Identities and Many-Body Approaches in Bose-Einstein Condensates |
| S. Watabe
Faculty of Science Division I, Department of Physics, Tokyo University of Science, Tokyo, Japan |
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| This paper discusses exact relations in the Bose-Einstein condensates, starting from basic properties of an ideal Bose gas. In particular, focused on are the Hugenholtz-Pines relation, Nepomnyashchii-Nepomnyashchii identity, and identities for the density response function. After introducing these exact relations, a few approaches of many-body approximations are discussed, which satisfy the exact relations in the Bose-Einstein condensates. This paper will serve as a bridge between theories on exact relations and those on approximations in the Bose-Einstein condensates. |
DOI:10.12693/APhysPolA.135.1222 topics: Bose-Einstein condensates, many-body physics, Hugenholtz-Pines relation, Nepomnyashchii-Nepomnyashchii identity, density response function, compressibility sum-rule |