A Stochastic Approach to Thermodiffusion

In presence of thermal inhomogeneities, particle diffusion is known to occur even without concentration gradients. This phenomenon, known as “thermodiffusion” or “Ludwig-Soret effect” is well documented since the nineteenth century, and has numerous current applications which range from astrophysics to polymer physics and chemistry. In this contribution, we propose new microscopic stochastic models of thermodiffusion. These models are variants of the Ornstein-Uhlenbeck process; they remedy problems encountered with earlier models and their large scale behaviour coincides with the predictions of standard continuous media theories.