Maxwell's demonとは 意味・読み方・使い方

名詞

Maxwell's demon (plural Maxwell's demons)

1. A hypothetical creature in a thought experiment. Maxwell’s demon, if it existed, would act as a sort of gate guard by sorting between higher-energy molecules and lower-energy molecules within an enclosed space. Because such a sorting process would tend to decrease entropy, it would violate the second law of thermodynamics.
   • 1966 March, Thomas Pynchon, chapter 5, in The Crying of Lot 49, New York, N.Y.: Bantam Books, published November 1976, →ISBN, page 77:

     She did gather that there were two distinct kinds of this entropy. One having to do with heat-engines, the other to do with communication. The equation for one, back in the ’30's, had looked very like the equation for the other. It was a coincidence. The two fields were entirely unconnected, except at one point: Maxwell's Demon.

参考

• information engine
• perpetual motion machine of the second kind

Further reading

• Maxwell's demon on Wikipedia.Wikipedia
• Second law of thermodynamics on Wikipedia.Wikipedia