Camati Patrice A, Peterson John P S, Batalhão Tiago B, Micadei Kaonan, Souza Alexandre M, Sarthour Roberto S, Oliveira Ivan S, Serra Roberto M
Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Avenida dos Estados 5001, 09210-580 Santo André, São Paulo, Brazil.
Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Rio de Janeiro, Brazil.
Phys Rev Lett. 2016 Dec 9;117(24):240502. doi: 10.1103/PhysRevLett.117.240502. Epub 2016 Dec 5.
Maxwell's demon explores the role of information in physical processes. Employing information about microscopic degrees of freedom, this "intelligent observer" is capable of compensating entropy production (or extracting work), apparently challenging the second law of thermodynamics. In a modern standpoint, it is regarded as a feedback control mechanism and the limits of thermodynamics are recast incorporating information-to-energy conversion. We derive a trade-off relation between information-theoretic quantities empowering the design of an efficient Maxwell's demon in a quantum system. The demon is experimentally implemented as a spin-1/2 quantum memory that acquires information, and employs it to control the dynamics of another spin-1/2 system, through a natural interaction. Noise and imperfections in this protocol are investigated by the assessment of its effectiveness. This realization provides experimental evidence that the irreversibility in a nonequilibrium dynamics can be mitigated by assessing microscopic information and applying a feed-forward strategy at the quantum scale.
麦克斯韦妖探讨了信息在物理过程中的作用。这个“智能观察者”利用关于微观自由度的信息，能够补偿熵的产生（或提取功），这显然对热力学第二定律构成了挑战。从现代的观点来看，它被视为一种反馈控制机制，并且热力学的极限在纳入信息到能量转换的情况下被重新表述。我们推导出了信息论量之间的一种权衡关系，这有助于在量子系统中设计高效的麦克斯韦妖。该妖通过一个自旋 - 1/2量子存储器在实验中得以实现，这个量子存储器获取信息，并通过自然相互作用利用它来控制另一个自旋 - 1/2系统的动力学。通过评估该协议的有效性来研究其中的噪声和缺陷。这一实现提供了实验证据，表明在非平衡动力学中的不可逆性可以通过在量子尺度上评估微观信息并应用前馈策略来减轻。
