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Universal van der Waals Force between Heavy Polarons in Superfluids.
Keisuke Fujii1, Masaru Hongo2,3, Tilman Enss1
1Institut für Theoretische Physik, Universität Heidelberg, D-69120 Heidelberg, Germany.
Physical Review Letters
|December 23, 2022
Summary
We explore the Casimir interaction between impurities in superfluid cold atomic gases. The study reveals a universal relativistic van der Waals attraction at long distances, with temperature-dependent corrections.
Area of Science:
- Quantum physics
- Condensed matter physics
- Atomic physics
Background:
- Superfluid cold atomic gases host quantum phenomena.
- Interactions between impurities (polarons) are crucial for understanding many-body physics.
- Casimir interactions arise from quantum fluctuations.
Purpose of the Study:
- Investigate the long-range Casimir interaction between two spinless heavy impurities in superfluids.
- Analyze the influence of temperature on this interaction.
- Develop a universal theoretical framework applicable to various superfluids.
Main Methods:
- Utilized effective field theory (EFT) for Galilean invariant superfluids.
- Analyzed the exchange of two superfluid phonons to determine interaction potentials.
- Calculated temperature-dependent corrections to the interaction.
Main Results:
- Discovered a universal relativistic van der Waals-like attraction (∼1/r⁷) at long distances between impurities.
- Identified temperature-dependent corrections, leading to nonrelativistic behavior (∼T/r⁶) at larger distances.
- The sound velocity of the superfluid dictates the magnitude of the van der Waals potential.
Conclusions:
- The EFT provides a unified description for weakly coupled and strongly correlated superfluids.
- The induced Casimir interaction is universally attractive and exhibits distinct temperature dependencies.
- This work offers insights into impurity interactions in diverse superfluid systems.
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