制备局域哈密顿量的基态是理解量子多体系统的关键问题，在多个物理学领域具有应用，并与组合优化存在联系。虽然已有多种量子算法能够从初始近似出发，以高精度和可证明的保证制备基态，但当前设备仍受限于浅层电路。本文考虑分布式量子计算架构中 Alice 和 Bob 希望制备同一哈密顿量本征态的场景。我们证明，当设备之间可以共享有限纠缠时，本征态制备算法的电路深度可以降低。尤其是在其中一方拥有近乎完美的本征态时，该本征态可以更高效地广播给另一方。我们的方法只需要每个设备有一个辅助量子比特与外部纠缠。我们表明，在近收敛区域，协议每次运行对非目标振幅的平均相对抑制改善为 $1/(2\sqrt{e}) \approx 0.30$，优于单一设备单独运行同一协议所达到的平均相对抑制 $1/e\approx 0.37$。
英文摘要：
Preparing the ground state of a local Hamiltonian is a crucial problem in understanding quantum many-body systems, with applications in a variety of physics fields and connections to combinatorial optimization. While various quantum algorithms exist which can prepare the ground state with high precision and provable guarantees from an initial approximation, current devices are limited to shallow circuits. Here we consider the setting where Alice and Bob, in a distributed quantum computing architecture, want to prepare the same Hamiltonian eigenstate. We demonstrate that the circuit depth of the eigenstate preparation algorithm can be reduced when the devices can share limited entanglement. Especially so in the case where one of them has a near-perfect eigenstate, which is more efficiently broadcast to the other device. Our approach requires only a single auxiliary qubit per device to be entangled with the outside. We show that, in the near-convergent regime, the average relative suppression of unwanted amplitudes is improved to $1/(2\sqrt{e}) \approx 0.30$ per run of the protocol, outperforming the average relative suppression of $1/e\approx 0.37$ achieved with a single device alone for the same protocol.
Agent-assisted experimental strategy transfer across quantum processors
College of Physics and Electronic Engineering, Center for Computational Sciences, Sichuan Normal University（四川师范大学物理与电子工程学院计算科学中心）；Shenzhen SpinQ Technology Co., Ltd.（深圳-spinq科技有限公司）；College of Physics and Optoelectronic Engineering, Shenzhen University（深圳大学物理与光电工程学院）
Efficient quantum phase estimation with adaptive entanglement-assisted Hadamard test
School of Mathematical Sciences, Fudan University（复旦大学数学科学学院）；QICI Quantum Information and Computation Initiative, School of Computing and Data Science, The University of Hong Kong（香港大学计算与数据科学学院量子信息与计算倡议中心）；Shanghai Key Laboratory for Contemporary Applied Mathematics（当代应用数学上海市重点实验室）
Quantum-Selected Configuration Interaction: classical diagonalization of Hamiltonians in subspaces selected by quantum computers
QunaSys Inc.（QunaSys公司）；Graduate School of Engineering Science, Osaka University（大阪大学工学研究科）；Center for Quantum Information and Quantum Biology, Osaka University（大阪大学量子信息与量子生物学中心）
Determining Molecular Ground State with Quantum Imaginary Time Evolution using Broken-Symmetry Wave Function
Graduate School of Media and Governance, Keio University（庆应义塾大学媒体治理研究生院）；Quantum Computing Center, Keio University（庆应义塾大学量子计算中心）；Faculty of Environment and Information Studies, Keio University（庆应义塾大学环境信息学部）
