Large-scale quantum phenomena in spin systems

大尺度量子现象在凝聚态系统中特别有趣，尽管它们也在粒子理论和宇宙学中得到了研究。对它们的理论理解需要从退相干理论和环境中的非平衡过程理论中得到广泛的结果。目前的工作集中在cerain统计力学模型（特别是模型的自旋网络耦合到环境模拟振荡器或自旋浴），并在其应用到真实的系统。这样的系统包括磁性分子或稀土自旋的网络或阵列，或超导SQUIDS。该模型也可应用于量子自旋玻璃或偶极玻璃。最后，在这个项目中，我们还将研究固体He-3，我们相信在其中可以观察到涉及宏观畴壁的壮观量子现象。主要的理论重点将是利用退相干理论，量子信息理论和弦理论的方法来理解自旋网络的动力学。研究的模型包括耗散的Hofstadter模型，以及“量子行走”的一般研究。该项目最重要的部分将是应用于自旋阵列（磁性分子和稀土离子）、偶极和量子spinglasses以及固体He-3的实验。我们将主要关注与自旋回波、磁弛豫、热力学和输运测量（以及He-3系统中的NMR）等实验相关的现象。我们还将关注中子散射实验，以及量子自旋玻璃中量子相变动力学的研究。将与实验学家进行广泛的合作，主要是在磁学方面，但也在玻璃物理学方面（可能也在超导方面），也与一些理论家合作。

Large-scale quantum phenomena are particularly interesting in condensed matter systems, although they have also been studied in particle theory and cosmology. Their theoretical understanding needs extensive results from the theory of decoherence and non-equilibrium processes in the environment. The present work focuses on cerain statistical mechanical models (notably on models of spin networks coupled to environments modelled by oscillator or spin baths), and on their application to real systems. Such systems include networks or arrays of magnetic molecules or rare earth spins, or of supeconducting SQUIDS. The models also can be applied to quantum spin glasses or dipolar glasses. Finally, in this project we will also look at solid He-3, in whihc we believe that spectacular quantum phenomena involving macroscopic domain walls may be observable.The main theoretical focus will be on an understanding on the dynamics of spinnetworks, using methods from decoherence theory, and also from quantum information theory and string theory. Models to be studied include the dissipative Hofstadter model, as well as a general study of 'quantum walks'.The most important part of the project will be the application to experiments on spin arrays (of magnetic molecules and rare earth ions), on dipolar and quantum spinglasses, and on solid He-3. We will bemainly looking at phenomena related to experiments like spin echo, magnetic relaxation, and thermodynamic and transport measurements (and NMR in the He-3 system).We will also be looking at neutron scattering experiments, in the context of work on the dynamics of quantum phase transitions in quantum spin glasses. There will be extensive collaboration with experimentalists, working mostly in magnetism but also in glass physcs (and possibly also in superconductivity), and also with some theorists.