Theory of Phase Transitions in Quantum and Disordered Systems

量子和无序系统中的相变理论

• 批准号: 9111576
• 负责人: Allan Peter Young
• 金额: $ 24.6万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-08-01 至 1995-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9111576&HistoricalAwards=false
• 关键词: Theory; Phase; Transitions; Quantum; Disordered

Research will be conducted on phase transitions in frustrated systems such as spin glasses. In addition to studying a number of aspects of the spin glass problem, application of spin glass ideas to the issue of the existence of a vortex glass in a type II superconductor with disorder in a magnetic field will also be pursued. This will determine whether high temperature superconductors have strictly zero resistance in a magnetic field. Work on phase transitions in quantum systems will also be developed. In particular, the universal conductance expected at the zero temperature transition between insulating and superconducting phases in disordered thin films will be investigated. Since analytic approaches have turned out to be very complicated for the proposed problems, the emphasis will be on numerical simulations. %%% Numerical techniques will be applied to study phase transitions in a variety of systems in which quantum effects and disorder dominate. Included will be studies of spin glasses, vortex glasses in high temperature superconductors and the insulator- superconductor transition in disordered thin films at zero temperature. All of these problems are of great current interest in condensed matter and materials physics.

将对受阻系统（例如自旋玻璃）中的相变进行研究。 除了研究自旋玻璃问题的多个方面外，还将研究将自旋玻璃思想应用于磁场无序的II型超导体中是否存在涡旋玻璃的问题。 这将决定高温超导体在磁场中是否具有严格的零电阻。 量子系统相变方面的工作也将得到发展。 特别是，将研究无序薄膜中绝缘相和超导相之间零温度转变时预期的通用电导。 由于分析方法对于所提出的问题来说非常复杂，因此重点将放在数值模拟上。 %%% 数值技术将用于研究量子效应和无序占主导地位的各种系统中的相变。 其中包括对高温超导体中的自旋玻璃、涡流玻璃以及零温度无序薄膜中的绝缘体-超导体转变的研究。 所有这些问题目前在凝聚态物质和材料物理学中引起了极大的兴趣。