Two-electron-entanglement enhancement by an inelastic scattering process

Abstract

In order to assess inelastic effects on two fermion entanglement production, we address an exactly solvable two-particle scattering problem where the target is an excitable scatterer. Useful entanglement, as measured by the two particle concurrence, is obtained from post-selection of oppositely scattered particle states. The S matrix formalism is generalized in order to address nonunitary evolution in the propagating channels. We find the striking result that inelasticity can actually increase concurrence as compared to the elastic case by increasing the uncertainty of the single particle subspace. Concurrence zeros are controlled by either single particle resonance energies or total reflection conditions that ascertain precisely one of the electron states. Concurrence minima also occur and are controlled by entangled resonance situations where the electron becomes entangled with the scatterer, and thus does not give up full information of its state. In this model, exciting the scatterer can never fully destroy phase coherence due to an intrinsic limit to the probability of inelastic events.

Spin polarization of entangled and mixed electron states in a beam splitter geometry coupled to an electron reservoir

“…Such electron density in the reservoir lead, partly stores and cedes information to the two electron system (see this effect in another context in ref. 26). This is consistent with the behavior of the persistent current states in contact with such a reservoir model e.g.…”