Non-equilibrium dynamics of quantum-impurity systems close to quantum critical points

接近量子临界点的量子杂质系统的非平衡动力学

• 批准号: 210230633
• 负责人: Professor Dr. Frithjof B. Anders
• 金额: --
• 依托单位: Lehrstuhl für Theoretische Physik II (aufgelöst)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/210230633?language=en
• 关键词: Non; equilibrium; dynamics; quantum; impurity

The minimum of two qbits are required for coherent information exchange. A Fermionic environment coupled to the qbits causes not only dephasing but can also induce an effective spin-spin coupling via RKKY interaction. Another paradigm system for understanding dissipation of electrons in solids is the Bose-Fermi model where an additional dissipative Bosonic bath is coupled to the electronic subsystem. Both classes of systems can show quantum phase transitions. Little is known about the real-time dynamics out of equilibrium of such quantum systems close to the quantum phase transition.We plan to use the time-dependent numerical renormalization group approach to explore the dephasing and the information transfer between two quantum impurities close to the quantum phase transition. We are particularly interested in the question of thermalization in systems with residual impurity entropy. We want to investigate how the real-time dynamics changes when approaching the critical coupling. Do coherent oscillation prevail at the critical coupling which is strong enough to cause a change of ground state? We also will study the coherent control of the quantum information transfer by a periodic switching of the externally applied gate voltage.

连贯的信息交换需要两个QBIT。与QBITS结合的费米子环境不仅会引起逐渐变化，而且还可以通过Rkky相互作用诱导有效的自旋旋转耦合。了解固体中电子耗散的另一个范式系统是Bose-Fermi模型，其中额外的耗散性骨浴与电子子系统耦合。两类系统都可以显示量子相变。对于接近量子相变的此类量子系统的平衡的实时动力学知之甚少。我们计划使用时间依赖性的数值重新归一化组方法来探索接近量子相过渡的两个量子杂质之间的dephasing和信息传递。我们对具有残留杂质熵的系统中的热化问题特别感兴趣。我们想研究实时动力学在接近关键耦合时如何变化。连贯的振荡是否在临界耦合上占上风，该耦合足以引起基态的变化？我们还将通过外部施加的栅极电压的周期性切换来研究量子信息传输的连贯控制。

项目成果

Transfering spin into an extended π orbital of a large molecule

• DOI: 10.1103/physrevb.91.144415
• 发表时间: 2015-04-20
• 期刊: PHYSICAL REVIEW B
• 影响因子: 3.7
• 作者: Esat, Taner;Deilmann, Thorsten;Tautz, F. Stefan
• 通讯作者: Tautz, F. Stefan

A chemically driven quantum phase transition in a two-molecule Kondo system

• DOI: 10.1038/nphys3737
• 发表时间: 2016-09-01
• 期刊: NATURE PHYSICS
• 影响因子: 19.6
• 作者: Esat, Taner;Lechtenberg, Benedikt;Tautz, F. Stefan
• 通讯作者: Tautz, F. Stefan

Real-time dynamics induced by quenches across the quantum critical points in gapless Fermi systems with a magnetic impurity

• DOI: 10.1103/physrevb.90.235145
• 发表时间: 2014-12-24
• 期刊: PHYSICAL REVIEW B
• 影响因子: 3.7
• 作者: Kleine, Christian;Musshoff, Julian;Anders, Frithjof B.
• 通讯作者: Anders, Frithjof B.

Spatial and temporal propagation of Kondo correlations

近藤相关性的空间和时间传播

• DOI: 10.1103/physrevb.90.045117
• 发表时间: 2014
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Benedikt Lechtenberg;Frithjof B. Anders
• 通讯作者: Frithjof B. Anders