CE30 - Physique de la matière condensée et de la matière diluée

Dilute quantum droplets of potassium – Droplets

1D quantum droplets

Our project deals with the creation and the study of a new type of quantum liquid droplets in yet dilute ultracold atomic samples of Potassium 39. Their existence emerges because of quantum fluctuations in a mixture of two Bose-Einstein condensates for which the overall mean-field energy cancels because of attractive interspecies interaction. The system offers a unique opportunity to quantitatively study beyond-mean field effects dominating the dynamics of the system.

Measurement of quantum fluctuations effects in dilute quantum gases

Quantum fluctuations typically play a major role in strongly correlated materials that have more and more applications. In contrast, quantum fluctuations are usually having a small effect in Bose-Einstein condensate (BEC) physics because a BEC is in essence a dilute system. However, the objectives of our projet is the precise measurements and characterization of beyond-mean-field effects in mixtures of BEC in a regime where usual mean-field energy is tuned to zero such that quantum fluctuations are dominant.

We plan to focus on the quasi one-dimensional (1D) geometry where the physics of droplets is most counter-intuitive. Key observations will be the self-trapped nature of droplets as well as their flat bulk region. Quantitative studies of the collective excitations will be performed. We will also approach the strongly interacting regime, which corresponds to lowering the density in 1D. Furthermore, we plan to demonstrate radio-frequency dressing as a novel method to control interaction in atomic Bose-Einstein condensates. It will permit not only the control of two-body interactions but also of three-body interactions, offering an alternative mechanism for the stabilization of dilute atomic droplets.

Crossover from 3D to 1D quantum droplets
Measurement of the beyond-mean field equation of state in a Rabi-coupled two-component BEC.
Apparition of three-body interaction in BEC physics
Study of collective excitations in a 1D quantum droplet.

Measurement of the beyond-mean field equation of state in a Rabi-coupled two-component BEC. Creation of a new type of droplets in RF-coupled BEC.

1. PRA 103, 033312 (2021)
2. PRA 100, 042707 (2019)
3. PRA 103, 033326 (2021)
4. PRA 101, 051601(R) (2020)
5. PRA 101, 041602(R) (2020)
6. PRL 126, 115301 (2021)
7. arXiv:2105.11723 submitted to PRL

Our project deals with the creation and the study of a new type of quantum liquid droplets in yet dilute ultracold atomic samples of Potassium 39. Their existence emerges because of quantum fluctuations in a mixture of two Bose-Einstein condensates for which the overall mean-field energy cancels because of attractive interspecies interaction. The system offers a unique opportunity to quantitatively study beyond-mean field effects dominating the dynamics of the system. We plan to focus on the quasi one-dimensional (1D) geometry where the physics of droplets is most counter-intuitive. Key observations will be the self-trapped nature of droplets as well as their flat bulk region. Quantitative studies of the collective excitations will be performed. We will also approach the strongly interacting regime, which corresponds to lowering the density in 1D. Furthermore, we plan to demonstrate radio-frequency dressing as a novel method to control interaction in atomic Bose-Einstein condensates. It will permit not only the control of two-body interactions but also of three-body interactions, offering an alternative mechanism for the stabilization of dilute atomic droplets.

Project coordination

Thomas Bourdel (Laboratoire Charles Fabry (LCF))

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

LCF Laboratoire Charles Fabry (LCF)
LPTMS Laboratoire de physique théorique et modèles statistiques

Help of the ANR 300,417 euros
Beginning and duration of the scientific project: December 2019 - 48 Months

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