Editing H-theorem (section)

=== Fluctuations of ''H'' in small systems ===

Since ''H'' is a mechanically defined variable that is not conserved, then like any other such variable (pressure, etc.) it will show [[thermal fluctuations]]. This means that ''H'' regularly shows spontaneous increases from the minimum value. Technically this is not an exception to the ''H'' theorem, since the ''H'' theorem was only intended to apply for a gas with a very large number of particles. These fluctuations are only perceptible when the system is small and the time interval over which it is observed is not enormously large.

If ''H'' is interpreted as entropy as Boltzmann intended, then this can be seen as a manifestation of the [[fluctuation theorem]].{{cn|date=February 2025}}