Entangled states from simple quantum graphs

Abstract: This work deals with quantum transport in open quantum graphs with two scattering channels. They are used as a two-level system whose weights are defined by its reflection and transmission amplitudes. We propose a controlled operation between two quantum graphs, where the scattering in a quantum graph modifies the second one, changing its outcome. Our findings show that the scattering measurements in this system are linked to recent results on randomized quantum graphs. The main results reveal the presence of entangled states according to the wave-number values in each quantum graph and the applied controlled operation. It was possible to determine the criteria for maximal entanglement or separability. In particular, we uncovered the presence of entanglement in a simple system consisting of two simple quantum graphs, with only one edge and a controlled phase.