From: utzoo!decvax!harpo!npoiv!npois!houxi!ihps3!ihuxv!lew
Newsgroups: net.physics
Title: Re: leichter on entropy
Article-I.D.: ihuxv.387
Posted: Tue Oct 12 09:35:25 1982
Received: Sun Oct 17 03:51:25 1982

Jerry Leichter said,

"In fact, thermodynamics gives you a lower bound on how much energy ANY
chip you could build would require to store a bit."

We can think of a bit as a bistable potential well with the 0 and 1 bit
states separated by energy E. Then E must be > kT for the bit
to be stable. But the entropy production per bit flip is E/T which
must be >k. Right?

The energy can be made small by cooling but it is entropy we are talking
about. I don't think that it's our knowledge of the state of a memory
that makes its entropy zero, but its stability. The bit transitions
must have a high enough energy to be "frozen out" at the operation
temperature.

Lew Mammel, Jr. ihuxv!lew