Application of the no-signaling principle to obtain quantum cloners for any allowed value of fidelity

TL;DR

This paper derives a unique class of quantum cloners for any allowed fidelity using the no-signaling principle, providing explicit constructions and analyzing their properties, including prime cloners with multiplicative fidelities.

Contribution

It introduces a method to construct quantum cloners for any fidelity based solely on the no-signaling principle and an assumed Schmidt form.

Findings

Explicit form of universal quantum cloners for all fidelities

Introduction of prime cloners with multiplicative fidelities

Fidelity of prime cloners approaches 1/2 in the infinite copy limit

Abstract

Special relativity forbids superluminal influences. Using only the no-signaling principle and an assumption about the form of the Schmidt decomposition, we show that for "any" allowed fidelity there is a "unique" approximate qubit cloner which can be written explicitly. We introduce the prime cloners whose fidelities have multiplicative property and show that the fidelity of the prime cloners for the infinite copy limit is 1/2.