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Scientists at the University of Bristol and the Technical University of Denmark have achieved quantum teleportation between two computer chips for the first time. The team managed to send information from one chip to another instantly without them being physically or electronically connected, in a feat that opens the door for quantum computers and quantum internet.
This kind of teleportation is made possible by a phenomenon called quantum entanglement, where two particles become so entwined with each other that they can “communicate” over long distances. Changing the properties of one particle will cause the other to instantly change too, no matter how much space separates the two of them. In essence, information is being teleported between them.
Hypothetically, there’s no limit to the distance over which quantum teleportation can operate – and that raises some strange implications that puzzled even Einstein himself. Our current understanding of physics says that nothing can travel faster than the speed of light, and yet, with quantum teleportation, information appears to break that speed limit. Einstein dubbed it “spooky action at a distance.”
Harnessing this phenomenon could clearly be beneficial, and the new study helps bring that closer to reality. The team generated pairs of entangled photons on the chips, and then made a quantum measurement of one. This observation changes the state of the photon, and those changes are then instantly applied to the partner photon in the other chip.
“We were able to demonstrate a high-quality entanglement link across two chips in the lab, where photons on either chip share a single quantum state,” says Dan Llewellyn, co-author of the study. “Each chip was then fully programmed to perform a range of demonstrations which utilize the entanglement. The flagship demonstration was a two-chip teleportation experiment, whereby the individual quantum state of a particle is transmitted across the two chips after a quantum measurement is performed. This measurement utilizes the strange behavior of quantum physics, which simultaneously collapses the entanglement link and transfers the particle state to another particle already on the receiver chip.”
The team reported a teleportation success rate of 91 percent, and managed to perform some other functions that will be important for quantum computing. That includes entanglement swapping (where states can be passed between particles that have never directly interacted via a mediator), and entangling as many as four photons together.
Information has been teleported over much longer distances before – first across a room, then 25 km (15.5 mi), then 100 km (62 mi), and eventually over 1,200 km (746 mi) via satellite. It’s also been done between different parts of a single computer chip before, but teleporting between two different chips is a major breakthrough for quantum computing.