Thermodynamic Measurements in a Strongly Interacting Fermi Gas

Abstract

We conduct a series of measurements on the thermodynamic properties of an optically-trapped strongly interacting Fermi gas, including the energy $E$, entropy $S$, and sound velocity $c$. Our model-independent measurements of $E$ and $S$ enable a precision study of the finite temperature thermodynamics. The $E(S)$ data are directly compared to several recent predictions. The temperature in both the superfluid and normal fluid regime is obtained from the fundamental thermodynamic relation $T=\partial E/\partial S$ by parameterizing the $E(S)$ data. Our $E(S)$ data are also used to experimentally calibrate the endpoint temperatures obtained for adiabatic sweeps of the magnetic field between the ideal and strongly interacting regimes. This enables the first experimental calibration of the temperature scale used in experiments on fermionic pair condensation. Our calibration shows that the ideal gas temperature measured for the onset of pair condensation corresponds closely to the critical temperature estimated in the strongly interacting regime from the fits to our $E(S)$ data. The results are in very good agreement with recent predictions. Finally, using universal thermodynamic relations, we estimate the chemical potential and heat capacity of the trapped gas from the $E(S)$ data.

29 pages, 12 figures. To appear in JLTP online, and in the January, 2009 volume

References in corpus (49)

• Observation of resonance condensation of fermionic atom pairs
• Condensation of Pairs of Fermionic Atoms Near a Feshbach Resonance
• Observation of a Strongly-Interacting Degenerate Fermi Gas of Atoms
• Vortices and Superfluidity in a Strongly Interacting Fermi Gas
• Pairing and Phase Separation in a Polarized Fermi Gas
• Observation of Bose-Einstein Condensation of Molecules
• Fermionic Superfluidity with Imbalanced Spin Populations and the Quantum Phase Transition to the Normal State
• Observation of the Pairing Gap in a Strongly Interacting Fermi Gas
• Evidence for Superfluidity in a Resonantly Interacting Fermi Gas
• Collective excitations of a degenerate gas at the BEC-BCS crossover
• Superfluid Fermi Gases with Large Scattering Length
• Using photoemission spectroscopy to probe a strongly interacting Fermi gas
• Equation of state of a Fermi gas in the BEC-BCS crossover: a quantum Monte Carlo study
• Universal Thermodynamics of Degenerate Quantum Gases in the Unitarity Limit
• Molecular Probe of Pairing in the BEC-BCS Crossover
• Heat Capacity of a Strongly-Interacting Fermi Gas
• Thermodynamics of the BCS-BEC crossover
• Measurement of interaction energy near a Feshbach resonance in a 6Li Fermi gas
• Direct Observation of the Superfluid Phase Transition in Ultracold Fermi Gases
• Fermi systems with long scattering lengths
• Precise determination of ${}^6$Li cold collision parameters by radio-frequency spectroscopy on weakly bound molecules
• Spin 1/2 Fermions in the Unitary Regime: A Superfluid of a New Type
• Precision Measurements of Collective Oscillations in the BEC-BCS Crossover
• The unitary gas in an isotropic harmonic trap: symmetry properties and applications
• Quantum Monte Carlo Studies of Superfluid Fermi Gases
• BCS-BEC crossover at finite temperature for superfluid trapped Fermi atoms
• Virial Theorem and Universality in a Unitary Fermi Gas
• The potential energy of a ${}^{40}$K Fermi gas in the BCS-BEC crossover
• Measurement of the Entropy and Critical Temperature of a Strongly Interacting Fermi Gas
• Elastic and inelastic collisions of 6Li in magnetic and optical traps
• Universal thermodynamics of strongly interacting Fermi gases
• Vanishing bulk viscosities and conformal invariance of unitary Fermi gas
• Pairing gap and in-gap excitations in trapped fermionic superfluids
• Mechanical Stability of a Strongly-Interacting Fermi Gas of Atoms
• Determination of the Fermion Pair Size in a Resonantly Interacting Superfluid
• Viscous relaxation and collective oscillations in a trapped Fermi gas near the unitarity limit
• Critical Temperature Curve in the BEC-BCS Crossover
• Finite-Temperature Collective Dynamics of a Fermi Gas in the BEC-BCS Crossover
• Polarization Measurements and the Pairing Gap in the Universal Regime
• Virial theorems for trapped cold atoms
• Thermodynamics of a Trapped Unitary Fermi Gas
• Thermodynamics of Interacting Fermions in Atomic Traps
• Comparative study of strong coupling theories of a trapped Fermi gas at unitarity
• Thermodynamics of a trapped unitary Fermi gas
• The quark-gluon plasma at RHIC
• Observation of a quenched moment of inertia in a rotating strongly interacting Fermi gas
• Superfluid Expansion of a Strongly Interacting Fermi Gas
• Understanding the superfluid phase diagram in trapped Fermi gases
• A simple mean field equation for condensates in the BEC-BCS crossover regime

Cited by in corpus (87)

• Revealing the Superfluid Lambda Transition in the Universal Thermodynamics of a Unitary Fermi Gas
• Skyrme Interaction and Nuclear Matter Constraints
• Exploring the Thermodynamics of a Universal Fermi Gas
• Relativistic Mean-Field Hadronic Models under Nuclear Matter Constraints
• Universal Quantum Viscosity in a Unitary Fermi Gas
• The BCS-BEC crossover: From ultra-cold Fermi gases to nuclear systems
• From dia- to paramagnetic orbital susceptibility of Dirac cones
• Strongly Correlated Quantum Fluids: Ultracold Quantum Gases, Quantum Chromodynamic Plasmas, and Holographic Duality
• General relations for quantum gases in two and three dimensions. Two-component fermions
• Viscosity and scale invariance in the unitary Fermi gas
• Cooling in strongly correlated optical lattices: prospects and challenges
• Two-terminal transport measurements with cold atoms
• Auxiliary Field quantum Monte Carlo for Strongly Paired Fermions
• Measurement of the Homogeneous Contact of a Unitary Fermi gas
• Resonantly Interacting Fermions In a Box
• An upper bound on transport
• Observation of shock waves in a strongly interacting Fermi gas
• Collisional Stability of 40K Immersed in a Strongly Interacting Fermi Gas of 6Li
• Exact Numerical Results on the Ground State of Strongly Interacting Fermi Gases in Two Dimensions
• Time-Dependent Density Functional Theory and the Real-Time Dynamics of Fermi Superfluids
• Thermodynamics of balanced and slightly spin-imbalanced Fermi gases at unitarity
• Quantum Monte Carlo approaches to nuclear and atomic physics
• Realization of a Resonant Fermi Gas with a Large Effective Range
• Achieving the Landau bound to precision of quantum thermometry in systems with vanishing gap
• Shear viscosity of a universal Fermi gas near the superfluid phase transition
• Electromagnetic properties of viscous charged fluids
• Heavy-Light Fermion Mixtures at Unitarity
• Universal contact of strongly interacting fermions at finite temperatures
• Lattice methods for strongly interacting many-body systems
• Lattice Monte Carlo calculations for unitary fermions in a finite box
• Pseudogaps in strongly interacting Fermi gases
• Anomalous minimum in the shear viscosity of a Fermi gas
• Short-range correlations and entropy in ultracold atomic Fermi gases
• Universal thermodynamics of a strongly interacting Fermi gas: theory versus experiment
• Hydrodynamic fluctuations and the minimum shear viscosity of the dilute Fermi gas at unitarity
• Hydrodynamics of cold atomic gases in the limit of weak nonlinearity, dispersion and dissipation
• Searching for Perfect Fluids: Quantum Viscosity in a Universal Fermi Gas
• Perfect Fluids and Bad Metals: Transport Analogies Between Ultracold Fermi Gases and High $T_c$ Superconductors
• Measuring the Hydrodynamic Linear Response of a Unitary Fermi Gas
• The contact in the unitary Fermi gas across the superfluid phase transition
• Inelastic Collisions of a Fermi Gas in the BEC-BCS Crossover
• Metastability in Spin-Polarized Fermi Gases
• Dissipative fluid dynamics for the dilute Fermi gas at unitarity: Free expansion and rotation
• Scaling Flows and Dissipation in the Dilute Fermi Gas at Unitarity
• Localization of a Bose-Fermi mixture in a bichromatic optical lattice
• Precision benchmark calculations for four particles at unitarity
• Rashba spin-orbit coupling, strong interactions, and the BCS-BEC crossover in the ground state of the two-dimensional Fermi Gas
• Specific heat and effects of pairing fluctuations in the BCS-BEC crossover regime of an ultracold Fermi gas
• Is an Ultra-Cold Strongly Interacting Fermi Gas a Perfect Fluid?
• Scaling solutions of the two fluid hydrodynamic equations in a harmonically trapped gas at unitarity
• Critical Behaviour in Trapped Strongly Interacting Fermi Gases
• Effective-range dependence of resonant Fermi gases
• BCS-BEC crossover in a trapped Fermi super-fluid using a density-functional equation
• Some Early Ideas on the Metric Geometry of Thermodynamics
• Viscosity-entropy ratio of the unitary Fermi gas from zero-temperature elementary excitations
• Parametric cooling of a degenerate Fermi gas in an optical trap
• Phase separation in low-density neutron matter
• Superfluid Condensate Fraction and Pairing Wave Function of the Unitary Fermi Gas
• Unitarity potentials and neutron matter at the unitary limit
• The finite-temperature thermodynamics of a trapped unitary Fermi gas within fractional exclusion statistics
• Theory of strongly paired fermions with arbitrary short-range interactions
• Shear viscosity and Strong-Coupling Corrections in the BCS-BEC crossover Regime of an Ultracold Fermi Gas
• Machine-learning approach to finite-size effects in systems with strongly interacting fermions
• Generalized Crossover in Interacting Fermions within the Low-Energy Expansion
• Spin-polarized low-density neutron matter
• Excess energy of an ultracold Fermi gas in a trapped geometry
• Zero density limit extrapolation of the superfluid transition temperature in a unitary atomic Fermi gas on a lattice
• Unitary thermodynamics from thermodynamic geometry
• Adiabatic sound velocity and compressibility of a trapped d-dimensional ideal anyon gas
• Mean-field vs RPA calculation of the energy of an impurity immersed in a spin 1/2 superfluid
• Viscosity Bound Violation in Viscoelastic Fermi Liquids
• Quantum Many-Body Calculations using Body-Centered Cubic Lattices
• Toward large-scale Hybrid Monte Carlo simulations of the Hubbard model on graphics processing units
• Dipolar Bose-Einstein condensate for large scattering length
• Energy fluctuation and discontinuity of specific heat
• Unitary thermodynamics from thermodynamic geometry II: Fit to a local density approximation
• Isothermal compressibility and effects of multi-body molecular interactions in a strongly interacting ultracold Fermi gas
• Unitary Fermi superfluid near the critical temperature: thermodynamics and sound modes from elementary excitations
• A Composite Fermion Approach to the Ultracold Dilute Fermi Gas
• Unitary limit and linear scaling of neutrons in harmonic trap with tuned CD-Bonn and square-well interactions
• Bose-like few-fermion systems
• Thermodynamic Properties of Universal Fermi Gases
• Strong Coupling Effects on the Specific Heat of an Ultracold Fermi Gas in the Unitarity Limit
• An Effective Series Expansion to the Equation of State of Unitary Fermi Gases
• A proof to Biswas-Mitra-Bhattacharyya conjecture for ideal quantum gas trapped under generic power law potential $U={\sum }_{i=1}^d{c}_i|\frac{x_i}{a_i}{|}^{n_i}$ in $d$ dimension
• Strong coupling effects on specific heat in the BCS-BEC crossover
• Characterizing Real-space Topology in Rice-Mele Model by Thermodynamics