Hidden bridge between quantum experiments and graph theory uncovered

December 19, 2017, University of Vienna
The algorithm Melvin, developed by researchers of the Austrian Academy of Sciences and the University of Vienna, is used to calculate technical solutions of experiments in quantum physics. Credit: Mehul Malik/University of Vienna

An answer to a quantum-physical question provided by the algorithm Melvin has uncovered a hidden link between quantum experiments and the mathematical field of Graph Theory. Researchers from the Austrian Academy of Sciences and the University of Vienna found the deep connection between experimental quantum physics and this mathematical theory in the study of Melvin's unusual solutions, which lies beyond human intuition. They now report in the journal Physical Review Letters.

Phenomena of are perfectly computable—but often elude human logic. In the future, it would be precisely computer algorithms that could make a decisive contribution to the solution of -physical questions, where human logic does not get any further, as was demonstrated now by Melvin. The algorithm developed by researchers of the Austrian Academy of Sciences (ÖAW) and the University of Vienna is actually being created for the calculation of technical solutions for quantum physical experiments. For a general question asked last year, Melvin provided a solution that proved to be surprisingly practical—but initially completely out of touch with human intuition.

Remarkable number sequence

"The solution could practically be implemented in the form of an experiment in the laboratory," confirms quantum physicist Mario Krenn from the research group of Anton Zeilinger, professor at the University of Vienna and group leader at the Institute of Quantum Optics and Quantum Information of the Austrian Academy of Sciences. "But at first we did not understand how it actually works," the researcher continues.

In the analysis of this calculated by Melvin, the researchers initially groped in the dark. Until they came up with a remarkable sequence of numbers known only in the so-called —a sophisticated area of mathematics that has been used to describe networks such as the Internet or neural networks.

New experimental methods

The unusual approach, which would have remained hidden to quantum physicists, prompted the scientists to further investigate this connection. As they now report in the journal Physical Review Letters, there are great similarities between experimental quantum physics and mathematical graph theory: If methods and knowledge from graph theory are used to calculate and plan a quantum experiment, it is possible to make very precise and novel statements about the results. "Properties of quantum experiments can be calculated using graph theory, and questions in can be answered in quantum experiments," explains Krenn. In this way, it is also possible to grasp quantum technology as a graph or a network in order to explore new experimental possibilities.

Also for quantum physicist Anton Zeilinger this bridge, discovered thanks to Melvin, is very promising: "It was very surprising to see that there is a new deep connection between quantum physics and mathematics." What concrete potential this finding holds, is currently not yet to estimate. "It is to be expected," says Zeilinger, "that this knowledge will be of importance for the development of both areas in the future."

Explore further: Quantum experiments designed by machines

More information: Mario Krenn et al. Quantum Experiments and Graphs: Multiparty States as Coherent Superpositions of Perfect Matchings, Physical Review Letters (2017). DOI: 10.1103/PhysRevLett.119.240403

Related Stories

Quantum experiments designed by machines

February 22, 2016

Quantum physicist Mario Krenn and his colleagues in the group of Anton Zeilinger from the Faculty of Physics at the University of Vienna and the Austrian Academy of Sciences have developed an algorithm which designs new useful ...

Worldwide quantum web may be possible with help from graphs

June 8, 2016

(Phys.org)—One of the most ambitious endeavors in quantum physics right now is to build a large-scale quantum network that could one day span the entire globe. In a new study, physicists have shown that describing quantum ...

Recommended for you

Muons spin tales of undiscovered particles

April 20, 2018

Scientists at U.S. Department of Energy (DOE) national laboratories are collaborating to test a magnetic property of the muon. Their experiment could point to the existence of physics beyond our current understanding, including ...

Integrating optical components into existing chip designs

April 19, 2018

Two and a half years ago, a team of researchers led by groups at MIT, the University of California at Berkeley, and Boston University announced a milestone: the fabrication of a working microprocessor, built using only existing ...

3 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Nik_2213
5 / 5 (1) Dec 19, 2017
Pay-walled, of course.

But, as mix of arcane quantum and graph theories, I'd need the kindergarten version...
RNP
5 / 5 (1) Dec 19, 2017
An open access copy of the paper can be found here; https://arxiv.org...6646.pdf
Nik_2213
5 / 5 (1) Dec 19, 2017
Thank you.
Sadly, my ageing brain went 'TILT' ...

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.