Fermion-Mediated Interactions Between Bosons in a Quantum Degenerate $^{133}$ Cs- $^6$ Li Bose-Fermi MixtureFermion-Mediated Interactions Between Bosons in a Quantum Degenerate $^{133}$Cs-$^6$Li Bose-Fermi Mixture

Geyue Cai, Krutik Patel, B. J. DeSalvo +1 more

Bulletin of the American Physical SocietyMay 29, 20190 citations

Luttinger's theorem and Phase Transitions in Bose-Fermi mixtures

Stephen Powell, Subir Sachdev A, Hans Peter Büchler

Bulletin of the American Physical SocietyMar 15, 20060 citations

Mediated interactions in mixtures of ultracold atoms

Ando, Henry, Geyue Cai, Cheng Chin +1 more

We describe recent theoretical and experimental developments on mediated interactions in mixtures of bosonic and fermionic atoms. We discuss how particle-hole excitations of a Fermi sea can induce long-range interactions between heavy impurities or atoms in a Bose-Einstein condensate. Conversely, phonon excitations of a Bose-Einstein condensate induce interactions between fermionic atoms. These mediated interactions exhibit different short-range and long-range scaling regimes with distance and, if strong enough, can induce fermion superfluidity. We discuss the prospects for observing new phenomena that could arise from mediated interactions. Experimentally, we outline recent studies of the 133Cs-6Li Bose-Fermi mixture, a platform well-suited for investigating fermion-mediated interactions. A Cs Bose-Einstein condensate immersed in a degenerate Li Fermi gas is prepared with tunable interspecies interactions. In the weak-coupling regime, precision measurements of condensate properties reveal fermion-mediated attractions between bosons, matching theoretical predictions. In the strong-coupling regime, we observe suppression and revival of sound modes and novel many-body resonances. Altogether, we aim to highlight both instances where experiment and theory agree well, and promising prospects to engineer long-range interactions in atomic quantum gases.We describe recent theoretical and experimental developments on mediated interactions in mixtures of bosonic and fermionic atoms. We discuss how particle-hole excitations of a Fermi sea can induce long-range interactions between heavy impurities or atoms in a Bose-Einstein condensate. Conversely, phonon excitations of a Bose-Einstein condensate induce interactions between fermionic atoms. These mediated interactions exhibit different short-range and long-range scaling regimes with distance and, if strong enough, can induce fermion superfluidity. We discuss the prospects for observing new phenomena that could arise from mediated interactions. Experimentally, we outline recent studies of the 133Cs-6Li Bose-Fermi mixture, a platform well-suited for investigating fermion-mediated interactions. A Cs Bose-Einstein condensate immersed in a degenerate Li Fermi gas is prepared with tunable interspecies interactions. In the weak-coupling regime, precision measurements of condensate properties reveal fermion-mediated attractions between bosons, matching theoretical predictions. In the strong-coupling regime, we observe suppression and revival of sound modes and novel many-body resonances. Altogether, we aim to highlight both instances where experiment and theory agree well, and promising prospects to engineer long-range interactions in atomic quantum gases.

arXiv:2511.09745Nov 12, 20250 citations

All-optical production of dual Bose–Einstein condensates of paired fermions and bosons with 6 Li and 7 Li

Takuya Ikemachi, Aki Ito, Yukihito Aratake +4 more

Abstract We report the first all-optical production of dual Bose–Einstein condensates (BECs) of paired 6 Li (fermion) and one spin state of 7 Li (boson) at the magnetic field where the s -wave interactions between fermions are resonant. Fermions are cooled efficiently by evaporative cooling and they serve as coolant for bosons. As a result, the dual condensates can be achieved by using a simple experimental apparatus and procedures, as in the case of the all-optical production of a single BEC. We show that the all-optical method enables us to realize variety of ultracold Bose–Fermi mixtures.Abstract We report the first all-optical production of dual Bose–Einstein condensates (BECs) of paired 6 Li (fermion) and one spin state of 7 Li (boson) at the magnetic field where the s -wave interactions between fermions are resonant. Fermions are cooled efficiently by evaporative cooling and they serve as coolant for bosons. As a result, the dual condensates can be achieved by using a simple experimental apparatus and procedures, as in the case of the all-optical production of a single BEC. We show that the all-optical method enables us to realize variety of ultracold Bose–Fermi mixtures.

arXiv:1606.09404Journal of Physics B Atomic Molecular and Optical PhysicsDec 15, 201623 citations

Stability of fermionic molecules in a Bose-Fermi mixture

Daniele C. E. Bortolotti, А. V. Avdeenkov, John L. Bohn

Bulletin of the American Physical SocietyMay 17, 20060 citations

Observation of a Degenerate Fermi Gas Trapped by a Bose-Einstein Condensate

B. J. DeSalvo, Krutik Patel, Jacob Johansen +1 more

We report on the formation of a stable quantum degenerate mixture of fermionic ^{6}Li and bosonic ^{133}Cs in an optical trap by sympathetic cooling near an interspecies Feshbach resonance. New regimes of quantum degenerate Bose-Fermi mixtures are identified. With moderate attractive interspecies interactions, we show that a degenerate Fermi gas of Li can be fully confined in a Cs Bose-Einstein condensate without external potentials. For stronger attraction where mean-field collapse is expected, no such instability is observed. Potential mechanisms to explain this phenomenon are discussed.We report on the formation of a stable quantum degenerate mixture of fermionic ^{6}Li and bosonic ^{133}Cs in an optical trap by sympathetic cooling near an interspecies Feshbach resonance. New regimes of quantum degenerate Bose-Fermi mixtures are identified. With moderate attractive interspecies interactions, we show that a degenerate Fermi gas of Li can be fully confined in a Cs Bose-Einstein condensate without external potentials. For stronger attraction where mean-field collapse is expected, no such instability is observed. Potential mechanisms to explain this phenomenon are discussed.

arXiv:1706.01220Physical Review LettersDec 7, 201773 citations

Metastability range of the Bose condensate in

\mathsf{^7}

Li-fermion mixtures at T = 0

Fermion-Mediated Interactions Between Bosons in a Quantum Degenerate

^{133}

Cs-

^6

Li Bose-Fermi Mixture