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Sand as Maxwell's demon

Jens Eggers
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Abstract

We consider a dilute gas of granular material inside a box, kept in a stationary state by shaking. A wall separates the box into two identical compartments, save for a small hole at some finite height $h$. As the gas is cooled, a second order phase transition occurs, in which the particles preferentially occupy one side of the box. We develop a quantitative theory of this clustering phenomenon and find good agreement with numerical simulations.

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Jens Eggers. 1999-06-17. Sand as Maxwell's demon. https://doi.org/10.1103/physrevlett.83.5322

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