Thermodynamical approaches to efficient sympathetic cooling in ultracold Fermi-Bose atomic mixtures

Abstract

We discuss the cooling efficiency of ultracold Fermi-Bose mixtures in species-selective traps using a thermodynamical approach. The dynamics of evaporative cooling trajectories is analyzed in the specific case of bichromatic optical dipole traps also taking into account the effect of partial spatial overlap between the Fermi gas and the thermal component of the Bose gas. We show that large trapping frequency ratios between the Fermi and the Bose species allow for the achievement of a deeper Fermi degeneracy, consolidating in a thermodynamic setting earlier arguments based on more restrictive assumptions. In particular, we confirm that the minimum temperature of the mixture is obtained at the crossover between boson and fermion heat capacities, and that below such a temperature sympathetic cooling vanishes. When the effect of partial overlap is taken into account, optimal sympathetic cooing of the Fermi species may be achieved by properly tuning the relative trapping strength of the two species in a time-dependent fashion. Alternatively, the dimensionality of the trap in the final stage of cooling can be changed by increasing the confinement strength, which also results in a crossover of the heat capacities at deeper Fermi degeneracies. This technique may be extended to Fermi-Bose degenerate mixtures in optical lattices.

13 pages, 9 figures, higher quality figures in published version

References in corpus (64)

• Theory of Bose-Einstein condensation in trapped gases
• Realization of Bose-Einstein condensates in lower dimensions
• 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
• A quasi-pure Bose-Einstein condensate immersed in a Fermi sea
• BCS-BEC Crossover: From High Temperature Superconductors to Ultracold Superfluids
• Crossover from a molecular Bose-Einstein condensate to a degenerate Fermi gas
• Exploring phase coherence in a 2D lattice of Bose-Einstein condensates
• Exciting Collective Oscillations in a Trapped 1D Gas
• Observation of Phase Separation in a Strongly-Interacting Imbalanced Fermi Gas
• Confinement induced molecules in a 1D Fermi gas
• Heat Capacity of a Strongly-Interacting Fermi Gas
• Calculation of accurate permanent dipole moments of the lowest ${}^{1,3}{\Sigma }^{+}$ states of heteronuclear alkali dimers using extended basis sets
• Direct Observation of the Superfluid Phase Transition in Ultracold Fermi Gases
• Bose-Fermi Mixtures in a Three-dimensional Optical Lattice
• Localization of bosonic atoms by fermionic impurities in a 3d optical lattice
• Spin 1/2 Fermions in the Unitary Regime: A Superfluid of a New Type
• Quantum degenerate two-species Fermi-Fermi mixture coexisting with a Bose-Einstein condensate
• Trapped Fermi gases
• Suppression and enhancement of impurity scattering in a Bose-Einstein condensate
• Species-specific optical lattices
• Mixtures of Bosonic and Fermionic Atoms in Optical Lattices
• Fifty-fold improvement in the number of quantum degenerate fermionic atoms
• Noise Thermometry with Two Weakly Coupled Bose-Einstein Condensates
• Critical velocity for superfluid flow across the BEC-BCS crossover
• Measurement of the Entropy and Critical Temperature of a Strongly Interacting Fermi Gas
• Bose-Einstein condensation of atomic gases in a harmonic oscillator confining potential trap
• Quantum-degenerate mixture of fermionic lithium and bosonic rubidium gases
• Evaporative Cooling of a Two-Component Degenerate Fermi Gas
• Measurement of the interaction strength in a Bose-Fermi mixture with 87Rb and 40K
• Observation of deviations from ideal gas thermodynamics in a trapped Bose-Einstein condensed gas
• A Degenerate Bose-Fermi Mixture of Metastable Atoms
• Feshbach resonances in mixtures of ultracold ${}^6$Li and ${}^{87}$Rb gases
• Intermediate temperature superfluidity in an atomic Fermi gas with population imbalance
• High-Temperature Atomic Superfluidity in Lattice Boson-Fermion Mixtures
• A Primary Noise Thermometer for Ultracold Bose Gases
• Degenerate fermion gas heating by hole creation
• Bose-Einstein Condensation in Anisotropic Harmonic Traps
• Engineering Superfluidity in Bose-Fermi Mixtures of Ultracold Atoms
• Inhomogeneous atomic Bose-Fermi mixtures in cubic lattices
• Optimized production of large Bose Einstein Condensates
• Bose-Einstein Condensation, Fluctuations, and Recurrence Relations in Statistical Mechanics
• Reaching Fermi degeneracy in two-species optical dipole traps
• Sympathetic cooling of an atomic Bose-Fermi gas mixture
• Bose-Fermi mixtures in an optical lattice
• Cooling dynamics of ultracold two-species Fermi-Bose mixtures
• Superfluid and insulating phases of fermion mixtures in optical lattices
• Theory of evaporative cooling with energy-dependent elastic scattering cross section and application to metastable helium
• Understanding the superfluid phase diagram in trapped Fermi gases
• Expansion of a Fermi gas interacting with a Bose-Einstein condensate
• Ultracold Thermalization of ${}^7$Li and ${}^{87}$Rb
• Ultracold atomic Fermi-Bose mixtures in bichromatic optical dipole traps: a novel route to study fermion superfluidity
• Optimal cooling strategies for magnetically trapped atomic Fermi-Bose mixtures
• Three-Fluid Description of the Sympathetic Cooling of a Boson-Fermion Mixture
• Ideal Fermi gases in harmonic oscillator potential traps
• Formation of Ultracold Heteronuclear Dimers in Electric Fields
• Limits to Sympathetic Evaporative Cooling of a Two-Component Fermi Gas
• Sympathetic cooling route to Bose-Einstein condensate and Fermi-liquid mixtures
• Limits of sympathetic cooling of fermions: The role of the heat capacity of the coolant
• Calorimetry of Bose-Einstein condensates
• Heat capacity of a two-component superfluid Fermi gas
• Atomic dynamics in evaporative cooling of trapped alkali atoms in strong magnetic fields
• Development of an apparatus for cooling 6Li-87Rb Fermi-Bose mixtures in a light-assisted magnetic trap

Cited by in corpus (6)

• Cooling in strongly correlated optical lattices: prospects and challenges
• Cooling and thermometry of atomic Fermi gases
• Optimized sympathetic cooling of atomic mixtures via fast adiabatic strategies
• Effective microscopic models for sympathetic cooling of atomic gases
• Universal and anomalous behavior in the thermalization of strongly interacting harmonically trapped gas mixtures
• Bose-like few-fermion systems