Thermal fluctuations in non-equilibrium: From quantum to classical systems. Focus: Nonlinear systems

非线性系统，特别是远离平衡的非线性系统，是统计物理学中一个令人兴奋的领域：平均值和波动的行为在很大程度上没有被探索，无论是理论上还是实验上。在本项目中，我们的目的是通过以下具体情况的研究，从理论上描述这类非平衡非线性系统：i)非线性系统中电磁场的（量子）涨落，ii)非线性槽中驱动粒子的布朗运动，以及iii)胶体模型系统的非线性响应及其与非摄动状态涨落的联系。

Nonlinear systems, especially if far from equilibrium, are an exciting field of statistical physics: The behavior of mean values as well as fluctuations are largely unexplored, both theoretically as well as experimentally. In this project, we aim at the theoretical description of such nonlinear systems out of equilibrium, by investigation of the following specific cases: i) The (quantum-) fluctuations of the electromagnetic field in nonlinear systems, ii) the Brownian motion of a driven particle in nonlinear bath, and iii) the nonlinear response of a colloidal model system, and its connection to fluctuations in the unperturbed state.