| 日期 26 September 2025
The DPG Fall Meeting 2025 (Quantum25) in Göttingen was a special edition of the traditional meetings of the German Physical Society (DPG). Usually, DPG organizes its large conferences in spring, but this autumn gathering was arranged to mark 100 years since Werner Heisenberg published the first paper on quantum mechanics in 1925. The event brought together researchers, students, and industry to reflect on a century of quantum physics and discuss today’s developments in quantum communication, quantum optics, and condensed matter.
At our booth, visitors could experience our instruments in action. We demonstrated how they integrate with synchronization methods to achieve picosecond-level precision, and we brought along the well-known Red Button Game. Many participants already recognized it from earlier trade shows, but the excitement was the same; there was lively competition to set the fastest reaction times, with people trying to beat records and compare results. The game again showed how reliably our instruments measure even the smallest time differences.
In addition to the booth, we also contributed with a talk and had the chance to meet many researchers who are already applying our instruments in their projects. Seeing our devices featured in posters and presentations was both motivating and a confirmation of the role they play in advancing experiments in quantum science.
During DPG 2025, our colleague Dr. Timon Eichhorn gave a talk introducing how remote Time Taggers can be synchronized for use in quantum communication applications. He began with an overview of the Swabian Instrument’s Time Tagger as a time-to-digital converter with flexible software options such as adjustable settings, event filters, and an intuitive API and GUI. Tools that make it easier for researchers to conduct precise timing experiments while keeping the workflow manageable.
The talk then focused on Time Tagger networks, which allow multiple devices at remote locations to operate as if they were local. This setup enables the streaming of TimeTags over a network so that a client PC can directly access and analyze them. Such functionality supports joint measurements on merged data streams, which is especially useful in collaborative experiments spanning different labs.
Timon explained how White Rabbit technology is used to provide a common clock signal with sub-nanosecond accuracy and picosecond precision for applications in remote synchronization. Measurements showed that the additional jitter of this synchronization layer remained below 4 ps. Building on this, he described the concept of the Time Tagger Network class of the software in order to merge time tag streams from several servers at remote locations.
Finally, this talk highlighted a practical use case: establishing a quantum communication link between remote laboratories. Using two optical fibers for single-photon transmission and an Ethernet link for data transfer, the system required synchronized timing electronics in each lab. The Time Tagger network provided a scalable solution by ensuring a common time base across sites, enabling precise correlation of photon events even over long distances.
One of the most rewarding parts of DPG was seeing how many research groups are already applying our instruments in their work. Several of our customers presented their results at the conference, showcasing applications ranging from quantum communication and quantum key distribution (QKD) to quantum photonics and single-photon sources. It was a great opportunity to hear how our technology supports experiments across universities, research institutes, and companies.
The following examples provide a glimpse into the diversity of projects presented:
Ali Hreibi (PTB): PTB Testbed for Quantum Key Distribution Metrology
Ali presented work on building a testbed for metrology in QKD, including calibrating single-photon detectors under realistic conditions, characterizing entangled photon sources, and multiplexing different QKD signals in optical fiber to improve system fidelity.
Thomas Volz (Quandela): Driven by Quantum, Empowered by Quandela
Thomas discussed Quandela’s development of photonic quantum computing, highlighting their quantum-dot single-photon source technology, efforts to scale hardware, middleware, and software together, and applications in areas such as cybersecurity, energy, and finance.
Peter Lodahl (Sparrow Quantum): Deterministic Photon-Emitter Interfaces for Quantum Technology
Peter described progress toward deterministic photon-emitter interfaces using quantum dots, showing how combining nanophotonics and atomic physics enables on-demand photon sources and their integration into scalable quantum networks or fault-tolerant computing architectures.
Lennart Jehle (University of Vienna): Two-Photon Spectrum and Dynamics of a Quantum Dot under Phonon-Assisted Excitation
Lennart presented research on quantum dot dynamics under phonon-assisted excitation, providing new insights into photon emission processes that are relevant for future quantum optics and communication experiments.
Siavash Qodratipour (Humboldt-Universität zu Berlin) – Towards Time-Bin Entangled Photon Cluster States
Siavash reported progress on generating time-bin entangled photon cluster states, an important step toward scalable one-way quantum computation using photonic cluster states.
Sebastian Neumann (ZeroThird/Quantum Industries GmbH): Entanglement-based Quantum Key Distribution
Sebastian presented on entanglement-based QKD , explaining the security benefits of entanglement, the commercial applications under development at ZeroThird, and the challenges of achieving high key rates over long distances and in multi-user quantum networks.
Kevin Füchsel (Quantum Optics Jena GmbH): From Entangled Photon-Pair Sources to Post-Quantum Cyber Security Solutions
Kevin described the path from designing entangled photon-pair sources to implementing them in real IT infrastructures, showing how his startup translates lab-scale photon-pair generation into practical cybersecurity solutions and what lessons they’ve learned along the way.
DPG in Göttingen was an important opportunity to connect with the quantum research community. From our own talk on the specifications and applications of Swabian Instruments’ time-to-digital converters to the many customer presentations that featured our instruments, the conference showed the range of projects where precise timing plays a key role.
We thank everyone who visited our booth, joined the discussions, or presented their work. Seeing how our instruments are already part of ongoing research motivates us to continue improving our tools and supporting the community in advancing quantum science and technology.
Key breakthroughs in quantum networking, science, telecommunications, finance, and computing rely on precise synchronization of time measurements across multiple locations. Examples include quantum key distribution (QKD) and time verification, which involve event detection with very high fidelity time‐to‐digital conversion (time tagging) at different sites many kilometers apart, sharing a common time base (synchronization).
Read more