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Quantum liquid droplets in a mixture of Bose-Einstein condensates
C R Cabrera1, L Tanzi1, J Sanz1
1ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.
Science (New York, N.Y.)
|December 16, 2017
Summary
Researchers observed novel quantum droplets stabilized by contact interactions in Bose-Einstein condensates. These ultradilute liquids, several orders of magnitude less dense than liquid helium, offer a new platform for quantum many-body theories.
Area of Science:
- Atomic, Molecular & Optical Physics
- Condensed Matter Physics
- Quantum Many-Body Systems
Background:
- Quantum droplets are exotic states of matter formed by self-bound atoms.
- Bose-Einstein condensates (BECs) provide a controllable environment for studying quantum phenomena.
- Understanding droplet formation requires balancing attractive and repulsive interatomic forces.
Purpose of the Study:
- To report the observation of quantum droplets stabilized purely by contact interactions.
- To characterize the properties of these droplets, including their density and size.
- To investigate the role of quantum fluctuations and interaction strength in droplet stability and phase transitions.
Main Methods:
- Utilizing a mixture of two Bose-Einstein condensates.
- Employing in situ imaging techniques for direct measurement of droplet size and density.
- Systematically varying interaction strength to study phase transitions.
Main Results:
- Observed quantum droplets solely stabilized by contact interactions.
- Demonstrated droplets are orders of magnitude more dilute than liquid helium.
- Identified a minimum atom number required for droplet stability, with quantum pressure driving a liquid-to-gas transition below this threshold.
- Mapped the liquid-to-gas transition as a function of interaction strength.
Conclusions:
- Contact interactions alone can stabilize ultradilute quantum droplets.
- Quantum fluctuations are crucial for stabilizing droplets against collapse.
- These ultradilute, weakly interacting liquids serve as an ideal system for benchmarking quantum many-body theories.
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