Quantum Microwaves from Superconducting Quantum Circuits

超导量子电路是基础和应用量子研究的成熟平台，谷歌、英特尔、D-Wave和IBM的重大投资以及北美、欧洲和亚洲的政府都证明了这一点。在这笔探索基金的支持下，我们将为世界范围内开发这项令人兴奋的技术做出重要贡献。模拟量子模拟是一种构建量子电路以直接模拟或“模拟”感兴趣的系统的范例。其原理与使用简单的半导体电路来模拟火箭的轨迹是相同的，这在20世纪60年代数字计算能力变得便宜之前很常见。类似地，模拟量子模拟是在大规模数字量子计算机出现之前解锁量子计算潜在优势的一条很有前途的途径。作为第一个试验台，我们将模拟强相互作用的量子场论。这些理论描述了量子色动力学等基本模型，但也描述了一系列具有重要技术意义的量子材料，如高温超导体。具有参数腔的光量子计算--光量子计算(OQC)是量子信息的主要范式。在标准的OQC中，量子信息是由激光在大桌面上传输来处理的。取而代之的是，我们将使用集成电路中的芯片传输微波。本课题组开发的参数腔是利用微波光子进行片上光学质量控制的一个很有前途的平台。我们已经演示的功能实现了线性量子光学的所有工具。然而，已经证明，即使是一组完整的线性运算也不能提供量子加速比。需要所谓的非高斯态作为输入才能获得量子优势。特别令人感兴趣的是一种被称为立方相态的“魔力状态”，这种状态对实验者来说仍然难以捉摸。我的团队最近取得的进展使我们能够展示这种神奇状态的重要组成部分。我们将继续我们的工作，以产生有用的魔力状态，并开发片上OQC。量子照明作为提高雷达灵敏度的一种可能途径，近年来受到了广泛的关注。齐应用了一种独特的量子效应，称为纠缠。与许多潜在的量子应用不同，QI似乎对传输过程中的噪声和损耗非常健壮，这表明它可能有实际应用。最近的实验已经证明了光学频率下QI的基本原理。这是一个重要的原则证明，但传统雷达系统通常使用微波频率。我们的参数腔也是量子干涉所需的纠缠微波光子的极好来源。我们将在现有结果的基础上，演示环境条件下的微波QI。展示环境微波的量子优势将是一项重要的突破。

Superconducting quantum circuits are a well-established platform for both fundamental and applied quantum research, as evidenced by major investments from Google, Intel, D-Wave and IBM, as well as by governments across North America, Europe and Asia. Supported by this Discovery grant, we will make important contributions to the world-wide effort to exploit this exciting technology. Analog quantum simulation is a paradigm where a quantum circuit is constructed to directly mimic or "simulate" a system of interest. The principle is the same as using a simple semiconductor circuit to simulate the trajectory of a rocket, as was common through the 1960s before digital computing power became inexpensive. Similarly, analog quantum simulation is a promising path to unlock the potential advantages of quantum computing before large-scale digital quantum computers become available. As a first testbed, we will simulate strongly-interacting quantum field theories. These theories describe fundamental models such as quantum chromodynamics, but also a wide array of technologically important quantum materials such as high-temperature superconductors. Optical Quantum Computing with Parametric Cavities - Optical quantum computing (OQC) is a major paradigm of quantum information. In standard OQC, quantum information is processed by laser light traveling on a large table top. We would instead use microwaves traveling on chip in an integrated circuit. The parametric cavities developed by my group are a promising platform for on-chip OQC using microwave photons. The functionality we have already demonstrated implements all the tools of linear quantum optics. However, it has been shown the even a complete set of linear operations cannot give a quantum speedup. So-called non-Gaussian states are needed as inputs to achieve a quantum advantage. Of particular interest is a type of "magic state," called the cubic-phase state, which has remained elusive to experimenters. Recent advances by my group have allowed us to demonstrate important building blocks of this magic state. We will continue our work to produce a useful magic state and develop on-chip OQC. Quantum illumination (QI) has recently gained attention as a possible avenue to improve the sensitivity of radar. QI applies a unique quantum effect, called entanglement. Unlike many potential quantum applications, QI seems to be very robust to noise and losses during transmission, suggesting that it may have practical applications. Recent experiments have demonstrated the basic principle of QI at optical frequencies. This is an important proof of principle, but conventional radar systems typically use microwave frequencies. Our parametric cavities are also an excellent source of the entangled microwave photons need for QI. We will build on our existing results to demonstrate microwave QI in ambient conditions. Demonstrating a quantum advantage for ambient microwaves would be an important breakthrough.