Dynamics of superatom quantum dots: single photon emission

目前大多数量子信息技术平台都依赖于低温，要么通过低温冷却产生，比如量子点，要么通过激光冷却产生，比如原子和离子阱。在所有情况下，这种冷却都会带来相当大的开销，从而降低了扩展的可能性。在本提案中，我们探索了一种基于高激发室温原子的新型量子技术。关键的量子成分是高激发里德伯态之间的强相互作用。里德伯这个术语是用来描述一个原子在外层电子的平均位置离原子核很远的状态下，比基态原子要远10000个数量级。里德伯原子对电场极其敏感，对彼此也极其敏感。如果用激光将原子激发到里德伯态，则由强原子相互作用引起的能级转移通过一个称为封锁的过程抑制了多重激发。这种封锁机制导致高度纠缠的量子态被称为超原子。在超原子态中，单激发在所有组成原子中均匀分布。由于超原子只能支持一个电子激发，它可以被认为是半导体量子点的原子类似物。与大多数其他量子信息技术相比，热集成中的超原子量子点既不需要低温冷却，也不需要激光冷却，因此为量子信息科学提供了一个强大而实用的平台。该项目的目标是开发一种高带宽探针来探测热原子系综中超原子的动力学，并研究超原子的单光子发射。该项目将为可扩展、室温、量子计算奠定基础。

Most current platforms for quantum information technology rely on low temperature, either produced by cryogenic cooling as in the case of quantum dots or laser cooling as in the case of atom and ion traps. In all cases this cooling carries a considerable overhead which reduces the potential for scaling. In this proposal we explore a novel quantum technology based on highly excited room temperature atoms. The key quantum ingredient is the strong interactions between highly excited Rydberg states. The term Rydberg is used to describe an atom in a state where the average position of the outer electron is very far from the nucleus, of order 10,000 farther away than for a ground state atom. Rydberg atoms are extremely sensitive to electric fields and extremely sensitive to each other. If a laser is applied to excite atoms to a Rydberg state the energy level shifts induced by strong atomic interactions inhibit multiple excitations by a process known as blockade. This blockade mechanism results in a highly entangled quantum state known as a superatom. In the superatom state the single excitation is distributed equally among all the constituent atoms. As the superatom can support only one electronic excitation, it may be considered as the atomic analogue of a semiconductor quantum dot. In contrast to most other quantum information technologies, superatom quantum dots in thermal ensembles require neither cryogenic nor laser cooling, and consequently offer a robust and practical platform for quantum information science.The goal of the project is to develop a high bandwidth probe to detect the dynamics of superatoms in thermal atomic ensembles, and investigate single photon emission from a superatom. The project will lay the foundations for scalable, room temperature, quantum computing.