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来为包括计算、通信和传感在内的一系列应用提供新的能力。人们正在探索各种物理系统在编码和操作量子比特(Qubit)方面的潜力，每种系统都呈现出不同的优势和挑战。在QIST中，光在量子信息的传输和提取中扮演着重要的角色。到目前为止，大多数在光场中对量子信息进行编码的方法都集中在光束的偏振和空间分布上，这与将构成未来量子互联网主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编码量子信息，其中光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，这个项目将通过培训研究生和本科生来促进量子就绪的劳动力队伍。该项目将开发在单光子水平上控制和测量光脉冲的方法，并将其应用于执行量子信息应用的有针对性的操作。对光学激光脉冲进行整形的常见方法使用了滤波或放大，这些方法与量子光不兼容。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一(仅相位)变换。对于量子应用，大多数努力都集中在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。主要的研究目标是在时间模式上实现么正变换。所提出的方法是通过使用现成的元件顺序地应用时间相位调制和频谱色散来实现这种时间模式转换。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方面的挑战，射频驱动场将由产生待操纵的单个光子的光脉冲直接产生。为了验证目标时间模式转换是在实验中实现的，将开发一种基于光谱干涉测量学的表征转换的方法-一种称为量子过程层析成像的技术。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.