Rydberg atoms are a promising platform for hybrid quantum systems due to their dipole-allowed transitions spanning frequencies from the optical to the microwave regime and their strong coupling to electric fields. To investigate their integration with solid-state devices, we are developing a cryogenic experimental platform combining ultracold rubidium atoms with an electromechanical resonator...
White Etching Cracks (WEC) are complex crack networks that cause premature damage under rolling contact fatigue. Hydrogen is suspected of promoting crack formation, but its exact role remains unclear. Crack initiation and propagation are still insufficiently understood because of the interaction between microstructure, inclusions, and crack evolution.
A major challenge is that conventional...
Since 2015, the Gender Equity Task Force of the international society for optics and photonics (SPIE) has been working to identify how the professional environment and culture of the optics and photonics community can better enable equal opportunities, rewards, and recognition for its members, independent of gender. The Task Force focuses on identifying and recommending specific steps our...
In this work, we explore how a magnon Bose–Einstein condensate (BEC) responds to external perturbations and how its stability and lifetime can be controlled. The magnon BEC is created by populating the magnon gas above the thermal equilibrium level using pulsed parallel parametric pumping. A second pulse at a different frequency—with its parametric excitation frequency tuned from below the...
Understanding the origin of the Ultra-High-Energy Cosmic Rays (UHECRs) requires explaining the features of their energy spectrum, mass composition, and arrival directions. Current modeling approaches neglect the time evolution of UHECR observables, a factor that is particularly important in the case of bursting UHECR sources. This study focuses on the influence of time delays caused by the...
The recovery of phosphate from wastewater is essential for a healthy aquatic ecosystem. One of the most commonly used methods for recovering phosphate from wastewater is chemical precipitation. In this process Fe(III) reacts with phosphate to form ferric phosphate that settles as Fe-P particles. However, the molecular mechanisms that govern iron-phosphate interactions under different chemical...
Neutral-atom platforms offer a promising route toward scalable quantum simulation and computation, but combining large system sizes with precise local control remains a central challenge. We address this using a hybrid platform that combines a large optical lattice with individually controlled optical tweezers. In strontium-88, the lattice provides more than 10,000 trapping sites and supports...
The investigation of superconducting Josephson junctions requires low-noise and configurable DC measurement setups capable of resolving superconducting features. To improve the experimental capabilities of a Bluefors® dilution refrigerator, a modular upgrade of the Fast Sample Exchange (FSE) puck was developed, focusing on flexible wiring, integrated filtering, and improved sample...
In the face of 28 million tonnes of spent refractories annually, recycling and upcycling strategies for MgO-C refractories are crucial to more sustainable and environmentally friendly materials management in high-temperature industries. The research training group GRK 2802 funded by the German Research Foundation (DFG) investigates two core ideas addressing the use of spent MgO-C.
The...
Atomic Force Microscopy (AFM) is a versatile tool for studying biological systems from the single cell to the nanoscale. By combining tailored surface functionalization, single-cell force spectroscopy, FluidFM-based cell manipulation, and correlative AFM–confocal microscopy, we establish an experimental framework to investigate biological interfaces and microbial adhesion.
Silicon...
Silicon is a promising lithium-ion anode material, storing about ten times more lithium than graphite, but its large volume change and unstable solid-electrolyte interphase (SEI) limit the lifetime and quality of the cell. Whether the crystal lattice or the native-oxide/SEI surface layer governs how deep lithium penetrates remains unsolved, as the two contributions are difficult to separate in...
Nanodiamonds with crystal defects have gained increasing importance in biological and chemical applications [1]. Most prominent are fluorescent nanodiamonds (FNDs) with nitrogen-vacancy (NV) centers due to their unique properties such as high photostability, chemical inertness and sensitivity towards magnetic and electric fields [2,3]. These properties make them highly suitable for the in-situ...
Functional materials embedded in three-dimensional photonic microstructures offer new routes for advanced photonic devices. We present two different approaches towards such devices: the incorporation of colloidal quantum dots (QDs) into 3D-printed microstructures for hyperspectral sensing applications, and the integration of the nonlinear organic molecule DDMEBT into 3D microstructures to...
ZnO is a prototypical wide-band-gap material with long-lived excitons, making it a central platform for modern optoelectronic and catalytic technologies, especially for investigating exciton-related phenomena [1]. Excitons—bound electron–hole pairs that can exist in various forms near the surface, significantly shape the material’s optical and electronic response and play an essential role in...
Nitrogen-vacancy (NV) centers in diamond are an attractive platform for quantum sensing because they exhibit stable optical and spin properties at room temperature [1, 2]. An NV center consists of a nitrogen atom substituting a carbon atom and a neighbouring vacancy in the diamond lattice [2]. Owing to their environmental sensitivity, high spatial resolution, and excellent biocompatibility, NV...
Group-IV color centers in diamond are well known for their suitability as nodes within quantum networks due to their excellent spin and optical coherence. The tin-vacancy center (SnV-) in particular shows Fourier limited linewidths, a small inhomogeneous distribution of emission wavelengths, and excellent long-term spectral stability [1-3]. The latter two of which have been observed for deep...
Quantum-based approaches are emerging as a promising alternative for high-accuracy pressure metrology, offering direct SI traceability and the potential to reduce measurement uncertainties. This work presents the development and improvement of a Fabry–Perot refractometer as part of ongoing efforts to realize quantum-based pressure standards. The system was designed, assembled, and used to...
High-spin nuclei have emerged as a promising resource for quantum computing, owing to their large, high-dimensional state spaces and the maturity of the solid-state hosts in which they reside. Because each nucleus behaves as a qudit rather than a two-level qubit, its extra dimensions can be used to encode and protect quantum information, opening new routes to quantum error...
The negatively charged Tin-Vacancy (SnV$^-$) color center in diamond is a promising candidate for solid-state quantum network nodes due to its long spin coherence times and fourier limited optical transitions.
Diamond, as a host material, has a large refractive index of $n=2.4$ which limits the amount of light that can escape past its boundary surface caused by total internal reflection. This...
Without DNA replication human life would not be possible because cells would be unable to divide and renew themselves [1]. The enzyme responsible for DNA replication, DNA polymerase, cannot synthesize new DNA de novo from the DNA template [2]. It requires a primer, which is produced by primase [3]. The primary sequence of human primase II contains a binding motive for a [4Fe4S] cluster which...
Iridium complexes have highly interesting photochemical, photophysical and catalytic properties. They are used for example in organic light-emitting diodes (OLEDs), organic solar cells and automotive exhaust catalysts.[1,2,3] Iridium complexes have also been used to initiate "water oxidation reactions“.[4,5] They also hold promise as photosensitisers and photocatalysts for directed...
The Fluorescence Detector (FD) of the Pierre Auger Observatory provides energy measurements of primary cosmic rays that are largely independent of specific interaction models. These measurements are crucial for calibrating the energy reconstruction of the Surface Detector. Consequently, the accuracy of the FD energy calibration plays a key role in the systematic uncertainties associated with...
Physics continues to be regarded as a male-dominated subject with a ‘leaky pipeline’ throughout the career progression – from the beginning of undergraduate studies right through to a professorship. Since 2021, the "Mehr für Physikstudentinnen" ("More (for) Female Physics Students") project at the Department of Physics and the Gender Equality Office at Marburg University has been addressing...
Quantum error correction protects fragile quantum information by encoding it non-locally across many physical qubits, and stabilizer measurements, the syndromes used to diagnose errors, are performed continuously on any error-corrected device. In this work we ask what this routinely collected data certifies about entanglement, at no additional measurement cost. Focusing on the seven-qubit...
Ge₂SeTe is a promising phase-change material (PCM) for programmable photonic integrated circuits (PICs) operating in the infrared spectral range. Since continuous tuning of such devices requires a detailed understanding of thickness-dependent switching behavior, thin films of 40, 80, and 160nm were investigated using a Phase-Change Optical Tester.
Under laser-induced crystallization, the...
Carola Meyer, Dagmar Paarmann, Agnes Sandner,
Beate Klösgen ( für die AKC-Kommission)
Der Arbeitskreis Chancengleichheit (AKC) wurde 1998 als ein Arbeitskreis
innerhalb der Deutschen Physikalischen Gesellschaft e.V. (DPG) gegründet.
Das Ziel des AKC ist die Verbesserung der Chancengleichheit für alle
Physiker:innen, beginnend auf allen Ebenen der DPG und im Sinne der
umfassenden...
Selma Memić, Rafael Wagner, Susana F. Huelga, Martin B. Plenio
*Institut für Theoretische Physik, Universität Ulm, Ulm, Germany
Finite-time quantum heat engines suffer from quantum friction, generation of
coherences as the working fluid is driven – which, if not addressed, results in lowering the
efficiency of an engine1. Lubrication protocols address quantum friction by coupling...
