Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2207.13599 · Physical Review Research

Dipole dynamics of an interacting bosonic mixture

Luca Cavicchioli, C. Fort, Michele Modugno, F. Minardi, A. Burchianti

Published Oct 31, 2022• 17 citations
arXivHTMLPDF

Abstract

We unravel the coupled dipole dynamics of a two-species Bose-Einstein condensate with tunable interspecies interaction. We produce a degenerate mixture of $^{41}\mathrm{K}\text{\ensuremath{-}}^{87}\mathrm{Rb}$ in an optical trap and we study the dipole oscillations of both atomic species in the linear response regime. Varying the interspecies interaction from the weakly to the strongly attractive side, we measure the frequencies and the composition of the two dipole eigenmodes. For sufficiently strong interactions, even beyond the mean-field collapse, we find that the frequency of the low-energy eigenmode is determined only by the bare trap frequencies and the species population imbalance. The experimental results are well reproduced by numerical simulations based on two coupled Gross-Pitaevskii equations. Our findings provide a detailed picture of the dipole excitations in asymmetric bosonic mixtures.

DOI
10.1103/physrevresearch.4.043068

Related papers

Dynamics of a degenerate Cs-Yb mixture with attractive interspecies interactions

Kali Wilson, Alexander Guttridge, I-Kang Liu +5 more

We probe the collective dynamics of a quantum degenerate Bose-Bose mixture of $^{133}\mathrm{Cs}$ and $^{174}\mathrm{Yb}$ with attractive interspecies interactions. Specifically, we excite vertical center-of-mass oscillations of the Cs condensate. We observe significant damping for the Cs dipole mode, due to the rapid transfer of energy to the larger Yb component and the ensuing acoustic dissipation. Numerical simulations based on coupled Gross-Pitaevskii equations provide excellent agreement with experiment and additionally reveal the possibility of late-time revivals (beating), which are found to be highly sensitive to the Cs and Yb atom number combinations. By further tuning the interaction strength of Cs using a broad Feshbach resonance, we explore the stability of the degenerate mixture. We observe collapse of the Cs condensate mediated by the attractive Cs-Yb interaction when ${a}_{\mathrm{Cs}}<50\phantom{\rule{0.28em}{0ex}}{a}_{0}$, well above the single-species collapse threshold, in good agreement with simulations.

arXiv:2012.11008•Physical Review Research•Jul 27, 2021•10 citations

Dynamics of a degenerate Cs-Yb mixture with attractive interspecies interactions

KE Wilson, A Guttridge, I-Kang Liu +5 more

We probe the collective dynamics of a quantum degenerate Bose-Bose mixture of 133Cs and 174Yb with attractive interspecies interactions. Specifically, we excite vertical center-of-mass oscillations of the Cs condensate. We observe significant damping for the Cs dipole mode, due to the rapid transfer of energy to the larger Yb component and the ensuing acoustic dissipation. Numerical simulations based on coupled Gross-Pitaevskii equations provide excellent agreement with experiment and additionally reveal the possibility of late-time revivals (beating), which are found to be highly sensitive to the Cs and Yb atom number combinations. By further tuning the interaction strength of Cs using a broad Feshbach resonance, we explore the stability of the degenerate mixture. We observe collapse of the Cs condensate mediated by the attractive Cs-Yb interaction when aCs<50a0, well above the single-species collapse threshold, in good agreement with simulations.

•Jul 27, 2021•0 citations

A Dual-Species Bose-Einstein Condensate with Attractive Interspecies Interactions

Alessia Burchianti, Chiara D’Errico, Marco Prevedelli +5 more

We report on the production of a 41 K- 87 Rb dual-species Bose–Einstein condensate with tunable interspecies interaction and we study the mixture in the attractive regime; i.e., for negative values of the interspecies scattering length a 12 . The binary condensate is prepared in the ground state and confined in a pure optical trap. We exploit Feshbach resonances for tuning the value of a 12 . After compensating the gravitational sag between the two species with a magnetic field gradient, we drive the mixture into the attractive regime. We let the system evolve both in free space and in an optical waveguide. In both geometries, for strong attractive interactions, we observe the formation of self-bound states, recognizable as quantum droplets. Our findings prove that robust, long-lived droplet states can be realized in attractive two-species mixtures, despite the two atomic components possibly experiencing different potentials.

arXiv:2003.13362•Condensed Matter•Mar 21, 2020•54 citations

Bose-Einstein condensate immersed in a Fermi sea: Theory of static and dynamic behavior across phase separation

Bo Huang

We theoretically study the static and dynamic behavior of a BEC immersed in a large Fermi sea of ultracold atoms under conditions of tunable interspecies interaction. The degenerate Bose-Fermi mixture is kept in an elongated trap, typical for a single-beam optical dipole trap. We focus on the case of repulsive Bose-Fermi interaction and develop mean-field models to simulate the system over a wide range of repulsion strength. We further get analytical solutions in the regimes of phase separation and weak interaction. We obtain static density profiles and the frequency of the radial breathing mode, which is an elementary dynamic phenomenon of the mixture. Our results unveil the structure of the Bose-Fermi interface and describe the origin of the frequency shift of the breathing mode when the components become phase-separated at strong repulsion. We show that the mediated interaction between bosons induced by the Fermi sea can be understood as an adiabatic second-order mean-field effect, which is valid also beyond the weak-interaction regime for relevant experimental conditions. These results are consistent with our recent observations [Lous et al., Phys. Rev. Lett. 120, 243403 (2018); Huang et al., Phys. Rev. A 99, 041602(R) (2019)] in a mixture of $^{41}\mathrm{K}$ and $^{6}\mathrm{Li}$.

arXiv:2004.09227•Physical Review A•Jun 15, 2020•5 citations

Coupled dipole oscillations of a mass-imbalanced Bose-Fermi superfluid mixture

Yu-Ping Wu, Xing-Can Yao, Xiangpei Liu +6 more

Recent experimental realizations of superfluid mixtures of Bose and Fermi quantum gases provide a unique platform for exploring diverse superfluid phenomena. We study dipole oscillations of a double superfluid in a cigar-shaped optical dipole trap, consisting of $^{41}\mathrm{K}$ and $^{6}\mathrm{Li}$ atoms with a large mass imbalance, where the oscillations of the bosonic and fermionic components are coupled via the Bose-Fermi interaction. In our high-precision measurements, the frequencies of both components are observed to be shifted from the single-species ones, and exhibit unusual features. The frequency shifts of the $^{41}\mathrm{K}$ component are upward (downward) in the radial (axial) direction, whereas the $^{6}\mathrm{Li}$ component has downshifted frequencies in both directions. Most strikingly, as the interaction strength is varied, the frequency shifts display a resonantlike behavior in both directions, for both species, and around a similar location at the BCS side of the fermionic superfluid. These rich phenomena challenge the theoretical understanding of superfluids.

arXiv:1705.04496•Physical review. B./Physical review. B•Jan 22, 2018•30 citations

Dual-species Bose-Einstein condensate of K 41 and Rb 87 in a hybrid trap

A. Burchianti, Chiara D’Errico, S. Rosi +4 more

We report on the production of a $^{41}\mathrm{K}\text{\ensuremath{-}}^{87}\mathrm{Rb}$ dual-species Bose-Einstein condensate in a hybrid trap, consisting of a magnetic quadrupole and an optical dipole potential. After loading both atomic species in the trap, we cool down $^{87}\mathrm{Rb}$ first by magnetic and then by optical evaporation, while $^{41}\mathrm{K}$ is sympathetically cooled by elastic collisions with $^{87}\mathrm{Rb}$. We eventually produce two-component condensates with more than ${10}^{5}$ atoms and tunable species population imbalance. We observe the immiscibility of the quantum mixture by measuring the density profile of each species after releasing them from the trap.

arXiv:1810.08394•Physical Review A•Dec 12, 2018•38 citations
We unravel the coupled dipole dynamics of a two-species Bose-Einstein condensate with tunable interspecies interaction. We produce a degenerate mixture of 41K\ensuremath-87Rb^{41}\mathrm{K}\text{\ensuremath{-}}^{87}\mathrm{Rb}41K\ensuremath-87Rb in an optical trap and we study the dipole oscillations of both atomic species in the linear response regime. Varying the interspecies interaction from the weakly to the strongly attractive side, we measure the frequencies and the composition of the two dipole eigenmodes. For sufficiently strong interactions, even beyond the mean-field collapse, we find that the frequency of the low-energy eigenmode is determined only by the bare trap frequencies and the species population imbalance. The experimental results are well reproduced by numerical simulations based on two coupled Gross-Pitaevskii equations. Our findings provide a detailed picture of the dipole excitations in asymmetric bosonic mixtures.
We probe the collective dynamics of a quantum degenerate Bose-Bose mixture of 133Cs^{133}\mathrm{Cs}133Cs and 174Yb^{174}\mathrm{Yb}174Yb with attractive interspecies interactions. Specifically, we excite vertical center-of-mass oscillations of the Cs condensate. We observe significant damping for the Cs dipole mode, due to the rapid transfer of energy to the larger Yb component and the ensuing acoustic dissipation. Numerical simulations based on coupled Gross-Pitaevskii equations provide excellent agreement with experiment and additionally reveal the possibility of late-time revivals (beating), which are found to be highly sensitive to the Cs and Yb atom number combinations. By further tuning the interaction strength of Cs using a broad Feshbach resonance, we explore the stability of the degenerate mixture. We observe collapse of the Cs condensate mediated by the attractive Cs-Yb interaction when aCs<50a0{a}_{\mathrm{Cs}}<50\phantom{\rule{0.28em}{0ex}}{a}_{0}aCs​<50a0​, well above the single-species collapse threshold, in good agreement with simulations.
We probe the collective dynamics of a quantum degenerate Bose-Bose mixture of 133Cs and 174Yb with attractive interspecies interactions. Specifically, we excite vertical center-of-mass oscillations of the Cs condensate. We observe significant damping for the Cs dipole mode, due to the rapid transfer of energy to the larger Yb component and the ensuing acoustic dissipation. Numerical simulations based on coupled Gross-Pitaevskii equations provide excellent agreement with experiment and additionally reveal the possibility of late-time revivals (beating), which are found to be highly sensitive to the Cs and Yb atom number combinations. By further tuning the interaction strength of Cs using a broad Feshbach resonance, we explore the stability of the degenerate mixture. We observe collapse of the Cs condensate mediated by the attractive Cs-Yb interaction when aCs<50a0, well above the single-species collapse threshold, in good agreement with simulations.
We report on the production of a 41 K- 87 Rb dual-species Bose–Einstein condensate with tunable interspecies interaction and we study the mixture in the attractive regime; i.e., for negative values of the interspecies scattering length a 12 . The binary condensate is prepared in the ground state and confined in a pure optical trap. We exploit Feshbach resonances for tuning the value of a 12 . After compensating the gravitational sag between the two species with a magnetic field gradient, we drive the mixture into the attractive regime. We let the system evolve both in free space and in an optical waveguide. In both geometries, for strong attractive interactions, we observe the formation of self-bound states, recognizable as quantum droplets. Our findings prove that robust, long-lived droplet states can be realized in attractive two-species mixtures, despite the two atomic components possibly experiencing different potentials.
We theoretically study the static and dynamic behavior of a BEC immersed in a large Fermi sea of ultracold atoms under conditions of tunable interspecies interaction. The degenerate Bose-Fermi mixture is kept in an elongated trap, typical for a single-beam optical dipole trap. We focus on the case of repulsive Bose-Fermi interaction and develop mean-field models to simulate the system over a wide range of repulsion strength. We further get analytical solutions in the regimes of phase separation and weak interaction. We obtain static density profiles and the frequency of the radial breathing mode, which is an elementary dynamic phenomenon of the mixture. Our results unveil the structure of the Bose-Fermi interface and describe the origin of the frequency shift of the breathing mode when the components become phase-separated at strong repulsion. We show that the mediated interaction between bosons induced by the Fermi sea can be understood as an adiabatic second-order mean-field effect, which is valid also beyond the weak-interaction regime for relevant experimental conditions. These results are consistent with our recent observations [Lous et al., Phys. Rev. Lett. 120, 243403 (2018); Huang et al., Phys. Rev. A 99, 041602(R) (2019)] in a mixture of 41K^{41}\mathrm{K}41K and 6Li^{6}\mathrm{Li}6Li.
Recent experimental realizations of superfluid mixtures of Bose and Fermi quantum gases provide a unique platform for exploring diverse superfluid phenomena. We study dipole oscillations of a double superfluid in a cigar-shaped optical dipole trap, consisting of 41K^{41}\mathrm{K}41K and 6Li^{6}\mathrm{Li}6Li atoms with a large mass imbalance, where the oscillations of the bosonic and fermionic components are coupled via the Bose-Fermi interaction. In our high-precision measurements, the frequencies of both components are observed to be shifted from the single-species ones, and exhibit unusual features. The frequency shifts of the 41K^{41}\mathrm{K}41K component are upward (downward) in the radial (axial) direction, whereas the 6Li^{6}\mathrm{Li}6Li component has downshifted frequencies in both directions. Most strikingly, as the interaction strength is varied, the frequency shifts display a resonantlike behavior in both directions, for both species, and around a similar location at the BCS side of the fermionic superfluid. These rich phenomena challenge the theoretical understanding of superfluids.
We report on the production of a $^{41}\mathrm{K}\text{\ensuremath{-}}^{87}\mathrm{Rb}$ dual-species Bose-Einstein condensate in a hybrid trap, consisting of a magnetic quadrupole and an optical dipole potential. After loading both atomic species in the trap, we cool down 87Rb^{87}\mathrm{Rb}87Rb first by magnetic and then by optical evaporation, while 41K^{41}\mathrm{K}41K is sympathetically cooled by elastic collisions with 87Rb^{87}\mathrm{Rb}87Rb. We eventually produce two-component condensates with more than 105{10}^{5}105 atoms and tunable species population imbalance. We observe the immiscibility of the quantum mixture by measuring the density profile of each species after releasing them from the trap.