无重置的浴辅助冷却
Bath-assisted cooling without resets
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- California Institute of Technology（加州理工学院）
- University of California, Berkeley（加州大学伯克利分校）
- Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）
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中文总结 AI 辅助
本文提出一种无需重置浴的冷却机制，通过将熵转移到随后解耦的浴自由度，在多项式对数时间内将任意混合态制备为相互作用基态，适用于弱相互作用有能隙费米子系统。
中文摘要 AI 辅助
将任意混合态冷却到纯基态需要将其熵转移到环境中。单次相干浴接触能否在不重复重置浴的情况下完成这一任务？我们开发了一种新的冷却机制，将输入信息转移到浴自由度中，这些自由度随后解耦，而系统和剩余的浴则沿基态路径演化。浴仅在最后被丢弃，系统哈密顿量在整个过程中保持开启且不变。我们针对一类具有局域相互作用的弱相互作用、有能隙费米子系统严格实现了这一机制。从任意混合态出发，我们的协议在总物理时间内制备相互作用基态，该时间与系统尺寸和逆全局迹范数误差呈多对数关系。该协议每个系统模式使用两个初始为空的浴模式，并在所有局域系统-浴耦合上共享单个脉冲。相同的脉冲可在不了解微观参数的情况下制备每个可容许系统自身的基态。这些保证直接源于非马尔可夫系统-浴动力学，无需有效的林德布拉德描述。
英文摘要
Cooling an arbitrary mixed state to a pure ground state requires transferring its entropy to an environment. Can a single coherent bath contact accomplish this without repeated bath resets? We develop a new cooling mechanism that transfers the input information into bath degrees of freedom that subsequently decouple, while the system and the remaining bath follow a ground-state path. The bath is discarded only at the end, and the system Hamiltonian remains on and unmodified throughout. We rigorously realize this mechanism for a class of weakly interacting, gapped fermionic systems with local interactions. Starting from any mixed state, our protocol prepares the interacting ground state in total physical time polylogarithmic in the system size and inverse global trace-norm error. It uses two initially empty bath modes per system mode and a single pulse shared across all onsite system--bath couplings. The same pulse prepares each admissible system's own ground state without knowledge of its microscopic parameters. The guarantees follow directly from a non-Markovian system--bath dynamics without an effective Lindbladian description.
