Entanglement distribution via separable states and incoherent dynamics

Description

Entanglement can be generated or increased between two systems (A and B) using a carrier (C) which is not entangled with either system at any point. One way to achieve this is to use CNOT gates, first acting on system A and carrier C, then on system B and carrier C [1]. In this work, we look at the effect of adding incoherent dynamics to this set-up. We allow A and C to interact according to this new dynamics for a limited time before B and C interact in the same way. Surprisingly, we find that in terms of the strength of the incoherent part of the dynamics, the encoding step of the process (between A and C) is much more restricted than the decoding step (between B and C) if we want to avoid entangling C with AB. Moreover, the addition of incoherent dynamics provides a slight advantage over the CNOT gate in certain cases for obtaining entanglement between A and B after tracing out the carrier C.

[1] Cubitt, T.S., Verstraete, F., Dür, W. and Cirac, J.I. Phys. Rev. Lett. 91, 037902 (2003)

Period	25 Jul 2019
Event title	Junior Quantum Days
Event type	Conference
Location	Trieste, ItalyShow on map
Degree of Recognition	International