Error-correcting entanglement swapping using a practical logical photon encoding

TL;DR

This paper introduces a logical encoding protocol for photonic qubits that overcomes photon loss and success probability limitations in Bell state measurements, advancing quantum communication and computing.

Contribution

It develops a tree graph state logical encoding method that enables near-deterministic, error-resistant Bell state measurements using a few quantum emitters.

Findings

Achieves record loss-tolerance threshold for photonic Bell measurements

Enables near-deterministic logical Bell state measurements

Uses a deterministic protocol with few quantum emitters

Abstract

Several emerging quantum technologies, including quantum networks, modular and fusion-based quantum computing, rely crucially on the ability to perform photonic Bell state measurements. Therefore, photon losses and the 50\% success probablity upper bound of Bell state measurements pose a critical limitation to photonic quantum technologies. Here, we develop protocols that overcome these two key challenges through logical encoding of photonic qubits. Our approach uses a tree graph state logical encoding, which can be produced deterministically with a few quantum emitters, and achieves near-deterministic logical photonic Bell state measurements while also protecting against errors including photon losses, with a record loss-tolerance threshold.