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.

相干信息交换至少需要两个量子比特。与量子比特耦合的费米子环境不仅可以引起失相，还可以通过RKKY相互作用诱导有效的自旋-自旋耦合。另一个理解固体中电子耗散的范例系统是玻色-费米模型，其中一个额外的耗散玻色子浴耦合到电子子系统。这两类系统都可以显示量子相变。对于这种接近量子相变的量子系统脱离平衡的实时动力学，我们所知甚少。我们计划使用时间相关的数值重整化群方法来探索接近量子相变的两个量子杂质之间的脱相和信息传递。我们对有残余杂质熵的系统的热化问题特别感兴趣。我们想研究当接近临界耦合时实时动力学是如何变化的。相干振荡是否在足以引起基态变化的临界耦合处盛行？我们还将研究通过外部外加栅极电压的周期性开关对量子信息传输的相干控制。

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