Simulating Electron - Phonon Processes with Photonics

量子计算有望给计算化学领域带来革命性的变化，因为它提供的计算机将随着它们要模拟的系统的规模呈指数级增长。然而，尽管已经提出了许多在量子计算机上执行计算化学计算的有希望的算法，但其中大多数算法需要的量子比特和门计数远远超过目前实验可用的数量。此外，虽然存在许多不同的实现量子技术的体系结构，但光子学，即操纵单个光子的过程，已经确立了自己作为提供短期量子优势的领先体系结构之一。玻色子和高斯玻色子采样等技术以相对较低的实验开销为量子优势提供了明确的途径。通过这个项目，我们希望建立能够利用光子学相对实验的简单性的算法，以便为计算化学提供短期的量子优势。该项目的目标是提出适用于计算化学的算法，这些算法可以在近期的量子光子器件上实现。在这个项目中，我们希望在以前工作的基础上，提出更广泛适用于量子化学的算法，特别是在电子结构理论和电子-玻色子结构理论中的算法。电子-声子相互作用被认为是导致一系列现象的原因，然而，用从头算方法模拟和预测它们仍然具有挑战性。我们希望提出可以使用低实验成本的技术来模拟这些系统的方法，从而为它们的工作提供新的见解。我们的目标是利用量子光子学固有的技术来提出模拟风格的量子器件，这种器件可以用于模拟量子化学，而不需要大量的量子比特/门计数。以前的工作已经表明，高斯玻色子采样可以用来模拟分子的振动光谱，而这里我们要看看玻色子采样(和其他相关技术)是否可以应用于计算化学中更广泛的问题。光子学提供了一个奇妙的技术“工具箱”，我们希望找到将其应用于计算化学的方法，希望为算法提供近期的实现。在整个项目中，我们希望与光子硬件团队和公司合作，实现我们提出的算法。我们目前正在与二元性量子光子公司合作，实现一种用线性光学解决电子结构理论问题的新算法，并希望在整个项目中继续合作。该项目属于EPSRC量子技术研究领域。

Quantum computing promises to revolutionise the field of computational chemistry by providing computers which scale exponentially in size along with the systems they aim to model. However, whilst many promising algorithms for performing computational chemistry calculations on quantum computers have been proposed most of these require qubit and gate counts far beyond what is currently available experimentally. Additionally, whilst many different architectures for implementing quantum technologies exist, photonics, the process of manipulating individual photons, has established itself as one of the leading architectures for providing near term quantum advantage. Techniques such as boson and gaussian boson sampling offer clear routes to quantum advantage with relatively low experimental overheads. With this project we hope to build algorithms which can utilise the relative experimental simplicity of photonics in order to provide near term quantum advantage for computational chemistry. The objective of the project is to propose algorithms useful for computational chemistry which can be implemented on near term quantum photonic devices. In this project we look to build on previous work which has shown the applicability of techniques such as gaussian boson sampling to quantum chemistry to propose algorithms which find more general applicability for quantum chemistry, particularly those in electronic structure theory and electron-boson structure theory. Electron - phonon interactions are posited to be responsible for a wide range of phenomena however simulating and predicting them from ab-initio methods remains challenging. We hope to propose ways in which low experimental cost techniques can be used to simulate these systems and thus offer new insights into their working. We aim to exploit techniques native to quantum photonics to propose analog style quantum devices which can be used to simulate quantum chemistry without the need to large qubit / gate counts. Previous work has shown that gaussian boson sampling can be used to simulate the vibrational spectra of molecules whereas here we look to see whether boson sampling (and other related techniques) can be applied to more broader problems in computational chemistry. Photonics offers a fantastic "toolbox" of techniques which we hope to find ways to apply to computational chemistry in the hopes of providing algorithms with near term implementations. Throughout this project we hope to collaborate with photonic hardware groups and companies to implement our proposed algorithms. We are currently involved with a collaboration with Duality Quantum Photonics to implement a novel algorithm for solving problems in electronic structure theory with linear optics and hope to continue the collaboration throughout the project. This project falls within the EPSRC quantum technologies research area.