Measurement and feedforward induced entanglement negativity transition

We study the interplay between measurement-induced dynamics and conditional unitary evolution

in quantum systems. We numerically and analytically investigate commuting random measurement

and feedforward (MFF) processes, and find a sharp transition in their ability to generate entan-

glement negativity as the number of MFF channels varies. We also establish a direct connection

between these findings and transitions induced by random dephasing from an environment with

broken time-reversal symmetry. In one variant of the problem, we employ free probability theory to

rigorously prove the transition’s existence. Furthermore, these MFF processes have dynamic circuit

representations that can be experimentally explored on current quantum computing platforms.