Quantum Monte Carlo Simulations of the BCS-BEC Crossover at Finite Temperature
arXiv:0803.3238 · doi:10.1103/PhysRevA.78.023625
Abstract
The Quantum Monte Carlo method for spin 1/2 fermions at finite temperature is formulated for dilute systems with an s-wave interaction. The motivation and the formalism are discussed along with descriptions of the algorithm and various numerical issues. We report on results for the energy, entropy and chemical potential as a function of temperature. We give upper bounds on the critical temperature T_c for the onset of superfluidity, obtained by studying the finite size scaling of the condensate fraction. All of these quantities were computed for couplings around the unitary regime in the range -0.5 \le (k_F a)^{-1} \le 0.2, where a is the s-wave scattering length and k_F is the Fermi momentum of a non-interacting gas at the same density. In all cases our data is consistent with normal Fermi gas behavior above a characteristic temperature T_0 > T_c, which depends on the coupling and is obtained by studying the deviation of the caloric curve from that of a free Fermi gas. For T_c < T < T_0 we find deviations from normal Fermi gas behavior that can be attributed to pairing effects. Low temperature results for the energy and the pairing gap are shown and compared with Green Function Monte Carlo results by other groups.
24 pages, 20 figures, published version, additional material and figures
References in corpus (13)
- Vortices and Superfluidity in a Strongly Interacting Fermi Gas
- Observation of Bose-Einstein Condensation of Molecules
- Observation of the Pairing Gap in a Strongly Interacting Fermi Gas
- Crossover from a molecular Bose-Einstein condensate to a degenerate Fermi gas
- Collective excitations of a degenerate gas at the BEC-BCS crossover
- Pure Gas of Optically Trapped Molecules Created from Fermionic Atoms
- Normal state of a polarized Fermi gas at unitarity
- Critical Temperature and Thermodynamics of Attractive Fermions at Unitarity
- Strongly paired fermions: Cold atoms and neutron matter
- Measurement of the Entropy and Critical Temperature of a Strongly Interacting Fermi Gas
- Local Density Functional Theory for Superfluid Fermionic Systems: The Unitary Gas
- Thermodynamics of a Trapped Unitary Fermi Gas
- Spin 1/2 Fermions in the Unitary Regime at Finite Temperature
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- The Equation of State of a Low-Temperature Fermi Gas with Tunable Interactions
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- A Unitary Fermi Supersolid: The Larkin-Ovchinnikov Phase
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- Higgs mode in a strongly interacting fermionic superfluid
- Momentum Distribution and Contact of the Unitary Fermi gas
- Thermodynamics of balanced and slightly spin-imbalanced Fermi gases at unitarity
- Particle-hole fluctuations in the BCS-BEC Crossover
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- Ultracold atoms and the Functional Renormalization Group
- Excitation Spectrum and Superfluid Gap of an Ultracold Fermi Gas
- Cooper pairing above the critical temperature in a unitary Fermi gas
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- Shear Viscosity of a Unitary Fermi Gas
- Phase structure of spin-imbalanced unitary Fermi gases
- Perturbative quantum Monte Carlo method for nuclear physics
- Universality in one-dimensional fermions at finite temperature: Density, pressure, compressibility, and contact
- Shock waves in strongly interacting Fermi gas from time-dependent density functional calculations
- Nuclear Reactions from Lattice QCD
- Hyperbolic Bloch equations: atom-cluster kinetics of an interacting Bose gas
- Low-temperature thermodynamics of the unitary Fermi gas: superfluid fraction, first sound and second sound
- Cold Atom Quantum Simulator for Dilute Neutron Matter
- Precision benchmark calculations for four particles at unitarity
- Comparative study of the finite-temperature thermodynamics of a unitary Fermi gas
- Improved lattice operators for non-relativistic fermions
- Static response, collective frequencies and ground state thermodynamical properties of spin saturated two-component cold atoms and neutron matter
- Excitation picture of an interacting Bose gas
- The finite-temperature thermodynamics of a trapped unitary Fermi gas within fractional exclusion statistics
- Finite range and upper branch effects on itinerant ferromagnetism in repulsive Fermi gases: Bethe-Goldstone ladder resummation approach
- Interaction energy and itinerant ferromagnetism in a strongly interacting Fermi gas in the absence of molecule formation
- Dynamical properties of the unitary Fermi gas: collective modes and shock waves
- Sensitivity to the initial conditions of the Time-Dependent Density Functional Theory
- Perturbative quantum Monte Carlo calculation with high-fidelity nuclear forces
- Exact renormalisation group flow for ultracold Fermi gases in unitary limit
- Virial coefficients for Bose and Fermi trapped gases beyond the unitary limit: an S-Matrix approach
- Quantum Many-Body Calculations using Body-Centered Cubic Lattices
- Three-body contact for fermions. I. General relations
- Infinite Variance in Monte Carlo Sampling of Lattice Field Theories
- Path Integral Monte Carlo study of particles obeying quantum mechanics and classical statistics
- Quantum Monte Carlo method applied to strongly correlated dilute fermi gases with finite effective range
- Detecting the phase transition in a strongly-interacting Fermi gas by unsupervised machine learning
- A Composite Fermion Approach to the Ultracold Dilute Fermi Gas
- Unitary Fermi superfluid near the critical temperature: thermodynamics and sound modes from elementary excitations
- Spin-dipole mode in a trapped Fermi gas near unitarity
- Hartree shift and pairing gap in ultracold Fermi gases in the framework of low-momentum interactions
- Lattice calculation for unitary fermions in a finite box
- Local energy density functional for superfluid Fermi gases from effective field theory
- Fluctuation-induced first-order superfluid transition in unitary Fermi gases
- Density of states for the Unitary Fermi gas and the Schwarzschild black hole
- Temporal fluctuation induced order in conventional superconductors
- Hole-induced anomaly in the thermodynamic behavior of a one-dimensional Bose gas