近日，瑞典查尔姆斯理工大学的Simone Gasparinetti&Mohammed Ali Aamir及其研究小组与美国NIST和马里兰大学的Nicole Yunger Halpern等人合作并取得一项新进展。经过不懈努力，他们利用热驱动量子制冷机自动重置超导量子比特。相关研究成果已于2025年1月9日在国际知名学术期刊《自然—物理学》上发表。
该研究团队展示了一种由超导电路构成的有用量子吸收式制冷机。研究人员利用它将一个跨导量子比特冷却到低于任何单一可用热浴所能达到的温度，从而将量子比特重置为适合量子计算的初始状态。这一过程由热梯度驱动，且是自主的，无需外部反馈。该制冷机利用了目标量子比特与两个辅助量子电码之间经过设计的三体相互作用。
每个辅助量子电码都与一个物理热浴耦合，该热浴是通过充满合成准热辐射的微波波导实现的。如果目标量子比特最初处于完全激发状态，其有效温度将达到约22毫开尔文的稳定水平，低于现有最先进的重置协议所能达到的水平。这项研究结果表明，具有传播热场的超导电路可以用于实验探索量子热力学，并将其应用于量子信息处理任务。
据悉，尽管经典热机驱动着工业发展和现代生活，但量子热机尚未展现其实际应用价值。
附：英文原文
Title: Thermally driven quantum refrigerator autonomously resets a superconducting qubit
Author: Aamir, Mohammed Ali, Jamet Suria, Paul, Marn Guzmn, Jos Antonio, Castillo-Moreno, Claudia, Epstein, Jeffrey M., Yunger Halpern, Nicole, Gasparinetti, Simone
Issue&Volume: 2025-01-09
Abstract: Although classical thermal machines power industries and modern living, quantum thermal engines have yet to prove their utility. Here, we demonstrate a useful quantum absorption refrigerator formed from superconducting circuits. We use it to cool a transmon qubit to a temperature lower than that achievable with any one available bath, thereby resetting the qubit to an initial state suitable for quantum computing. The process is driven by a thermal gradient and is autonomous, requiring no external feedback. The refrigerator exploits an engineered three-body interaction between the target qubit and two auxiliary qudits. Each auxiliary qudit is coupled to a physical heat bath, realized with a microwave waveguide populated with synthesized quasithermal radiation. If the target qubit is initially fully excited, its effective temperature reaches a steady-state level of approximately 22mK, lower than what can be achieved by existing state-of-the-art reset protocols. Our results demonstrate that superconducting circuits with propagating thermal fields can be used to experimentally explore quantum thermodynamics and apply it to quantum information-processing tasks.
DOI: 10.1038/s41567-024-02708-5
Source: https://www.nature.com/articles/s41567-024-02708-5