Physicists successfully perform long-range stable quantum teleportation

In recent years, quantum computing has become an active area of ​​research, with the goal of finding a way to effectively control, manage and transfer quantum information (qubits) so that certain complex calculations and calculations can be performed. establish communication networks. The development of a quantum Internet, for the speed and security it would bring to users, is in particular a major area of ​​research. And recently, a collaboration of institutions succeeded for the first time in carrying out a stable quantum teleportation of qubits over 22 km. Such a result is extremely promising for a future quantum Internet, of which the quantum teleportation mechanism is one of the key elements.

Led by Caltech, a collaboration between Fermilab, AT&T, Harvard University, the Jet Propulsion Laboratory of NASA and the University of Calgary, reports having successfully teleported qubits, the basic unit of quantum information, over 22 kilometers of fiber in two test beds: the Caltech Quantum Network and the Fermilab quantum network.

Although the collaboration knew it had “achieved significant results” in the spring of 2020, says physicist Maria Spiropulu, they refrained from sharing the news, even informally on social media, until the publication of the report. full study this week.

« We wanted to push the boundaries of this type of research and take important steps to realize both real applications for communications and quantum networks and to test ideas in fundamental physics. So when we finally did, the team was thrilled, very proud to have achieved these high quality results. And we are very happy to be able to move on to the next phase, using the know-how and technologies of this work towards the deployment of quantum networks. Says Panagiotis Spentzouris, manager of the quantum sciences program at Fermilab.

The researchers say their experiment uses “plug and play” equipment compatible with both existing telecommunications infrastructure and emerging quantum technologies. The results “provide a realistic basis for a high-fidelity quantum internet with practical devices,” according to the study published in the journal As PRX.

Teleportation of entangled quantum states: the basis of a future quantum Internet

Quantum teleportation does not involve the actual transfer of matter, but involves entangled particles. The study aimed to teleport the state of qubits, or “quantum bits”, which are the basic units of quantum computing. According to the study, the researchers set up what is essentially a compact network with three nodes: Alice, Charlie and Bob.

In this experiment, Alice sends Charlie a qubit. Bob has a pair of entangled qubits and also sends a qubit to Charlie, where he interferes with Alice’s qubit. Charlie projects Alice’s qubit onto an entangled quantum Bell state which transfers the state of Alice’s original qubit to Bob’s remaining qubit.

The breakthrough is notable for several reasons. Many previous demonstrations of quantum teleportation have been shown to be unstable over long distances. For example, in 2016, researchers at the University of Calgary were able to perform a quantum teleportation at a distance of six kilometers. It was the world record at the time and was considered a major achievement.

The ultimate goal is to create quantum networks that would use entanglement and superposition to dramatically increase computational speed, power, and security compared to conventional computers. For example, the US Department of Energy has an ambitious plan to build a quantum network between its national laboratories.

Towards the development of larger-scale networks