Thermodynamic stability, compressibility matrix, and effects of mediated interactions in a strongly-interacting Bose-Fermi mixture

Abstract

We theoretically investigate the thermodynamic stability of a normal-state Bose-Fermi mixture, with a tunable Bose-Fermi pairing interaction $-U_{\mathrm{BF}}<0$ associated with a hetero-nuclear Feshbach resonance, as well as a weak repulsive Bose-Bose interaction $U_{\mathrm{BB}}\ge 0$. Including strong hetero-pairing fluctuations associated with the former interaction within the self-consistent $T$-matrix approximation, as well as the latter within the mean-field level, we calculate the compressibility matrix, to assess the stability of this system against density fluctuations. In the weak- and the intermediate-coupling regime with respect $-U_{\mathrm{BF}}$, we show that an effective attractive interaction between bosons mediated by density fluctuations in the Fermi component makes the system unstable below a certain temperature $T_{\mathrm{clp}}$ (leading to density collapse). When $U_{\mathrm{BB}}=0$, $T_{\mathrm{clp}}$ is always higher than the Bose-Einstein condensation (BEC) temperature $T_{\mathrm{c}}$. When $U_{\mathrm{BB}}>0$, the density collapse is suppressed, and the BEC transition becomes possible. It is also suppressed by the formation of tightly bound Bose-Fermi molecules when the hetero-pairing interaction $-U_{\mathrm{BF}}$ is strong; however, since the system may be viewed as a molecular Fermi gas in this case, the BEC transition does not also occur. Since quantum gases involving Bose atoms are known to be sensitive to inter-particle correlations, our results would be useful for the study of many-body properties of a Bose-Fermi mixture in a stable manner, without facing the unwanted density collapse.

arXiv comment30 pages, 12 figures

References in corpus (53)

• Many-Body Physics with Ultracold Gases
• Feshbach Resonances in Ultracold Gases
• Quantum Simulation
• A High Phase-Space-Density Gas of Polar Molecules
• Observation of resonance condensation of fermionic atom pairs
• Condensation of Pairs of Fermionic Atoms Near a Feshbach Resonance
• Dynamics of collapsing and exploding Bose-Einstein condensates
• Evidence for Superfluidity in a Resonantly Interacting Fermi Gas
• Collective excitations of a degenerate gas at the BEC-BCS crossover
• The BCS-BEC Crossover in a Gas of Fermi Atoms with a Feshbach Resonance
• Controlled Collapse of a Bose-Einstein Condensate
• Thermodynamics of the BCS-BEC crossover
• Observation of Heteronuclear Feshbach Resonances in a Bose-Fermi Mixture
• A Fermi Degenerate Gas of Polar Molecules
• Influence of Induced Interactions on the Superfluid Transition in Dilute Fermi Gases
• A Mixture of Bose and Fermi Superfluids
• Direct observation of growth and collapse of a Bose-Einstein condensate with attractive interactions
• The BCS-BEC crossover: From ultra-cold Fermi gases to nuclear systems
• Zero-temperature phase diagram of binary boson-fermion mixtures
• Phonon exchange in dilute Fermi-Bose mixtures: tailoring the Fermi-Fermi interaction
• Exciton-polariton mediated superconductivity
• On the correct strong-coupling limit in the evolution from BCS superconductivity to Bose-Einstein condensation
• Tuning of heteronuclear interactions in a quantum-degenerate Fermi-Bose mixture
• Interaction-driven Dynamics of 40K / 87Rb Fermi-Bose Gas Mixtures in the Large Particle Number Limit
• Fermion-Mediated Interactions Between Bosonic Atoms
• Superconductivity and other phase transitions in a hybrid Bose-Fermi mixture formed by a polariton condensate and an electron system in two dimensions
• Quantum degenerate Bose-Fermi mixture of chemically different atomic species with widely tunable interactions
• Control of the interaction in a Fermi-Bose mixture
• Structure and stability of trapped atomic boson-fermion mixtures
• Cooling and thermometry of atomic Fermi gases
• p-wave Cooper Pairing of Fermions in Mixtures of Dilute Fermi and Bose Gases
• Mean-field analysis of the stability of a K-Rb Fermi-Bose mixture
• Observation of a Degenerate Fermi Gas Trapped by a Bose-Einstein Condensate
• Probing the Interface of a Phase-Separated State in a Repulsive Bose-Fermi Mixture
• Simulating dense QCD matter with ultracold atomic boson-fermion mixtures
• Observation of spin-spin fermion-mediated interactions between ultracold bosons
• Induced $p$-wave pairing in Bose-Fermi mixtures
• Induced instability for boson-fermion mixed condensate of Alkali atoms due to attractive boson-fermion interaction
• Topological superfluid in a Fermi-Bose mixture with a high critical temperature
• Pairing and condensation in a resonant Bose-Fermi mixture
• Fermi gas throughout the BCS-BEC crossover: Comparative study of t-matrix approaches with various degrees of self-consistency
• Stability Condition of a Strongly Interacting Boson-Fermion Mixture across an Inter-Species Feshbach Resonance
• Bose-Fermi Pair Correlations in Attractively Interacting Bose-Fermi Atomic Mixtures
• Rotons in a hybrid Bose-Fermi system
• Boson-Fermion pairing in a Boson-Fermion environment
• Induced interactions in dilute atomic gases and liquid helium mixtures
• Observation of Weak Collapse in a Bose-Einstein Condensate
• From superconducting fluctuations to the bosonic limit in the response functions above the critical temperature
• Bose-Fermi mixtures in the molecular limit
• Shear viscosity and Strong-Coupling Corrections in the BCS-BEC crossover Regime of an Ultracold Fermi Gas
• Single-Particle properties of a strongly-interacting Bose-Fermi mixture with mass and population imbalance
• Single-particle Excitations and Effects of Hetero-pairing Fluctuations in a Bose-Fermi Mixture with a Feshbach Resonance
• Bose-Einstein condensation and density collapse in a weakly coupled boson-fermion mixture

Cited by in corpus (6)

• Strongly interacting Bose-Fermi mixture: mediated interaction, phase diagram and sound propagation
• Probing Goldstino excitation through the tunneling transport in a Bose-Fermi mixture with explicitly broken supersymmetry
• Mediated Interactions and Damping Effects in Superfluid Mixtures of Bose and Fermi Gases
• Isothermal compressibility and effects of multi-body molecular interactions in a strongly interacting ultracold Fermi gas
• Non-equilibrium dynamics and atom-pair coherence in strongly interacting Bose-Fermi mixtures
• Mechanical stability of resonant Bose-Fermi mixtures