Experimental demonstration of optimal universal asymmetric quantum cloning of polarization states of single photons by partial symmetrization

TL;DR

This paper demonstrates an experimental implementation of an optimal universal asymmetric quantum cloning machine for single-photon polarization qubits, showcasing a robust measurement method resilient to detector calibration imperfections.

Contribution

It introduces a linear optical method for asymmetric quantum cloning using partial symmetrization, with a measurement approach tolerant to detector efficiency mismatches.

Findings

Successful experimental realization of asymmetric cloning with high fidelity

Measurement method remains reliable despite detector calibration issues

Provides a practical approach for quantum cloning in real-world conditions

Abstract

We report on experimental implementation of the optimal universal asymmetric 1->2 quantum cloning machine for qubits encoded into polarization states of single photons. Our linear optical machine performs asymmetric cloning by partially symmetrizing the input polarization state of signal photon and a blank copy idler photon prepared in a maximally mixed state. We show that the employed method of measurement of mean clone fidelities exhibits strong resilience to imperfect calibration of the relative efficiencies of single-photon detectors used in the experiment. Reliable characterization of the quantum cloner is thus possible even when precise detector calibration is difficult to achieve.