Quantum-QuBIC: Deterministic Cavity Quantum Electrodynamics for Quantum Information Studies

加州大学伯克利分校的Dan M.Stamper-Kurn标题：用于量子信息研究的确定性腔量子电动力学在量子信息科学的年轻领域，理论研究很快发现了范围如此惊人的潜力(计算的指数级加速，当前加密方案的不安全性)，以至于必须进行集中的实验活动。该项目致力于在一个潜在的领域取得根本性的实验进展，以实现这些理论想法：通过腔量子电动力学(CQED)合成光学和原子量子信息资源。虽然理论发展表明，CQED器件为量子信息处理提供了一种可扩展和强大的体系结构，但阻碍进一步发展的关键缺失元素是原子-腔系统的确定性负载。为了弥补这一差距，激光冷却、磁囚禁和玻色-爱因斯坦凝聚与腔量子电动力学等实验技术的强大而直接的整合正在进行中。这种合成显然对量子信息处理是有利的，它结合了由囚禁原子组成的控制良好的静止量子比特，其中量子信息存储在长寿命的内态中，以腔内发射的光子的形式飞行量子比特，以及将两者强耦合的一种手段。这一雄心勃勃的努力将使量子信息科学领域取得广泛的突破和创新。在这个项目中，在高精细光学腔的限制之外产生蒸发冷却的原子气体，然后绝热地放置在腔内，以提供超冷原子的储存库。单个原子，或数量可数的原子，通过原子超精细态之间的跃迁，从这个“被动”储存库被“激活”，然后被用于与量子信息和通信方案直接相关的广泛的基本应用。这些应用包括按需产生单光子，产生光场的非经典数态，实现拉曼CQED，通过它可以编程地打开和关闭原子-腔系统，以及在单光子水平上探索量子简并气体的量子和非线性光学性质。

EIA- 0130414Dan M. Stamper-KurnUniversity of California-BerkeleyTitle: Deterministic Cavity quantum Electrodynamics for Quantum Information StudiesIn the young field of quantum information science, theoretical investigations have quickly identified potentialities which are so astounding in scope (exponential speed-up of computation, the insecurity of current cryptographic schemes) that a focused experimental activity must be undertaken. This project is pursuing a fundamental experimental advance in one potential arena for the implementation of these theoretical ideas is proposed: the synthesis of optical and atomic quantum information resources through cavity quantum electrodynamics (CQED). While theoretical developments indicate that CQED devices offer a scalable and powerful architecture for quantum information processing, a key missing element which stands in the way of further progress is the deterministic loading of the atom-cavity system. To mend this gap, a powerful yet straightforward integration of the experimental techniques of laser cooling, magnetic trapping and Bose-Einstein condensation with cavity quantum electrodynamics is underway. This synthesis is clearly beneficial to quantum information processing, combining well controlled, stationary qubits comprised of trapped atoms wherein quantum information is stored in long-lived internal states, "flying qubits" in the form of photons emitted from the cavity, and a means of strongly coupling the two. This ambitious effort will enable a broad range of breakthroughs and innovations in the field of quantum information science.For this project, an evaporatively-cooled, and at times quantum degenerate, atomic gas is produced outside the confines of a high-finesse optical cavity, and then adiabatically placed inside the cavity to provide a reservoir of ultracold atoms. Single atoms, or a countable number of atoms, are "activated" from this "passive" reservoir by a transition between atomic hyperfine states, and are then used for a wide range of basic applications with direct relevance to quantum information and communication schemes. These applications include the generation of single photons on demand, the generation of non-classical number states of the optical field, the implementation of Raman CQED by which the atom-cavity system can be programmatically switched on and off, and an exploration of quantum and non-linear optical properties of quantum degenerate gases at the single photon level.