Light-Matter Systems Out of Equilibrium: from Random Lasers to Circuit Quantum Electrodynamics

这个提案包含两个关于光-物质系统物理学的子项目，它们都有共同的主题和方法，但在目标和细节上也有很大的不同。我建议从理论上研究两类人工量子器件的物理学：随机激光器和超导电路。无序光子介质中的随机激光是一种相对较新的现象，人们对其了解并不完全，其中散射和增益机制决定了激光的光谱和方向性，而空腔边界仅起次要作用。随机激光器具有很强的应用潜力，因为它们易于制造、成型，而且相对便宜。该项目的第二部分涉及超导电路的物理学，这是由一个叫做电路量子电动力学（电路QED）的理论框架描述的。这是一个新兴领域，旨在研究超导量子比特和量子信息处理和量子光学电路的实现，重点是控制系统各个组件的方法。在这些系统中已经证明了固态器件中的第一个量子算法，并且近年来电路的复杂性在规模上经历了稳定的增长，预计这种增长将继续下去。本提案旨在解决这两个领域的一些理论需求，这些需求对它们的发展至关重要，通过这些需求，我们还将探索多体非平衡量子理论的前沿，并开发量子控制的计算方法。光-物质相互作用的非平衡物理是这两个系统的基础，因此我们建议采用类似的理论方法来研究量子涨落在这两个系统的光学非线性响应中的作用。在电路QED中，这项工作将扩展超导量子比特的现有分析理论，并补充精确模拟的拟议发展。对于随机激光器，我们将深入了解激光模式的时空波动，以及光子无序在随机光谱统计研究中的作用。

This proposal contains two subprojects about the physics of light-matter systems, both sharing a common theme and methods, but also quite different in aims and specifics. I propose to theoretically investigate the physics of two classes of artificial quantum devices: random lasers and superconducting circuits. Random lasing in a disordered photonic medium is relatively new and only partially understood phenomenon, in which the mechanisms of scattering and gain determine the lasing spectrum and directionality, and the cavity boundaries play only a secondary role. There is a strong potential for applications of random lasers, since they are easy to manufacture, shape, and are relatively cheap. The second part of the project concerns the physics of superconducting circuits, which is described by a theoretical framework called Circuit Quantum Electrodynamics (circuit QED). This is an emerging field which aims to study the implementation of superconducting qubits and circuits to quantum information processing and quantum optics, with an emphasis on methods of control of the individual components of the system. The first quantum algorithms in a solid state device have been demonstrated in these systems, and the complexity of the circuits experienced a steady growth in scale in the recent years, which is expected to continue. This proposal aims to address some of the theoretical needs of both fields which are central to their development, by which we will also explore a frontier of many-body non-equilibrium quantum theory and develop computational methods for quantum control. Non-equilibrium physics of light-matter interaction stands at the basis of both systems and therefore we propose to employ similar theoretical methods to investigate the role of quantum fluctuations in the optical nonlinear response of the two systems. In circuit QED this effort will extend existing analytical theory of superconducting qubits, and complement the proposed development of exact simulations. For random lasers we will gain insight into the temporal and spatial fluctuations of the lasing modes, as well as to the role of photonic disorder in statistical studies of random spectra.