Quantum: Ultrastable heterodyne quantum information

量子：超稳定外差量子信息

• 批准号: 0622100
• 负责人: Olivier Pfister
• 金额: $ 27.5万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0622100&HistoricalAwards=false
• 关键词: Quantum; Ultrastable; heterodyne; quantum; information

The proposal "Ultrastable heterodyne quantum information" is a renewal request to support theactivity of the Quantum Optics and Quantum Information (QOQI) group in the Physics Department of the University of Virginia (UVa).The foundation of quantum information is the use of the mathematical axioms of quantum mechanics to process, store, and transmit information. One expects several benefits from such an approach. First and foremost, quantum computing can yield an exponential speedup over classical computation for certain problems, such as predicted by Feynman for simulating quantum systems and by Shor for factoring integers. Moreover, quantum key distribution also brings complete security against eavesdropping to cryptography.Daunting challenges face attempts at experimentally realizing a quantum computer. On the one hand, one needs scalability, i.e. a large number of quantum logic units ("qubits" if binary ones or "qudits" if multi-state ones), all individually addressable and able to interact pairwise to become entangled. On the other hand, one needs this interaction to be strictly controlled and limited to the qubits or qudits, in order to avoid decoherence, which is the measurement-like, irreversible random evolution that results from interaction of a quantum register with the environment, a reservoir of quantum systems. Spontaneous emission is an example of decoherence for atoms.This project is dedicated to all-optical implementation of quantum information. Light has remarkable resistance to decoherence, due to its extremely weak (photon-photon) interaction. This, is turn, may present a difficulty for generating quantum entanglement (aforementioned pairwise interactions) but this problem is solved by the use of the mature and ever more sophisticated techniques of nonlinear optics and, in our case, of the laser-like, highly spatially and temporally coherent optical beams emitted by the optical parametric oscillator (OPO). The potential of OPO's for quantum information and, in particular, quantum communication, is very well known but is still far from having been fully exploited. The experimental approach of the proposal is centered on marrying the principles and techniques of ultra-high resolution laser spectroscopy and time-frequency metrology to those of nonlinear and quantum optics. This proposal aims at extending classical signal processing techniques into the quantum domain, in particular by using the frequency domain to encode the qudits and realize "quantum multiplexing," a quantum optical version of FM versus AM radio signals. This will be realized with state-of-the-art phase- and frequency-stabilized OPO's and will subsequently enable the transfer of quantum information, by teleportation or direct entanglement, between different types of physical qudits, such as alkali atoms (quantum memory) or photons in optical fibers (quantum bus). Applications of qudit-based dense coding to ultrasensitive optical measurements impossible with qubits are also discussed.Broader impacts of the proposed work comprise an active contribution to the UVa Physics graduate program, with the direct research advising of five students, of several Departmental seminars per year, and of a new advanced course "Quantum Optics and Quantum Information" (Phys 888), which was created in the spring of 2005 by the P.I. In addition, undergraduate students are periodically joining in the research effort at various levels, including graduate research. Also included are collaborative efforts with UVa Engineering faculty to foster cross-Departmental research. Finally, broader dissemination of research results includes the organization of interdisciplinary conferences at UVa, in association with the Department of Mathematics. The P.I. co-organized one such conference, "Coding Theory and Quantum Computing," in May 2003 and has plans to reiterate in the near future.

“超稳定外差量子信息”提案是一项更新请求，旨在支持弗吉尼亚大学 (UVa) 物理系量子光学和量子信息 (QOQI) 小组的活动。量子信息的基础是使用数学处理、存储和传输信息的量子力学公理。人们预计这种方法会带来很多好处。首先也是最重要的是，对于某些问题，量子计算可以比经典计算产生指数级的加速，例如费曼预测的模拟量子系统和肖尔预测的整数因式分解。此外，量子密钥分发还为密码学带来了完全的安全性，防止窃听。通过实验实现量子计算机的尝试面临着艰巨的挑战。一方面，需要可扩展性，即大量的量子逻辑单元（如果是二进制单元，则为“量子位”；如果是多态单元，则为“qudits”），所有这些单元都可以单独寻址，并且能够成对交互以变得纠缠。另一方面，需要严格控制这种相互作用并将其限制在量子位或量子数，以避免退相干，退相干是由量子寄存器与环境相互作用产生的类似测量的不可逆随机演化，量子系统的储存库。自发发射是原子退相干的一个例子。该项目致力于量子信息的全光学实现。由于其极弱的（光子-光子）相互作用，光具有显着的抗退相干性。反过来，这可能会给产生量子纠缠（前面提到的成对相互作用）带来困难，但这个问题可以通过使用成熟且越来越复杂的非线性光学技术来解决，在我们的例子中，是类似激光的高度光学技术。由光参量振荡器（OPO）发射的空间和时间相干光束。 OPO 在量子信息（特别是量子通信）方面的潜力是众所周知的，但仍远未得到充分开发。该提案的实验方法集中于将超高分辨率激光光谱和时频计量的原理和技术与非线性和量子光学的原理和技术结合起来。该提案旨在将经典信号处理技术扩展到量子域，特别是通过使用频域对量子进行编码并实现“量子复用”，即 FM 与 AM 无线电信号的量子光学版本。这将通过最先进的相位和频率稳定 OPO 来实现，随后将通过隐形传态或直接纠缠在不同类型的物理量子（例如碱原子（量子存储器））之间实现量子信息的传输或光纤中的光子（量子总线）。还讨论了基于 qudit 的密集编码在量子位不可能实现的超灵敏光学测量中的应用。拟议工作的更广泛影响包括对 UVa 物理学研究生项目的积极贡献，每年为五名学生提供直接研究建议，并举行几次院系研讨会，以及新的高级课程“量子光学和量子信息”（Phys 888），该课程由 P.I. 于 2005 年春季创建。此外，本科生定期参与各个级别的研究工作，包括研究生研究。还包括与弗吉尼亚大学工程学院的合作努力，以促进跨部门研究。最后，更广泛地传播研究成果包括与数学系联合在弗吉尼亚大学组织跨学科会议。 P.I. 2003 年 5 月共同组织了一场这样的会议，“编码理论和量子计算”，并计划在不久的将来重申。