Quantum Input-Output Modeling in the Ultra-Fast Domain: Theoretical Foundations and Experimental Validation

该项目的主要目的是发展新的理论和新的实验室工具来分析超快（极短）光脉冲的量子力学特性。该项目将超越我们所熟悉的条件，主要局限于长时间尺度和缓慢变化的光模式（光学模式）。这一进展将支持未来量子工程的努力，利用超快光脉冲进行计算、通信和传感。在量子技术的背景下，超快量子光有望通过提高计算速度、信息通过通信通道传输的速率或传感器的带宽（响应速度）来提供比缓慢变化的光更大的优势。该项目的主要主题是探索产生具有明显量子特性的超快光脉冲的实用方法（与传统光脉冲不同，例如，表现出极低的噪声），改进分析超快光脉冲之间量子纠缠的方法，以及开发一类新的类似激光的光学器件，称为超快光学参量振荡器。这对未来量子技术的潜在应用具有广泛的工程研究意义。从技术上讲，该项目的理论部分是围绕纳米光子器件和电路的新器件概念的具体研究，以产生和操纵具有非高斯量子态的超快光脉冲的少光子态。这项工作将解决具有超快泵浦和信号场的纳米光子器件中量子非线性建模的基本问题，其应用动机包括立方相门的合成（用于量子计算）和在少光子状态下实现具有泵浦阈值的超快光学参量振荡器。后一种器件预计需要在具有许多（成千上万）相关光学模式的光学系统的量子动力学有效建模方面取得重大进展。该项目的实验部分旨在开发和验证用于表征同步泵浦光参量振荡器中信号脉冲时域纠缠的测量方法，这有望与凝聚态物理（如张量网络状态）的概念建立紧密的联系。实验部分还将包括对原型同步泵浦光参量振荡器的进一步研究，其中相干反馈用于建立跨输出脉冲串的可编程纠缠结构。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The primary aims of this project are to develop new theory and new laboratory tools for analyzing the quantum-mechanical properties of ultrafast (very short) pulses of light. The project will push beyond familiar conditions, which is largely limited to long timescales and slowly-varying patterns of light (optical modes). The advances made will support future quantum engineering efforts to utilize ultrafast light pulses for computing, communication, and sensing. In the context of quantum technology, ultrafast quantum light may be expected to provide advantages over slowly-varying light by increasing the speed of computation, the rate at which information can be transmitted through a communication channel, or the bandwidth (response speed) of a sensor. The major themes of the project are the exploration of practical approaches to generating ultrafast light pulses with manifestly quantum properties (distinguished from conventional light pulses, for example, by exhibiting extremely low noise), the improvement of methods for analyzing quantum entanglement among ultrafast light pulses, and the development of a new class of laser-like optical devices called ultrafast optical parametric oscillators, which are of great interest to a broad spectrum of engineering research for potential use in future quantum technologies.Technically speaking, the theoretical component of this project is structured around concrete studies of new device concepts for nanophotonic devices and circuits to generate and manipulate few-photon states of ultrafast optical pulses with non-Gaussian quantum states. The work will address fundamental issues in the modeling of quantum nonlinearities in nanophotonic devices with ultrafast pump and signal fields, motivated by applications such as the synthesis of cubic phase gates (for quantum computing) and realizing ultrafast optical parametric oscillators with pump thresholds in the few-photon regime. The latter devices are expected to require significant advances in efficiently modeling the quantum dynamics of optical systems with many (tens of thousands) of relevant optical modes. The experimental component of this project aims at the development and validation of measurement methods for characterizing time-domain entanglement among signal pulses in synchronously-pumped optical parametric oscillators, which is expected to develop strong connections with concepts from condensed matter physics (such as tensor network states). The experimental component will also include further work on a prototype synchronously-pumped optical parametric oscillator in which coherent feedback is utilized to establish programmable structures of entanglement across the output pulse train.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.