I wish to apply a series of quantum channels on a specific site. For example, consider a dephasing channel, it has the form that \(\rho\rarr(1p)I\rho+pZ\rho Z\), which means, for a density matrix, \(\rho\)=\pmatrix{a&b\\c&d}, it will has the form \pmatrix{a&(12p)b\\(12p)c&d}.
How could this function be realized in TenPy?
How to apply a quantum channel?
Re: How to apply a quantum channel?
I'm confused  what state do you start with? Some ground state, or other pure state, represented as an MPS? What do you want to calculate afterwards? You can use TeNPy to get the singlesite reduced density matrix, and then apply the dephasing channel, but you can not apply it on the whole MPS: it's no longer a pure state afterward, so it can't be represented directly by an MPS. Are you thinking about using purification?

 Posts: 4
 Joined: 20 May 2022, 00:40
Re: How to apply a quantum channel?
Yeah, I am thinking about applying the dephasing channel to a single site and then considering the whole system's evolution afterward. That is, the whole system is no longer a pure state.