Maxwell's demon

English

Etymology

Named after physicist James Clerk Maxwell (1831–1879) and demon, and probably from Greek daemon, a mythological being intermediate between gods and men.

Noun

Maxwell's demon (plural Maxwell's demons)

1. A hypothetical creature created for 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.

Translations

Hypothetical creature

• Catalan: dimoni de Maxwell m
• Chinese:

  Mandarin: 麥克斯韋妖／麦克斯韦妖 (màikèsīwéiyāo)

• Finnish: Maxwellin demoni
• German: Maxwellscher Dämon m
• Hungarian: Maxwell-démon
• Japanese: マクスウェルの悪魔 (Makusuweru No Akuma))
• Korean: 맥스웰의 도깨비 (Maekseuwerui dokkaebi)
• Spanish: demonio de Maxwell m

See also

• information engine
• perpetual motion machine of the second kind

Further reading

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