Integrating quantum sensors with bespoke quantum error correction

将量子传感器与定制量子纠错集成

• 批准号: EP/W028115/1
• 负责人: Yingkai Ouyang
• 金额: $ 142.17万
• 依托单位: University of Sheffield
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FW028115%2F1
• 关键词: Integrating; quantum; sensors; bespoke; error

Physical quantities such as time, phase, and entanglement cannot be measured directly, but instead must be inferred through indirect measurements. An important category of such indirect measurements is parameter estimation. Ideal quantum sensors would estimate physical quantities with unprecedented precision, but practical quantum sensors lose their quantum advantage because of noise. Incorporating quantum error correction codes into quantum sensors is an attractive theoretical approach to reduce noise, but is beset with practical difficulties. Namely, most quantum error correction codes (1) cannot be readily prepared in actual physical systems, (2) would introduce more errors than they correct during imperfect quantum error correction, and (3) can destroy the signal meant to be measured during quantum error correction.Most quantum error correction schemes are studied by abstracting away the physics of sensors, while quantum sensors are typically studied in the absence of quantum error correction. Mainstream approaches treat both quantum sensors and quantum error correction components as black boxes to be optimised separately. This project aims to break down the boundary between the quantum error correction black box and the quantum sensor black box, and integrate them to make an overall quantum error correction-integrated quantum sensor, by optimising over bespoke quantum error correction codes.A critical problem that using bespoke quantum error correction codes in optimising quantum sensors can overcome is the intractability of current numerical approaches in optimising quantum error correction codes for quantum sensors. These numerical methods impose no apriori structure on quantum error correction codes, and suffer from a runtime that increases exponentially in the number of particles. By choosing bespoke quantum codes that can be described with a tractable number of parameters, quantum sensors can be numerically optimised with respect to these codes in a scalable way.A prominent family of bespoke quantum error correction codes that this project will consider are symmetric codes. These codes are invariant under any permutation of the underlying particles, and have other practical advantages apart from the scalability in their numerical optimisations. First symmetric codes are very promising candidates for near-term implementation in physical devices, because their controllability by global fields could allow for their scalable physical implementations in near-term devices where addressability without cross-talk is difficult. Second, such symmetric codes can correct untracked particle losses, which are impossible to correct using conventional quantum error correction codes.This project will find optimal bespoke quantum error correction codes that maximise the quantum advantage attainable in the quantum estimation of classical fields, while also being easy to prepare in actual physical systems. The performance of symmetric codes will be compared with the performance of other families of bespoke quantum error correction codes. In the mathematical optimisation of the quantum sensor's precision, the project will take an integrated approach. Namely, the physical constraints of the quantum sensor such as the number of allowed qubits, operating temperature, and energy budget will be fixed, and the best quantum error correction codes for quantum sensors will be found. In doing so, this project will provide theoretical blueprints on how sensitivities of quantum sensors may be improved using existing quantum hardware.

时间、相位、纠缠等物理量无法直接测量，必须通过间接测量来推断。这种间接测量的一个重要类别是参数估计。理想的量子传感器将以前所未有的精度估计物理量，但实用的量子传感器由于噪声而失去了量子优势。将量子纠错码纳入量子传感器是一种有吸引力的降低噪声的理论方法，但面临实际困难。也就是说，大多数量子纠错码（1）在实际物理系统中不容易准备，（2）在不完美的量子纠错期间会引入比它们纠正的更多的错误，并且（3）可能会破坏在量子错误期间要测量的信号大多数量子纠错方案是通过抽象传感器的物理原理来研究的，而量子传感器通常是在没有量子纠错的情况下进行研究的。主流方法将量子传感器和量子纠错组件视为需要单独优化的黑匣子。该项目旨在通过对定制的量子纠错码进行优化，打破量子纠错黑匣子和量子传感器黑匣子之间的界限，将它们集成在一起，形成一个整体的量子纠错集成量子传感器。使用定制的量子纠错码来优化量子传感器可以克服当前数值方法在优化量子传感器的量子纠错码时的棘手问题。这些数值方法没有对量子纠错码强加先验结构，并且会受到粒子数量呈指数增长的运行时间的影响。通过选择可以用大量参数描述的定制量子代码，量子传感器可以以可扩展的方式针对这些代码进行数值优化。该项目将考虑的一个著名的定制量子纠错代码系列是对称代码。这些代码在底层粒子的任何排列下都是不变的，并且除了数值优化的可扩展性之外，还具有其他实际优势。第一个对称码是近期在物理设备中实现的非常有前途的候选者，因为它们的全局场可控性可以允许它们在近期设备中实现可扩展的物理实现，而在这些设备中，没有串扰的可寻址性是困难的。其次，这种对称码可以纠正未跟踪的粒子损失，这是使用传统量子纠错码无法纠正的。该项目将找到最佳的定制量子纠错码，最大限度地提高经典场量子估计中可获得的量子优势，同时也易于在实际物理系统中准备。对称码的性能将与其他定制量子纠错码系列的性能进行比较。在量子传感器精度的数学优化方面，该项目将采取综合方法。即，量子传感器的物理约束，例如允许的量子比特数、工作温度和能量预算将被固定，并且将找到量子传感器的最佳量子纠错码。在此过程中，该项目将提供有关如何使用现有量子硬件提高量子传感器灵敏度的理论蓝图。

项目成果

Approximate reconstructability of quantum states and noisy quantum secret sharing schemes

• DOI: 10.1103/physreva.108.012425
• 发表时间: 2023-02
• 期刊: ArXiv
• 作者: Yingkai Ouyang;K. Goswami;J. Romero;B. Sanders;Min-Hsiu Hsieh;M. Tomamichel