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Superfluid Fraction in an Interacting Spatially Modulated Bose-Einstein Condensate
G Chauveau1, C Maury1, F Rabec1
1Laboratoire Kastler Brossel, Collège de France, CNRS, ENS-PSL University, Sorbonne Université, 11 Place Marcelin Berthelot, 75005 Paris, France.
Physical Review Letters
|June 16, 2023
Summary
Superfluid density in Bose fluids is reduced by breaking Galilean invariance with a periodic potential. This study quantifies superfluid fraction using Leggett
Area of Science:
- Quantum fluid dynamics
- Condensed matter physics
- Bose-Einstein condensates
Background:
- Bose fluids at zero temperature are typically fully superfluid.
- Galilean invariance is a key principle for superfluid behavior.
- External potentials can break symmetries in quantum systems.
Purpose of the Study:
- Investigate the reduction of superfluid density in Bose-Einstein condensates.
- Understand the impact of broken Galilean invariance on superfluidity.
- Quantify the superfluid fraction under specific conditions.
Main Methods:
- Theoretical investigation of a dilute Bose-Einstein condensate.
- Experimental study using a 1D periodic potential.
- Determination of superfluid fraction via Leggett's bound and sound velocity anisotropy.
Main Results:
- Superfluid density is quenched by breaking translational invariance.
- Leggett's bound and sound velocity anisotropy yield consistent superfluid fractions.
- A large-period lattice highlights the role of two-body interactions.
Conclusions:
- External periodic potentials significantly reduce superfluid density.
- Two-body interactions play a crucial role in superfluidity within periodic potentials.
- The study provides a consistent method for determining superfluid fractions.
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