Category: Scientific publication

Together with Jan Wiersig from Magdeburg/Germany, we just published an article in Reports on Progress in Physics (open access) that combines two research thrusts in our group: Fisher information (FI) and Exceptional Points (EPs). We demonstrate how EPs can enhance the FI and how moving away from the EP can lead to an even greater improvement in measurement precision. Our work establishes a general framework for understanding the role of non-Hermitian degeneracies in parameter estimation and clarifies under which conditions EPs provide genuine metrological advantages.

A joint paper with colleagues from Graz and Cardiff has just appeared in Laser & Photonics Reviews. In this work, we develop a resonant-state theory for finite photonic systems that are periodically modulated in time. While these photonic time crystals are often discussed in terms of bulk bandgaps, realistic implementations are finite and open. We show that their dynamics is governed by resonant states (quasinormal modes), revealing how parametric amplification emerges as a resonant process. Congratulations to Adrià, Sergei, David, Egor, Thomas and everyone involved!

In the group of Jörg Schmiedmayer (Atominstitut), self-induced microwave pulses were observed in nitrogen-vacancy centre spins coupled to a superconducting microwave cavity. With input by Thomas Pohl and collaborators from Japan (Bill Munro, Kae Nemoto), Oliver Diekmann could finally resolve the theory for this puzzling effect – see our new paper in Nature Physics and the corresponding press release.

In a collaboration with our former Marie-Curie fellow Nicolas Bachelard from Bordeaux, we have just published a new article in Nature Communications. We show both theoretically and experimentally that tailoring the wavefront of the trapping light allows one to control optical scattering forces and significantly enhance the confinement of nanoparticles levitated in vacuum without increasing laser power. Our results challenge the conventional view of diffraction limited trapping and open new perspectives for optomechanics experiments approaching the quantum regime.

In a collaboration with Kostya Bliokh and Zeyu from our group, we just published a new article in Reports on Progress in Physics. We show there how the decomposition of the phase in a wave’s evolution in a geometric and a dynamic part can be extended to scattering problems – opening up many new and interesting research avenues. See also the highlight by Paul Mabey in Physics World.

In a joint work with the team of Alexandre Aubry, from the Institute Langevin in Paris, we demonstrate how to detect and localize objects that are hidden from view inside a highly scattering medium. As laid out in the corresponding article published today in Nature Physics, the key ingredient is the “fingerprint matrix” of the object – see also the press release by TU Wien and a very nice News & Views piece by I. Starshynov.

A new paper by Max on the flow of Fisher information through artificial neural networks just came out in PRX – congratulations! Many thanks go to our collaborators in Scotland, France and Germany!

Together with Nicholas Lambert, Jevon Longdell, and Harald Schwefel from New Zealand as well as our previous group member Alexander Schumer, we just published a paper in Nature Physics, demonstrating both theoretically and experimentally how to use an exceptional point to control magnon-polaritons. See also the accompanying News&Views from Changhao Meng and Zhenghua An.

In a new paper with Max, Lukas and Günther, recently published in Nature Photonics, we explored how artificial intelligence can extract the maximum possible information from distorted optical signals. Using neural networks trained on seemingly chaotic light patterns, we approached — and nearly reached — the theoretical limit of precision, which we showed to be defined by the Cramér–Rao bound. Many thanks go to our collaborators in France (Dorian Bouchet) and Scotland (Ilya Starshynov and Daniele Faccio) as well as to Oliver for creating the great feature image shown on the top left. Check here for TU Wien’s press release.

Together with the group of Matthieu Davy in Rennes (France) we published a letter in the Physical Review, demonstrating how to optimally focus microwaves on a nonlinear target such as a low-noise amplifier embedded in a disordered environment (see image on the left).