The potential energy of a ${}^{40}$K Fermi gas in the BCS-BEC crossover

Abstract

We present a measurement of the potential energy of an ultracold trapped gas of ${}^{40}$K atoms in the BCS-BEC crossover and investigate the temperature dependence of this energy at a wide Feshbach resonance, where the gas is in the unitarity limit. In particular, we study the ratio of the potential energy in the region of the unitarity limit to that of a non-interacting gas, and in the T=0 limit we extract the universal many-body parameter $\beta$. We find $\beta =-0.54_{-0.12}^{+0.05}$; this value is consistent with previous measurements using ${}^6$Li atoms and also with recent theory and Monte Carlo calculations. This result demonstrates the universality of ultracold Fermi gases in the strongly interacting regime.

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• Observation of pseudogap behavior in a strongly interacting Fermi gas
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• Ultra-cold Polarized Fermi Gases
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• Tomographic RF Spectroscopy of a Trapped Fermi Gas at Unitarity
• Measurement of the Entropy and Critical Temperature of a Strongly Interacting Fermi Gas
• Thermodynamic Measurements in a Strongly Interacting Fermi Gas
• Large-N expansion for unitary superfluid Fermi gases
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• Finite-Temperature Collective Dynamics of a Fermi Gas in the BEC-BCS Crossover
• Energetics and Structural Properties of Trapped Two-Component Fermi Gases
• Unitary Fermi Gas in a Harmonic Trap
• Virial theorems for trapped cold atoms
• Nonlinear Schrödinger equation for a superfluid Fermi gas from BCS to Bose crossover
• Thermodynamics of balanced and slightly spin-imbalanced Fermi gases at unitarity
• Thermodynamics of a Trapped Unitary Fermi Gas
• The ground state energy at unitarity
• Universal contact of strongly interacting fermions at finite temperatures
• Determination of the Equation of State of a Two-Component Fermi Gas at Unitarity
• Comparative study of strong coupling theories of a trapped Fermi gas at unitarity
• Spin diffusion in Fermi gases
• Imbalanced Superfluid Phase of a Trapped Fermi Gas in the BCS-BEC Crossover Regime
• Polarized superfluidity in the attractive Hubbard model with population imbalance
• Dilute neutron matter on the lattice at next-to-leading order in chiral effective field theory
• Three fermions in a box at the unitary limit: universality in a lattice model
• Molecular Bose-Einstein condensation in a versatile low power crossed dipole trap
• Precision benchmark calculations for four particles at unitarity
• Shell-Model Monte Carlo Simulations of BCS-BEC Crossover in Few-Fermion Systems
• Quantum rearrangement and self-consistent BCS-BEC crossover thermodynamics
• Ground-state energy of the unitary Fermi gas from the epsilon expansion
• Comparative study of the finite-temperature thermodynamics of a unitary Fermi gas
• Reentrant BCS-BEC crossover and a superfluid-insulator transition in optical lattices
• BEC-BCS crossover of a trapped Fermi gas without using the local density approximation
• Universal behavior of a trapped Fermi superfluid in the BCS-unitarity crossover
• Superfluid Condensate Fraction and Pairing Wave Function of the Unitary Fermi Gas
• Low-momentum ring diagrams of neutron matter at and near the unitary limit
• The virial equation of state for unitary fermion thermodynamics with non-Gaussian correlations
• In Situ Momentum Distribution Measurement of a Quantum Degenerate Fermi Gas using Raman Spectroscopy
• Quantum Many-Body Calculations using Body-Centered Cubic Lattices
• Many-body theories of density response for a strongly correlated Fermi gas
• Bose-like few-fermion systems
• An Effective Series Expansion to the Equation of State of Unitary Fermi Gases