EAGER: QAC: QCH: Holographic Quantum Algorithms for Simulating Many-Body Systems

准确的材料建模对于指导材料的发现和设计先进的电子器件至关重要。然而，在微观尺度上模拟材料的量子力学特性带来了巨大的计算挑战，甚至超过了最先进的超级计算机的能力。量子计算机提供了一种潜在的手段，通过利用量子物理的相同方面来规避这些挑战，这些方面使得传统计算机对材料模拟具有挑战性。虽然这是一种很有前途的方法，但用当前技术构建的量子计算机与在现实世界相关材料挑战中取得进展所需的量子计算机在尺寸和精度方面存在很大差距。为了缩小这一差距，该项目将开发量子软件和硬件原型，其中量子计算在有效压缩的量子数据上执行，以显着减少模拟大规模材料模型所需的资源。这些技术被称为“全息”，因为它们在低维物理系统上编码高维数据，就像全息图一样。这项研究将加速近期量子计算机在现实材料和化学建模方面的应用，量子计算机具有有限的内存和准确性。该项目将开发全息量子模拟技术，以有效压缩的形式间接编码材料的量子态，从而大大减少所需量子比特的数量，并从根本上限制噪声和错误的影响。这种压缩是通过一种算法来实现的，该算法在相干纠缠门和测量选定的量子位子集之间交替进行。这种方法代表了对传统量子算法框架的巨大背离，需要对量子算法和硬件设计进行根本性的重新思考。本项目将进行研究，为全息模拟技术建立一个基本的理论和实验原理证明。将开发先进的全息模拟技术来处理电子材料，2d和3d模型，并计算与现实世界设备相关的非平衡电子和热输运和光谱。量子态全息表示的基本能力和局限性将被严格地表征。项目团队将制作一个电路量子电动力学（cQED）测试平台，其中两级超导量子比特控制多级超导腔模式。多级空腔模式提供了比传统的两级量子比特更大的量子存储器，并且混合量子比特/空腔系统为创建量子纠缠提供了强大的方法。总之，与传统的仅量子位系统相比，这些优势将使使用相同数量的量子器件模拟更复杂的材料状态成为可能。项目团队将在cQED测试平台上演示开发的全息算法，并将其性能与商业量子计算平台上的互补模拟进行基准测试。从这个探索阶段获得的经验教训将用于设计可扩展的cQED设备，用于超越当前经典超级计算机能力的大规模问题的全息模拟。该奖项由材料研究部与化学部联合支持。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical SummaryAccurately modeling materials is essential for guiding materials discovery and designing advanced electronic devices. However, simulating the quantum-mechanical properties of materials on a microscopic scale poses tremendous computational challenges that often exceed the capabilities of even the most advanced supercomputers. Quantum computers offer a potential means to circumvent these challenges by harnessing the same aspects of quantum physics that make material simulation challenging for conventional computers. While a promising approach, there is a large gap in size and accuracy between quantum computers that can be built with current technology and those needed to make progress on real-world relevant materials challenges.To close this gap, this project will develop quantum software and hardware prototypes in which quantum computations are performed on efficiently compressed quantum data, to dramatically reduce the resources required to simulate large-scale material models. These techniques are dubbed “holographic” as they encode high-dimensional data on a lower-dimensional physical system, much like a hologram. This research will expedite the application of near-term quantum computers, with limited memory and accuracy, to realistic materials and chemical modeling.Technical summaryThis project will develop holographic quantum simulation techniques that indirectly encode the quantum state of a material in an efficiently compressed representation that greatly reduces the number of required qubits, and fundamentally limits the impact of noise and errors. This compression is achieved by an algorithm that alternates between coherent entangling gates and measurement of a selected subset of qubits. This approach represents a dramatic departure from conventional quantum algorithmic frameworks and will require a fundamental rethinking of quantum algorithm and hardware design.This project will conduct research to establish a basic theoretical and experimental proof-of-principle for holographic simulation techniques. Advanced holographic simulation techniques will be developed to treat electronic materials, 2d and 3d models, and compute non-equilibrium electronic and thermal transport and optical spectra relevant for real-world devices. The fundamental capabilities and limitations of holographic representations of quantum states will be rigorously characterized. The project team will fabricate a circuit quantum electrodynamics (cQED) testbed in which a two-level superconducting qubit controls a multi-level superconducting cavity mode. The multi-level cavity mode provides a larger quantum memory than a conventional two-level qubit, and the hybrid qubit/cavity system provides powerful methods to create quantum entanglement. Together, these advantages will enable simulation of more complex material states with the same number of quantum devices compared to conventional qubit-only systems. The project team will demonstrate the developed holographic algorithms on this cQED testbed and benchmark its performance against complementary simulations on commercial quantum computing platforms. Lessons learned from this exploratory phase will be used to design scalable cQED devices for holographic simulations of large-scale problems that exceed the capabilities of current classical supercomputers.This EAGER award by the Division of Materials Research is jointly supported with the Division of Chemistry.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.