Single Photon and Single Atom Sources for Quantum Information Processing

美国威斯康星大学麦迪逊分校量子信息处理的单光子和单原子源本研究项目为量子信息科学的一系列应用展示了单光子和单原子源的工程新方法。实验方法从几千个Rb原子开始，这些原子以超高密度被困在远共振光束中。然后使用偶极子封锁机制创建多原子纠缠态，该机制是由Lukin等人（2001）最近提出的稠密原子蒸气中的原子-原子相互作用产生的。在单原子和单光子水平上，对纠缠原子的捕获系综进行光学操纵，以产生新的光源。使用额外的近共振激光束，原子根据其内部状态选择性地从陷阱中弹出。这使得光阱中单个原子的确定性加载，以及具有光学可控轨迹的“单”或“多原子按需”源成为可能。通过利用原子在基态和激发态之间的纠缠，一种具有衍射极限、可操纵发射模式的单光子源被创造出来。这种方法为在单量子对象层面上操纵物质和场提供了许多新颖的解决方案，并应用于量子通信、密码学和计算。这项工作的一个关键组成部分是通过外联和教育活动加强其影响。在当地学校的演讲和面向公众的量子信息和计算讲座使威斯康星大学能够与当地社区交流，包括麦迪逊地区蓬勃发展的光子学产业，这个研究项目的重要性和智力兴奋。

EIA-0218341Mark Saffman University of Wisconsin-MadisonSingle-Photon and single atom sources for quantum informaiton processingThis research project is demonstrating new ways of engineering single photon and single atom sources for a range of applications in quantum information science. The experimental approach starts with several thousand Rb atoms that are trapped at ultrahigh densities in a far-off-resonance optical beam. A many atom entangled state is then created using the dipole blockade mechanism that arises from atom-atom interactions in a dense atomic vapor as proposed recently by Lukin, et al. (2001).The trapped ensemble of entangled atoms is manipulated optically to create novel sources at the level of single atoms and single photons. Using additional near-resonant laser beams atoms are selectively ejected from the trap depending on their internal state. This enables deterministic loading of a single atom in an optical trap, as well as "single-" or "multiple-atom-on-demand" sources with optically controllable trajectories. By using entanglement between atoms in ground and excited internal states a single-photon source is being created that has a diffraction limited, steerable emission pattern. This approach is enabling a number of novel solutions to manipulation of matter and fields at the level of single quantum objects with applications to quantum communication, cryptography, and computing. A key component of this work is the enhancement of its impact through outreach and educational activities. Presentations at local schools and lectures for the general public on quantum information and computation are allowing the University of Wisconsin to communicate to the local community, including the burgeoning photonics industry in the Madison area, the importance and intellectual excitement of this research program.