标题： 可证明有效的局部驱动量子热态准备 显示英文标题

标题： Provably Efficient Quantum Thermal State Preparation via Local Driving

摘要： 构建对应于给定哈密顿量 $H$ 的热密度矩阵 $\rho_{\beta}\propto e^{-\beta H}$ 是量子多体物理学中一项核心研究任务，在使用量子计算机进行研究时尤为重要。 尽管{原则上}可以通过近期构建的高效可模拟林德布拉德主方程得到解决——这些方程可证明 $\rho_{\beta}$ 为稳态 [C.-F. Chen {\it et al}, arXiv:2311.09207]——但它们的实现需要大规模量子计算资源，因此在当前甚至近期的量子设备上{在实践中}都具有挑战性。 在此，我们提出了一种近似构建量子热态的方案，该方案仅需要[重复]实现三个现成的要素：(a) $H$ 的模拟；(b) 与辅助量子比特进行严格局域但时间相关的耦合；以及 (c) 重置辅助设备。 我们给出了严格的性能保证，这些保证独立于对$H$的详细物理知识，除了它的局域性之外。 显示英文摘要

摘要： Preparing the thermal density matrix $\rho_{\beta}\propto e^{-\beta H}$ corresponding to a given Hamiltonian $H$ is a task of central interest across quantum many-body physics, and is particularly salient when attempting to study it with quantum computers. Although solved {in principle} by recent constructions of efficiently simulable Lindblad master equations -- that provably have $\rho_{\beta}$ as a steady state [C.-F. Chen {\it et al}, arXiv:2311.09207] -- their implementation requires large-scale quantum computational resources and is hence challenging {in practice} on current or even near-term quantum devices. Here, we propose a scheme for approximately preparing quantum thermal states that only requires the [repeated] implementation of three readily available ingredients: (a) analog simulation of $H$; (b) strictly local but time-dependent couplings to ancilla qubits; and (c) reset of the ancillas. We give rigorous performance guarantees independent of detailed physical knowledge of $H$ beyond its locality.