| Project/Area Number |
17540368
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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 |
原子・分子・量子エレクトロニクス・プラズマ
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| Research Institution | University of Tsukuba |
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Principal Investigator |
MATSUMOTO Hideki University of Tsukuba, Graduate School of Pure and Applied Sciences, Professor, 大学院数理物質科学研究科, 教授 (40209648)
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| Co-Investigator(Kenkyū-buntansha) |
OHASHI Yoji Keio University, Faculty of Science and Technology, Associate Professor, 理工学部, 助教授 (60272134)
KOYAMA Tomio Tohoku University, IMR, Research Associate, 金属材料研究所, 助手 (30153696)
MACHIDA Masahiko Japan Atomic Energy Agency, CCSE, Principal Reseacher, システム計算科学センター, 研究主幹 (60360434)
YAMADA Susumu Japan Atomic Energy Agency, CCSE, Reseacher, システム計算科学センター, 研究員 (80360436)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2005: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | quantum atomic gas / Bose-Einstein condensation / BCS / BEC crossover / insulator-superfluid transiton / optical lattice / Feshbach resonance / superfluid vortex state / Hubbard model |
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| Research Abstract |
In this research project, we investigated the BEC/BCS states, and obtained the following results.
1) Single-particle excitations and related phenomena in BCS/BEC crossover : We find that, in the Fermi gas trapped in a harmonic potential, the energy gap of the single-particle excitation is determined by the Andereev mode localized near the surface of the condensate. The rf-tunneling current spectral has a peak at the position of the Andreev mode in the weak coupling region, while it has a peak at the energy determined by the order parameter at the cencer of the potential.
3) Vortex states and process of vortex nucleation. : We investigated vortex states and energy spectrum of particle excitations in the BCS/BEC crossover region, by solving the BdG equation. With increasing the strength of the interaction, the particle distribution at the vortex center is reduced and descrete core levels are formed. We also showed that the vortex state in this coupling region is described by use of two components GL equation.
4) Nonequilibrium processes : We performed numerical simulation of the GP equation and investigated the formation processes of superfuild vortex states. We find that, in an early state of vortex formation, turbulent states are formed as results of the Kelvin waves, and then the system settles down to the state of the triangular lattice.
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