Tell me more ×  If you take two ideal gases at different
temperatures, and allow them to share energy through heat,
they'll eventually reach a thermodynamic equilibrium state that
has higher entropy than the original. The time evolution of that
entropy increase is easy to predict, because we know the time
evolution of $T$ and $U$ for each of the gases (assuming we have
the necessary constants). This is OK.  Now take a system beyond
the scope of thermodynamics. A single box containing a gas that
is not in thermodynamic equilibrium (doesn't follow the Boltzman
distribution). One would expect that gas to quickly thermalise,
and reach said equilibrium. Entropy can still be defined using
statistical mechanics, and the final state will have higher
entropy than the initial state.  I'm looking for quantitative
experimental evidence of this effect. Ideally, I'd like
references measuring the time a gas takes to thermalise.
Obviously this time depends on many factors and is not always
doable. I wasn't more specific bec