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Spectrum of pure $R^2$ gravity: full Hamiltonian analysis
Will Barker, Dra\v{z}en Glavan
https://arxiv.org/abs/2510.08201 https://arxiv.org/pdf/2510.08201

Spectrum of pure $R^2$ gravity: full Hamiltonian analysis
We perform a full Hamiltonian constraint analysis of pure Ricci-scalar-squared ($R^2$) gravity to clarify recent controversies regarding its particle spectrum. While it is well established that the full theory consistently propagates three degrees of freedom, we confirm that its linearised spectrum around Minkowski spacetime is empty. moreover, we show that this is not a feature unique to Minkowski spacetime, but a generic property of all traceless-Ricci spacetimes that have a vanishing Ricci s…

PyPAS -- Python package for Positron Annihilation Spectroscopy Doppler Broadening Analysis
Achiya Yosef Amrusi, Sharon May-Tal Beck, Hadar Steinberg, Guy Ron
https://arxiv.org/abs/2509.08023

PyPAS -- Python package for Positron Annihilation Spectroscopy Doppler Broadening Analysis
Doppler Broadening (DB) of annihilation radiation is a well-established technique within Positron Annihilation Spectroscopy (PAS), used for probing the electronic structure of materials. The analysis of DB experimental data relies on gamma spectroscopy analysis tools, while depth profiling using variable-energy slow positron beams depends on solving the positron diffusion equation. Traditional Variable Energy Doppler Broadening (VEDB) analysis tools, such as VEPFIT and ROYPROF, often present li…

Spectral localization of single-nanoparticle plasmons through photonic substrate engineering
Shihao Feng, Juan-Feng Zhu, Xinyi Fan, Jindong Ai, Wenjie Zhou, Guangxin Liu, Jing-Feng Liu, Renming Liu, Wei Li, Lijun Guo, Lin Wu
https://arxiv.org/abs/2509.07699

Spectral localization of single-nanoparticle plasmons through photonic substrate engineering
Surface plasmon resonances (SPRs) are crucial for confining light beyond the diffraction limit, yet heavy metal losses often limit their spectral localization. Here, we propose a practical strategy for enabling the spectral localization of single-nanoparticle SPRs through photonic substrate engineering, which creates distinct optical pathways (OPs) to tailor the electromagnetic environments around plasmonic nanoparticles. By analyzing the multiplication factor spectrum of the projected local de…

Spatial-Spectral Chromatic Coding of Interference Signatures in SAR Imagery: Signal Modeling and Physical-Visual Interpretation
Huizhang Yang, Chengzhi Chen, Liyuan Chen, Zhongling Huang, Zhong Liu, Jian Yang
https://arxiv.org/abs/2509.08693

Spatial-Spectral Chromatic Coding of Interference Signatures in SAR Imagery: Signal Modeling and Physical-Visual Interpretation
Synthetic Aperture Radar (SAR) images are conventionally visualized as grayscale amplitude representations, which often fail to explicitly reveal interference characteristics caused by external radio emitters and unfocused signals. This paper proposes a novel spatial-spectral chromatic coding method for visual analysis of interference patterns in single-look complex (SLC) SAR imagery. The method first generates a series of spatial-spectral images via spectral subband decomposition that preserve…

Unified Spectrospatial Forward Models: Spatially Continuous Maps of Weak Emission Lines in the Rosette Nebula with SDSS-V LVM
Thomas Hilder, Andrew R. Casey, Julianne J. Dalcanton, Kathryn Kreckel, Amelia M. Stutz, Amrita Singh, Guillermo A. Blanc, Sebasti\'an F. S\'anchez, J. E. M\'endez-Delgado, Andrew K. Saydjari, Luciano Vargas-Herrera, Niv Drory, Dmitry Bizyaev, Jos\'e G. Fern\'andez-Trincado, Carlos G. Rom\'an-Z\'u\~niga, Juna A. Kollmeier, Evelyn J. J…

Unified Spectrospatial Forward Models: Spatially Continuous Maps of Weak Emission Lines in the Rosette Nebula with SDSS-V LVM
Analyses of IFU data are typically performed on a per-spaxel basis, with each spectrum modelled independently. For low signal-to-noise (S/N) features such as weak emission lines, estimating properties is difficult and imprecise. Arbitrary binning schemes boost S/N at the cost of resolution, and risk introducing biases. We present a general forward-modelling approach that assumes spectra close on the sky are more similar than distant ones, and so can be modelled jointly. These "spectrospatial" m…

LLM Analysis of 150 years of German Parliamentary Debates on Migration Reveals Shift from Post-War Solidarity to Anti-Solidarity in the Last Decade
Aida Kostikova, Ole P\"utz, Steffen Eger, Olga Sabelfeld, Benjamin Paassen
https://arxiv.org/abs/2509.07274

LLM Analysis of 150+ years of German Parliamentary Debates on Migration Reveals Shift from Post-War Solidarity to Anti-Solidarity in the Last Decade
Migration has been a core topic in German political debate, from millions of expellees post World War II over labor migration to refugee movements in the recent past. Studying political speech regarding such wide-ranging phenomena in depth traditionally required extensive manual annotations, limiting the scope of analysis to small subsets of the data. Large language models (LLMs) have the potential to partially automate even complex annotation tasks. We provide an extensive evaluation of a mult…

Minimal Denominators Lying in Subsets of the Ring of Polynomials over a Finite Field
Noy Soffer Aranov
https://arxiv.org/abs/2510.07787 https://arxiv.org/p…

Minimal Denominators Lying in Subsets of the Ring of Polynomials over a Finite Field
Given a subset $\mathcal{S}\subseteq \mathbb{F}_q[x]$ and fixed $n,m\in \mathbb{N}$, one can study the distribution of the value of the smallest denominator $Q\in \mathcal{S}$, for which there exists $\mathbf{P}\in \mathbb{F}_q[x]^m$ such that $\frac{P}{Q}\in B(\boldsymbolα,q^{-n})$, where $Q\in \mathcal{S}$. On the other hand, one can study the discrete analogue, when $N\in \mathbb{F}_q[x]$ is a polynomial with $°(N)=n$ and $\boldsymbolα\in \frac{1}{N}\mathbb{F}_q[x]^m$ as a discrete probab…

A Tensor Network Framework for Lindbladian Spectra and Steady States
Philipp Westhoff, Mattia Moroder, Ulrich Schollw\"ock, Sebastian Paeckel
https://arxiv.org/abs/2509.07709

A Tensor Network Framework for Lindbladian Spectra and Steady States
Quantum systems coupled to (non-)Markovian environments attract increasing attention due to their peculiar physical properties. Exciting prospects such as unconventional non-equilibrium phases beyond the Mermin-Wagner limit, or the environment-assisted, robust preparation of highly entangled states, demand a systematic analysis of quantum many-body phases out of equilibrium. Akin to the equilibrium case, this requires the computation of the low-lying eigenstates of Lindbladians, a problem chall…

Automated Spectroscopic Wavelength Calibration using Dynamic Time Warping
James R. A. Davenport, Francisca Chabour Barra, K. Azalee Bostroem, Sarah Tuttle, Josue Torres, Jessica Birky, Anastasios Tzanidakis, Kal Kadlec, Yuankun Wang, Suzanne L. Hawley, Trevor Z. Dorn-Wallenstein, William Ketzeback, Julene Elias, Abdullah Korra, Anna Panova, Kathryn Devine, Kevin R. Covey

Automated Spectroscopic Wavelength Calibration using Dynamic Time Warping
Here we present an automated method for obtaining wavelength calibrations for one-dimensional spectra, using Dynamic Time Warping (DTW). DTW is a flexible and well-understood algorithm for pattern matching, which has not been widely used in astronomy data analysis. Employing a calibrated template spectrum as a reference, DTW can recover non-linear and even discontinuous dispersion solutions without an initial guess. The algorithm is robust against differing spectral resolution between the templ…

Spectral Transitions of the Entanglement Hamiltonian in Monitored Free Fermions
Karim Chahine, Michael Buchhold
https://arxiv.org/abs/2509.08584 https://ar…

Spectral Transitions of the Entanglement Hamiltonian in Monitored Free Fermions
We numerically investigate measurement-induced phase transitions in monitored free fermions through the spectral and eigenstate properties of the entanglement Hamiltonian. By analyzing entanglement scaling, we identify three non-trivial fixed points, for which the entanglement follows exact analytical scaling forms: chaotic unitary dynamics at infinitesimal monitoring, characterized by a Gaussian Page law; a Fermi-liquid fixed point at moderate monitoring, defining a metallic phase with logarit…