Experimental continuous variable cloning of partial quantum information

TL;DR

This paper demonstrates that prior partial information about quantum states enhances cloning fidelity, introducing new state-dependent cloning schemes using linear optics that outperform universal cloning.

Contribution

It proposes and experimentally demonstrates near-optimal state-dependent cloning schemes for coherent states utilizing simple linear optics and feedforward.

Findings

Superior cloning fidelity with partial prior information

Implementation of near-optimal state-dependent cloning schemes

First demonstration of such schemes with linear optics

Abstract

The fidelity of a quantum transformation is strongly linked with the prior partial information of the state to be transformed. We illustrate this interesting point by proposing and demonstrating the superior cloning of coherent states with prior partial information. More specifically, we propose two simple transformations that under the Gaussian assumption optimally clone symmetric Gaussian distributions of coherent states as well as coherent states with known phases. Furthermore, we implement for the first time near-optimal state-dependent cloning schemes relying on simple linear optics and feedforward.