Study on Systems with Strong Quantum Fluctuation

强量子涨落系统研究

基本信息

  • 批准号:
    08044081
  • 负责人:
  • 金额:
    $ 6.46万
  • 依托单位:
  • 依托单位国家:
    日本
  • 项目类别:
    Grant-in-Aid for international Scientific Research
  • 财政年份:
    1996
  • 资助国家:
    日本
  • 起止时间:
    1996 至 1997
  • 项目状态:
    已结题

项目摘要

We have studied systems with strong quantum fluctuation in order to find new peculiar properties due to the quantum mechanical effects. We investigate the effects due to the structure of the lattice on the ordering configuration in the Heisenberg antiferromagnets. Here 'ordering configuration' means the configuration of singlet bonds which is classified with the VBS picture. In particular we investigated a chain which consists of two of S = 1 spins and two of S = 1/2 spins.We investigated effects of inhomogeneity on quantum mechanical order. In particular, we study the effect of random coupling in S = 1 chain, effects of impurities of S = 1/2 spins and effects of dilution on the ladder lattice and square lattice. In the last project, we find so-called quantum Griffiths phase where the any correlation in the spatial direction decays exponentially but the correlation in the time axis diverges. This divergence causes the divergence of the local susceptibility.We studied a new phase due to the quantum fluctuation in the magnetization curve in the ground state of antiferromagnetic Heisenberg model with XY anisotropy. There a collinear configuration which is unfavorite in classical case becomes stable. The transition is clearly observed by investigating the wavefunction although the transition is not clear in the changes of physical quantities.We investigated the low temperature properties of quantum spin systems by quantum Monte Carlo method, transfer matrix method and Bethe anzatz method. We found a new mechanism of the ferromagnetism in the Hubbard model and analyzed the nature of the ferromagnetism.We also started to study the dynamics of system where the quantum fluctuation has a dominant role.
我们研究了具有强量子涨落的系统,以发现由于量子力学效应而产生的新的特殊性质。我们研究了晶格结构对海森伯反铁磁体有序组态的影响。这里的有序组态是指与VBS图一起分类的单线态键的组态。特别地,我们研究了由两个S=1自旋和两个S=1/2自旋组成的链,考察了不均匀性对量子力学有序性的影响。特别地,我们研究了S=1链中的随机耦合效应,S=1/2自旋杂质的影响,以及稀释对梯形晶格和正方晶格的影响。在最后一个项目中,我们发现了所谓的量子Griffiths相,其中空间方向上的任何关联都呈指数衰减,但时间轴上的关联发散。这种发散导致了局域磁化率的发散。我们研究了具有XY各向异性的反铁磁海森堡模型基态磁化曲线中的量子涨落引起的新相。在经典情况下不受欢迎的共线构型变得稳定。我们用量子蒙特卡罗方法、转移矩阵方法和Bethe azatz方法研究了量子自旋系统的低温性质。我们在Hubbard模型中发现了一种新的铁磁性机制,分析了铁磁性的性质,并开始研究量子涨落起主导作用的系统动力学。

项目成果

期刊论文数量(43)
专著数量(0)
科研奖励数量(0)
会议论文数量(0)
专利数量(0)
T.Tonegawa,T.Nakano,& M.Kaburagi: "Ground State Phase diagram and Magnetization Curves of the S=1 Anfifernomagnetic Heisenbeag model" J.Phys.Soc.Jpn. 65・10. 3317-3330 (1996)
T.Tonekawa、T.Nakano 和 M.Kaburagi:“S=1 Anfifernomagic Heisenbeag 模型的基态相图和磁化曲线”J.Phys.Soc.Jpn 65・10(1996)。
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S.Miyashita: "Nature of the Ordered Phase and the Critical Properties of the Three Dimensional Six-state Clock Model" J.Phys.Soc.Jpn.66. 3411-3420 (1997)
S.Miyashita:“有序相位的本质和三维六态时钟模型的关键属性”J.Phys.Soc.Jpn.66。
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S.Miyashita, K.Saito and H.De Raedt: "Nontrivial resonance of nanoscale uniaxial magnets to alternating field" Phys.Rev.Lett.80. 1525-1528 (1998)
S.Miyashita、K.Saito 和 H.De Raedt:“纳米级单轴磁体对交变场的非​​平凡共振”Phys.Rev.Lett.80。
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S.Miyashita and T.Nakamura: "Monte Carlo Studies on Frustrated Quantum Spin Systems by a New Appoach to the Negative-sign Problem" Int.J.Mod Phys.C7・3. 425-431 (1996)
S. Miyashita 和 T. Nakamura:“通过负号问题的新方法对受阻量子自旋系统进行蒙特卡罗研究” Int.J.Mod Phys.C7・3 (1996)
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U.Schollwock,O Gohinelli and T.Jolicoeur: "S=2 Antiferomagnetic Quantum Spin Chain" Phys.Res.B. 54. 4038-4051 (1996)
U.Schollwock、O Gohinelli 和 T.Jolicoeur:“S=2 反铁磁量子自旋链”Phys.Res.B。
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MIYASHITA Seiji其他文献

MIYASHITA Seiji的其他文献

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{{ truncateString('MIYASHITA Seiji', 18)}}的其他基金

Quantum mechanical response to time-dependent external field and related cooperative phenomena
对时间相关外场的量子力学响应及相关合作现象
  • 批准号:
    16540308
  • 财政年份:
    2004
  • 资助金额:
    $ 6.46万
  • 项目类别:
    Grant-in-Aid for Scientific Research (C)
Study on mechanism and dynamical control of quantum dynamics of magnets
磁体量子动力学机理及动力学控制研究
  • 批准号:
    14540353
  • 财政年份:
    2002
  • 资助金额:
    $ 6.46万
  • 项目类别:
    Grant-in-Aid for Scientific Research (C)
Mechanism of magnetization induction and its dynamics in strongly correlated quantum spin systems
强相关量子自旋系统中的磁化感应机制及其动力学
  • 批准号:
    12640368
  • 财政年份:
    2000
  • 资助金额:
    $ 6.46万
  • 项目类别:
    Grant-in-Aid for Scientific Research (C)
New ordered states and response to dynamical field of strongly fluctuating quantum systems
新有序态及对强涨落量子系统动力场的响应
  • 批准号:
    10640368
  • 财政年份:
    1998
  • 资助金额:
    $ 6.46万
  • 项目类别:
    Grant-in-Aid for Scientific Research (C)
Relaxation of metastable state through the quantum dynamics
通过量子动力学弛豫亚稳态
  • 批准号:
    10044084
  • 财政年份:
    1998
  • 资助金额:
    $ 6.46万
  • 项目类别:
    Grant-in-Aid for Scientific Research (B).
Quantum Monte Carlo Study on Strongly Quantum Fluctuated Systems
强量子涨落系统的量子蒙特卡罗研究
  • 批准号:
    08640485
  • 财政年份:
    1996
  • 资助金额:
    $ 6.46万
  • 项目类别:
    Grant-in-Aid for Scientific Research (C)
Study of relaxation phenomena in strongly fluctuating quantum syetems
强涨落量子系统中弛豫现象的研究
  • 批准号:
    06640503
  • 财政年份:
    1994
  • 资助金额:
    $ 6.46万
  • 项目类别:
    Grant-in-Aid for General Scientific Research (C)
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