Collective-mode dispersion of atomic Fermi gases in a honeycomb optical lattice: Speed of sound of the attractive Kane–Mele–Hubbard model at half filling
| Autor: | Zlatko Koinov |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Physics Optical lattice Physics and Astronomy (miscellaneous) Hubbard model Bubble General Physics and Astronomy 01 natural sciences Superfluidity Speed of sound Quantum mechanics 0103 physical sciences Collective mode 010306 general physics Random phase approximation Fermi Gamma-ray Space Telescope |
| Zdroj: | Low Temperature Physics. 46:516-524 |
| ISSN: | 1090-6517 1063-777X |
| Popis: | We examine the superfluid states that emerge in the Kane–Mele model as a result of the on-site short-range attractive interaction U. The collective-mode dispersion is defined by the solutions of the Bethe–Salpeter (BS) equation in the generalized random phase approximation. The slope of the low-energy (Goldstone) mode and the corresponding sound velocity at half filling, calculated within the BS formalism, has been compared with the corresponding results obtained previously by the T-matrix approximation. The difference between the two approaches is that the T-matrix approximation takes into account only the ladder diagrams, and neglects the bubble ones. For this reason, the sound velocity in the direction toward point M, calculated within the T-matrix approximation, is about 4% less than the result obtained by employing the BS equation. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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