# Superposition of causal order enables perfect quantum teleportation with very noisy singlets

## TL;DR

This paper demonstrates that using a quantum switch to superpose causal orders significantly enhances quantum teleportation fidelity with noisy singlet states, surpassing classical limits and achieving perfect fidelity under high noise conditions.

## Contribution

It introduces a novel scheme leveraging superposition of causal order to improve teleportation fidelity with noisy resources, extending to multiple pathways.

## Key findings

- Teleportation fidelity exceeds classical threshold with superposed causal order.
- Perfect teleportation achievable even with very noisy singlet states.
- Generalization to multiple pathways discussed.

## Abstract

We show that the fidelity of the standard quantum teleportation protocol, which utilizes an impure resource state, applied successively, can be significantly improved, when used in conjunction with a quantum switch. In particular, we find that for two such teleportation channels conjugated with the superposition of causal order, teleportation fidelity beyond the classical threshold is achieved for significantly larger noise than would be possible conventionally. One can even make the effective teleportation channel perfectly faithful for very large noise. We also discuss the generalization of our scheme for more than two pathways, and define a figure of merit in that context.