• physics 17, 66
A quantum light source is touring European laboratories in preparation for the International Year of Quantum Science and Technology 2025.
A. Böttcher/DPG
Like the flame that departed from Ancient Olympia today for the 2024 Paris Olympics, the “Quantum Torch” has just begun its European journey to commemorate the upcoming 2025 International Year of Quantum Science and Technology. Held in Berlin. Quantum torches are tiny dart-shaped devices that emit one photon at a time, embodying the precise control at the heart of quantum technology. “We want to get everyone excited about quantum physics,” says QuanTour organizer Doris Reiter of TU Dortmund in Germany.
The quantum torch, built by Tobias Heindel and his team at the Technical University of Berlin, plans to visit 12 different laboratories in 12 different countries over the next 12 months. Each stop will feature events related to the International Year of Quantum Science and Technology, a global initiative highlighting the contribution of quantum physics to our daily lives. QuanTour organizers are planning public demonstrations of quantum mechanics concepts and “behind the scenes” tours of quantum physics laboratories. A video of scientists explaining their work to science communicator and QuanTour organizer Pranoti Kshirsagar will also be shown.
The launch included a discussion on the importance of quantum science and technology in our daily lives. Claus Lämmerzahl, a theoretical physicist at the University of Bremen in Germany and spokesman for the German Physical Society (DPG), provides motivation for the upcoming quantum year. He said 2025 was chosen to mark the 100th anniversary of Werner Heisenberg’s theoretical breakthrough in elaborating the mathematics of quantum mechanics. “Quantum theory is one of humanity’s fundamental discoveries,” Lamezal said.
Next year also marks the 125th anniversary of Max Planck’s introduction of the concept of “quanta,” packets of energy that can explain the spectrum of light emitted by a heat source, such as a burning torch. Cornelia Denz, Director of the German National Metrology Institute (PTB), describes the efforts made at the end of the 19th century to achieve this development and single-photon quantum light sources such as quantum torches. “Quantum emitters are very important for quantum technology,” Denz said.
A key use of single-photon emitters is communications. “Quantum physics can provide enhanced security and functionality for our communications networks,” Heindel said. Enhanced security relies on single-photon emitters, he said, because these devices can provide a steady stream of photons that are highly sensitive to any type of eavesdropping.
Heindel, whose research focuses on quantum communications, describes QuanTour’s Quantum Torch device as a “nanophoton dart” with a quantum dot emitter in the bullseye. The 4-µm-wide element is etched into a thin sheet of gallium arsenide, a semiconductor material, and consists of concentric rings surrounding a central point. These rings increase the rate at which single photons are produced, and they orient the emission of photons in a direction perpendicular to the plane of the dart.
L. Rickert/TU Berlin
Users can test the quantum properties of the torch by performing the so-called Hanbury-Brown-Tewes (HBT) experiment. In such a demonstration, light from the device is sent to a beam splitter with a detector on each of its two outputs. A time delay is introduced into one of the detectors, and the number of simultaneously detected photons is counted as the time delay changes.
If the light source is a classical light source (as in the case of a light bulb or a burning flame), the measurement should show a large peak at zero time delay. For single quantum emitters, users should see a drop because single photon sources do not produce consistent counts with zero time delay. Scientists will conduct the HBT experiment in 12 laboratories and then present the data to the public.
The launch ceremony ended with a skit, in which two guards in “Quantum Security” uniforms escorted a suitcase carried by Lucas Rickert, a graduate student at the Technical University of Berlin. The suitcase is opened and the audience can clearly see the Quantum Torch inside. QuanTour organizers then closed the suitcases and affixed travel “stickers” from DPG and other supporting agencies. The Quantum Torch is ready for its first trip to Linz, Austria (the public can follow its progress on social media).
Michael Schilber
Michael Schirber is the author ofjournal of physics Headquartered in Lyon, France.
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Image Source : physics.aps.org