Effective temperature tuning with random optical forces

  Galor Geva  ,  Tamir Admon  ,  Guri Achi Dror  ,  Yael Roichman  
Tel Aviv university
School of chemistry

We examine the properties of an effective temperature in a driven-dissipative model system, in which the timescale of the driving is on the same order of that of the fluctuations.
We use holographic optical tweezers, in order to create an array of randomly placed optical traps, which change their location randomly in a given frequency. These randomly placed traps act on colloidal Silica partices, giving them randomly oriented "kicks". We show that the relation between the mean square displacement and the lag time is still linear, but the slope depends on the parameters of our optical traps. We managed to fine-tune the Diffusion coefficient, thus creating an effective temperature.