitions and phase separation in polarized resonantly-paired superfluids
• Dense nuclear matter in a strong magnetic field
• Gapless Color-Flavor-Locked Quark Matter
• Epsilon expansion for a Fermi gas at infinite scattering length
• Quantum Monte Carlo Calculations of Neutron Matter
• Stability Criteria for Breached Pair Superfluidity
• Universal thermodynamics of strongly interacting Fermi gases
• Phase diagram of a cold polarized Fermi gas
• Breached pairing superfluidity: Possible realization in QCD
• Charge Neutrality Effects on 2-flavor Color Superconductivity
• Large-N expansion for unitary superfluid Fermi gases
• Thermodynamics of $n$-$p$ condensate in asymmetric nuclear matter
• Zero Temperature Thermodynamics of Asymmetric Fermi Gases at Unitarity
• Polarization Measurements and the Pairing Gap in the Universal Regime
• LOFF Pairing vs. Breached Pairing in Asymmetric Fermion Superfluids
• Phase Diagram of Cold Polarized Fermi Gas in Two Dimensions
• Spatially inhomogeneous condensate in asymmetric nuclear matter
• Finite Temperature Phase Diagram of a Two-Component Fermi Gas with Density Imbalance
• Phases of asymmetric nuclear matter with broken space symmetries
• Phase Separation and an upper bound for $\Delta$ for Fermi fluids in the Phase Separation and an upper bound for $\Delta$ for Fermi fluids in the unitary regime
• Neutron Matter: A Superfluid Gas
• Fermion Cooper Pairing with Unequal Masses: Standard Field Theory Approach
• Phase Diagram of Neutron-Proton Condensate in Asymmetric Nuclear Matter

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