Heralded Noiseless Amplification of a Photon Polarization Qubit

TL;DR

This paper demonstrates the first heralded noiseless linear amplification of a photon polarization qubit, significantly improving transmission fidelity and advancing quantum communication capabilities.

Contribution

It introduces a coherent two-mode amplifier capable of noiselessly amplifying a polarization-encoded qubit, a novel achievement in quantum information processing.

Findings

Increased qubit transmission fidelity by up to five times

First demonstration of heralded noiseless amplification of a polarization qubit

Potential to extend secure quantum communication range

Abstract

Non-deterministic noiseless amplification of a single mode can circumvent the unique challenges to amplifying a quantum signal, such as the no-cloning theorem, and the minimum noise cost for deterministic quantum state amplification. However, existing devices are not suitable for amplifying the fundamental optical quantum information carrier, a qubit coherently encoded across two optical modes. Here, we construct a coherent two-mode amplifier, to demonstrate the first heralded noiseless linear amplification of a qubit encoded in the polarization state of a single photon. In doing so, we increase the transmission fidelity of a realistic qubit channel by up to a factor of five. Qubit amplifiers promise to extend the range of secure quantum communication and other quantum information science and technology protocols.