Universal covariant quantum cloning circuits for qubit entanglement manipulation

TL;DR

This paper explores how universal covariant quantum cloning circuits can manipulate entanglement in qubit systems, revealing unique behaviors in bipartite and tripartite states, including partial entanglement extraction.

Contribution

It demonstrates the entanglement manipulation capabilities of covariant quantum cloners for bipartite and tripartite states, highlighting new behaviors in concurrence and entanglement extraction.

Findings

Nontrivial concurrence behavior in bipartite pure states

Partial bipartite entanglement extraction from GHZ states

Cloning circuits enable entanglement manipulation in quantum systems

Abstract

We consider the entanglement manipulation capabilities of the universal covariant quantum cloner or quantum processor circuit for quantum bits. We investigate its use for cloning a member of a bipartite or a genuine tripartite entangled state of quantum bits. We find that for bipartite pure entangled states a nontrivial behavior of concurrence appears, while for GHZ entangled states a possibility of the partial extraction of bipartite entanglement can be achieved.