2. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany.
Phys Rev Lett. 2012 Jun 1;108(22):220601. doi: 10.1103/PhysRevLett.108.220601.
The validity of the fluctuation theorem for entropy production as deduced from the observation of trajectories implicitly requires that all slow degrees of freedom are accessible. We experimentally investigate the role of hidden slow degrees of freedom in a system of two magnetically coupled driven colloidal particles. The apparent entropy production based on the observation of just one particle obeys a fluctuation theorem-like symmetry with a slope of 1 in the short time limit. For longer times, we find a constant slope, but different from 1. We present theoretical arguments for a generic linear behavior both for small and large apparent entropy production but not necessarily throughout. By fine-tuning experimental parameters, such an intermediate nonlinear behavior can indeed be recovered in our system as well.
从轨迹观测推导出的熵产生涨落定理的有效性隐含地要求所有慢自由度都是可及的。我们通过实验研究了两个磁耦合驱动胶体粒子系统中隐藏慢自由度的作用。仅观察一个粒子的明显熵产生符合涨落定理对称性，在短时间限制内斜率为 1。对于更长的时间，我们发现斜率是一个常数，但不同于 1。我们提出了一个通用的线性行为的理论论点，无论是在小还是大的明显熵产生的情况下，但不一定是整个过程。通过微调实验参数，我们的系统中确实可以恢复这种中间非线性行为。
