"Try not to get lost!" - Photons on the move in a 3D maze
Scientists at the University of Rostock developed a new platform for intricate optical networks. Photons can enjoy this newly found freedom in powerful new quantum computational architectures. These discoveries were published in the renowned journal "Science Advances".
Imagine that you enter the term Light in your search engine, click on the link to Photons and get to Quantum computers via the entries Photoelectric effect, Albert Einstein, Quantum physics, and Quantum teleportation. "Of course, you also go straight from Light to Quantum physics," notes Professor Alexander Szameit. With his group, the physicist is conducting groundbreaking experiments on those very topics at the University of Rostock. Light powers a wealth of possible applications: Materials processing, eye surgery and of course the mind-boggling stream of data routed through fiber-optic cables represent just a fraction of today's indispensable optical technologies. "And it can put computers on warp speed, too," Szameit adds with regard to his fundamental research on quantum computing with light particles.
The work of Szameit's team is also connected to our imagined internet search. The World Wide Web consists of a staggering hodgepodge of entries connected by hyperlinks. Matching this degree of complexity poses a significant challenge for today's quantum technologies. "Sketching the World Wide Web on paper is easy. All you need for this pen—and a lots and lots of patience," the professor quips in light of the mind-boggling complexity of social networks. The technical implementation for quantum networks is even more difficult. "The devil is in the connections," Szameit sums up the physical obstacles.
The team of Rostock physicists routinely use laser-written optical circuitry to mold the flow of light particles in glass chips. In collaboration with scientists from Freiburg and Innsbruck, their most recent breakthrough involves polarization—the direction in which light oscillates—as an additional degree of freedom for propagation. "We have literally added a new dimension for the light particles" explains Szameit. Dr. Matthias Heinrich, a member of Professor Szameit's team and co-author, elaborates: "This really is a big deal. By one fell swoop, we have not only doubled the number of points, but each of them also has twice as many connections."
Beyond design and manufacturing, the team also put the novel chips through their paces with photon pairs. "If all roads lead to Rome, then light really does take all of them, at the same time," is how Max Ehrhardt, doctoral student and first author of the paper, outlines the photons' curious behavior in these versatile networks. "In some ways, they tend to behave like people. As soon as two of them have paired up, they become inseparable," the young researcher jokes. Professor Szameit's team was able to give the photons some breathing space by creating dedicated areas in which they can only found individually. "We not only allow photons to socially distance, but also to gather once more," is how Professor Szameit summarizes the experiments.
These result represent a significant advance in fundamental research on quantum optics and integrated photonics. Indeed, many challenges remain before ultimately light-based quantum technologies and neural networks can revolutionise our daily lives. Yet, given the rapid pace of progress, these ideas that today may seem like science fiction, may become reality sooner than expected.
The work was funded by the German Research Foundation (DFG), the European Union and the Alfried Krupp von Bohlen und Halbach Foundation.
More information:
Contact:
Prof. Dr. Alexander Szameit
Experimental Solid-State Optics Group
Institute for Physics
University of Rostock
Tel.: +49 381 498-6790
E-Mail: alexander.szameit@uni-rostock.de
Provided by University of Rostock
