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题名	基于超冷碱土金属原子的重费米子系统的量子模拟
作者	姜伯楠
学位类别	博士
答辩日期	2015
授予单位	中国科学院上海光学精密机械研究所
导师	王育竹
关键词	超冷碱土金属原子 重费米子系统 近藤晶格模型 无序势 量子自旋霍尔效应 近藤单重态
其他题名	Quantum simulation of heavy-fermion systems with ultracold alkaline-earth-metal atoms
中文摘要	本论文研究了由超冷碱土金属原子系统模拟的几种不同重费米子系统的基态和动力学，使用杂化平均场理论、准确对角化和密度矩阵重整群求解了不同外势场中和不同维度下的近藤晶格模型。主要结果概述如下： （1）通过近藤双阱模型和杂化平均场理论对无序势中的超冷碱土金属原子构成的近藤晶格模型进行了定性和定量的研究。除了指出无序势造成的杂化能隙收缩和完全封闭外，也对无序势作用下处于金属相和近藤绝缘相的体系可压缩性进行了细致的分析；并针对实验中存在简谐阱的情况进行了数值求解，预测了近藤绝缘体平台融化和低巡游原子密度区域的可压缩性反常等现象。 （2）以原子间的超冷碰撞和激光辅助隧穿技术为基础，提出了使用二维方格上的超冷碱土金属费米原子研究近藤相互作用与量子自旋霍尔效应间相互影响的方案。在强近藤相互作用的参数区域，虽然巡游原子不再存在回旋轨迹，但是由两种钟态原子组成的近藤单重态却表现出自旋依赖的回旋轨道，这就实现了近藤单重态的量子自旋霍尔效应。理论上证明，零自旋近藤单重态的回旋动力学由有效Harper-Hofstadter模型和二阶对角隧穿项构成的哈密顿量描述。
英文摘要	In this thesis, the ground state and the dynamics of ultracold alkaline-earth-metal atomic gases, which can simulate a variety of heavy-fermion systems, have been investigated in detail. Hybridization mean-field theory, exact diagonalization and density matrix renormalization group have been used to solve the Kondo-lattice model in different cases of external potentials and the dimensions. Main results are briefly reviewed as follows: （1）The effect of disorder on ultracold alkaline-earth-metal atoms in optical lattices governed by the Kondo lattice model has been theoretically studied in the frameworks of double-well model and hybridization mean-field theory, respectively. Disorder-induced narrowing and even complete closure of the hybridization gap have been predicted and the compressibility of the system has also been investigated for the metallic and Kondo insulator phases in the presence of the disordered potential. To make connection to the experimental situation, we have numerically solved the disordered Kondo lattice model with an external harmonic trap and shown both the melting of Kondo insulator plateau and a compressibility anomaly at low-density. （2）We propose a scheme to investigate the interplay between Kondo-exchange interaction and quantum spin Hall effect with ultracold fermionic alkaline-earth-metal atoms trapped in two-dimensional optical lattices using ultracold collision and laser-assisted tunneling. In the strong Kondo-coupling regime, although the loop trajectory of the mobile atom disappears, collective dynamics of an atom pair in two clock states can exhibit an unexpected spin-dependent cyclotron orbit in a plaquette, realizing the quantum spin Hall effect of the Kondo singlet. It is demonstrated that the collective cyclotron dynamics of the spin-zero Kondo singlet is governed by an effective Harper-Hofstadter model in addition to second-order diagonal tunneling.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/15898]
专题	上海光学精密机械研究所_学位论文
推荐引用方式 GB/T 7714	姜伯楠. 基于超冷碱土金属原子的重费米子系统的量子模拟[D]. 中国科学院上海光学精密机械研究所. 2015.

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