One of this year’s grants from the VILLUM FOUNDATION’s Young Investigator Programme has been awarded to Postdoc Jonas Schou Neergaard-Nielsen from DTU Physics. The grant will be used to develop a method for teleporting larger volumes of quantum information than is currently possible. The ultimate goal is lightning-fast secure communication networks.
By Jonas Schou Neergaard-Nielsen and Anne Hansen
On hearing the word teleportation, most of us assume it means transporting people in a split second from one place to another in true Star Trek style. However, while anything is possible in the world of fiction, we are still a long way off from being able to teleport people. On the other hand, teleportation is considered a key element in the high-speed and unbreakable encrypted communication networks of the future.
As yet, the technology—which involves moving information that only fills a single light particle, or photon—is still in its infancy. But Jonas Schou Neergaard-Nielsen, a postdoc at DTU Physics, will now try to push the boundaries of what is feasible. Jonas has just been awarded a grant from the VILLUM FOUNDATION’s Young Investigator Programme of DKK 4 million, which will be spent on developing a method for transporting information which is distributed between several photons along several separate light beams before gathering the information again at the recipient.
“At the sub-microscopic level, where quantum mechanics rule, you find a completely different logic to what we are used to in our macroscopic reality,” says Jonas. “For example, particles can be in two places at the same time, and they can even be ‘entangled’ with twin particles, so that they can feel everything that happens to each other, even when they are separated by considerable distance.”
Teleportation to replace optical fibres
Researchers can use the rather odd quantum phenomena, especially the ‘here and there’ (quantum superpositions), to, for example, design unbreakable quantum encryption and computers that can handle massive calculations that would be insurmountable for ordinary supercomputers. However, to make the most of such quantum computers, they should preferably be connected to a network.
“The obvious thing to do would be to connect the computers in an optical fibre network, where the quantum information is transferred via individual photons. However, photons are fragile, and the information is therefore easily lost. If, instead, we make an entanglement of two twin light beams found at the sender and the recipient, respectively, the sender can transfer his quantum data instantly to the recipient’s light beam without the photons having to physically travel through the fibre,” says Jonas, adding:
“Quantum teleportation is a 20-year old process which has been demonstrated experimentally by many different research groups. Nevertheless, there are still several challenges that need addressing before it can be applied in practice. Among other things, it is difficult to teleport quantum states that ‘occupy’ more than a single photon with a high degree of precision.
This is what we want to explore with this project. Roughly speaking, the idea is to distribute a ‘full’ quantum state between several light beams, which will each be teleported using a traditional one-photon teleporter. At the receiver, the individual parts are reassembled so that the original multi-photon state is restored.”
“It is a technically difficult experiment, but if we can overcome the challenges and the experiment succeeds, we will have demonstrated a method which in future, once the technology is mature, will offer a good alternative to other types of teleportation. It would then make sense to continue the research with a demonstration of how teleportation can be applied in a simple quantum computer network,” says Jonas.