Tootfinder

Invariant sets for the wind-tree model
Yuriy Tumarkin
https://arxiv.org/abs/2510.10760 https://arxiv.org/pdf/2510.10760

Invariant sets for the wind-tree model
We consider the wind-tree model, a $\mathbb{Z}^2$ - periodic billiard. In the case when the underlying compact translation surface lies on a periodic orbit of the Teichmüller geodesic flow, and at least one of the two homology classes defining the $\mathbb{Z}^2$ - cover is unstable for the Kontsevich-Zorich cocycle, we prove that every orbit closure of the billiard has Hausdorff dimension strictly smaller than 2. The proof relies on a construction of explicit invariant functions, which along t…

Large Language Model-Empowered Channel Prediction and Predictive Beamforming for LEO Satellite Communications
Zhixiong Chen, Hyundong Shin, Arumugam Nallanathan, Jonathon Chambers
https://arxiv.org/abs/2510.10561

Large Language Model-Empowered Channel Prediction and Predictive Beamforming for LEO Satellite Communications
Accurate channel prediction and effective beamforming are essential for low Earth orbit (LEO) satellite communications to enhance system capacity and enable high-speed connectivity. Most existing channel prediction and predictive beamforming methods are limited by model generalization capabilities and struggle to adapt to time-varying wireless propagation environments. Inspired by the remarkable generalization and reasoning capabilities of large language models (LLMs), this work proposes an LLM…

Identifying the secondary jet in the RadioAstron image of OJ~287
Mauri J. Valtonen, Lankeswar Dey, Staszek Zola, Alok C. Gupta, Shubham Kishore, Achamveedu Gopakumar, Paul J. Wiita, Minfeng Gu, Kari Nilsson, Zhongli Zhang, Rene Hudec, Katsura Matsumoto, Marek Drozdz, Waldemar Ogloza, Andrei V. Berdyugin, Daniel E. Reichart, Markus Mugrauer, Tapio Pursimo, Stefano Ciprini, Tatsuya Nakaoka, Makoto Uemura, Ryo Imazawa, Michal Zejmo, Vladimir V. Kouprianov, James W. Davidson, Jr., Alberto …

Identifying the secondary jet in the RadioAstron image of OJ~287
The 136 year long optical light curve of OJ~287 is explained by a binary black hole model where the secondary is in a 12 year orbit around the primary. Impacts of the secondary on the accretion disk of the primary generate a series of optical flares which follow a quasi-Keplerian relativistic mathematical model. The orientation of the binary in space is determined from the behavior of the primary jet. Here we ask how the jet of the secondary black hole projects onto the sky plane. Assuming that…

In-flight performance of the IXPE telescopes
Riccardo Ferrazzoli, Enrico Costa, Sergio Fabiani, Philip Kaaret, Stephen L. O'Dell, Brian D. Ramsey, Paolo Soffitta, Luca Baldini, Ronaldo Bellazzini, Alessandro Di Marco, Fabio La Monaca, Luca Latronico, Alberto Manfreda, Fabio Muleri, John Rankin, Carmelo Sgr\`o, Stefano Silvestri, Martin C. Weisskopf
https://…

In-flight performance of the IXPE telescopes
We present a comprehensive characterization of the on-orbit imaging performance of the three telescopes on board the Imaging X-ray Polarimetry Explorer (IXPE). Each telescope comprises a Wolter-I mirror module assembly and a Gas Pixel Detector focal-plane detector unit (DU). We analyze data from point-like X-ray sources and fit a composite point spread function (PSF) model that we compare with ground calibrations. We study the dependence of the PSF parameters and of the angular resolution, in t…

Efficiency of the superconducting diode effect of pair-density-wave states in two-dimensional $d$-wave altermagnets
Igor de M. Froldi, Hermann Freire
https://arxiv.org/abs/2510.07506

Efficiency of the superconducting diode effect of pair-density-wave states in two-dimensional $d$-wave altermagnets
We systematically study the efficiency of the intrinsic superconducting diode effect of several pair-density-wave states that can emerge in two-dimensional $d$-wave metallic altermagnets. To this end, we investigate several scenarios using an effective minimal microscopic model and Ginzburg-Landau analysis in order to derive the corresponding pairing phase diagrams. In addition, we examine also whether the presence of a Rashba spin-orbit coupling and an applied external magnetic field are benef…