Researchers achieve long-distance quantum teleportation

21 Dec 20204.84k Views

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A team of researchers at Fermilab and partner institutions have demonstrated sustained long-distance teleportation of qubits of photons.

US Department of Energy Office national laboratory Fermilab and partner institutions have taken a significant step towards realising a quantum internet.

Earlier this month, a joint team of researchers was able to use quantum teleportation to send information over a distance of 44km.

In a paper published in PRX Quantum, the team said it demonstrated a “sustained, long-distance teleportation” of qubits of photons for the first time, with a fidelity of more than 90pc. The qubits were teleported over a fibre-optic network using state-of-the-art single-photon detectors and off-the-shelf equipment.

A viable quantum internet would work through a system of interconnected quantum computers, using quantum signals to send information rather than radio waves. Quantum communication records information in qubits, similar to the way digital systems use bits and bytes. Whereas a bit can only take the value of zero or one, a qubit can use the principles of quantum physics to take the value of zero and one at the same time.

Quantum teleportation is a ‘disembodied’ transfer of quantum states from one location to another. The quantum teleportation of a qubit is achieved using quantum entanglement, in which two or more particles are inextricably linked to each other. If an entangled pair of particles is shared between two separate locations, no matter the distance between them, the encoded information is teleported.

If successfully implemented, quantum internet would transform the fields of data storage, precision sensing and computing, ushering in a new era of communication.

Panagiotis Spentzouris, head of the Fermilab quantum science programme and one of the paper’s co-authors, said the team is thrilled with the results. “This is a key achievement on the way to building a technology that will redefine how we conduct global communication.”

As well as Fermilab, the team comprised researchers from AT&T, Caltech, Harvard University, NASA Jet Propulsion Laboratory and University of Calgary.

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The achievement comes just a few months after the US Department of Energy unveiled its blueprint for a national quantum internet.

Another major quantum breakthrough

Meanwhile in Denmark, researchers have advanced their quantum technology with a chip that could be scaled up and used to build the quantum simulator of the future.

In an article published to Science Advances, researchers from the University of Copenhagen’s Niels Bohr Institute, in collaboration with the University of Bochum, explained how they have developed a nanochip that allows them to produce enough stable photons encoded with quantum information to scale up the technology.

The chip, which is said to be less than one-tenth of the thickness of a human hair, may enable the team to achieve ‘quantum advantage’ – where a quantum device can solve a given computational task faster than the world’s most powerful supercomputer.

Prof Peter Lodahl of the Center for Hybrid Quantum Networks at University of Copenhagen said this is a “major breakthrough” and the first step into unchartered territory in the world of quantum physics.

“We now possess the tool that makes it possible to build a quantum simulator that can outperform a classical computer,” he added.

While the results are promising, researchers have yet to conduct an actual quantum advantage experiment, due to the high costs of running such an experiment.

Lead author of the results, assistant Prof Ravitej Uppu said: “It could cost us €10m to perform an actual experiment that simultaneously controls 50 photons … We simply can’t afford that. However, what we as scientific researchers can do is to develop a photon source and prove that it can be used to achieve quantum advantage. We have developed the fundamental building block.”

Jenny Darmody is the deputy editor of Silicon Republic