Non-Ergodic Quantum Manipulation

非遍历量子操纵

• 批准号: EP/R029075/1
• 负责人: Michael Pepper
• 金额: $ 896.09万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FR029075%2F1
• 关键词: Non; Ergodic; Quantum; Manipulation

The subject of electron transport when states are localized by disorder has been an important topic in physics for a considerable time. It was first realized in 2006 that a closed quantum system in which there is both disorder and many body interactions shows a completely new regime of behaviour termed Many Body Localization, MBL. This regime is characterised by a breakdown of equilibrium statistical mechanics, it predicts a zero conductance state at a finite temperature, entanglement can spread although there is a lack of thermalisation due to the breakdown of ergodicity expressed as a violation of the Eigenstate Thermalisation Hypothesis, ETH. Ergodicity is assumed in many areas of condensed matter science, namely that a sub-system of the whole is typical of the whole and that the behaviour averaged over time is identical to that averaged over space. Consequently the fact that it does not hold in this situation allows new phenomena as does the lack of equilibration due to the ETH no longer holding. Possible new states can be formed by the application of high frequencies to MBL and these will be investigated in the project.To date there has been no sustained experimental investigation of these predictions in condensed matter systems although there is considerable activity using cold atoms which naturally form a closed quantum system. Enormous theoretical interest has been expressed in the hundreds of papers published on the topic. It is in the area of condensed matter that this new state of matter would have a major impact if realised - which is the purpose of the project. We will comprehensively investigate this regime of behaviour using semiconductor technology and the fabrication techniques used in investigating mesoscopic devices and semiconductor nanostructures. By fabricating free standing nanostructures we will ensure a closed system by drastically reducing the coupling to the phonons which act as a heat bath. The temperature of measurements will be down the milliKelvin region and the length scale of the disorder will be varied as will other parameters such as dimensionality. Electrical and thermal techniques will be utilised as probes of the MBL state. In addition to the importance for basic physics this work will be extremely significant in quantum information and topological physics as this new state provides a means of quantum protection not presently available.

相当长一段时间以来，当状态因无序局域化时的电子传输问题一直是物理学中的一个重要话题。人们于 2006 年首次认识到，一个既存在无序又存在多种物体相互作用的封闭量子系统显示出一种全新的行为机制，称为多体定位 (MBL)。这种状态的特点是平衡统计力学的崩溃，它预测在有限温度下的零电导状态，尽管由于遍历性的崩溃而缺乏热化，但纠缠可以扩散，表现为违反本征态热化假说，ETH 。凝聚态科学的许多领域都假设遍历性，即整体的子系统是整体的典型，并且随时间平均的行为与随空间平均的行为相同。因此，在这种情况下它不成立的事实允许出现新的现象，就像由于 ETH 不再持有而导致缺乏平衡一样。通过将高频应用于 MBL 可以形成可能的新状态，这些将在该项目中进行研究。迄今为止，尽管有相当多的活动使用自然形成的冷原子，但在凝聚态物质系统中还没有对这些预测进行持续的实验研究封闭的量子系统。关于该主题发表的数百篇论文表达了巨大的理论兴趣。这种新的物质状态如果实现，将在凝聚态物质领域产生重大影响——这就是该项目的目的。我们将利用半导体技术和用于研究介观器件和半导体纳米结构的制造技术来全面研究这种行为机制。通过制造独立式纳米结构，我们将通过大幅减少与充当热浴的声子的耦合来确保封闭系统。测量温度将低于毫开尔文区域，无序的长度尺度将发生变化，其他参数（例如维度）也会发生变化。电学和热学技术将被用作 MBL 态的探针。除了对基础物理学的重要性之外，这项工作在量子信息和拓扑物理学中也将极其重要，因为这种新状态提供了一种目前尚不可用的量子保护手段。

项目成果

Boundary chaos: Exact entanglement dynamics

边界混沌：精确的纠缠动力学

• DOI: 10.21468/scipostphys.15.3.092
• 发表时间: 2023
• 期刊: SciPost Physics
• 影响因子: 5.5
• 作者: Fritzsch F

Quantized charge transport driven by a surface acoustic wave in induced unipolar and bipolar junctions

感应单极和双极结中表面声波驱动的量子化电荷传输

• DOI: 10.1103/physrevb.100.245401
• 发表时间: 2019
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Chung Y

Suspended two-dimensional electron gases in In0.75Ga0.25As quantum wells

In0.75Ga0.25As量子阱中悬浮的二维电子气

• DOI: 10.1063/5.0013902
• 发表时间: 2020
• 期刊: Applied Physics Letters
• 影响因子: 4
• 作者: Chen C

Certification of spin-based quantum simulators

• DOI: 10.1103/physreva.101.052344
• 发表时间: 2019-05
• 期刊: Physical Review A
• 影响因子: 2.9
• 作者: A. Bayat;B. Voisin;G. Buchs;J. Salfi;S. Rogge;S. Bose

Multiple electron pumping

• DOI: 10.1140/epjqt/s40507-023-00203-z
• 发表时间: 2023-10
• 期刊: EPJ Quantum Technology
• 影响因子: 5.3
• 作者: M. Blumenthal;Declan Mahony;Salahuddeen Ahmad;Dominique Gouveia;H. Howe;H. Beere;Thomas Mitchel