@article{21370, abstract = {Through digital imaging, microscopy has evolved from primarily being a means for visual observation of life at the micro- and nano-scale, to a quantitative tool with ever-increasing resolution and throughput. Artificial intelligence, deep neural networks, and machine learning (ML) are all niche terms describing computational methods that have gained a pivotal role in microscopy-based research over the past decade. This Roadmap encompasses key aspects of how ML is applied to microscopy image data, with the aim of gaining scientific knowledge by improved image quality, automated detection, segmentation, classification and tracking of objects, and efficient merging of information from multiple imaging modalities. We aim to give the reader an overview of the key developments and an understanding of possibilities and limitations of ML for microscopy. It will be of interest to a wide cross-disciplinary audience in the physical sciences and life sciences.}, author = {Volpe, Giovanni and Wählby, Carolina and Tian, Lei and Hecht, Michael and Yakimovich, Artur and Monakhova, Kristina and Waller, Laura and Sbalzarini, Ivo F. and Metzler, Christopher A. and Xie, Mingyang and Zhang, Kevin and Lenton, Isaac C and Rubinsztein-Dunlop, Halina and Brunner, Daniel and Bai, Bijie and Ozcan, Aydogan and Midtvedt, Daniel and Wang, Hao and Li, Tongyu and Sladoje, Nataša and Lindblad, Joakim and Smith, Jason T. and Ochoa, Marien and Barroso, Margarida and Intes, Xavier and Qiu, Tong and Yu, Li Yu and You, Sixian and Liu, Yongtao and Ziatdinov, Maxim A. and Kalinin, Sergei V. and Sheridan, Arlo and Manor, Uri and Nehme, Elias and Goldenberg, Ofri and Shechtman, Yoav and Moberg, Henrik K. and Langhammer, Christoph and Špačková, Barbora and Helgadottir, Saga and Midtvedt, Benjamin and Argun, Aykut and Thalheim, Tobias and Cichos, Frank and Bo, Stefano and Hubatsch, Lars and Pineda, Jesus and Manzo, Carlo and Bachimanchi, Harshith and Selander, Erik and Homs-Corbera, Antoni and Fränzl, Martin and De Haan, Kevin and Rivenson, Yair and Korczak, Zofia and Adiels, Caroline Beck and Mijalkov, Mite and Veréb, Dániel and Chang, Yu Wei and Pereira, Joana B. and Matuszewski, Damian and Kylberg, Gustaf and Sintorn, Ida Maria and Caicedo, Juan C. and Cimini, Beth A. and Lediju Bell, Muyinatu A. and Saraiva, Bruno M. and Jacquemet, Guillaume and Henriques, Ricardo and Ouyang, Wei and Le, Trang and Gómez-De-Mariscal, Estibaliz and Sage, Daniel and Muñoz-Barrutia, Arrate and Lindqvist, Ebba Josefson and Bergman, Johanna}, issn = {2515-7647}, journal = {Journal of Physics: Photonics}, number = {1}, publisher = {IOP Publishing}, title = {{Roadmap on deep learning for microscopy}}, doi = {10.1088/2515-7647/ae0fd1}, volume = {8}, year = {2026}, } @article{21371, abstract = {There may be a newly identified early phase of supermassive black hole growth}, author = {Matthee, Jorryt J}, issn = {1095-9203}, journal = {Science}, number = {6787}, pages = {767--768}, publisher = {AAAS}, title = {{Black holes disguised as little red dots}}, doi = {10.1126/science.adz8603}, volume = {391}, year = {2026}, } @article{21373, abstract = {Cold atom experiments show that a mobile impurity particle immersed in a weakly interacting Bose-Einstein condensate forms a well-defined quasiparticle (Bose polaron) for weak to moderate impurity-boson interaction strengths, whereas a significant line broadening is consistently observed for strong interactions. Motivated by this, we introduce a phenomenological theory based on the assumption that the most relevant states are characterized by the impurity correlated with at most one boson, since they have the largest overlap with the uncorrelated states to which the most common experimental probes couple. These experimentally relevant states can, however, decay to lower energy states characterized by correlations involving multiple bosons, and we model this using a minimal variational wave function combined with a complex impurity-boson interaction strength. We first motivate this approach by comparing to a more elaborate theory that includes correlations with up to two bosons. Our phenomenological model is shown to recover the main results of two recent experiments probing both the spectral and the nonequilibrium properties of the Bose polaron. Our work offers an intuitive framework for analyzing experimental data and highlights the importance of understanding the complicated problem of the Bose polaron decay in a many-body setting.}, author = {Al Hyder, Ragheed and Bruun, G. M. and Pohl, T. and Lemeshko, Mikhail and Volosniev, Artem}, issn = {2643-1564}, journal = {Physical Review Research}, publisher = {American Physical Society}, title = {{Phenomenological model of decaying Bose polarons}}, doi = {10.1103/16dk-5dgx}, volume = {8}, year = {2026}, } @inproceedings{21374, abstract = {Let . S be a set of distinct points in general position in the Euclidean plane. A plane Hamiltonian path on . S is a crossing-free geometric path such that every point of .S is a vertex of the path. It is known that, if. S is sufficiently large, there exist three edge-disjoint plane Hamiltonian paths on . S. In this paper we study an edge-constrained version of the problem of finding Hamiltonian paths on a point set. We first consider the problem of finding a single plane Hamiltonian path . π with endpoints .s, t ∈ S and constraints given by a segment . ab, where .a, b ∈ S. We consider the following scenarios: (i) .ab ∈ π; (ii) .ab π. We characterize those quintuples . S, a, b, s, t for which . π exists. Secondly, we consider the problem of finding two plane Hamiltonian paths . π1, π2 on a set . S with constraints given by a segment . ab, where .a, b ∈ S. We consider the following scenarios: (i) .π1 and .π2 share no edges and .ab is an edge of . π1; (ii) .π1 and .π2 share no edges and none of them includes .ab as an edge; (iii) both .π1 and .π2 include .ab as an edge and share no other edges. In all cases, we characterize those triples . S, a, b for which .π1 and .π2 exist.}, author = {Antić, Todor and Džuklevski, Aleksa and Fiala, Jiří and Kratochvíl, Jan and Liotta, Giuseppe and Saghafian, Morteza and Saumell, Maria and Zink, Johannes}, booktitle = {51st International Conference on Current Trends in Theory and Practice of Computer Science}, isbn = {9783032178008}, issn = {1611-3349}, location = {Krakow, Poland}, pages = {532--546}, publisher = {Springer Nature}, title = {{Edge-constrained Hamiltonian paths on a point set}}, doi = {10.1007/978-3-032-17801-5_39}, volume = {16448}, year = {2026}, } @article{21379, abstract = {We study a (1 + 1)-dimensional semi-discrete random variational problem that can be interpreted as the geometrically linearized version of the critical 2-dimensional random field Ising model. The scaling of the correlation length of the latter was recently characterized in Probab. Duke Math. J. 172(9), 1781–1811 (2023) and arXiv:2011.08768v3, (2022); our analysis is reminiscent of the multi-scale approach of the latter work and of Combinatorica 9, 161–187 (1989) . We show that at every dyadic scale from the system size down to the lattice spacing the minimizer contains at most order-one Dirichlet energy per unit length. We also establish a quenched homogenization result in the sense that the leading order of the minimal energy becomes deterministic as the ratio system size / lattice spacing diverges. To this purpose we adapt arguments from arXiv:2401.06768, (2024) on the (d + 1)-dimensional version our the model, with a Brownian replacing the white noise potential, to obtain the initial large-scale bounds. Based on our estimate of the (p = 3)-Dirichlet energy, we give an informal justification of the geometric linearization. Our bounds, which are oblivious to the microscopic cut-off scale provided by the lattice spacing, yield tightness of the law of minimizers in the space of continuous functions as the lattice spacing is sent to zero.}, author = {Otto, Felix and Palmieri, Matteo and Wagner, Christian}, issn = {1432-2064}, journal = {Probability Theory and Related Fields}, publisher = {Springer Nature}, title = {{On minimizing curves in a Brownian potential}}, doi = {10.1007/s00440-026-01468-y}, year = {2026}, } @article{21380, abstract = {Context. Extreme emission line galaxies (EELGs) are believed to significantly contribute to the star formation activity and mass assembly in galaxies. EELGs likely also play a leading role in the cosmic re-ionization as their interstellar medium may allow a significant fraction of their ionizing photons to escape (> 5%). Finding low-redshift analogues of these high-z galaxies is therefore essential to characterizing the physical conditions in the interstellar medium of these galaxies and understanding the processes that re-ionized the Universe. Aims. We aimed to develop a robust and efficient method for the photometric identification of EELGs using the J-PAS survey. J-PAS will cover approximately 8500 deg2 of the sky with 54 narrow-band filters in the optical range plus i-SDSS, enabling detailed studies of the physical properties of these galaxies. In this work we focused on an initial subset of the survey: a 30 square degree area with complete observations in all bands. Methods. We combine equivalent width (EW) measurements from J-PAS narrow-band photometry with artificial intelligence techniques to identify galaxies with emission lines exceeding 300 Å. We validated our selection using spectroscopic data from DESI DR1 and characterized the selected sample through spectral energy distribution fitting with CIGALE. Results. We identify 917 EELGs up to z = 0.8 over 30 deg2, achieving a purity of 95% and a completeness of 96% for i-SDSS < 22.5 mag. Importantly, active galactic nucleus contamination was carefully considered and is estimated to be around 5%. Furthermore, a cross-match with DESI yielded 79 counterparts; their redshifts are in excellent agreement with our photometric estimates, thereby confirming the reliability of our redshift determination. In addition, the derived emission line fluxes are in good agreement with spectroscopic measurements. Moreover, the selected sample reveals strong correlations between the ionizing photon production efficiency (ξion) and EW(Hβ), which are consistent with previous observational studies at low and high redshifts and theoretical expectations. Finally, most of the sources surpass the ionizing efficiency threshold required for re-ionization, highlighting their relevance as local analogues of early-Universe galaxies.}, author = {Giménez-Alcázar, A. and Amorín, R. and Vílchez, J. M. and Hernán-Caballero, A. and González-Otero, M. and Arroyo-Polonio, A. and Iglesias-Páramo, J. and Lumbreras-Calle, A. and Fernández-Ontiveros, J. A. and López-Sanjuan, C. and Bonatto, L. and González Delgado, R. M. and Kehrig, C. and Torralba Torregrosa, Alberto and Rahna, P. T. and Jiménez-Teja, Y. and Márquez, I. and Breda, I. and Álvarez-Candal, A. and Abramo, R. and Alcaniz, J. and Benitez, N. and Bonoli, S. and Carneiro, S. and Cenarro, J. and Cristóbal-Hornillos, D. and Dupke, R. and Ederoclite, A. and Hernández-Monteagudo, C. and Marín-Franch, A. and Mendes de Oliveira, C. and Moles, M. and Sodré, L. and Taylor, K. and Varela, J. and Vázquez Ramió, H.}, issn = {1432-0746}, journal = {Astronomy & Astrophysics}, publisher = {EDP Sciences}, title = {{J-PAS: First identification, physical properties, and ionization efficiency of extreme emission line galaxies}}, doi = {10.1051/0004-6361/202557358}, volume = {706}, year = {2026}, } @article{21382, abstract = {The exceptional energy-harvesting efficiency of lead-halide perovskites arises from unusually long photocarrier diffusion lengths and recombination lifetimes that persist even in defect-rich, solution-grown samples. Paradoxically, perovskites are also known for having very short exciton decay times. Here, we resolve this apparent contradiction by showing that key optoelectronic properties of perovskites can be explained by localized flexoelectric polarization confined to interfaces between domains of spontaneous strain. Using birefringence imaging, electrochemical staining, and zero-bias photocurrent measurements, we visualize the domain structure and directly probe the associated internal fields in nominally cubic single crystals of methylammonium lead bromide. We demonstrate that localized flexoelectric fields spatially separate electrons and holes to opposite sides of domain walls, exponentially suppressing recombination. Domain walls thus act as efficient mesoscopic transport channels for long-lived photocarriers, microscopically linking structural heterogeneity to charge transport and offering mechanistically informed design principles for perovskite solar-energy technologies.}, author = {Rak, Dmytro and Lorenc, Dusan and Balazs, Daniel and Zhumekenov, Ayan A. and Bakr, Osman M. and Alpichshev, Zhanybek}, issn = {2041-1723}, journal = {Nature Communications}, publisher = {Springer Nature}, title = {{Flexoelectric domain walls enable charge separation and transport in cubic perovskites}}, doi = {10.1038/s41467-026-68660-5}, volume = {17}, year = {2026}, } @article{21383, abstract = {Planarian flatworms are known for their remarkable regenerative capacity; however, the precise intercellular communication mechanisms underlying this process remain unsolved. Here, we report the discovery and characterization of abundant extracellular vesicles (EVs) in planarians. Using imaging and molecular analysis, we show conservation of biogenesis, morphology, and protein composition of planarian EVs. Environmental stressors significantly elevate EV release, indicating that planarians dynamically regulate vesicle production. Functionally, planarian EVs mediate intercellular communication by transferring regulatory signals: We find that they shuttle small RNAs that effect systemic RNA interference (RNAi) throughout the organism. Notably, gene knockdown experiments reveal a crucial role for AGO-3, a member of the Argonaute family of proteins, in modulating the association of small interfering RNAs with EVs, linking the intracellular RNAi machinery to EV-based signaling. These findings highlight EVs as pivotal mediators of cell-cell communication in planarians, with broad implications for understanding the coordination of gene regulation and tissue regeneration in animals.}, author = {Sasidharan, Vidyanand and Ancellotti, Laura and Doddihal, Viraj and Brewster, Carolyn and Mann, Frederick and McKinney, Mary Cathleen and Varberg, Joseph and Ross, Eric and Deng, Fengyan and Yi, Kexi and Sánchez Alvarado, Alejandro}, issn = {2375-2548}, journal = {Science Advances}, number = {6}, publisher = {American Association for the Advancement of Science}, title = {{Extracellular vesicles mediate stem cell signaling and systemic RNAi in planarians}}, doi = {10.1126/sciadv.ady1461}, volume = {12}, year = {2026}, } @article{21384, abstract = {Cell migration in vivo is often guided by chemical signaling, i.e., chemotaxis. For immune cells performing chemotaxis in the organism, this process is influenced by the complex geometry of the tissue environment. In this study, we use a theoretical model of branched cell migration on a network to explore the cellular response to chemical gradients. The model predicts the response of a branched cell to a chemical gradient: how the cell reorients its internal polarity and how it navigates through a complex environment up a chemical gradient. We then compare the model’s predictions with experimental observations of neutrophils migrating to the site of a laser-inflicted wound in a zebrafish larva fin, and neutrophils migrating in vitro inside a regular lattice of pillars. We find that the model captures the details of the subcellular response to the chemokine gradient, as well as qualitative characteristics of the large-scale migration, suggesting that the neutrophils behave as fast cells, which explains the functionality of these immune cells.}, author = {Liu, Jiayi and Ron, Jonathan E. and Rinaldi, Giulia and Williantarra, Ivanna and Georgantzoglou, Antonios and de Vries, Ingrid and Sixt, Michael K and Sarris, Milka and Gov, Nir S.}, issn = {1553-7358}, journal = {PLOS Computational Biology}, number = {2}, publisher = {Public Library of Science}, title = {{Modelling chemotaxis of branched cells in complex environments provides insights into immune cell navigation}}, doi = {10.1371/journal.pcbi.1013934}, volume = {22}, year = {2026}, } @unpublished{21400, abstract = {This document is a blueprint for the formalization in Lean of the structural theory of regular matroids underlying Seymour's decomposition theorem. We present a modular account of regularity via totally unimodular representations, show that regularity is preserved under 1-, 2-, and 3-sums, and establish regularity for several special classes of matroids, including graphic, cographic, and the matroid R10. The blueprint records the logical structure of the proof, the precise dependencies between results, and their correspondence with Lean declarations. It is intended both as a guide for the ongoing formalization effort and as a human-readable reference for the organization of the proof.}, author = {Sergeev, Ivan and Dvorak, Martin and Rampell, Cameron and Sandey, Mark and Monticone, Pietro}, booktitle = {arXiv}, pages = {18}, title = {{A blueprint for the formalization of Seymour's matroid decomposition theorem}}, doi = {10.48550/arXiv.2601.01255}, year = {2026}, } @phdthesis{21401, abstract = {Runtime verification offers scalable solutions to improve the safety and reliability of systems. However, systems that require verification or monitoring by a third party to ensure compliance with a specification might contain sensitive information, causing privacy concerns when usual runtime verification approaches are used. Privacy is compromised if protected information about the system, or sensitive data that is processed by the system, is revealed. In addition, revealing the specification being monitored may undermine the essence of third-party verification. In this thesis, we propose a protocol for privacy-preserving runtime verification of systems against formal sequential specifications. We develop the protocol in two steps. In the first step, the monitor verifies whether the system satisfies the specification without learning anything else, though both parties are aware of the specification. In the second step, we extend the protocol to ensure that the system remains oblivious to the monitored specification, while the monitor learns only whether the system satisfies the specification and nothing more. Our protocol adapts and improves existing techniques used in cryptography, and more specifically, multi-party computation. The sequential specification defines the observation step of the monitor, whose granularity depends on the situation (e.g., banks may be monitored on a daily basis). Our protocol exchanges a single message per observation step, after an initialization phase. This design minimizes communication overhead, enabling relatively lightweight privacy-preserving monitoring. We implement our approach for monitoring specifications described by register automata and evaluate it experimentally. }, author = {Karimi, Mahyar}, issn = {2791-4585}, keywords = {Privacy-preserving verification, Runtime verification, Monitoring, Reactive functionalities, Cryptographic protocols}, pages = {60}, publisher = {Institute of Science and Technology Austria}, title = {{Privacy-preserving runtime verification}}, doi = {10.15479/AT-ISTA-21401}, year = {2026}, } @article{21407, abstract = {This note proves that only a linear number of holes in a Cech complex of n points in R^d can persist over an interval of constant length. Specifically, for any fixed dimension p < d and fixed ε > 0, the number of p-dimensional holes in the ˇ Cech complex at radius 1 that persist to radius 1+ε is bounded above by a constant times n,where n is the number of points. The proof uses a packing argument supported by relating theCˇ ech complexes with corresponding snap complexes over the cells in a partition of space. The argument is self-contained and elementary, relying on geometric and combinatorial constructions rather than on the existing theory of sparse approximations or interleavings. The bound also applies to Alpha complexes and Vietoris–Rips complexes. While our result can be inferred from prior work on sparse filtrations, to our knowledge, no explicit statement or direct proof of this bound appears in the literature.}, author = {Edelsbrunner, Herbert and Kahle, Matthew and Kanazawa, Shu}, issn = {2367-1734}, journal = {Journal of Applied and Computational Topology}, publisher = {Springer Nature}, title = {{Maximum persistent Betti numbers of Čech complexes}}, doi = {10.1007/s41468-026-00233-3}, volume = {10}, year = {2026}, } @article{21408, abstract = {Rational design strategies for self-assembly require a detailed understanding of both the equilibrium state and the assembly kinetics. While the former is starting to be well understood, the latter remains a major theoretical challenge, especially in programmable systems and the so-called semi-addressable regime, where binding is often nondeterministic and the formation of off-target structures negatively influences the assembly. Here, we show that it is possible to simultaneously sculpt the assembly outcome and the assembly kinetics through the underexplored design space of binding energies and particle concentrations. By formulating the assembly process as a complex reaction network, we calculate and optimize the tradeoff between assembly speed and quality and show that parameter optimization can speed up assembly by many orders of magnitude without lowering the yield of the target structure. Although the exact speedup varies from design to design, we find the largest speedups for nondeterministic systems where unoptimized assembly is the slowest, sometimes even making them assemble faster than optimized, fully addressable designs. Therefore, these results not only solve a key challenge in semi-addressable self-assembly but further emphasize the utility of semi-addressability, where designs have the potential to be faster as well as cheaper (fewer particle species) and better (higher yield). More broadly, our results highlight the importance of parameter optimization in programmable self-assembly and provide practical tools for simultaneous optimization of kinetics and yield in a wide range of systems.}, author = {Hübl, Maximilian and Goodrich, Carl Peter}, issn = {1089-7690}, journal = {Journal of Chemical Physics}, number = {8}, publisher = {AIP Publishing}, title = {{Simultaneous optimization of assembly time and yield in programmable self-assembly}}, doi = {10.1063/5.0304731}, volume = {164}, year = {2026}, } @article{21409, abstract = {Meiotic drivers are selfish genetic elements that gain transmission advantages by distorting equal, Mendelian segregation. For decades, biologists have considered meiotic drivers as interesting, albeit esoteric, case studies. It is now clear, however, that meiotic drive is more common and phylogenetically widespread than previously supposed. Indeed, intensive study of a few well-known cases has begun to reveal the evolutionary genomic consequences of meiotic drive. We argue here that many features of genome evolution, content, and organization that are seemingly inexplicable by organismal adaptation or nearly neutral processes are instead best accounted for by recurrent histories of meiotic drive. We review how meiotic drive can affect the evolution of sequences, gene copy numbers, genes with functions in meiosis and gametogenesis, signatures of “selection,” chromosome rearrangements, and karyotype evolution. We also explore the interactions of meiotic drive elements with other classes of selfish genetic elements, including satellite DNAs, transposable elements, and with the endogenous host genes involved in drive suppression. Finally, we argue that some aspects of drive-mediated genome evolution are now sufficiently well established that we might reverse the direction of discovery—rather than ask how drive affects genome evolution, we can use genome data to discover new putative drive elements.}, author = {Presgraves, Daven C. and Dawe, R. Kelly and Dyer, Kelly A. and Fishman, Lila and Bhide, Soumitra A. and Bradshaw, Sasha L. and Brady, Meghan J. and Burga, Alejandro and Courret, Cécile and Fagen, Brandon L. and Machado Ferretti, Ana Beatriz Stein and Kelemen, Réka K and Kitano, Jun and Liu, Yiran and Martí, Emiliano and Erlenbach, Theresa and Reinhardt, Josephine A. and Ross, Laura and Runge, Jan Niklas and Swanepoel, Callie M. and Vicoso, Beatriz and Vogan, Aaron A. and Lindholm, Anna K. and Larracuente, Amanda M. and Unckless, Robert L.}, issn = {1537-1719}, journal = {Molecular Biology and Evolution}, number = {2}, publisher = {Oxford University Press}, title = {{The evolutionary genomics of meiotic drive}}, doi = {10.1093/molbev/msag020}, volume = {43}, year = {2026}, } @inproceedings{21410, abstract = {Given a finite set of red and blue points in R^d, the MST-ratio is defined as the total length of the Euclidean minimum spanning trees of the red points and the blue points, divided by the length of the Euclidean minimum spanning tree of their union. The MST-ratio has recently gained attention due to its direct interpretation in topological models for studying point sets with applications in spatial biology. The maximum MST-ratio of a point set is the maximum MST-ratio over all proper colorings of its points by red and blue. We prove that finding the maximum MST-ratio of a given point set is NP-hard when the dimension is part of the input. Moreover, we present a quadratic-time 3-approximation algorithm for this problem. As part of the proof, we show that in any metric space, the maximum MST-ratio is smaller than 3. Furthermore, we study the average MST-ratio over all colorings of a set of n points. We show that this average is always at least n-2/n-1, and for n random points uniformly distributed in a d-dimensional unit cube, the average tends to (math formular) in expectation as n approaches infinity.}, author = {Jabal Ameli, Afrouz and Motiei, Faezeh and Saghafian, Morteza}, booktitle = {20th International Conference and Workshops on Algorithms and Computation}, isbn = {9789819571260}, issn = {1611-3349}, location = {Perugia, Italy}, pages = {386--401}, publisher = {Springer Nature}, title = {{On the MST-ratio: Theoretical bounds and complexity of finding the maximum}}, doi = {10.1007/978-981-95-7127-7_26}, volume = {16444}, year = {2026}, } @inproceedings{21411, abstract = {To achieve fast recovery from link failures, most modern communication networks feature fully decentralized fast re-routing mechanisms. These re-routing mechanisms rely on pre-installed static re-routing rules at the nodes (the routers), which depend only on local failure information, namely on the failed links incident to the node. Ideally, a network is perfectly resilient: the re-routing rules ensure that packets are always successfully routed to their destinations as long as the source and the destination are still physically connected in the underlying network after the failures. Unfortunately, there are examples where achieving perfect resilience is not possible. Surprisingly, only very little is known about the algorithmic aspect of when and how perfect resilience can be achieved. We investigate the computational complexity of analyzing such local fast re-routing mechanisms. Our main result is a negative one: we show that even checking whether a given set of static re-routing rules ensures perfect resilience is coNP-complete. Additionally, we investigate other fundamental variations of the problem. In particular, we show that our coNP-completeness proof also applies to scenarios where the re-routing rules have specific patterns (known as skipping in the literature). On the positive side, for scenarios where nodes do not have information about the link from which a packet arrived (the so-called in-port), we present a linear-time algorithm to realize perfect resilience whenever possible (which we show can also be determined in linear time). }, author = {Bentert, Matthias and Ceylan, Esra and Hübner, Valentin and Schmid, Stefan and Srba, Jiří}, booktitle = {29th International Conference on Principles of Distributed Systems}, isbn = {9783959774093}, issn = {1868-8969}, location = {Iaşi, Romania}, publisher = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik}, title = {{Fast re-routing in networks: On the complexity of perfect resilience}}, doi = {10.4230/LIPIcs.OPODIS.2025.31}, volume = {361}, year = {2026}, } @unpublished{21438, abstract = {Antiferromagnets (AFMs) hold promise for applications in digital logic. However, switching AFM domains is challenging, as magnetic fields do not couple to the bulk antiferromagnetic order parameter. Here we show that magnetic-field-driven switching of AFM domains can in many cases be enabled by a generic reduction of magnetic exchange at surfaces. We use statistical mechanics and Monte Carlo simulations to demonstrate that an inequivalence in magnetic exchange between top and bottom surface moments, combined with the enhanced magnetic susceptibility of surface spins, can enable deterministic selection of antiferromagnetic domains depending on the magnetic-field ramping direction. We further show that this mechanism provides a natural interpretation for experimental observations of hysteresis in magneto-optical response of the van der Waals AFM $\mathrm{MnBi_2Te_4}$. Our findings highlight the critical role of surface spins in responses of antiferromagnets to magnetic fields. Furthermore, our results suggest that antiferromagnetic domain selection via purely magnetic means may be a more common and experimentally accessible phenomenon than previously assumed.}, author = {Weber, Sophie F. and Sunko, Veronika}, booktitle = {arXiv}, title = {{Deterministic domain selection of antiferromagnets via magnetic fields}}, doi = {10.48550/arXiv.2601.06646}, year = {2026}, } @article{21449, abstract = {Three-dimensional (3D) crystals offer a route to scaling up trapped-ion systems for quantum sensing and quantum simulation applications; however, engineering coherent spin-motion couplings and effective spin-spin interactions in large crystals poses technical challenges associated with decoherence and prolonged timescales to generate appreciable entanglement. Here, we explore the possibility of speeding up these interactions in 3D crystals via parametric amplification. For this purpose, we derive a general Hamiltonian for the parametric amplification of spin-motion coupling that is broadly applicable to normal modes with motion transverse to or along the spatial extent of the crystal. Unlike in lower-dimensional crystals, we find that the ability to faithfully (uniformly) amplify the spin-spin interactions in 3D crystals depends on the physical implementation of the spin-motion coupling. We consider the light-shift gate, and the so-called phase-insensitive and phase-sensitive Mølmer-Sørensen (MS) gates, and we find that only the phase-sensitive MS gate can be faithfully amplified in general 3D crystals. We discuss a situation where nonuniform amplification can be advantageous. We also reconsider the effect of counter-rotating terms on parametric amplification and find that they are not as detrimental as previous studies suggest.}, author = {Hawaldar, Samarth and Nikhil, N. and Rey, Ana Maria and Bollinger, John J. and Shankar, Athreya}, issn = {2331-7019}, journal = {Physical Review Applied}, number = {3}, publisher = {American Physical Society}, title = {{Parametric amplification of spin-motion coupling in three-dimensional trapped-ion crystals}}, doi = {10.1103/h1m9-h3yw}, volume = {25}, year = {2026}, } @article{21450, abstract = {Stellar wind mass loss of massive stars is often assumed to depend on their metallicity Z. Therefore, evolutionary models predict that massive stars in lower-Z environments are able to retain more of their hydrogen-rich layers and evolve into brighter cool supergiants (cool SGs; Teff < 7 kK). Surprisingly, in galaxies in the metallicity range 0.2 ≲ Z/Z⊙ ≲ 1.5, previous studies have not found a metallicity dependence on the upper luminosity limit Lmax of cool SGs. Here, we add four galaxies to the sample studied for this purpose with data from the Hubble Space Telescope and the James Webb Space Telescope (JWST). Observations of the extremely metal-poor dwarf galaxy I Zw 18 from JWST allow us to extend the studied metallicity range down to Z/Z⊙ ≈ 1/40. For cool SGs in all studied galaxies, including I Zw 18, we find a constant value of Lmax ≈ 105.6 L⊙, similar to literature results for 0.2 ≲ Z/Z⊙ ≲ 1.5. In I Zw 18 and the other studied galaxies, the presence of Wolf-Rayet stars has been previously inferred. Although we cannot rule out that some of them become intermediate-temperature objects, this paints a picture in which evolved stars with L > 105.6 L⊙ burn helium as hot, helium-rich stars down to extremely low metallicity. We argue that metallicity-independent late-phase mass loss would be the most likely mechanism responsible for this. Regardless of the exact stripping mechanism (winds or, for example, binary interaction), for the Early Universe our results imply a limitation on black hole masses and a contribution of stars born with M ≳ 30 M⊙ to its surprisingly strong nitrogen enrichment. We propose a scenario in which single stars at low metallicity emit sufficiently hard ionizing radiation to produce He II and C IV lines. In this scenario, late-phase metallicity-independent mass loss produces hot, helium-rich stars. Due to the well-understood metallicity dependence on the radiation-driven winds of hot stars, a window of opportunity would open below 0.2 Z⊙, where self-stripped helium-rich stars can exist without dense Wolf-Rayet winds that absorb hard ionizing radiation.}, author = {Schootemeijer, Abel and Götberg, Ylva Louise Linsdotter and Langer, Norbert and Bortolini, Giacomo and Hirschauer, Alec S. and Patrick, Lee}, issn = {1432-0746}, journal = {Astronomy & Astrophysics}, publisher = {EDP Sciences}, title = {{A constant upper luminosity limit of cool supergiant stars down to the extremely low metallicity of I Zw 18}}, doi = {10.1051/0004-6361/202557675}, volume = {707}, year = {2026}, } @article{21451, abstract = {The population of the little red dots (LRDs) may represent a key phase of supermassive black hole (SMBH) growth. A cocoon of dense excited gas is emerging as a key component to explain the most striking properties of LRDs, such as strong Balmer breaks and Balmer absorption, as well as the weak IR emission. To dissect the structure of LRDs, we analyzed new deep JWST/NIRSpec PRISM and G395H spectra of FRESCO-GN-9771, one of the most luminous known LRDs at z = 5.5. These spectra reveal a strong Balmer break, broad Balmer lines, and very narrow [O III] emission. We revealed a forest of optical [Fe II] lines, which we argue are emerging from a dense (nH = 109 − 10 cm−3) warm layer with electron temperature Te ≈ 7000 K. The broad wings of Hα and Hβ have an exponential profile due to electron scattering in this same layer. The high Hα : Hβ : Hγ flux ratio of ≈10.4 : 1 : 0.14 is an indicator of collisional excitation and resonant scattering dominating the Balmer line emission. A narrow Hγ component, unseen in the other two Balmer lines due to outshining by the broad components, could trace the ISM of a normal host galaxy with a star formation rate of ∼5 M⊙ yr−1. The warm layer is mostly opaque to Balmer transitions, producing a characteristic P Cygni profile in the line centers suggesting outflowing motions. This same layer is responsible for shaping the Balmer break. The broadband spectrum can be reasonably matched by a simple photoionized slab model that dominates the λ > 1500 Å continuum and a low-mass (∼108 M⊙) galaxy that could explain the narrow [O III], with only a subdominant contribution to the UV continuum. Our findings indicate that Balmer lines are not directly tracing the gas kinematics near the SMBH and that the BH mass scale is likely much lower than virial indicators suggest.}, author = {Torralba Torregrosa, Alberto and Matthee, Jorryt J and Pezzulli, Gabriele and Naidu, Rohan P. and Ishikawa, Yuzo and Brammer, Gabriel B. and Chang, Seok Jun and Chisholm, John and De Graaff, Anna and D’Eugenio, Francesco and Di Cesare, Claudia and Eilers, Anna Christina and Greene, Jenny E. and Gronke, Max and Iani, Edoardo and Kokorev, Vasily and Kotiwale, Gauri and Kramarenko, Ivan and Ma, Yilun and Mascia, Sara and Navarrete, Benjamín and Nelson, Erica and Oesch, Pascal and Simcoe, Robert A. and Wuyts, Stijn}, issn = {1432-0746}, journal = {Astronomy & Astrophysics}, publisher = {EDP Sciences}, title = {{The warm outer layer of a little red dot as the source of [Fe ii] and collisional Balmer lines with scattering wings}}, doi = {10.1051/0004-6361/202557537}, volume = {707}, year = {2026}, }