Enhancing quantum teleportation efficacy with noiseless linear amplification

Continuous-variable quantum networks are easier to implement than discrete-variable ones, but suffer from a lower teleportation fidelity. Here, the authors demonstrate a CV teleportation protocol exploiting heralded noiseless amplification to increase the fidelity, at the expense of probabilistic operation. Quantum teleportation constitutes a fundamental tool for various applications in quantum communication and computation. However, state-of-the-art continuous-variable quantum teleportation is restricted to moderate fidelities and short-distance configurations. This is due to unavoidable experimental imperfections resulting in thermal decoherence during the teleportation process. Here we present a heralded quantum teleporter able to overcome these limitations through noiseless linear amplification. As a result, we report a high fidelity of 92% for teleporting coherent states using a modest level of quantum entanglement. Our teleporter in principle allows nearly complete removal of loss induced onto the input states being transmitted through imperfect quantum channels. We further demonstrate the purification of a displaced thermal state, impossible via conventional deterministic amplification or teleportation approaches. The combination of high-fidelity coherent state teleportation alongside the purification of thermalized input states permits the transmission of quantum states over significantly long distances. These results are of both practical and fundamental significance; overcoming long-standing hurdles en route to highly-efficient continuous-variable quantum teleportation, while also shining new light on applying teleportation to purify quantum systems from thermal noise.

Automated summary

This article presents a protocol that uses heralded noiseless amplification to increase the fidelity of continuous-variable quantum teleportation. The method allows for high-fidelity teleportation of coherent states and purification of thermalized input states, overcoming long-standing hurdles in continuous-variable quantum teleportation. These results have both practical and fundamental significance.