Heat Transport on Brownian Motors

C. M. ARIZMENDI; K. I. MAZZITELLO; F. FAMILY

Davis

Conferencia; XXX IUPAP Conference on Computational Physics; 2018

University of California

Thermal ratchets or Brownianmotors achieve a net current of particles through thermalfluctuations rectification. The contact with one or several thermalbaths is the source of thermal fluctuations. Brownian motors are keptaway from equilibrium by external fluctuations or temperaturegradients that make them completely different from Carnot engines.Studies on the Thermodynamics of these motors are mainly focused onefficiency. Nevertheless, high efficiency may be achieved withunintended heat dissipation. In this work we use a novelcomputational approach to elucidate the mechanism by which heat isdissipated to the thermal bath. The process of heat transport isrelated to the effective temperature through the generalization ofthe fluctuation?dissipation theorem on far from equilibriumsystems. The effective temperature is defined by the comparisonbetween induced and spontaneous fluctuations. We applied the replicamethod to the Brownian motor. Two replicas of the system with andwithout a perturbative force were computationally simulated tocalculate the induced fluctuations and the response function. Wefound that the heat transport is different from Fourier´s Law and isproportional to the nthpower of the difference between the effective temperature of ratchetand the temperature of the bath. The power ndepends only on the temperature of the bath. On the other hand thethermal conductivity depends on the bath temperature and also onboth, the ratchet potential and the amplitude of the external source.In this way an expression of heat transport is obtained as anon-equilibrium measure.p { margin-bottom: 0.1in; direction: ltr; line-height: 120%; text-align: left; }p.western { font-size: 11pt; }p.cjk { font-size: 11pt; }p.ctl { font-size: 11pt; }