A quantum computing protocol makes it possible to extract energy from seemingly empty space, teleport it to a new location, then store it for later use.
Energy cannot be created from nothing, but physicists found a way to do the next best thing: extract energy from seemingly empty space, teleport it elsewhere and store it for later use. The researchers successfully tested their protocol using a quantum computer.
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| A quantum computing chip IBM |
The laws of quantum physics reveal that perfectly empty space cannot exist – even places fully devoid of atoms still contain tiny flickers of quantum fields. In 2008, Masahiro Hotta at Tohoku University in Japan proposed that those flickers, together with the quantum property of entanglement, could be used to teleport energy between two places.
Very few physicists engaged with his work until 2023, when two research groups independently implemented the idea in a pair of experiments. But both hit the same snag: once energy was teleported, it could not be stored – instead, it leaked into the environment, says Sabre Kais at Purdue University in Indiana. He and his colleagues have now worked out how to remedy this.
In their protocol, an entangled pair of qubits, or quantum bits – the building blocks of a quantum computer – is in its lowest energy state. For a more conventional object, this would mean it has zero energy, the energetic equivalent of empty space. But quantum objects like qubits can never have zero energy: they always have some energy because of those tiny flickers of quantum fields.
Imagine the entangled qubits are separated and handed off to two people, say Alice and Bob. When Alice makes a measurement on her qubit, it both reveals information about the qubit’s fluctuations and slightly increases its energy. Because the qubits are entangled, their quantum state changes as a pair. But Bob cannot see that just by looking at his qubit, or without making a measurement that would also disturb the two.
Then Alice calls Bob and communicates the details of the measurement, which tells Bob just how much energy the qubit pair gained from Alice’s actions – and how to extract it. Bob uses this information to harvest the extra energy from his half of the qubit pair. Crucially, he then transfers that energy to a third qubit, which will be used for storage.
Songbo Xie, also at Purdue University, says that the teleported energy is small and fragile, so using this additional storage qubit saves it from getting lost. “This was our goal, to save it for future use,” he says. The researchers tested the protocol by running it on an actual quantum computer. The results agreed well with what their calculations predicted.
Hotta says that, though he proposed teleported energy storage technology years ago, past experiments did not implement it. “Such a teleported energy storage technology will be important in the future, since the stored energy can be used for other quantum tasks in quantum computers and other devices,” he says.
Eduardo Martin-Martinez at the University of Waterloo in Canada, who worked on one of the 2023 experiments, says that Hotta’s original idea was a revolutionary trick for skirting the rules of how energy is usually transferred. Building on it, as the new work does, continues to expand the physicists’ toolbox for transferring energy in novel ways.
However, he says that more definitive experiments are needed to test the protocol, such as using two carbon atoms in the roles of Alice and Bob. Although the researchers tested their theory within a quantum computer program, that was more akin to a simulation rather than an experiment, Martinez says.
This is exactly what Kais and his team are currently working on. As a chemist, Kais also already has a clear use for the new protocol in mind: he wants to use the stored energy to jump-start new and well-controlled chemical reactions.
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