World first: Delft researchers succeed in teleporting data

Researchers in Delft managed to bring teleportation from science fiction into the real world, well, the quantum world at least. The QuTech researchers are the first in the world to succeed in teleporting data - an important development in the research into the quantum internet, Trouw reports. The research was published in the journal Nature this week.

According to the classical laws of physics, nothing of significance can travel faster than light. So making matter or information disappear from one point and reappear on the other side of the world simultaneously should be impossible, right? Wrong, according to researchers at QuTech, a collaboration between TU Delft and TNO. Teleportation is possible, albeit in not in the ordinary world of classic physics, but in quantum physics.

Four years ago, QuTech, and other scientists in the world, proved that teleportation of quantum information is possible in principle. Now the QuTech researchers managed to do it in practice. The magic happens when two elementary particles are brought into the same quantum state. The two then remain eternally connected, even if they end up in different corners of the universe. If one changes, the other one changes at the same time.

This phenomenon is called entanglement, and it can be used to transfer quantum information. QuTech demonstrated it in a network with three nodes, three quantum processors, which the researchers dubbed Alice, Bob, and Charlie. Bob is connected to both Alice and Charlie by fiberglass, but Alice and Charlie don't have any physical connection - they are the start and end point of this network. Bob facilitates the teleportation by entangling his condition with Alice's and doing the same with Charlie. With a quantum trick, Bob reconciles those two entanglements, and viola! The two endpoints of the networks are now also entagled.

Now, if you change Charlie's quantum state, that information shows up in Alice at the exact same time. The remarkable thing about quantum states, or "qubits" in jargon, is that they can't be transferred. They exist in the dark until you measure them. Once they're measured, their information is lost. So Charlie's quantum state is measured when it's changed and disappears, showing up at Alice at the exact same time. Teleportation!

The vulnerability of qubits is what makes this research so complicated - as soon as you do anything to them, their information is lost. You can't even copy them. But that is also a major advantage. Because in the as-yet theoretical quantum internet, the privacy of communication is guaranteed. If anyone tries to intercept a message, it disappears. Only the sender and the receiver can get it.

In the future, the quantum internet will form one whole with quantum computers, which are also in the making. Quantum computers use another bit of magic from quantum physics - the phenomenon that particles can assume multiple quantum states simultaneously. Unlike today's bits, qubits don't have to be either 0 or 1 but can be both at the same time. As a result, quantum computers can calculate many times faster than today's fastest computer, among many other things.