| Project/Area Number |
14540380
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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 |
物理学一般
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| Research Institution | Tokyo Metropolitan University |
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Principal Investigator |
YABU Hiroyuki Tokyo Metropolitan University, Department of Physics, Assistant Professor, 理学研究科, 助手 (60202371)
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| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Toru Tokyo Metropolitan University, Department of Physics, Assistant Professor, 理学研究科, 教授 (20175409)
MARUYAMA Tomoyuki Nihon University, Collage of Bioresource Sciences, Associated Professor, 生物資源科学部, 助教授 (50318391)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2004: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2003: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2002: ¥900,000 (Direct Cost: ¥900,000)
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| Keywords | Quantum Many-Body Syst / Atom Gas / Bose-Einstein Condensation / Fermi Liquid / Collective Motion / Chemical Equibrium / Low-Dimensional Physics / Quantum Vortex / フェルミ気体 / 密度波 / スピン密度波 / 乱雑位相近似 / パイエルス不安定性 / 集団励起 / 強磁性 / 有限多体系 / 計算物理 |
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| Research Abstract |
Theoretical studies have been done on finite Bose-Fermi mixed condensates on the basis of the microscopic theory, and their dynamics caused by the interatomic interaction between the boson and the fermion have been clarified.
A) Microscopic studies of finite Bose-Fermi mixed condensates in random phase approximation (RPA):
We have formulated and developed computer programs for finite mixtures in the RPA, Which have been performed to evaluated the excited levels of the finite mixtures. From the results, we clarified the applicability of the results obtained by macroscopic calculations, And also understood the detailed structure of the instability caused by the attractive interactions. In strong repulsive interaction, the novel shell structure has been suggested for the finite mixed condensates, where fermions are pushed out and distribute outside bosons. We applied the RPA calculation to the shell-structured condensates and found a new phenomenon-the oscillational-rotational transition in
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the one-particle fermionic levels. We also applied our method to the quasi-one-dimensional mixed condensates and studied the Kohn anomaly In the excitation spectrum, which leads to the instability of the condensates for charge-density wave creation. We studied the possibility and structures of the charge-density and spin-density wave states in quasi-one-dimensional mixed condensates.
B) Simulations for time-developments of finite Bose-Fermi mixed condensates:
We developed and performed the computer programs that simulate the time-developments of the mixed condensates. Using them, we studied the monopole oscillation of the mixed condensates.
C) Molecular formation and Law of quantum mass action:
We estimated the binding energy of the composite fermion (molecule) from boson and fermion in the mixed condensates. We extended the law of mass action used in chemical equilibrium theory into that with the quantum statistical effects (law of quantum mass action), which was applied to the molecular formation process in the mixed condensates. Using this method, we clarified the phase structure of the condensates under the equilibrium with molecules.
D) Applications of the obtained results to other areas of physics:
As applications of the present research, we studied the condensation phenomena in other system-positronium and quark many-body system. These researches also include new aspects in each area of physics. Less
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