Comment by PaulHoule
5 days ago
Notably the physical limit is
https://en.wikipedia.org/wiki/Landauer%27s_principle
it doesn't necessarily take any energy at all to process information, but it does take roughly kT work of energy to erase a bit of information. It's related to
https://en.wikipedia.org/wiki/Maxwell%27s_demon
as, to complete cycles, the demon has to clear its memory.
Does it not take energy to process information? Can any computable function be computed with arbitrarily low energy input/entropy increase?
No, and yes, so long as you don't delete information.
Think of a marble-based computer, whose inner workings are frictionless and massless. The marbles roll freely without losing energy unless they are forced to stop somehow, but computation is nonetheless performed.
I don't know how to compute with marbles without mass and stopping. Marble computers I've seen rely on gravity and friction, though I'd love to see one that didn't.