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.
Dan Llewellyn, co-author of the study said.
“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. 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.
COMMENTARY: I am a physics hobbyist and indulge myself by reading physics topics like quantum theory, string theory, quantum computing and so forth. So when this article appeared in Nature Physics, I immediately understood the implications for computing, data exchange and communications over vast distances. If you are a B-Theorist then you support the theory that space-time is an illusion that the past, present and future are equally real, and that time is tenseless. The latter is a scary thought because it theorizes that there may not be this thing we call time.
Having said the above, it could stand to reason that space-time is neutral. There is no such thing as time (past, present or future) and that everything really happens at the same time. The quantum chips are strictly a reflection of that observation, so it should come as no surprise that if I were on Mars and send a message back to Earth using a quantum computer, each key stroke on my computer (quantum computer A) would appear instantly on computer B back on Earth. The same thing for voice and video communication. I could see you on my video screen and you could see me, and we could talk to each other in real-time without missing a beat. Even though I might be four light-years away. I am really in the future, and you are in my past, but we are able to communicate as though we were in the same room.
If quantum computing can evolve into practical applications, this changes everything. If we can teleport data, how far away are we from teleporting inert objects or real people over vast distances? This just drives me crazy with excitement.
Courtesy of an article dated December 23, 2019 appearing in Nature Physics
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