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What is the impact on the state equation of a Gibbs ensemble if we change the base to 2. For example,

$$ \begin{align} &Z=\sum_i{2^{-\beta (E_i+pdV)}} & \text{partition function} \\ &dE=TdS-pdV & \text{state equation} \end{align} $$

Does the change of basis changes the state equation?

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Changing this is the equivalent of changing the temperature of your system. This can be seen just by recasting the new basis into the old basis. First note that $$\gamma^x=(e^{\log\gamma})^x=e^{x \log\gamma},$$ where I choose $\gamma > 1$. Hence your partition function becomes $$Z=\sum_i{e^{-\log\gamma~\beta (E_i+pdV)}} = \sum_i{e^{-\beta' (E_i+pdV)}}.$$ Where we see it is unchanged, if we change our temperature such that $\beta' = \beta\log\gamma $. That is $T'\rightarrow \frac{T}{\log\gamma}$.

Hence the equation of state would be $$dE=T'dS-pdV=\frac{T}{\log \gamma}dS - pdV$$

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