Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires Ciudad Universitaria, 1428, Buenos Aires, Argentina.
Instituto de Física de Buenos Aires, CONICET-UBA, Ciudad Universitaria, 1428, Buenos Aires, Argentina.
Nat Commun. 2017 Nov 1;8(1):1241. doi: 10.1038/s41467-017-01308-7.
Work is an essential concept in classical thermodynamics, and in the quantum regime, where the notion of a trajectory is not available, its definition is not trivial. For driven (but otherwise isolated) quantum systems, work can be defined as a random variable, associated with the change in the internal energy. The probability for the different values of work captures essential information describing the behaviour of the system, both in and out of thermal equilibrium. In fact, the work probability distribution is at the core of "fluctuation theorems" in quantum thermodynamics. Here we present the design and implementation of a quantum work meter operating on an ensemble of cold atoms, which are controlled by an atom chip. Our device not only directly measures work but also directly samples its probability distribution. We demonstrate the operation of this new tool and use it to verify the validity of the quantum Jarzynksi identity.
工作是经典热力学中的一个基本概念，而在量子领域中，由于不存在轨迹的概念，其定义并不简单。对于受驱动（但其他方面处于隔离状态）的量子系统，可以将工作定义为一个与内能变化相关的随机变量。不同工作值的概率捕获了描述系统行为的基本信息，无论是在热平衡内外。事实上，工作概率分布是量子热力学中“涨落定理”的核心。在这里，我们介绍了一种基于冷原子集合的量子工作计的设计和实现，该原子集合由原子芯片控制。我们的设备不仅直接测量工作，还直接对其概率分布进行采样。我们展示了这个新工具的操作，并使用它验证了量子 Jarzynski 恒等式的有效性。
