“Quantum Internet” is getting closer and closer thanks to advances in data teleportation

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

Harnessing the mysterious powers of quantum mechanics, technology will perform tasks in minutes that even supercomputers could not complete in thousands of years. In the fall of 2019, Google unveiled a experimental quantum computer prove it was possible. Two years later, a laboratory in China did more or less the same.

But quantum computing won’t reach its potential without the help of another technological breakthrough. Call it the “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 across three physical locations. Previously, this was possible with only two.

The new experiment indicates that scientists can extend a quantum network across more and more sites. “We are now building small quantum networks in the lab,” said Ronald Hanson, the Delft-based physicist who oversees the team. “But the idea is to eventually build a quantum internet.”

Their research, unveiled this week with an article published in the scientific journal Nature, demonstrates the power of a phenomenon that Albert Einstein once thought impossible. Quantum Teleportation – what he called “ghostly action at a distance” — can transfer information between places without actually moving the physical matter that contains it.

This technology could profoundly change the way data travels from place to place. It draws on more than a century of research involving quantum mechanics, a field of physics that governs the subatomic realm and behaves unlike anything we experience in our daily lives. Quantum teleportation not only moves data between quantum computers, it also does it in such a way that no one can intercept it.

“This not only means that the quantum computer can solve your problem, but also that it doesn’t know what the problem is,” said Tracy Eleanor Northup, a researcher at the University of Innsbruck’s Institute for Experimental Physics who is also exploring the quantum teleportation. “Today it doesn’t work like that. Google knows what you are running on its servers.

A quantum computer taps into the strange ways some objects behave whether they’re very small (like an electron or a particle of light) or very cold (like an exotic metal cooled to near absolute zero, or minus 460 degrees Fahrenheit). In these situations, a single object can behave like two separate objects at the same time.

Traditional computers perform calculations by processing “bits” of information, with each bit containing a 1 or a 0. Taking advantage of the strange behavior of quantum mechanics, a quantum bit, or qubit, can store a combination of 1s and 0s, a bit like the way a spinning coin holds the tantalizing possibility that it will turn up heads or tails when it finally lands on the table.

This means that two qubits can hold four values ​​simultaneously, three qubits can hold eight, four can hold 16, and so on. As the number of qubits grows, a quantum computer becomes exponentially more powerful.

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

In 2019 Google announced that his machine had achieved what scientists call “quantum supremacy,” which meant it could perform an experimental task impossible with traditional computers. But most experts believe it will be many more years, at least, before a quantum computer can actually do something useful that another machine can’t do.

Part of the challenge is that a qubit breaks down, or “decoheres,” if you read information from it: It becomes an ordinary bit capable of holding only a 0 or a 1 but not both. But by stringing together many qubits and developing ways to protect against decoherence, scientists hope to build powerful and practical machines.

Eventually, ideally, these would be joined into networks that could send information between nodes, allowing them to be used from anywhere, just as Google and Amazon’s cloud computing services make computing power widely accessible today.

But this has its problems. Partly because of decoherence, quantum information cannot simply be copied and sent across a traditional network. Quantum teleportation provides an alternative.

While it can’t move objects from one place to another, it can move information by exploiting a quantum property called “entanglement”: a change in the state of one quantum system instantly affects the state of another, distant one.

“After entanglement, you can no longer describe these states individually,” said Dr. Northup. “Basically, it’s a system now.”

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

The team built three such quantum systems, called Alice, Bob and Charlie, and connected them online with fiber-optic strands. Scientists could then weave these systems together by sending single photons — particles of light — between them.

First, the researchers entangled two electrons, one belonging to Alice, the other to Bob. In effect, the electrons have been given the same spin, and thus have been joined, or entangled, into a common quantum state, each storing the same information: a particular combination of 1s and 0s.

The researchers could then transfer this quantum state to another qubit, a carbon nucleus, inside Bob’s synthetic diamond. This freed Bob’s electron and the researchers could then 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 entanglements together: Alice plus Bob glued to Bob plus Charlie.

The result: Alice got involved with Charlie, which allowed the data to teleport across all three nodes.

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

Furthermore, the information cannot be intercepted. A future quantum internet, powered by quantum teleportation, could provide a new type of encryption that is theoretically indestructible.

In the new experiment, the network nodes weren’t that far apart, only about 60 feet. 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 viable for many miles. “Now we’re trying to do that outside of the lab,” Dr. Hanson said.