Wang Cheng, Banniard Louise, Børkje Kjetil, Massel Francesco, Mercier de Lépinay Laure, Sillanpää Mika A
Department of Applied Physics, Aalto University, Aalto, Finland.
Department of Science and Industry Systems, University of South-Eastern Norway, Kongsberg, Norway.
Nat Commun. 2024 Aug 27;15(1):7395. doi: 10.1038/s41467-024-51645-7.
Dissipation and the accompanying fluctuations are often seen as detrimental for quantum systems since they are associated with fast relaxation and loss of phase coherence. However, it has been proposed that a pure state can be prepared if external noise induces suitable downwards transitions, while exciting transitions are blocked. We demonstrate such a refrigeration mechanism in a cavity optomechanical system, where we prepare a mechanical oscillator in its ground state by injecting strong electromagnetic noise at frequencies around the red mechanical sideband of the cavity. The optimum cooling is reached with a noise bandwidth smaller than but on the order of the cavity decay rate. At higher bandwidths, cooling is less efficient as suitable transitions are not effectively activated. In the opposite regime where the noise bandwidth becomes comparable to the mechanical damping rate, damping follows the noise amplitude adiabatically, and the cooling is also suppressed.
耗散以及随之而来的涨落通常被视为对量子系统有害，因为它们与快速弛豫和相位相干性的丧失有关。然而，有人提出，如果外部噪声诱导合适的向下跃迁，同时阻止激发跃迁，就可以制备纯态。我们在一个腔光机械系统中演示了这种制冷机制，在该系统中，我们通过在腔的红色机械边带附近的频率注入强电磁噪声，将一个机械振子制备到其基态。当噪声带宽小于但约为腔衰减率时，可达到最佳冷却效果。在更高的带宽下，由于合适的跃迁没有被有效激活，冷却效率较低。在噪声带宽变得与机械阻尼率相当的相反情况下，阻尼绝热地跟随噪声幅度，冷却也会受到抑制。
