Classical statistical mechanics: dimensions of partition function

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The partition function in classical statistical mechanics is an integral over phase space, which often results in it not being dimensionless. Consequently, the formula F = -T log Z becomes invalid since the logarithm can only be applied to dimensionless quantities. In quantum mechanics, this issue is addressed by incorporating Planck's constant and questioning the validity of the integration method. In classical settings, dimensions can be managed by postulating a constant to divide Z, but its specific value is irrelevant as only changes in free energy matter. The discussion highlights the striking resolution of this dimensional issue through quantum mechanics.
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The partition function in the classical theory is an integral over phase space. Thus, the partition function is often not dimensionless. Then the formula
F = -T \log Z
can no longer be valid, as you can only take the logarithm of a dimensionless number. In the quantum theory, this problem is easily taken care of by dividing out by Planck's constant and asserting that the method of integration is not really valid anyway. How are the dimensions taken care of in a classical setting?
 
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You have to postulate some constant (like the appropriate power of Planck's constant), and then divide Z by it. But, it's value doesn't matter, because only changes in the free energy are relevant.

But, my personal opinion is that it's pretty striking that this issue is resolved by quantum mechanics.
 
Avodyne said:
But, my personal opinion is that it's pretty striking that this issue is resolved by quantum mechanics.

I completely agree. I am wondering, from a historical perspective, what people must have thought about this.
 
For simple comparison, I think the same thought process can be followed as a block slides down a hill, - for block down hill, simple starting PE of mgh to final max KE 0.5mv^2 - comparing PE1 to max KE2 would result in finding the work friction did through the process. efficiency is just 100*KE2/PE1. If a mousetrap car travels along a flat surface, a starting PE of 0.5 k th^2 can be measured and maximum velocity of the car can also be measured. If energy efficiency is defined by...

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