Noisy quantum devices: Theory and realizations

量子技术有望在计算、通信、信息存储和传感方面实现变革性的应用。在目前的范例中，量子设备依赖于纯粹的量子相干(么正)动力学，假设系统与其周围环境完全隔离。然而，量子系统永远不会与环境完全隔离，导致相位退相干和能量耗散，导致运行退化。在这个项目中，我们将为量子器件提出一个截然不同的范例：我们将发展室温噪声(耗散)量子系统的理论、概念和应用，其运行基于量子相干和非相干效应之间的协同。该计划包括三个推进器，将同时推进。(I)外部控制的量子耗散多体系统的动力学的形成和演化构成了一个重大的理论和计算挑战。我们将开发理论工具来描述这些丰富的量子系统的动力学。我们的半解析方法将在计算量庞大的数值精确工具和不准确但直观的微扰方法之间提供平衡。(二)推进量子热力学理论。以热机为重点，我们将设计合理的和机器学习的量子控制方案，以优化这些噪声设备的性能，利用强大的系统-浴缸耦合效应，并揭示成本-精度权衡关系。(Iii)我们将把我们的方法付诸实践，并在不同的平台上提出噪音量子器件：原子尺度和分子电子导体，以及混合超导量子比特。具体地说，我们将研究分子和混合器件中电荷、能量和自旋输运中的噪声量子效应。在我们的工作中，我们将制定最小模型以获得洞察力，执行分子系统的模拟以确定候选系统，并与实验小组合作测试我们的预测。将要研究的特别有趣的主题包括：(I)纳米结构中的非传统电荷传输行为，例如，随着分子长度的增加而增加的电导。(Ii)纳米导体中电流噪声的来源、缓解和利用。(Iii)量子相干在手性分子自旋输运中的作用。(Iv)(噪声)加热机的量子控制和超导量子比特的实现建议。该项目将由不同的博士后研究员、研究生和具有化学、物理和工程背景的本科生组成。将努力接触在理论化学中传统上代表性不足的群体，并让他们参与这项研究努力。我们的研究将有助于知识的进步，发展处理复杂系统中受驱动的量子多体效应的方法，以及新的技术：室温、嘈杂的量子设备。

Quantum technologies promise transformative applications in computing, communication, information storage and sensing. In the present paradigm, quantum devices rely on pure, quantum coherent (unitary) dynamics, assuming perfect isolation of the system from its surroundings. However, quantum systems are never perfectly isolated from their environment, leading to phase decoherence and energy dissipation, resulting in a degraded operation. In this program, we will advance a radically distinct paradigm for quantum devices: We will develop the theory, concepts, and applications of room-temperature noisy (dissipative) quantum systems whose operation is based on the synergy between quantum coherent and incoherent effects. The program includes three thrusts, to be advanced simultaneously. (i) Formulating and evolving the dynamics of externally-controlled quantum dissipative many-body systems pose a significant theoretical and computational challenge. We will develop theoretical tools to describe the dynamics of these rich quantum systems. Our semi-analytic methods will offer a balance between computationally-massive numerically exact tools and inaccurate yet intuitive perturbative methods. (ii) We will advance the theory of quantum thermodynamics. Focusing on heat engines, we will devise rational and machine-learned quantum control schemes for optimizing performance of these noisy devices utilizing strong system-bath coupling effects and uncovering cost-precision tradeoff relations. (iii) We will put our methods to work and propose noisy quantum devices in different platforms: atomic-scale and molecular electronic conductors and hybrid superconducting qubits. Concretely, we will study noisy quantum effects in charge, energy, and spin transport in molecules and within hybrid devices. In our work, we will formulate minimal models to gain insights, perform simulations of molecular systems to identify candidate systems, and collaborate with experimental groups to test our predictions. Specific intriguing topics to be examined include: (i) Unconventional charge transport behavior in nanostructures, e.g. electrical conductance that increases with molecular length. (ii) The origin, mitigation, and harnessing of current noise in nanoscale conductors. (iii) Role of quantum coherence in spin transport through chiral molecules. (iv) Quantum control of (noisy) heat machines and proposals for realizations in superconducting qubits. The program will be tackled by a diverse group of postdoctoral fellows, graduate students and undergraduates with backgrounds in chemistry, physics, and engineering. Efforts will be made to reach out to groups traditionally under-represented in Theoretical Chemistry and involve them in this research endeavor. Our research will contribute to the advancement of knowledge with the development of approaches for treating driven quantum many-body effects in complex systems, and to new technologies: room-temperature, noisy quantum devices.