For the first time, Austrian and Chinese researchers have successfully teleported three-dimensional quantum states. Future quantum computers might rely heavily on high-dimensional teleportation.
What was previously merely a theoretical possibility has been empirically shown by researchers from the University of Vienna and Austrian Academy of Sciences. They have been successful in teleporting intricate high-dimensional quantum states along with quantum physicists from the University of Science and Technology of China. This global first is reported by the study teams in the journal Physical Review Letters.
In their investigation, the scientists transferred a photon’s quantum state from one faraway photon to another. Only two-level states, or “qubits,” or data with the values “0” or “1, had previously been conveyed. However, the researchers were able to transport a “qutrit,” a three-level condition. In contrast to classical computer science, “0” and “1” are not a “either/or” in quantum physics; they can exist simultaneously or in any combination. With a third option, “2,” the Austrian-Chinese team has now proven this in practise.
New experimental technique
Theoretically feasible multidimensional quantum teleportation has been known since the 1990s. But first, according to Manuel Erhard of the Vienna Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, “we had to establish an experimental method for implementing high-dimensional teleportation, as well as to develop the requisite technology.”
The potential routes a photon can take are coded with the quantum state that needs to be transported. These routes can be visualised as three optical cables. Most intriguingly, a single photon can actually exist simultaneously in all three optical fibres according to quantum physics. The team developed a novel experimental technique to transport this three-dimensional quantum state. The so-called Bell measurement is the essential component of quantum teleportation. It is based on a multiport beam splitter, which joins all optical fibres by routing photons through a number of inputs and outputs. The researchers also used supplementary photons, which can interfere with other photons and are also fed into the multiple beam splitter.
Without the two photons ever physically interacting, the quantum information can be transferred to another photon distance from the input photon by carefully choosing specific interference patterns. As Erhard underlines, the experimental concept is not restricted to three dimensions and can theoretically be expanded to any number of dimensions.
Increased information capacity for quantum computers
As high-dimensional quantum systems can carry more information than qubits, the worldwide research team has also taken a significant step toward real-world applications like a potential quantum internet. The creative potential of the new approach is highlighted by Anton Zeilinger, a quantum physicist at the Austrian Academy of Sciences and the University of Vienna. “This result could assist to connect quantum computers with information capabilities exceeding qubits,” he says.
The participating Chinese researchers think multidimensional quantum teleportation offers a lot of potential. According to Jian-Wei Pan of the University of Science and Technology of China, “the fundamentals for the next-generation quantum network systems are built on our foundational research today. On the request of the University of Vienna and the Academy, Pan recently gave a lecture in Vienna.
Future research by quantum physicists will concentrate on how to apply their newly acquired understanding to enable the teleportation of an atom or photon’s whole quantum state.
