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.
@article{arxiv.2101.11082,
title = {Error-correcting entanglement swapping using a practical logical photon encoding},
author = {Paul Hilaire and Edwin Barnes and Sophia E. Economou and Frédéric Grosshans},
journal= {arXiv preprint arXiv:2101.11082},
year = {2021}
}