Bose Polarons at Finite Temperature and Strong Coupling
A mobile impurity coupled to a weakly interacting Bose gas, a Bose polaron, displays several interesting effects. While a single attractive quasiparticle is known to exist at zero temperature, we show here that the spectrum splits into two quasiparticles at finite temperatures for sufficiently stron...
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| Published in | Physical review letters Vol. 120; no. 5; p. 050405 |
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| Main Authors | , , , |
| Format | Journal Article |
| Language | English |
| Published |
United States
01.02.2018
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| Online Access | Get more information |
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| Summary: | A mobile impurity coupled to a weakly interacting Bose gas, a Bose polaron, displays several interesting effects. While a single attractive quasiparticle is known to exist at zero temperature, we show here that the spectrum splits into two quasiparticles at finite temperatures for sufficiently strong impurity-boson interaction. The ground state quasiparticle has minimum energy at T_{c}, the critical temperature for Bose-Einstein condensation, and it becomes overdamped when T≫T_{c}. The quasiparticle with higher energy instead exists only below T_{c}, since it is a strong mixture of the impurity with thermally excited collective Bogoliubov modes. This phenomenology is not restricted to ultracold gases, but should occur whenever a mobile impurity is coupled to a medium featuring a gapless bosonic mode with a large population for finite temperature. |
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| ISSN: | 1079-7114 |
| DOI: | 10.1103/physrevlett.120.050405 |