Optimal Cloning and Singlet Monogamy

TL;DR

This paper establishes a quantitative link between entanglement monogamy and the quality of quantum cloning, introducing the concept of singlet monogamy and solving asymmetric cloning for d-dimensional spins.

Contribution

It introduces sufficient conditions for implementing optimal cloning as teleportation and defines singlet monogamy, providing exact solutions for asymmetric cloning of d-dimensional spins.

Findings

Derived conditions for optimal cloning via teleportation.

Introduced the concept of singlet monogamy.

Applied results to Heisenberg systems and compared with standard monogamy.

Abstract

The inability to produce two perfect copies of an unknown state is inherently linked with the inability to produce maximal entanglement between multiple spins. Despite this, there is no quantitative link between how much entanglement can be generated between spins (known as monogamy), and how well an unknown state can be cloned. This situation is remedied by giving a set of sufficient conditions such that the optimal Completely Positive map can be implemented as a teleportation operation into a standard, reference, state. The case of arbitrary 1 to N asymmetric cloning of d-dimensional spins can then be solved exactly, yielding the concept of `singlet monogamy'. The utility of this relation is demonstrated by calculating properties of Heisenberg systems, and contrasting them with the results from standard monogamy arguments.