@article{65611, abstract = {{ Spins confined in optically active quantum dot molecules (QDMs) can be used for the deterministic generation of photonic graph states with tailored entanglement structures. Their usefulness for the generation of such nonclassical states of light is determined by orbital and spin decoherence mechanisms, particularly phonon-mediated processes dominant at energy scales up to a few millielectronvolts. Here, we directly measure the spectral function of orbital phonon relaxation between the energy states of the neutral exciton in a QDM and benchmark our findings against microscopic k · p theory. Our results reveal pronounced resonances and antiresonances in the phonon-relaxation rates, ranging from tens of µ s − 1 up to tens of ns − 1 . Comparison with a kinetic model reveals the voltage (energy) dependent phonon coupling strength and fully explains the interplay between phonon-assisted relaxation and radiative recombination. The resonances and antiresonances enable further tunability of the exciton lifetime which can be leveraged to increase the lifetime of energetically unfavorable charge configurations needed for realizing efficient spin-photon interfaces and multidimensional cluster states. }}, author = {{Lienhart, Michelle and Gawarecki, Krzysztof and Stöcker, Markus and Bopp, Frederik and Cullip, Charlotte and Akhlaq, Nadeem and Thalacker, Christopher and Schall, Johannes and Rodt, Sven and Ludwig, Arne and Reuter, Dirk and Reitzenstein, Stephan and Müller, Kai and Machnikowski, Paweł and Finley, Jonathan J.}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, number = {{23}}, publisher = {{American Physical Society (APS)}}, title = {{{Resonant and antiresonant exciton-phonon coupling in quantum dot molecules}}}, doi = {{10.1103/xc25-1tph}}, volume = {{112}}, year = {{2025}}, } @inproceedings{50272, abstract = {{Despite the fundamental role the Quantum Satisfiability (QSAT) problem has played in quantum complexity theory, a central question remains open: At which local dimension does the complexity of QSAT transition from "easy" to "hard"? Here, we study QSAT with each constraint acting on a $k$-dimensional and $l$-dimensional qudit pair, denoted $(k,l)$-QSAT. Our first main result shows that, surprisingly, QSAT on qubits can remain $\mathsf{QMA}_1$-hard, in that $(2,5)$-QSAT is $\mathsf{QMA}_1$-complete. In contrast, $2$-SAT on qubits is well-known to be poly-time solvable [Bravyi, 2006]. Our second main result proves that $(3,d)$-QSAT on the 1D line with $d\in O(1)$ is also $\mathsf{QMA}_1$-hard. Finally, we initiate the study of 1D $(2,d)$-QSAT by giving a frustration-free 1D Hamiltonian with a unique, entangled ground state. Our first result uses a direct embedding, combining a novel clock construction with the 2D circuit-to-Hamiltonian construction of [Gosset, Nagaj, 2013]. Of note is a new simplified and analytic proof for the latter (as opposed to a partially numeric proof in [GN13]). This exploits Unitary Labelled Graphs [Bausch, Cubitt, Ozols, 2017] together with a new "Nullspace Connection Lemma", allowing us to break low energy analyses into small patches of projectors, and to improve the soundness analysis of [GN13] from $\Omega(1/T^6)$ to $\Omega(1/T^2)$, for $T$ the number of gates. Our second result goes via black-box reduction: Given an arbitrary 1D Hamiltonian $H$ on $d'$-dimensional qudits, we show how to embed it into an effective null-space of a 1D $(3,d)$-QSAT instance, for $d\in O(1)$. Our approach may be viewed as a weaker notion of "simulation" (\`a la [Bravyi, Hastings 2017], [Cubitt, Montanaro, Piddock 2018]). As far as we are aware, this gives the first "black-box simulation"-based $\mathsf{QMA}_1$-hardness result, i.e. for frustration-free Hamiltonians.}}, author = {{Rudolph, Dorian and Gharibian, Sevag and Nagaj, Daniel}}, booktitle = {{16th Innovations in Theoretical Computer Science (ITCS)}}, number = {{85}}, pages = {{1--24}}, title = {{{Quantum 2-SAT on low dimensional systems is $\mathsf{QMA}_1$-complete: Direct embeddings and black-box simulation}}}, doi = {{10.4230/LIPIcs.ITCS.2025.85}}, volume = {{325}}, year = {{2025}}, } @article{63513, author = {{Grimminger-Seidensticker, Elke and Treder, Alexandra and Niederhaus, Constanze}}, journal = {{Zeitschrift für Sportpädagogische Forschung}}, number = {{2}}, pages = {{189--212}}, publisher = {{Nomos}}, title = {{{Sprachbezogene Kompetenzerwartungen im Sportunterricht – Eine systematische Lehrplananalyse}}}, doi = {{https://doi.org/10.5771/2196-5218-2025-2-189}}, volume = {{13}}, year = {{2025}}, } @article{55037, abstract = {{Estimating ground state energies of many-body Hamiltonians is a central task in many areas of quantum physics. In this work, we give quantum algorithms which, given any $k$-body Hamiltonian $H$, compute an estimate for the ground state energy and prepare a quantum state achieving said energy, respectively. Specifically, for any $\varepsilon>0$, our algorithms return, with high probability, an estimate of the ground state energy of $H$ within additive error $\varepsilon M$, or a quantum state with the corresponding energy. Here, $M$ is the total strength of all interaction terms, which in general is extensive in the system size. Our approach makes no assumptions about the geometry or spatial locality of interaction terms of the input Hamiltonian and thus handles even long-range or all-to-all interactions, such as in quantum chemistry, where lattice-based techniques break down. In this fully general setting, the runtime of our algorithms scales as $2^{cn/2}$ for $c<1$, yielding the first quantum algorithms for low-energy estimation breaking the natural bound based on Grover search. The core of our approach is remarkably simple, and relies on showing that any $k$-body Hamiltonian has a low-energy subspace of exponential dimension.}}, author = {{Buhrman, Harry and Gharibian, Sevag and Landau, Zeph and Gall, François Le and Schuch, Norbert and Tamaki, Suguru}}, journal = {{Physical Review Letters}}, pages = {{030601}}, title = {{{Beating Grover search for low-energy estimation and state preparation}}}, doi = {{10.1103/29qw-bssx}}, volume = {{135}}, year = {{2025}}, } @unpublished{61776, abstract = {{We investigate the role of energy, i.e. average photon number, as a resource in the computational complexity of bosonic systems. We show three sets of results: (1. Energy growth rates) There exist bosonic gate sets which increase energy incredibly rapidly, obtaining e.g. infinite energy in finite/constant time. We prove these high energies can make computing properties of bosonic computations, such as deciding whether a given computation will attain infinite energy, extremely difficult, formally undecidable. (2. Lower bounds on computational power) More energy ``='' more computational power. For example, certain gate sets allow poly-time bosonic computations to simulate PTOWER, the set of deterministic computations whose runtime scales as a tower of exponentials with polynomial height. Even just exponential energy and $O(1)$ modes suffice to simulate NP, which, importantly, is a setup similar to that of the recent bosonic factoring algorithm of [Brenner, Caha, Coiteux-Roy and Koenig (2024)]. For simpler gate sets, we show an energy hierarchy theorem. (3. Upper bounds on computational power) Bosonic computations with polynomial energy can be simulated in BQP, ``physical'' bosonic computations with arbitrary finite energy are decidable, and the gate set consisting of Gaussian gates and the cubic phase gate can be simulated in PP, with exponential bound on energy, improving upon the previous PSPACE upper bound. Finally, combining upper and lower bounds yields no-go theorems for a continuous-variable Solovay--Kitaev theorem for gate sets such as the Gaussian and cubic phase gates.}}, author = {{Chabaud, Ulysse and Gharibian, Sevag and Mehraban, Saeed and Motamedi, Arsalan and Naeij, Hamid Reza and Rudolph, Dorian and Sambrani, Dhruva}}, booktitle = {{arXiv:2510.08545}}, title = {{{Energy, Bosons and Computational Complexity}}}, year = {{2025}}, } @unpublished{60432, abstract = {{The Quantum k-SAT problem is the quantum generalization of the k-SAT problem. It is the problem whether a given local Hamiltonian is frustration-free. Frustration-free means that the ground state of the k-local Hamiltonian minimizes the energy of every local interaction term simultaneously. This is a central question in quantum physics and a canonical QMA_1-complete problem. The Quantum k-SAT problem is not as well studied as the classical k-SAT problem in terms of special tractable cases, approximation algorithms and parameterized complexity. In this paper, we will give a graph-theoretic study of the Quantum k-SAT problem with the structures core and radius. These hypergraph structures are important to solve the Quantum k-SAT problem. We can solve a Quantum k-SAT instance in polynomial time if the derived hypergraph has a core of size n-m+a, where a is a constant, and the radius is at most logarithmic. If it exists, we can find a core of size n-m+a with the best possible radius in polynomial time, whereas finding a general minimum core with minimal radius is NP-hard.}}, author = {{Kremer, Simon-Luca and Rudolph, Dorian and Gharibian, Sevag}}, booktitle = {{arXiv:2506.17066}}, title = {{{Quantum k-SAT Related Hypergraph Problems}}}, year = {{2025}}, } @inbook{63439, author = {{Moritzer, Elmar and Brandes, Philipp and Claes, Leander and Henning, Bernd}}, booktitle = {{PIAE EUROPE 2025}}, editor = {{Wissensforum GmbH, VDI}}, pages = {{347–360}}, publisher = {{{VDI Verlag}}}, title = {{{Ultrasound based measurement of mechanical properties of continuous fiber reinforced thermoplastic laminates – A non-destructive method to identify changes in fiber matrix adhesion}}}, doi = {{10.51202/9783181024461-347}}, year = {{2025}}, } @article{63440, author = {{Moritzer, Elmar and Brandes, Philipp and Westphal, Max Siegfried and Claes, Leander and Wippermann, Mareen and Düchting, Julia and Henning, Bernd}}, journal = {{WAK Jahresmagazin}}, keywords = {{Faser-Kunststoff-Verbunde (FKV), Faserverstärkte Kunststoffe (FVK), Organobleche, Ultraschall}}, pages = {{26–29}}, title = {{{Zerstörungsfreie Ultraschall-Prüfung von Organoblechen}}}, volume = {{2025}}, year = {{2025}}, } @inbook{64988, author = {{Meyer, Anja and Dehn, Freya and Gövert, Andre and Schlegel-Matthies, Kirsten and Niederhaus, Constanze}}, booktitle = {{Sprache(n) im Beruf: Gestaltung und Förderung beruflicher Sprachbildung an den verschiedenen Lernorten.}}, editor = {{Gerholz, Karl-Heinz and Hochleitner, Thomas and Maidanjuk, Ilona and Beil, Shaleen Beil}}, pages = {{169--186}}, title = {{{Professionalisierung (angehender) Lehrkräfte für sprachbildenden Fachunterricht im Berufsfeld Ernährung und Hauswirtschaft mittels OER-Lektionen.}}}, year = {{2025}}, } @inproceedings{61256, author = {{Illian, Marvin and Luchterhandt, Björn and Wang, Lin}}, booktitle = {{Proceedings of the 20th Workshop on Mobility in the Evolving Internet Architecture (MobiArch)}}, location = {{Hong Kong, China}}, title = {{{Band Switching for Mobile Energy Optimization in 5G Networks and Beyond}}}, doi = {{10.1145/3737897.3767294}}, year = {{2025}}, } @techreport{62284, author = {{Kundisch, Dennis}}, pages = {{27 -- 28}}, title = {{{DFG fördert Forschungsprojekt - klare Wissensstrukturen in der Wirtschaftsinformatik}}}, volume = {{3}}, year = {{2025}}, } @article{59531, author = {{Ahmadi, Mehdi and Knorr, Lukas and Meschede, Henning}}, issn = {{0960-1481}}, journal = {{Renewable Energy}}, publisher = {{Elsevier BV}}, title = {{{Improvement of Wind Power Utilization Through Flexible Operation of Data Center in Wind Parks}}}, doi = {{10.1016/j.renene.2025.123073}}, year = {{2025}}, } @inproceedings{65663, author = {{Prina, Matteo Giacomo and Knorr, Lukas and Schlosser, Florian and Meschede, Henning and Misconel Schreiber, Steffi and Manepace, Andrea and Sparber, Wolfram}}, location = {{Dubrovnik}}, publisher = {{SDEWES}}, title = {{{Graph Neural Network Surrogates for Uncertainty Quantification in Multi-Node Energy System modeling}}}, year = {{2025}}, } @article{65669, abstract = {{Local droplet etching and subsequent refilling enables the fabrication of highly symmetric quantum dots with low fine structure splitting, suitable for generating polarization entangled photons. While well established in GaAs/AlxGa1−xAs, this approach does not yield emission in the telecom bands required for low loss fiber-based quantum communication. To achieve emission at 1.55 μm, local droplet etching must be adapted to alternative material platforms such as InP. Here, we systematically investigate how the etching material deposition rate and etching time influence nanohole morphology in In0.52Al0.48As layers lattice-matched to InP. In the first experiment, InAl was deposited at fluxes of 0.2–4.0 Å s−1 at Tetch = 350 °C and 460 °C. Lower fluxes produced nanoholes with lower density and larger ring diameters, indicating fewer and larger initial droplets, consistent with scaling theory. The average nanohole diameter decreased monotonically with increasing flux, whereas the average depth showed no clear dependence on flux. In the second experiment, etching times of 30–600 s were tested for InAl, In, and Al droplets. Average nanohole diameters remained constant for Al across all etching times, but decreased for In and InAl with increasing etching time, suggesting sidewall redeposition during etching. For all droplet types, depths peaked at intermediate times and decreased for prolonged etching, consistent with material diffusion into the nanohole after droplet consumption.}}, author = {{Deutsch, Dennis and Reuter, Dirk}}, issn = {{2073-4352}}, journal = {{Crystals}}, number = {{11}}, publisher = {{MDPI AG}}, title = {{{Influence of the Etching Material Deposition Rate and Annealing Time on Nanohole Morphology Etched into InP/In0.52Al0.48As Layers via Local Droplet Epitaxy}}}, doi = {{10.3390/cryst15110913}}, volume = {{15}}, year = {{2025}}, } @article{65657, author = {{Hoffmann, Jan Sören and Stoppel, Hans-Jürgen}}, journal = {{mathematik lehren}}, number = {{253}}, pages = {{8--12}}, title = {{{Das Sieb des Eratosthenes}}}, year = {{2025}}, } @article{63417, author = {{Niederhaus, Constanze and Dvorecky, Michal}}, issn = {{2751-059X}}, journal = {{Zeitschrift für Deutsch im Kontext von Mehrsprachigkeit}}, number = {{1-2}}, pages = {{183--206}}, publisher = {{Walter de Gruyter GmbH}}, title = {{{These I »Deutsch im beruflichen Kontext«. Status quo und Perspektiven}}}, doi = {{10.14220/zdkm.2025.41.1.183}}, volume = {{41}}, year = {{2025}}, } @techreport{59096, abstract = {{This study examines how strengthening tax enforcement by increasing human enforcement capacity and improving tax audit technology affect tax audit efficiency. I employ an economic model in which a tax manager’s tax planning effort shapes corporate tax planning and a strategic tax auditor makes a technology-based audit decision. I show that strengthening tax enforcement always increases tax revenues, but decreases the number of audits only under narrow conditions, so that its effect on tax audit efficiency is often ambiguous. Improving tax audit technology has more nuanced implications. When the strength of tax enforcement is sufficiently high, gradual improvements in tax audit technology crowd out audit incentives and, surprisingly, reduce tax revenues, while sufficiently large improvements can overturn this adverse revenue effect. At the same time, improved technology lowers unnecessary audits once the strength of tax enforcement exceeds a minimum level. Therefore, sufficiently large technology improvements improve tax audit efficiency once this minimum level is exceeded. The results have important policy and empirical implications in an environment of constrained fiscal budgets and rapidly advancing audit technologies.}}, author = {{Dyck, Daniel}}, title = {{{Corporate Tax Planning and Technology-Based Enforcement}}}, doi = {{10.2139/ssrn.5186857}}, year = {{2025}}, } @inbook{58518, author = {{Hartmann, Alexandra}}, booktitle = {{Political Education and American Studies}}, editor = {{Franke, Astrid and Küchler, Uwe and Luther, Katharina}}, isbn = {{978-3-8253-9615-2}}, pages = {{213--228}}, publisher = {{Winter}}, title = {{{(Re)Polizicizing the Teen Genre: On the (Queer) Utopian Potentials of Netflix's Sex Education}}}, year = {{2025}}, } @article{59673, abstract = {{This study analyzes the impact of tariff imposition announcements on the stock prices of 1,194 U.S. companies during the first Trump administration, using a unique sample of 4,624 announcements made by or against the U.S. between January 2018 and August 2019. We find that tariff announcements lead to negative (cumulative) average abnormal stock returns. These negative wealth effects occur regardless of whether the Trump administration imposes safeguard tariffs to protect domestic industries or foreign countries announce retaliatory tariffs. Moreover, the adverse impact is primarily driven by announcements involving China, with variations linked to sector-specific, tariff, trade, and firm characteristics.}}, author = {{Wengerek, Sascha Tobias and Uhde, André and Hippert, Benjamin}}, issn = {{1544-6123}}, journal = {{Finance Research Letters}}, keywords = {{Geopolitical risk, Protectionism, Strategic trade policy, Tariffs, Trade conflict, U.S. – China trade war}}, publisher = {{Elsevier BV}}, title = {{{Share price reactions to tariff imposition announcements during the first Trump administration}}}, doi = {{10.1016/j.frl.2025.107381}}, volume = {{80}}, year = {{2025}}, } @inproceedings{65706, abstract = {{Abstract. Saving emissions and a circular economy are key aspects of sustainable production and compliance global climate change targets. Friction-induced solid-state recycling of aluminum scrap to production endless semi-finished products. Scrap is fed into a continuously rotating wheel. This requires less energy compared to heat-based recycling processes. Different sizes, shapes and surfaces of chips can be used as starting material in the process. The influence of this has been shown in past publications. A native oxide layer is a fixed component of aluminum surface. This layer is broken up during the forming process, allowing the aluminum to bond. In addition to the geometry, the surface finishes and the thickness of the oxide layer are therefore also important input variables in friction-induced solid-state recycling. The oxide layers on the chips were determined for the investigation. In addition, different layer thicknesses were produced to survey their influence. The resulting semi-finished products were evaluated on the basis of their tensile strength and microstructure. The main result of the investigations is the fact that semi-finished products made from chips with thicker oxide layers tend to be more brittle. In addition, thick oxide layers cause microstructural and surface defects.}}, author = {{Gabsa, Steffen and Homberg, Werner and Goller, Timothy and Nordieker, Ansgar Bernhard and Grundmeier, Guido}}, booktitle = {{Materials Research Proceedings}}, issn = {{2474-395X}}, publisher = {{Materials Research Forum LLC}}, title = {{{Influence of different oxide thicknesses on the friction induced and continuous solid-state recycling of aluminum scrap}}}, doi = {{10.21741/9781644903599-272}}, volume = {{54}}, year = {{2025}}, }