How Does Pressure Fluctuate in Equilibrium?
Abstract
We study fluctuations of pressure in equilibrium for classical particle systems. In equilibrium statistical mechanics, pressure for a microscopic state is defined by the derivative of a thermodynamic function or, more mechanically, through the momentum current. We show that although the two expectation values converge to the same equilibrium value in the thermodynamic limit, the variance of the mechanical pressure is in general greater than that of the pressure defined through the thermodynamic relation. We also present a condition for experimentally detecting the difference between them in an idealized measurement of momentum transfer.
 Publication:

Journal of Statistical Physics
 Pub Date:
 October 2018
 DOI:
 10.1007/s1095501821346
 arXiv:
 arXiv:1803.00256
 Bibcode:
 2018JSP...173..285H
 Keywords:

 Thermodynamic fluctuation theory in equilibrium;
 Pressure fluctuation;
 LandauLifshitz fluctuation theory;
 Classical statistical mechanics;
 Condensed Matter  Statistical Mechanics
 EPrint:
 9 pages