Methods for simulating chemistry using quantum computers

使用量子计算机模拟化学的方法

• 批准号: 2446747
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2446747
• 关键词: Methods; simulating; chemistry; using; quantum

Electronic structure calculations are routinely used by researchers in chemistry, materials science, physics and engineering to model and predict molecular properties and processes from the well-established laws of quantum mechanics. They play a central role in computational quantum chemistry and are crucial for the discovery and rational design of new chemicals and materials such as catalysts, drugs, optoelectronic devices, and other functional molecular assemblies. However, they suffer from a practical difficulty: finding the exact solution to a quantum many-particle problem requires computational resources which scale exponentially with the size of the simulated system. This is a consequence of the exponential scaling of the space of possible solutions as a function of the number of degrees of freedom that are used in the simulation, which is proportional to the size of the simulated system. Hence, when performed on a conventional computer, quantum simulations of chemistry are constrained to very small molecules or require strong approximations which severely limit the accuracy of simulations.Quantum computers could perform certain computational tasks much faster than conventional ("classical") computers. In particular, they could circumvent the curse of dimensionality which limits the accuracy of quantum simulation on classical machines. Consequently, quantum simulation is widely believed to be one of the most promising applications of quantum computers.Currently available quantum devices can create and control quantum states with increasing complexity, despite being imperfect and limited in size. Due to the recent emergence of noisy, intermediate-scale quantum (NISQ) devices, much research is being devoted towards finding quantum algorithms which can exploit such near-term machines to achieve a significant speed-up when simulating chemical systems of interest (a prospect often termed "quantum advantage"). However, research on quantum algorithms involves techniques suited for both NISQ as well as long-term, fault tolerant quantum computers.This DPhil project will aim to investigate methods for efficiently simulating chemical systems using quantum computers. In particular, new approaches will be developed for finding accurate and efficient mappings which encode electronic molecular systems into states of qubits, as well as algorithms which can exploit the unique power of quantum computers to solve for the eigenstates of electronic Hamiltonians. Such developments could enable a fundamental leap forward in electronic structure calculations and unlock the possibility of accurate computational quantum-mechanical modeling of complex molecular systems.The project falls within the EPSRC Quantum Technologies research area.The DPhil student will be co-supervised by Prof. David Tew (Department of Chemistry, University of Oxford) and Prof. Simon Benjamin (Department of Materials, University of Oxford). The work will be theoretical but will involve a collaboration with the Quantum Photonics group of Prof. Anthony Laing, University of Bristol, where quantum algorithms will be tested on real quantum devices developed in the group.

电子结构计算通常被化学、材料科学、物理学和工程学的研究人员用来根据公认的量子力学定律对分子的性质和过程进行建模和预测。它们在计算量子化学中发挥着核心作用，对于发现和合理设计新的化学品和材料，如催化剂、药物、光电子器件和其他功能分子组件至关重要。然而，他们面临着一个实际困难：找到量子多粒子问题的准确解决方案需要计算资源，而计算资源随着模拟系统的大小呈指数级增长。这是可能解的空间作为模拟中使用的自由度数的函数的指数缩放的结果，而自由度数与模拟系统的大小成比例。因此，当在常规计算机上执行量子化学模拟时，量子化学模拟仅限于非常小的分子或需要强近似，这严重限制了模拟的准确性。量子计算机执行某些计算任务的速度比传统(经典)计算机快得多。特别是，它们可以绕过维度诅咒，后者限制了经典机器上量子模拟的准确性。因此，量子模拟被广泛认为是量子计算机最有前途的应用之一。目前可用的量子设备可以创建和控制越来越复杂的量子态，尽管这些设备并不完美，而且尺寸有限。由于最近出现了噪声、中等规模的量子(NISQ)设备，人们正致力于寻找量子算法，这些算法可以利用这种近期机器在模拟感兴趣的化学体系时实现显著的加速(这种前景通常被称为“量子优势”)。然而，量子算法的研究涉及到既适用于NISQ又适用于长期容错量子计算机的技术。这个DPhil项目的目标是研究使用量子计算机高效模拟化学系统的方法。特别是，将发展新的方法来寻找准确和有效的映射，将电子分子系统编码成量子比特态，以及可以利用量子计算机的独特能力来求解电子哈密顿本征态的算法。这些发展可能使电子结构计算实现根本性飞跃，并开启复杂分子系统精确计算量子力学模型的可能性。该项目属于EPSRC量子技术研究领域。DPhil的学生将由牛津大学化学系的David Tew教授和牛津大学材料系的Simon Benjamin教授共同指导。这项工作将是理论上的，但将涉及与布里斯托尔大学安东尼·莱恩教授的量子光子学小组的合作，量子算法将在该小组开发的真实量子设备上进行测试。