Quantum Error Correction in Neutral Atom Quantum Computer

中性原子量子计算机中的量子纠错

• 批准号: 2889069
• 金额: --
• 依托单位: University of Strathclyde
• 依托单位国家: 英国
• 项目类别: Studentship
• 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=studentship-2889069
• 关键词: Quantum; Error; Correction; Neutral; Atom

This project seeks to develop a dual-species platform for quantum computing and simulation with neutral atoms, providing a route to implementing active quantum error correction essential for future scaling beyond 100 qubits. This hardware will simultaneously provide a versatile platform for analogue computing and simulation due to the ability to independently control inter- and intra-species interactions, providing a route to performing studies of complex many-body physics as well as increasing the diversity of real-world optimisation problems that can be tackled using neutral atom hardware.Quantum computation (QC) offers a revolutionary approach to information processing, providing a route to efficiently solve classically hard problems encountered across a diverse range of sectors, including financial services (e.g. portfolio optimisation), energy (e.g. network design and energy distribution), logistics (e.g. route planning), and IT (e.g. search, machine learning). Using hardware operating under the laws of quantum mechanics also creates a platform for studying physical systems, such as complex materials and molecules, with early demonstrations showing applications in materials science and quantum chemistry that could eventually be scaled up to accelerate drug design or optimised materials for aerospace and manufacturing.Whilst large-scale applications will require thousands of qubits, in the near-term small (100 qubit) quantum processors will reach a regime in which the quantum hardware is able to solve problems not accessible even on the largest available conventional supercomputers. However, scaling of quantum systems remains a major experimental challenge, with high-fidelity performance demonstrated for small, state-of-the-art ion and superconductor systems but with significant technical barriers to extending this performance beyond around 10-20 qubits. Over the last decade, neutral atoms have emerged as one of the most promising platforms for quantum information processing, with a major advantage over competing technologies arising from the ability to scale to large numbers of identical qubits as required for performing practical quantum computing. To date, several experiments have demonstrated trapping of qubit arrays with > 256 qubits. To couple neutral atom qubits, highly excited Rydberg states are used which have extremely large electric dipole moments giving rise to strong and controllable interactions. These can be exploited to perform high fidelity multi-qubit gates, with F>0.95 demonstrated for two qubits and intrinsic fidelities of F>0.995 for multi-qubit gates, or for performing quantum simulation of controllable spin models as required for studying materials or solving optimisation problems.Whilst there has been significant experimental progress, a number of challenges currently limit scaling to larger array sizes for hardware based on a single atomic species. The first arises from finite vacuum lifetime due to collisions with background atoms ejecting atoms from the trap. For room temperature operation, this is typically 10s for 1 atom but means only 10ms for a 1000 atom array. This can be solved by moving to operation at cryogenic temperatures down to 4 K where the cold surfaces cause significant increase in lifetime upwards of > 6000 seconds meaning recovery of times > 6s even for 1000 atoms. The next issue lies in the long readout time for neutral atom qubits, typically requiring 10-50 ms to readout qubit states. With a single species, the cross-talk and scattered light mean readout is destructive across the whole array, with no clear pathway to performing local measurements required for error correction to reach fault tolerant operation.

该项目旨在开发一个用于中性原子量子计算和模拟的双物种平台，提供一种实现主动量子纠错的途径，这对于未来扩展到 100 个量子位以上至关重要。由于能够独立控制物种间和物种内相互作用，该硬件将同时为模拟计算和仿真提供多功能平台，为复杂多体物理研究以及增加现实世界的多样性提供一条途径可以使用中性原子硬件解决的优化问题。量子计算（QC）提供了一种革命性的信息处理方法，提供了一种有效解决各个领域遇到的经典难题的途径，包括金融服务（例如投资组合优化）、能源（例如网络设计和能源分配）、物流（例如路线规划）和 IT（例如搜索、机器学习）。使用在量子力学定律下运行的硬件还创建了一个用于研究物理系统（例如复杂材料和分子）的平台，早期演示展示了材料科学和量子化学中的应用，最终可以扩大规模以加速药物设计或优化材料航空航天和制造业。虽然大规模应用将需要数千个量子位，但在短期内，小型（100 个量子位）量子处理器将达到这样一种状态，即量子硬件能够解决即使在最大的可用传统超级计算机上也无法解决的问题。然而，量子系统的扩展仍然是一个主要的实验挑战，小型、最先进的离子和超导体系统已证明具有高保真性能，但要将这种性能扩展到约 10-20 个量子位以上，存在重大技术障碍。在过去的十年中，中性原子已成为量子信息处理最有前途的平台之一，与竞争技术相比，中性原子的主要优势在于能够根据执行实际量子计算的需要扩展到大量相同的量子位。迄今为止，多项实验已经证明了超过 256 个量子位的量子位阵列的捕获。为了耦合中性原子量子位，使用高度激发的里德堡态，其具有极大的电偶极矩，从而产生强且可控的相互作用。这些可用于执行高保真度多量子位门，两个量子位的 F>0.95 和多量子位门的 F>0.995 的固有保真度，或者根据研究材料或求解所需的可控自旋模型进行量子模拟优化问题。虽然实验取得了重大进展，但目前存在许多挑战限制基于单一原子种类的硬件扩展到更大的阵列尺寸。第一个原因是由于与背景原子的碰撞将原子从陷阱中喷射出来而导致有限的真空寿命。对于室温操作，1 个原子通常需要 10 秒，但对于 1000 个原子阵列来说仅需要 10 毫秒。这可以通过在低至 4 K 的低温下运行来解决，其中冷表面会导致寿命显着增加 > 6000 秒，这意味着即使对于 1000 个原子，恢复时间也 > 6 秒。下一个问题在于中性原子量子位的读出时间较长，通常需要 10-50 毫秒才能读出量子位状态。对于单一物种，串扰和散射光平均读数在整个阵列中具有破坏性，没有明确的途径来执行纠错所需的局部测量以达到容错操作。