For the first time, Austrian and Chinese researchers have successfully
teleported three-dimensional quantum states. Future quantum computers could
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. The only two-level states ("qubits")
that have previously been conveyed were "0" or "1" values. However, the
researchers were able to transport a three-level state, known as a "qutrit".
In contrast to traditional computer science, "0" and "1" are not a
"either/or" in quantum physics; they can exist concurrently or in any
combination. This has recently been proved in practice by the
Austrian-Chinese team using a third option, "2".
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 design an experimental method for implementing
high-dimensional teleportation, as well as to develop the necessary
technology."
The potential routes a photon can travel are programmed with the quantum
state that needs to be transported. These routes can be seen as three
optical cables. Most intriguingly, a single photon may really exist
simultaneously in all three optical fibers 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 fibers by routing photons through a
number of inputs and outputs. The researchers also utilized supplementary
photons, which can interfere with other photons and are also fed into the
multiple beam splitter.
Without the two photons ever physically touching, the quantum information
may be transmitted to another photon distance from the input photon by
carefully choosing specific interference patterns. As Erhard underlines, the
experimental notion is not restricted to three dimensions and may
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 help to connect quantum computers with information
capacities beyond qubits," he adds.
The involved Chinese researchers think multidimensional quantum
teleportation has 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 based 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.
