I have a question about statistical operator. In statistical physics you deal with temperature. So for example ##\hat{\rho}=\frac{1}{Z}e^{-\beta \hat{H}}## where ##\beta=\frac{1}{k_BT}##. In definition there is temperature. And also equivalent definition is(adsbygoogle = window.adsbygoogle || []).push({});

##\hat{\rho}=\sum_i w_i|\psi_i\rangle \langle \psi_i|## where in definition isn't temperature. I'm confused about this. Can you give me some explanation?

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# Statistical operator

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