The heralded amplification for the single-photon entanglement of the time-bin qubit

TL;DR

This paper proposes a simple, economical amplification protocol for single-photon entangled states of time-bin qubits, enhancing fidelity while preserving encoded information, suitable for current experimental setups.

Contribution

It introduces a novel, practical amplification method for single-photon time-bin entanglement using basic optical components, improving fidelity without complex procedures.

Findings

Increases fidelity of single-photon entangled states under certain conditions.

Uses only standard optical elements like beam splitters and auxiliary photons.

Compatible with current experimental technology.

Abstract

We put forward an effective amplification protocol for protecting the single-photon entangled state of the time-bin qubit. The protocol only requires one pair of the single-photon entangled state and some auxiliary single photons. With the help of the 50:50 beam splitters, variable beam splitters with the transmission of $t$ and the polarizing beam splitters, we can increase the fidelity of the single-photon entangled state under $t<\frac{1}{2}$. Moreover, the encoded time-bin information can be perfectly contained. Our protocol is quite simple and economical. More importantly, it can be realized under current experimental condition. Based on the above features, our protocol may be useful in current and future quantum information processing.