Waveguide QED: Quantum Optics of Multiple Two-Level-Systems Strongly Coupled to 1D Bosons

光与物质之间的强相互作用导致了新的物理现象和新的量子信息处理能力。迄今为止，显示出如此强交互作用的主要系统很难扩展和连接在一起。在这项工作中，从理论上研究了一个新的，开放的，具有强相互作用的可扩展系统：与一个或几个量子系统相互作用的一维波导。量子系统使波导中的光子纠缠和相关，产生一种新的多光子束缚态。这些束缚态的许多影响正在被研究，例如相关的光子封锁。目前正在评估它们在量子通信中的应用，特别是在量子密钥分发的加密任务中。该项目对两个更广泛的领域产生了重大影响。首先，奈米级光子装置通常包含波导和量子系统作为元件。这里研究的新物理效应正在导致对这些元素的更好理解，并可能导致定性的新设备。其次，新兴的“量子网络”范例包含了与此处提出的波导系统完全相似的元素。培养一名初级研究员是这个项目的一个关键影响：一名研究生涉及到所有方面，因此在多体和量子光学理论以及潜在的纳米光子学和量子信息应用方面得到了全面的培训。最后，共同项目负责人参与到当地学校的外展活动中。

Strong interaction between light and matter leads both to novel physical phenomena and to new quantum information processing capabilities. The main systems showing such strong interactions to date are difficult to scale and connect together. In this work, a new, open, scalable system with strong interactions is studied theoretically: a one-dimensional waveguide interacting with one or several quantum systems. The quantum systems cause the photons in the waveguide to become entangled and correlated, generating a new kind of multi-photon bound state. The many effects of these bound states are being investigated, such as the associated photon blockade. Their use for quantum communication, and in particular for the cryptography task known as quantum key distribution, are being evaluated. This project substantially impacts two broader fields. First, nanoscale photonic devices often involve such waveguides and quantum systems as building blocks. The new physical effects studied here are leading to a better understanding of such elements and may lead to qualitatively new devices. Second, the emerging paradigm of "quantum networks" involves elements that look exactly like the waveguide systems proposed here. Training a junior researcher is a key impact of this project: a graduate student is involved in all aspects and so is thoroughly trained in many-body and quantum optics theory as well as potential nano-photonics and quantum information applications. Finally, the co-PIs are involved in outreach in the local schools.