Condensed Matter Theory

该奖项支持强关联量子系统和量子光学的凝聚态物理学的理论研究。 这个项目建立在前一个资助期的理论进展基础上，并受到最近在二维电子气输运测量和电路量子力学（称为"电路QED"）方面的实验进展的激励。“受到最近关于量子霍尔边缘态热传输的令人惊讶的实验的启发，PI将研究为什么热激发的距离比电荷激发的距离短得多。PI将检查软边缘内部的能量耗散源以及与二维电子气中的固有高频耗散相关的外部源。受“电路量子电动力学”实验进展的启发，PI将研究量子比特和谐振器晶格中强相互作用微波极化激元的多体物理。PI旨在展示超导量子比特和谐振器的晶格如何用于模拟强关联玻色子以及受挫折的量子自旋。此外，研究所亦会继续与实验学者合作，研究电路量子电动力学的基本量子光学和量子计算，以及光纳米力学。这项研究包括研究物质不同重要量子相的量子力学和统计力学，课题包括：介观电子系统中的量子相干性，光机械系统，微波光子的新相关态，以及二维电子气。量子光学思想在超导电路和光机系统中的应用和扩展将继续得到发展。分析以及量子轨迹，经典的蒙特卡罗，和其他数值技术将被应用到这些现象的研究。将寻求、发展和研究具有广泛适用性的新的数值技术。这项工作将推进我们在这些广泛领域的知识，并将与实验密切联系。非技术性总结该奖项支持理论研究和教育，从超导材料制成的电路中创建人造原子。超导体表现出一种量子力学状态，它可以导电而不耗散。像真实的原子一样，这些人造原子可以与微波辐射的单个量子或光子相互作用。这些超导电路正在被开发为构建量子计算机的基本硬件。 量子计算机将通过操纵量子力学状态来执行计算，原则上可以在某些问题上超过现有最快的计算机。除了这种潜在的实际应用之外，这些超导电路还可以用于研究与电磁场相互作用的多粒子系统的基本量子力学。 正常情况下，电磁波可以不受影响地相互穿透。 在粒子语言中，光子通常不会碰撞。 然而，在人造原子的存在下，光子有效地开始相互作用并相互碰撞。 这可以用来研究许多强碰撞粒子的量子力学，并利用光粒子模拟固体材料的相变。 PI将提出利用光观察这些新的物质状态的实验，并发展光力学理论，即光施加的微弱压力可以用来引起小物体的机械运动，甚至冷却它们的运动。 通常情况下，激光照射物体会使其升温。 然而，激光冷却物质物体的运动是可能的，就像激光冷却单个原子的运动一样。 这是一项全新的技术，在光通信和测量中具有实际应用。

TECHNICAL SUMMARYThis award supports theoretical research in condensed matter physics of strongly correlated quantum systems and quantum optics. This project builds on theoretical progress during the previous grant period and is motivated by recent experimental advances in both two-dimensional electron gas transport measurements and quantum mechanics of electrical circuits known as "circuit QED."Motivated by recent surprising experiments on thermal transport in quantum Hall edge states, the PI will investigate why thermal excitations travel much shorter distances than charge excitations. The PI will examine sources of energy dissipation internal to soft edges as well as external sources associated with the intrinsic high-frequency dissipation in the bulk of the two-dimensional electron gas. Motivated by the remarkable recent experimental progress in "circuit QED", the PI will investigate the many-body physics of strongly interacting microwave polaritons in lattices of qubits and resonators. The PI aims to show how lattices of superconducting qubits and resonators can be used to simulate strongly correlated bosons as well as frustrated quantum spins. The PI will also continue research in collaboration with experimentalists on circuit QED both in terms of fundamental quantum optics and quantum computation, and on opto-nano-mechanics.This research includes investigations of the quantum and statistical mechanics of diverse important quantum phases of matter including such topics as: quantum coherence in mesoscopic electrical systems, opto-mechanical systems, novel correlated states of microwave photons, and two-dimensional electron gases. Applications and extensions of quantum optics ideas for superconducting circuits and opto-mechanical systems will continue to be developed. Analytical as well as quantum trajectory, classical Monte Carlo, and other numerical techniques will be applied to the study of these phenomena. New numerical techniques with wide applicability will be sought, developed and investigated. The proposed work will advance our knowledge on these broad fronts and will make close contact with experiment.NONTECHNICAL SUMMARYThis award supports theoretical research and education on artificial atoms created from electrical circuits made from materials that are superconductors. Superconductors exhibit a quantum mechanical state which can conduct electricity without dissipation. Like real atoms, these artificial atoms can interact with a single quantum or photon of microwave radiation. These superconducting electrical circuits are being developed as the basic hardware for the construction of a quantum computer. A quantum computer would perform computations by manipulating quantum mechanical states and in principle can outperform the fastest existing computers for some problems. In addition to this potential practical application, these superconducting circuits can be used to study the fundamental quantum mechanics of many-particle systems interacting with electromagnetic fields. Normally electromagnetic waves pass through each other unaffected. In particle language, photons do not normally collide. However in the presence of artificial atoms, the photons effectively begin to interact and collide with each other. This can be used to study the quantum mechanics of many strongly colliding particles and to simulate phase transitions of solid materials using particles of light. The PI will propose experiments that can observe these new states of matter using light.The PI will also develop a theory of opto-mechanics in which the feeble pressure exerted by light can be used to cause mechanical motion of small objects and even cool their motion. Normally shining a laser on an object heats it up. However that it is possible to laser cool the motion of a material object just as the motion of individual atoms can be laser cooled. This is opening up a whole new technology with practical applications in optical communications and measurements.