Channel-induced dynamics of quantum information in mixed state free quantum field theories

We propose a new framework for quantum field theory (QFT) studies that allows us to represent field excitations as quantum channels. We demonstrate the inner workings of the proposed scheme for three universal states: a regularized vacuum state, a thermal state of a one-dimensional QFT system, and the lattice-regulated thermofield double state of two identical free QFTs. We investigate the actions of unitary and nonunitary bosonic Gaussian channels (including Petz recovery maps). To evaluate and quantify the character of the channel static action and channel-induced dynamics, we calculate quantum entropies and fidelities.