‘Quantum Internet’ is closer with advances in data teleportation – Link

Through the quantum computer, scientists bet on the ‘quantum internet’ to transfer data between computers

From Santa Barbara, California, to Heifei, China, scientists are developing a new type of computer that will make today’s machines look like toys.

Harnessing the mysterious powers of quantum mechanics, the technology will perform tasks in minutes that even supercomputers could not complete in thousands of years.

In the second half of 2019, Google unveiled a pilot quantum computer showing that this was possible. Two years later, a laboratory in China did much the same.

But quantum computing will not reach its potential without the help of another technological innovation. call it “quantum internet” – a network of computers that can send quantum information between distant machines.

At Delft University of Technology in the Netherlands, a team of physicists has taken a significant step towards this computer network of the future, using a technique called “quantum teleportation” to send data from quantum machines to three physical places. Previously, this was only possible with two.

The new experiment indicates that scientists can extend a quantum network to an ever-increasing number of locations. “Now we’re building little quantum networks in the lab,” said Ronald Hanson, a physicist at Delft University who oversees the team. “But the idea is at some point to create a quantum internet.”

The research, published in an article published in the scientific journal nature, demonstrates the power of a phenomenon that was once considered impossible by Albert Einstein. O quantum teleportation – called by the German scientist “spooky action at a distance” – can transfer information between locations without actually moving the physical matter where it is stored.

This technology could profoundly change the way data is transmitted from one place to another. It is based on more than a century of research involving quantum mechanics, a field of physics that controls the subatomic world and behaves differently from anything we experience in our daily lives. Quantum teleportation not only transfers data between quantum computers, it also does so in a way that no one can intercept it.

“This doesn’t just mean that the quantum computer can solve its problem, it also means that it doesn’t know what the problem is,” said Tracy Eleanor Northup, a researcher at the Institute for Experimental Physics at the University of Innsbruck, who is also researching the problem. quantum teleportation.

“It doesn’t work that way with traditional machines, which we use today. Google knows what you’re running on their servers,” he says.

properties

A quantum computer assesses the strange ways some objects behave when they are very small (like an electron or a particle of light) or very cold (like an exotic metal cooled to near absolute zero, -273°C). In these situations, a single object can behave like two different objects at the same time.

Traditional computers perform calculations by processing “bits” of information, with each bit being represented by 1 or 0. By taking advantage of the strange behavior of quantum mechanics, a quantum bit (qubit) can store a combination of 1 and 0 – somewhat reminiscent of a spinning coin that has the fascinating possibility of flipping heads or tails when it finally stops spinning and lands on the table.

This means that two qubits can represent four values ​​at the same time, three qubits can represent eight, four can represent 16, and so on. As the number of qubits increases, a quantum computer becomes exponentially more powerful.

Utility

The researchers believe these devices could one day accelerate the creation of new drugs, fuel advances in artificial intelligence and quickly crack the encryption that protects computers vital to national security. Around the world, governments, academic research labs, startups and tech giants are spending billions of dollars investigating technology.

In 2019, Google announced that its machine had achieved what scientists call “quantum supremacy,” which meant it could perform an experimental task impossible for traditional computers. However, most experts believe that it will be many years yet – at the very least – before a quantum computer can actually do something useful and impossible to do with another machine.

Part of the challenge is that a qubit deciphers, or undergoes a “quantum decoherence” process, when you read information from it – it becomes an ordinary bit capable of representing only 0 or 1, but not both, which generates machine errors. But by putting together many qubits and developing ways to guard against quantum decoherence, scientists hope to build machines that are both powerful and practical.

teleportation

Ultimately, ideally, they would be integrated into networks that can send information between nodes (connection points), allowing them to be used from anywhere, just as Google’s and Amazon’s cloud computing services make processing power quite large. affordable today.

But this comes with its own problems. Partly because of the decoherence process, quantum information cannot simply be copied and sent over a traditional network. However, quantum teleportation offers an alternative.

While it cannot move objects from one place to another, it can transfer information by exploiting a quantum property called “entanglement”: a change in the state of one quantum system instantly affects the state of another that is far away.

“After entanglement, it is no longer possible to describe these states separately,” explains Tracy. “Basically, the systems will come as a single system,” she says.

These entangled systems can be electrons, light particles or other objects. In the Netherlands, Hanson and his team used what’s called a nitrogen-vacancy center — a tiny empty space in a synthetic diamond in which electrons can be trapped.

The team built three such quantum systems, called Alice, Bob and Charlie, and connected them to a line with fiber optic wires. Scientists were then able to entangle these systems by sending individual photons – particles of light – between them.

First, the researchers entangled two electrons – one belonging to Alice and the other to Bob. In practice, the electrons were given the same “spin” and thus were joined, or entangled, in a common quantum state, each storing the same information: a particular combination of 1 and 0.

The researchers were then able to transfer this quantum state to another qubit, a carbon core, inside Bob’s synthetic diamond. Doing so freed up Bob’s electron, and the researchers were then able to entangle it with another electron belonging to Charlie.

By performing a specific quantum operation on both of Bob’s qubits – the electron and the carbon nucleus – the researchers were then able to glue the two tangles together: Alice with Bob glued to Bob with Charlie.

Result: Alice was also entangled with Charlie, which allowed data to teleport across all three nodes.

When data is transferred in this way, without actually traveling the distance between nodes, it cannot be lost. “Information can be entered on one side of the connection and then appear on the other,” Hanson said.

The information also cannot be intercepted. A future quantum internet, powered by quantum teleportation, could offer a new kind of theoretically indecipherable encryption.

In the new experiment, the network nodes weren’t that far apart — just about 60 feet apart. But previous experiments have shown that quantum systems can be entangled over greater distances.

The hope is that after several years of research, quantum teleportation will be feasible for many kilometers. “Now we’re trying to do this outside of the lab,” Hanson said. / TRANSLATION OF ROMINA CACIA