| Project/Area Number |
10044084
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
物性一般(含基礎論)
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| Research Institution | The University of Tokyo (1999)
Osaka University (1998) |
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Principal Investigator |
MIYASHITA Seiji Department of Applied Physics, University of Tokyo, Professor, 大学院・工学系研究科, 教授 (10143372)
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| Co-Investigator(Kenkyū-buntansha) |
KAWASHIMA Naoki Tokyo Metropolitan University, Associate Professor, 理学部, 助教授 (30242093)
TASAKI Haruaki Department of Physics, Gakusyuin University, Professor, 理学部, 教授 (50207015)
FUKUYAMA Hidetoshi Institute of Solid State Physics, University of Tokyo, Professor, 物性研究所, 教授 (10004441)
SAITOH Keiji Department of Physics, University of Tokyo, research Associate, 大学院・工学系研究科, 助手 (90312983)
AJIRO Yoshitami Department of Physics, Kyusyu University, Professor, 理学部, 教授 (00025438)
VINCENT E. サクレー研究所, 主任研究員
YAUNG A.P. カリフォルニア大学(サンタクルツ), 物理学科, 教授
DE Raedt H. グローニンゲン大学, 理論物理学科, 教授
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥7,500,000 (Direct Cost: ¥7,500,000)
Fiscal Year 1999: ¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 1998: ¥4,000,000 (Direct Cost: ¥4,000,000)
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| Keywords | quantum spin system / quantum Monte Carlo / nanoscale magnets / ESR / nonadiabatic transitions / photoinduced phasetransition / 量子モンテカルロ法 / 準安定緩和 / 量子ダイナミックス |
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| Research Abstract |
We have studied the following phenomena in which the, quantum dynamics plays an important role. We investigated the quantum hysteresis phenomena in nanoscale molecular magnets such as Mn12, Fe8 and V15 in the view point of non adiabatic transition. We studied the effects of the environments, such as the phonon, the dipole interaction and hyperfine interactions with the nuclear spins, on the quantum dynamics. In particular, we clarified mechanisms of deceptive non-adiabatic transition at very low temperature, of the parity effect due to the thermally excited states and of the quantum foehn phenomena due to inflow of the heat. We also developed a new direct numerical method to study the line shape of ESR in strongly interacting quantum spin systems, and investigate the dynamical shift due to the dipole interaction, anisotropy and DM interactions. The slow dynamics due to the inhomogeneity in the systems such as spin glass and random bond system. In quantum systems, the local magnetization is often induced at inhomogeneous parts of lattice in the so-called gapped quantum spin systems which is non-magnetic in the ground state. We studied how the local magnetizations are induced in various systems and also investigate the dynamical properties. We also investigated the quantum spin dynamics for quantum computing, and found a kind of instability in the spin manipulation.
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