Thermodynamics and computation (con’t)
The principal results
- Computation has no inherent thermodynamic cost
- A reversible computation, that proceeds at an infinitesimal rate, consumes no energy
- Destroying information requires kTln2 joules per bit
- Information-theoretic bits (not binary digits)
- Driving a computation forward requires kTln(r) joules per step
- r is the probability of going forward rather than backward