Brownian Computation Is Thermodynamically Irreversible

The thermodynamics of computation applies ideas from thermal and statistical physics to physical devices implementing computations. Its major focus has been to characterize the principled limits to thermal dissipation in these devices. The best case of no dissipation arises when we use processes that create no thermodynamic entropy. They are thermodynamically reversible processes in which all driving forces are in perfect balance. Thermal fluctuations, such as arise through random molecular motions, are not normally a major consideration in thermodynamic analyses. However, they become decisive in the thermodynamics of computation. For the thermodynamic dissipation associated with