Temporal Multimode Transformations for Quantum Information Science

量子信息科学与技术（QIST）是一个快速发展的跨学科研究领域，旨在利用量子系统的行为，为包括计算，通信和传感在内的一系列应用提供新的能力。各种物理系统正在探索其编码和操纵量子比特（qubit）的潜力，每种系统都有不同的优势和挑战。在QIST中，光在量子信息的传输和提取中起着重要作用。迄今为止，在光场中编码量子信息的大多数方法都集中在光束的偏振和空间分布上，这与将形成未来量子互联网骨干的光纤网络不兼容。在这个项目中，该小组将开发一个实验平台，以量子光的时间模式对量子信息进行编码，其中光子（光“粒子”）的时间形状和颜色携带信息。通过时间模式编码实现的量子应用包括线性光学量子计算、量子通信、传感和模拟。除了科学和技术的影响，该项目将通过培训研究生和本科生，为量子准备的劳动力做出贡献。该项目将开发在单光子水平上控制和测量光脉冲的方法，并将其应用于量子信息应用的目标操作。整形光学激光脉冲的常用方法（采用滤波或放大）与量子光不兼容。因此，为了解决光的时间模式，需要修改光脉冲的光谱和时间相位的单位（仅相位）变换。对于量子应用，大多数努力都集中在用于脉冲控制的非线性光学手段上。在这里，该小组将使用具有电光时间相位调制和色散光谱相位的线性光学方法。首要的研究目标是实现时间模式上的酉变换。所提出的方法是通过使用现成组件顺序应用时间相位调制和频谱色散来实现这种时间模式变换。为了克服在使用电光调制器的时间相位的应用中出现的定时不稳定性的挑战，射频驱动场将直接从产生待操纵的单光子的光脉冲产生。为了验证有针对性的时间模式转换的实验实施，一种方法来表征的转换-一种技术称为量子过程层析成像-基于光谱干涉将developed.This奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Quantum information science and technology (QIST) is a rapidly evolving field of interdisciplinary research that aims to harness the behavior of quantum systems to enable new capabilities for a range of applications including computation, communications, and sensing. A variety of physical systems are being explored for their potential to encode and manipulate quantum bits (qubits), each of which presents different advantages and challenges. Within QIST, light plays an important role in the transport and extraction of quantum information. To date most approaches to encoding quantum information in light fields has focused on polarization and spatial profile of light beams, which are not compatible with optical fiber networks that will form the backbone of a future quantum Internet. In this project the group will develop an experimental platform to encode quantum information in temporal modes of quantum light, where the temporal shape and color of a photon, a light ‘particle,’ carries information. Quantum applications enabled by temporal mode encoding include linear optics quantum computing, quantum communications, sensing, and simulations. Beyond the scientific and technological impacts, this project will contribute to a quantum-ready workforce through training of graduate and undergraduate students. This project will develop methods to control and measure pulses of light at the single-photon level and its application to perform targeted operations for quantum information applications. Common approaches to shape optical laser pulses, which employ filtering or amplification, are not compatible with quantum light. To address the temporal modes of light thus requires unitary (phase only) transformations that modify the spectral and temporal phase of the light pulses. For quantum applications most efforts have focused on nonlinear optical means for pulse control. Here the group will use linear-optical methods with electro-optic temporal phase modulation and dispersive spectral phase. The overarching research goal is the implementation of unitary transformations on temporal modes. The proposed approach is to realize such temporal mode transformations by the sequential application of temporal phase modulation and spectral dispersion using off-the-shelf components. To overcome challenges in timing instability that arise in the application of temporal phase using electro-optic modulators, the radio-frequency driving field will be directly generated from the optical pulses that generate the single photons to be manipulated. To verify that the targeted temporal mode transformations are experimentally implemented, an approach to characterize the transformations – a technique known as quantum process tomography – based upon spectral interferometry will be developed.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.