Shin-ichi Sasa

The steady propagation of a (d−1)-dimensional planer interface in d-dimensional space is studied by analyzing mesoscopic nonconserved order parameter dynamics with two local minima under the influence of thermal noise. In this analysis, an entropic force generating interface propagation is formulated using a perturbation method. It is found that the entropic force singularly depends on an ultraviolet cutoff when d≥2. The theoretical calculation is confirmed by numerical simulations with d=2.

We derive a variational expression for the correlation time of physical observables in steady-state diffusive systems. As a consequence of this variational expression, we obtain lower bounds on the correlation time, which provide speed limits on the self-averaging of observables. In equilibrium, the bound takes the form of a trade-off relation between the long- and short-time fluctuations of an observable.

Abstract We propose a phase transition on the feasibility of efficient parallel assembly. By introducing the parallel efficiency that measures how efficiently the parallel assembly works, the parallelizable phase is defined by its positive value. The parallelizable-unparallelizable transition is then identified by the nonanalytic change in the parallel efficiency from a positive value to zero.