Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Can we use entropy change value to define the (perhaps fractional) number of bits of information that are lost by and, or, xor gates?

share|cite|improve this question
"these entropy changes" What entropy changes are you referring to? My guess is you're referring to adiabatic, isothermal etc. I don't see why energy entropy should be related to computing entropy so directly. Also, you might be interested in – raindrop Feb 25 '13 at 20:40
I am sorry for that error – abcdefg Feb 25 '13 at 20:45
Possible duplicate: v1 of this Phys.SE post. – Qmechanic Feb 25 '13 at 20:48
I have simple logic gates(and, or, xor). I want to calculate the entropy change due to this gates. Say "or" gate. we have 2 inputs(2 bits 0 or 1) and 1 output. This gate is not reversible, if we know the output, we cannot guess the input bits. We have computed entropy somehow, how to find the number of lost bits – abcdefg Feb 25 '13 at 20:49
@Raindrop Surprisingly, the information and thermodynamic entropies associated with the erasure of the bit are deeply related: see Bennett's seminal work, the Thermodynamics of Computation. – Mark Mitchison Feb 25 '13 at 21:45

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.