/Long-distance quantum teleportation enabled by multiplexed quantum memories

Long-distance quantum teleportation enabled by multiplexed quantum memories

Key idea:  Researchers report having achieved quantum teleportation from a photon to a solid-state qubit over a distance of 1km, with a novel approach using multiplexed quantum memories.

Original author and publication date: ICFO-The Institute of Photonic Sciences – April 19, 2023

Futurizonte Editor’s Note: Quantum teleportation, previously thought as a science-fiction trick to easily move people from one place to a distant other place, may be a reality sooner than expected.

From the article:   

Quantum teleportation is a technique allowing the transfer of quantum information between two distant quantum objects, a sender and a receiver, using a phenomenon called quantum entanglement as a resource. The unique feature of this process is that the actual information is not transferred by sending quantum bits (qubits) through a communication channel connecting the two parties; instead, the information is destroyed at one location and appears at the other one without physically travelling between the two. This surprising property is enabled by quantum entanglement, accompanied by the transmission of classical bits.

There is a deep interest in quantum teleportation nowadays within the field of quantum communications and quantum networks because it would allow the transfer of quantum bits between network nodes over very long distances, using previously shared entanglement. This would help the integration of quantum technologies into current telecommunication networks and extend the ultra-secure communications enabled by these systems to very long distances. In addition, quantum teleportation permits the transfer of quantum information between different kinds of quantum systems, e.g. between light and matter or between different kinds of quantum nodes.

Quantum teleportation was theoretically proposed in the early 90s and experimental demonstrations were carried out by several groups around the world.

While the scientific community has gained extensive experience on how to perform these experiments, there is still an open question on how to teleport information in a practical way, allowing reliable and fast quantum communication over an extended network.

It seems clear that such an infrastructure should be compatible with the current telecommunications network. In addition, the protocol of quantum teleportation requires a final operation to be applied on the teleported qubit, conditioned on the result of the teleportation measurement (transmitted by classical bits), in order to transfer the information faithfully and at a higher rate, a feature called active feed-forward. This means that the receiver requires a device known as a quantum memory that can store the qubit without degrading it until the final operation can be implemented. Finally, this quantum memory should be able to operate in a multiplexed fashion to maximize the speed of teleporting information when the sender and the receiver are far away. To date, no implementation had incorporated these three requirements in the same demonstration.

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