Calculating Purity of PurificationMPS
Posted: 14 May 2024, 00:14
Hi,
If I have a purification MPS representing a finite temperature thermal mixed state \(\rho\), is there an efficient way I can compute the purity \(Tr[\rho^2]\) of the thermal state? I am not sure if there is even a way to compute moments of the actual thermal state from the pure MPS in the purified space. I really just need any quantity that is a monotone in purity of the represented thermal state, not necessarily the purity.
Any help is appreciated, thank you!
If I have a purification MPS representing a finite temperature thermal mixed state \(\rho\), is there an efficient way I can compute the purity \(Tr[\rho^2]\) of the thermal state? I am not sure if there is even a way to compute moments of the actual thermal state from the pure MPS in the purified space. I really just need any quantity that is a monotone in purity of the represented thermal state, not necessarily the purity.
Any help is appreciated, thank you!