Entanglement Swapping of Two Arbitrarily Degraded Entangled States

Brian T. Kirby, Siddhartha Santra, Vladimir S. Malinovsky, Michael Brodsky

Published 2015-12-18Version 1

We consider entanglement swapping, a key component of quantum network operations and entanglement distribution. Pure entangled states, which are the desired input to the swapping protocol, are typically mixed by environmental interactions causing a reduction in their degree of entanglement. Thus an understanding of entanglement swapping with partially mixed states is of importance. Here we present a general analytical solution for entanglement swapping of arbitrary two-qubit states. We find upper and lower bounds on the concurrence of the state resulting from entanglement swapping for various classes of input states. Our result provides a comprehensive method for analyzing entanglement swapping in quantum networks.