2012 Fiscal Year Final Research Report
Theoretical study of Bose-Einstein condensates using a new self-consistent perturbation expansion
| Project/Area Number |
22540356
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | Hokkaido University |
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Principal Investigator |
KITA Takafumi 北海道大学, 大学院・理学研究院, 准教授 (20186224)
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| Project Period (FY) |
2010 – 2012
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| Keywords | ボーズ-アインシュタイン凝縮 / 自発的対称性の破れ / 場の量子論 |
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| Research Abstract |
A new self-consistent perturbation expansion, which was developed recently by the principal investigator, has been used to clarify basic properties of a single-component Bose-Einstein condensate. A widely accepted viewpoint on the elementary excitations of the system is that the single- and two-particle excitations are identical and described by the gapless excitation of the Bogoliubov theory. We have found, however, that the two excitations are different from each other. It is also found that the well-known expression on the ground-state energy of a dilute Bose gas by Lee, Huang and Yang should be modified due to a new class of Feynman diagrams for the self-energy.
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