The theory of Brownian motion is a cornerstone of modern physics set forth over a century ago by Einstein, Langevin and other pioneers. Describing the erratic motion of suspended colloidal particles due to thermal fluctuations of the solvent molecules in thermal equilibrium, this theory provides insights into a wealth of phenomena reigning the 'middle world' [M. Haw, 2006].
In my talk, I will discuss a nonequilibrium extension, namely the Brownian motion of a heated nanoparticle, for which we have recently developed an effective Markovian theory. In light of the plethora of optical particle trapping and tracking techniques, it is important to understand the behavior of laser-heated tracers. And moreover, deliberate heating of colloids is even put to good use in photothermal imaging and spectroscopy methods. I will sketch their working principle and point out further applications such as thermal Janus particles.
