High-Fidelity, Long-Term Coherent Memory with Bose-Einstein Condensates for Implementation of Quantum Repeater Architectures

采用玻色-爱因斯坦凝聚的高保真、长期相干存储器，用于实现量子中继器架构

• 批准号: 1104347
• 负责人: Lene Hau
• 金额: $ 56万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-15 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1104347&HistoricalAwards=false
• 关键词: Fidelity; Long; Term; Coherent; Memory

In the laboratory of the PI, light pulses are stored for 1.5 seconds in a coherent optical memory formed by a Bose-Einstein condensate. In the experiments, a light pulse is injected into the BEC, where it is converted to a matter imprint. Atom interactions in the condensate are manipulated with use of magnetic fields, and the system enters a phase separating regime: much like oil and water separate, the created matter imprint digs a hole for itself in the host condensate. The imprint is nestled in this void and avoids collisions with condensate atoms, thereby minimizing losses. As a result, the matter imprint can be stored over extended time scales. The imprint is then moved to the outer tip of the condensate where it is converted back to light, and, from this location, the light pulse exits the condensate with minimal loss. With optimization of the atom-trap design and optical storage mechanism, the efficiency for optical imprinting and retrieval is being increased ten-fold, and the storage time for the matter imprint is being extended to the one-minute regime. Such observations represent a milestone and will allow for entanglement distribution with quantum repeaters over distances well beyond what can be achieved with optical pulses and direct fiber coupling. Actual construction of a prototype quantum repeater setup is being carried out and the performance will be tested by Bell measurements. The results have important applications for creation of long-distance quantum networks for distributed quantum computing, teleportation, and cryptography for secure data transfer.In this project, the extreme manipulation of light is achieved and is being utilized for powerful optical information processing. The experiments are based on slowed and stopped light in ultra-cold Bose-Einstein condensates. Light pulses are injected into a condensate, where they are slowed and spatially compressed by factors of 100 millions, then extinguished and converted to matter copies. A resulting matter copy can easily be manipulated with lasers and magnetic fields, and can be stored over extended time scales: for seconds and even minutes. This is long enough for light -- under normal circumstances -- to travel back and forth to the Moon. The achieved storage times and control over the matter imprints have important applications for creation of entangled states of light and matter and for creation of long-distance quantum networks for quantum computing, teleportation, and quantum cryptography for secure data transfer. The research also continues to create tremendous interest among scientists and laymen alike. The research is getting exposure in media and at events that target very diverse audiences, including the Annenberg Online class on Manipulating Light, and Chicago's Museum of Science and Industry's new permanent exhibition and associated interactive games that are aimed at kids. The PI and her students dedicate significant amounts of their time to convey their excitement about science and to help educate the public about scientific research.

在PI的实验室中，光脉冲被存储在由玻色-爱因斯坦凝聚形成的相干光存储器中1.5秒。在实验中，光脉冲被注入BEC，在那里它被转换为物质印记。冷凝物中的原子相互作用通过磁场来控制，系统进入相分离状态：就像油和水分离一样，所产生的物质印记在宿主冷凝物中为自己挖了一个洞。印记位于这个空隙中，避免与凝聚原子碰撞，从而最大限度地减少损失。因此，物质印记可以在延长的时间尺度上存储。然后，印记被移动到冷凝物的外尖端，在那里它被转换回光，并且从这个位置，光脉冲以最小的损失离开冷凝物。随着原子阱设计和光学存储机制的优化，光学印记和检索的效率正在提高十倍，物质印记的存储时间正在延长到一分钟的制度。这样的观测是一个里程碑，将允许量子中继器在远超过光脉冲和直接光纤耦合所能实现的距离上进行纠缠分布。目前正在实际建造一个原型量子中继器，其性能将通过贝尔测量进行测试。这些结果对于创建用于分布式量子计算的长距离量子网络、隐形传态和用于安全数据传输的密码学具有重要的应用。在该项目中，实现了对光的极端操纵，并用于强大的光学信息处理。这些实验是基于超冷玻色-爱因斯坦凝聚体中减慢和停止的光。光脉冲被注入凝聚体中，在那里它们被减慢并在空间上压缩了1亿倍，然后熄灭并转化为物质副本。由此产生的物质副本可以很容易地用激光和磁场进行操纵，并且可以在很长的时间尺度上存储：几秒钟甚至几分钟。在正常情况下，这段时间足以让光往返月球。实现的存储时间和对物质印记的控制对于创建光和物质的纠缠态以及创建用于量子计算、隐形传态和用于安全数据传输的量子密码学的长距离量子网络具有重要的应用。这项研究也继续在科学家和外行之间产生巨大的兴趣。这项研究正在媒体和针对不同受众的活动中曝光，包括安嫩伯格在线操纵光课程，以及芝加哥科学与工业博物馆新的永久展览和针对儿童的相关互动游戏。 PI和她的学生投入大量的时间来传达他们对科学的兴奋，并帮助教育公众科学研究。