@article{21252,
  abstract     = {Context. Recent observational results from asteroseismic studies show that an important fraction of solar-like stars do not present detectable stochastically excited acoustic oscillations. This non-detectability seems to correlate with a high rotation rate in the convective envelope and a high surface magnetic activity. At the same time, the properties of stellar convection are affected by rotation and magnetism.
Aims. We investigate the role of rotation in the excitation of acoustic modes in the convective envelope of solar-like stars, to evaluate its impact on the energy injected in the oscillations.
Methods. We derived theoretical prescriptions for the excitation of acoustic waves in the convective envelope of rotating solar-like stars. We adopted the rotating mixing-length Theory to model the influence of rotation on convection. We used the MESA stellar evolution code and the GYRE stellar oscillation code to estimate the power injected in the oscillations from our theoretical prescriptions.
Results. We demonstrate that the power injected in the acoustic modes is insensitive to rotation if a Gaussian time-correlation function is assumed, while it can decrease by up to 60% for a Lorentzian time-correlation function, for a 20 Ω⊙ rotation rate. We show that the modification of the excitation rate by rotation depends not only on the rotation rate but also on the radial and angular orders of the considered oscillation mode. This result can allow for better constraints on the properties of stellar convection by studying observationally acoustic mode excitation.
Conclusions. These results demonstrate how important it is to take into account the modification of stellar convection by rotation when evaluating the amplitude of the stellar oscillations it stochastically excites. They open the path for understanding the large variety of observed acoustic-mode amplitudes at the surface of solar-like stars as a function of surface rotation rates.},
  author       = {Bessila, L. and Deckx van Ruys, A. and Buriasco, V. and Mathis, S. and Bugnet, Lisa Annabelle and García, R. A. and Mathur, S.},
  issn         = {1432-0746},
  journal      = {Astronomy & Astrophysics},
  publisher    = {EDP Sciences},
  title        = {{The impact of rotation on the stochastic excitation of stellar acoustic modes in solar-like pulsators}},
  doi          = {10.1051/0004-6361/202452093},
  volume       = {700},
  year         = {2025},
}

@article{21253,
  abstract     = {We solve a problem of Dujmović and Wood (2007) by showing that a complete convex geometric graph on n vertices cannot be decomposed into fewer than n - 1 star-forests, each consisting of noncrossing edges. This bound is clearly tight. We also discuss similar questions for abstract graphs.},
  author       = {Pach, János and Saghafian, Morteza and Schnider, Patrick},
  issn         = {0925-7721},
  journal      = {Computational Geometry},
  publisher    = {Elsevier},
  title        = {{Decomposition of geometric graphs into star-forests}},
  doi          = {10.1016/j.comgeo.2025.102186},
  volume       = {129},
  year         = {2025},
}

@inbook{21255,
  abstract     = {As an important plant hormone to regulate growth and development, auxin has been investigated for more than a century. It had been clearly demonstrated and well-accepted that the intracellular auxin receptors, TIR1/AFBs, are F-box proteins mediating transcriptional auxin signaling by their E3 ubiquitin ligase activity, which targets and sends for degradation the Aux/IAA transcriptional repressors. The recent discovery of adenylate cyclase (AC) and guanylate cyclase (GC) activities for TIR1/AFBs open entirely new perspectives on how auxin signaling can operate. This chapter traces back the history of how canonical transcriptional auxin signaling was established and introduces the discovery of the TIR1/AFBs-mediated nontranscriptional signaling branch. Finally, the current understanding and open questions of how TIR1/AFBs’ AC and GC activities contribute to the transcriptional and nontranscriptional auxin signaling are discussed, highlighting the possibility that cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) act as second messengers in auxin signal transduction.},
  author       = {Qi, Linlin and Friml, Jiří},
  booktitle    = {Cryptic Enzymes and Moonlighting Proteins},
  editor       = {Irving, Helen and Gehring, Chris and Wong, Aloysius},
  isbn         = {9780443157196},
  pages        = {299--322},
  publisher    = {Elsevier},
  title        = {{Nucleotidyl cyclase activities of TIR1/AFB auxin receptors: new insights into the mechanism of auxin signaling}},
  doi          = {10.1016/b978-0-443-15719-6.00015-5},
  year         = {2025},
}

@article{21256,
  abstract     = {Collagen IV is one of the main components of the basement membrane, a layer of material that lines the majority of tissues in multicellular organisms. Collagen IV molecules assemble into networks, providing stiffness and elasticity to tissues and informing cell and organ shape, especially during development. In this work, we develop two coarse-grained models for collagen IV molecules that retain biochemical bond specificity and coarse grain at different length scales. Through molecular-dynamics simulations, we test the assembly and mechanics of the resulting networks and measure their response to strain in terms of stress, microscopic alignment, and bond dynamics. Within the basement membrane, collagen IV networks rearrange by molecule turnover, which affects tissue organization and can be linked with enzyme activity. Here we explore network rearrangements via bond remodeling, the process of breaking and remaking of bonds between network molecules. We then investigate the effects of active (enzymatic) bond remodeling. We find that this nonequilibrium remodeling allows a network to keep its integrity under strain, while relaxing fully over a variety of timescales, a dynamic response that is unavailable to networks undergoing equilibrium remodeling.},
  author       = {Meadowcroft, Billie and Sorichetti, Valerio and Ratajczyk, Eryk and Perez Verdugo, Fernanda L and Khalilgharibi, Nargess and Mao, Yanlan and Palaia, Ivan and Šarić, Anđela},
  issn         = {2835-8279},
  journal      = {PRX Life},
  publisher    = {American Physical Society},
  title        = {{Nonequilibrium remodeling of collagen IV networks in Silico}},
  doi          = {10.1103/gdd5-rnh7},
  volume       = {3},
  year         = {2025},
}

@inbook{21257,
  abstract     = {We investigate the problem of accurate sparse fine-tuning of large language models (LLMs), that is, fine-tuning pre-trained LLMs on specialized tasks, while inducing sparsity in their weights. Our work is motivated by experiments showing that standard loss-based fine-tuning methods are not able to achieve high accuracy in this setting, especially at high sparsity targets. To address this issue, we perform a detailed study of knowledge distillation losses for fine-tuning of sparse models. We determine an L2-based distillation approach that we term ‘SquareHead’, which enables accurate recovery even at higher sparsities. Investigating the question of efficient inference, we show that sparse LLMs can be executed faster by taking advantage of sparsity. Specifically, we exhibit end-to-end results showing speedups enabled by sparsity, while recovering accuracy, on the following models and tasks, respectively: T5 for language translation, Whisper for speech translation, and open GPT-type models such as the Mosaic Pre-Trained Transformer (MPT) and Llama-2 models for text generation. In particular, for popular generative tasks, we show for the first time that sparse fine-tuning can reach 75% sparsity without drops in accuracy, and provide notable end-to-end speedups for inference on CPUs. Moreover, we also highlight that sparsity is compatible with other compression approaches, such as quantization.},
  author       = {Kurtic, Eldar and Kuznedelev, Denis and Frantar, Elias and Goinv, Michael and Pandit, Shubhra and Agarwalla, Abhinav and Nguyen, Tuan and Marques, Alexandre and Kurtz, Mark and Alistarh, Dan-Adrian},
  booktitle    = {Enhancing LLM Performance. Efficacy, Fine-Tuning, and Inference Techniques},
  editor       = {Passban, Peyman and Way, Andy and Rezagholizadeh, Mehdi},
  isbn         = {9783031857461},
  issn         = {2522-803X},
  pages        = {83--97},
  publisher    = {Springer Nature},
  title        = {{Sparse Fine-Tuning for Inference Acceleration of Large Language Models}},
  doi          = {10.1007/978-3-031-85747-8_6},
  year         = {2025},
}

@article{21260,
  abstract     = {We prove that there does not exist F∈Q[x,y] of degree 4 such that F(Z^2 )=Z ≥0. In particular, this answers a question by John S. Lew and Bjorn Poonen for quartic polynomials.},
  author       = {Yao Xiao, Stanley and Yamagishi, Shuntaro},
  issn         = {1435-9863},
  journal      = {Journal of the European Mathematical Society},
  publisher    = {EMS Press},
  title        = {{Quartic polynomials in two variables do not represent all non-negative integers}},
  doi          = {10.4171/jems/1697},
  year         = {2025},
}

@inproceedings{21262,
  abstract     = {Continuous Group Key Agreement (CGKA) is the primitive underlying secure group messaging. It allows a large group of N users to maintain a shared secret key that is frequently rotated by the
group members in order to achieve forward secrecy and post compromise security. The group messaging scheme Messaging Layer Security (MLS) standardized by the IETF makes use of a CGKA called TreeKEM which arranges the N group members in a binary tree. Here, each node is associated with a public-key, each user is assigned one of the leaves, and a user knows the corresponding secret keys from their leaf to the root. To update the key material known to them, a user must just replace keys at log(N) nodes, which requires them to create and upload log(N) ciphertexts. Such updates must be processed sequentially by all users, which for large groups is impractical. To allow for concurrent updates, TreeKEM uses the “propose and commit” paradigm, where multiple users can concurrently propose to update (by just sampling a fresh leaf key), and a single user can then commit to all proposals at once. Unfortunately, this process destroys the binary tree structure as the tree gets pruned and some nodes must be “blanked” at the cost of increasing the in-degree of others, which makes the commit operation, as well as, future commits more costly. In the worst case, the update cost (in terms of uploaded ciphertexts) per user can grow from log(N) to Ω(N). In this work we provide two main contributions. First, we show that MLS’ communication complexity is bad not only in the worst case but also if the proposers and committers are chosen at random: even if there’s just one update proposal for every commit the expected cost is already over √N, and it approaches N as this ratio changes towards more proposals. Our second contribution is a new variant of propose and commit for
TreeKEM which for moderate amounts of update proposals per commit provably achieves an update cost of Θ(log(N)) assuming the proposers and committers are chosen at random.},
  author       = {Auerbach, Benedikt and Cueto Noval, Miguel and Erol, Boran and Pietrzak, Krzysztof Z},
  booktitle    = {45th Annual International Cryptology Conference},
  isbn         = {9783032019127},
  issn         = {1611-3349},
  location     = {Santa Barbara, CA, United States},
  pages        = {141--172},
  publisher    = {Springer Nature},
  title        = {{Continuous group-key agreement: Concurrent updates without pruning}},
  doi          = {10.1007/978-3-032-01913-4_5},
  volume       = {16007},
  year         = {2025},
}

@article{21263,
  abstract     = {Two landmark results in combinatorial random matrix theory, due to Komlós and Costello–Tao–Vu, show that discrete random matrices and symmetric discrete random matrices are typically nonsingular. In particular, in the language of graph theory, when p is a fixed constant, the biadjacency matrix of a random Erdős–Rényi bipartite graph G(n,n,p) and the adjacency matrix of an Erdős–Rényi random graph G(n,p) are both nonsingular with high probability. However, very sparse random graphs (i.e., where p is allowed to decay rapidly with n) are typically singular, due to the presence of “local” dependencies such as isolated vertices and pairs of degree-1 vertices with the same neighbour. In this paper, we give a combinatorial description of the rank of a sparse random graph G(n,n,c/n) or G(n,c/n) in terms of such local dependencies, for all constants c=e (and we present some evidence that the situation is very different for c=e). This gives an essentially complete answer to a question raised by Vu (2014). As applications of our main theorem and its proof, we also determine the asymptotic singularity probability of the 2-core of a sparse random graph, we show that the rank of a sparse random graph is extremely well approximated by its matching number, and we deduce a central limit theorem for the rank of G(n,c/n).},
  author       = {Glasgow, Margalit and Kwan, Matthew Alan and Sah, Ashwin and Sawhney, Mehtaab},
  issn         = {1435-9863},
  journal      = {Journal of the European Mathematical Society},
  publisher    = {European Mathematical Society Press},
  title        = {{The exact rank of sparse random graphs}},
  doi          = {10.4171/jems/1692},
  year         = {2025},
}

@article{21264,
  abstract     = {Rodents' ability to encode the whisking phase has been extensively documented through neuronal recordings from ascending sensory pathways. Yet, while indicating that reafference originates from the mechanoreceptors, the mechanistic underpinnings of the whisking phase encoding within the follicle remain unclear. Here we present anatomical, histological, and biomechanical evidence for the presence of a distinctive elastic segment (ES) within the basal part of the whisker shaft inside the follicle. This ES, composed of immature keratin, is capable of both bending and twisting. Forces generated by whisker movement deform this segment, causing whisker shaft deflections that can stimulate specific mechanoreceptor subsets within the follicle at different phases of the whisking cycle. This mechanism appears to operate during both free‐air whisking and object contact. We propose that the ES enables torsion‐based mechanoreceptor activation, allowing encoding of the whisking phase.},
  author       = {Haidarliu, Sebastian and Nelinger, Guy and Gantar, Luka and Ahissar, Ehud and Saraf‐Sinik, Inbar},
  issn         = {1932-8494},
  journal      = {The Anatomical Record},
  publisher    = {Wiley},
  title        = {{An elastic segment of the whisker shaft enables coding of the whisking phase via whisker torsion in rats and mice}},
  doi          = {10.1002/ar.70051},
  year         = {2025},
}

@article{21265,
  abstract     = {We explain how the (shifted) Ratios Conjecture for $L(s,\chi )$ would extend a randomization argument of Harper from a conductor-limited range to an unlimited range of “beyond square-root cancellation” for character twists of the Liouville function. As a corollary, the Liouville function would have nontrivial cancellation in arithmetic progressions of modulus just exceeding the well-known square-root barrier. Morally, the paper passes from random matrices to random multiplicative functions.},
  author       = {Wang, Victor and Xu, Max Wenqiang},
  issn         = {1687-0247},
  journal      = {International Mathematics Research Notices},
  number       = {18},
  publisher    = {Oxford University Press},
  title        = {{Harper’s beyond square-root conjecture}},
  doi          = {10.1093/imrn/rnaf279},
  volume       = {2025},
  year         = {2025},
}

@article{21266,
  abstract     = {For a given elliptic curve E in short Weierstrass form, we show that almost all quadratic twists E 
D have no integral points, as D ranges over square-free integers ordered by size. Our result is conditional on a weak form of the Hall–Lang conjecture in the case that E has partial 2-torsion. The proof uses a correspondence of Mordell and the reduction theory of binary quartic forms in order to transfer the problem to counting rational points of bounded height on a certain singular cubic surface, together with extensive use of cancellation in character sum estimates, drawn from Heath-Brown’s analysis of Selmer group statistics for the congruent number curve.},
  author       = {Browning, Timothy D and Chan, Yik Tung},
  issn         = {1435-9863},
  journal      = {Journal of the European Mathematical Society},
  publisher    = {European Mathematical Society Press},
  title        = {{Almost all quadratic twists of an elliptic curve have no integral points}},
  doi          = {10.4171/jems/1704},
  year         = {2025},
}

@inproceedings{21268,
  abstract     = {We consider multiple-environment Markov decision processes (MEMDP), which consist of a finite set of MDPs over the same state space, representing different scenarios of transition structure and probability. The value of a strategy is the probability to satisfy the objective, here a parity objective, in the worst-case scenario, and the value of an MEMDP is the supremum of the values achievable by a strategy.
We show that deciding whether the value is 1 is a PSPACE-complete problem, and even in P when the number of environments is fixed, along with new insights to the almost-sure winning problem, which is to decide if there exists a strategy with value 1. Pure strategies are sufficient for theses problems, whereas randomization is necessary in general when the value is smaller than 1. We present an algorithm to approximate the value, running in double exponential space. Our results are in contrast to the related model of partially-observable MDPs where all these problems are known to be undecidable.},
  author       = {Chatterjee, Krishnendu and Doyen, Laurent and Raskin, Jean-Francois and Sankur, Ocan},
  booktitle    = {52nd International Colloquium on Automata, Languages, and Programming},
  isbn         = {9783959773720},
  location     = {Aarhus, Denmark},
  publisher    = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik},
  title        = {{The value problem for multiple-environment MDPs with parity objective}},
  doi          = {10.4230/LIPIcs.ICALP.2025.150},
  year         = {2025},
}

@article{21269,
  abstract     = {The spatial organization of chromatin within the nucleus plays a crucial role in gene expression and genome function. However, the quantitative relationship between this organization and nuclear biochemical processes remains under debate. In this study, we present a graph-based generative model, bioSBM, designed to capture long-range chromatin interaction patterns from Hi-C data and, importantly, simultaneously link these patterns to biochemical features. Applying bioSBM to Hi-C maps of the GM12878 lymphoblastoid cell line, we identified a latent structure of chromatin interactions, revealing seven distinct communities that strongly align with known biological annotations. Additionally, we infer a linear transformation that maps biochemical observables, such as histone marks, to the parameters of the generative graph model, enabling accurate genome-wide predictions of chromatin contact maps on out-of-sample data, both within the same cell line and on the completely unseen HCT116 cell line under RAD21 depletion. These findings highlight bioSBM's potential as a powerful tool for elucidating the relationship between biochemistry and chromatin architecture and predicting long-range genome organization from independent biochemical data.},
  author       = {Zhang, Chen Y and Rosa, Angelo and Sanguinetti, Guido},
  issn         = {2835-8279},
  journal      = {PRX Life},
  number       = {4},
  publisher    = {American Physical Society},
  title        = {{bioSBM: A random graph model to integrate epigenomic data in chromatin structure prediction}},
  doi          = {10.1103/gy1p-4256},
  volume       = {3},
  year         = {2025},
}

@article{21270,
  abstract     = {The one-dimensional Fröhlich model describing the motion of a single electron interacting with optical phonons is a paradigmatic model of quantum many-body physics. We predict the existence of an arbitrarily large number of bound excited states in the strong-coupling limit and calculate their excitation energies. Numerical simulations of a discretized model demonstrate the complete amelioration of the projector Monte Carlo sign problem by walker annihilation in an infinite Hilbert space. They reveal the threshold for the occurrence of the first bound excited states at a value of 𝛼≈1.73 for the dimensionless coupling constant. This puts the threshold into the regime of intermediate interaction strength. We find a significant spectral weight and increased phonon number of the bound excited state at threshold.},
  author       = {Taylor, J. and Čufar, M. and Mitrouskas, David Johannes and Seiringer, Robert and Pahl, E. and Brand, J.},
  issn         = {2469-9969},
  journal      = {Physical Review B},
  number       = {18},
  publisher    = {American Physical Society},
  title        = {{Bound excited states of Fröhlich polarons in one dimension}},
  doi          = {10.1103/s9p9-jflq},
  volume       = {112},
  year         = {2025},
}

@article{21271,
  abstract     = {For general non-Hermitian large random matrices X and deterministic deformation matrices A, we prove that the local eigenvalue statistics of A+X close to the typical edge points of its spectrum are universal. Furthermore, we show that, under natural assumptions, on A the spectrum of A+X does not have outliers at a distance larger than the natural fluctuation scale of the eigenvalues. As a consequence, the number of eigenvalues in each component of Spec(A+X) is deterministic.},
  author       = {Campbell, Andrew J and Cipolloni, Giorgio and Erdös, László and Ji, Hong Chang},
  issn         = {2168-894X},
  journal      = {The Annals of Probability},
  number       = {6},
  pages        = {2256--2308},
  publisher    = {Institute of Mathematical Statistics},
  title        = {{On the spectral edge of non-Hermitian random matrices}},
  doi          = {10.1214/25-aop1761},
  volume       = {53},
  year         = {2025},
}

@inproceedings{21272,
  abstract     = {Finding the ground state of Ising spin glasses is notoriously difficult due to disorder and frustration. Often, this challenge is framed as a combinatorial optimization problem, for which a common strategy employs simulated annealing, a Monte Carlo (MC)-based algorithm that updates spins one at a time. Yet, these localized updates can cause the system to become trapped in local minima. Cluster algorithms (CAs) were developed to address this limitation and have demonstrated considerable success in studying ferromagnetic systems; however, they tend to encounter percolation issues when applied to generic spin glasses. In this work, we introduce a novel CA designed to tackle these challenges by leveraging precomputed two-point correlations, aiming solve combinatorial optimization problems in the form of Max-Cut more efficiently. In our approach, clusters are formed probabilistically based on these correlations. Various classical and quantum algorithms can be employed to generate correlations that embody information about the energy landscape of the problem. By utilizing this information, the algorithm aims to identify groups of spins whose simultaneous flipping induces large transitions in configuration space with high acceptance probability - even at low energy levels - thereby escaping local minima more effectively. Notably, clusters generated using correlations from the Quantum Approximate Optimization Algorithm exhibit high acceptance rates at low temperatures. These acceptance rates often increase with circuit depth, accelerating the algorithm and enabling more efficient exploration of the solution space.},
  author       = {Eder, Peter J. and Kerschbaumer, Aron and Finžgar, Jernej Rudi and Medina Ramos, Raimel A and Schuetz, Martin J. A. and Katzgraber, Helmut G. and Braun, Sarah and Mendl, Christian B.},
  booktitle    = {2025 IEEE International Conference on Quantum Computing and Engineering},
  location     = {Albuquerque, NM, United States},
  publisher    = {IEEE},
  title        = {{Quantum-guided cluster algorithms for combinatorial optimization}},
  doi          = {10.1109/qce65121.2025.00033},
  year         = {2025},
}

@inproceedings{21280,
  abstract     = {We give an algorithm that, with high probability, maintains a (1-ε)-approximate s-t maximum flow in undirected, uncapacitated n-vertex graphs undergoing m edge insertions in Õ(m+ n F^*/ε) total update time, where F^{*} is the maximum flow on the final graph. This is the first algorithm to achieve polylogarithmic amortized update time for dense graphs (m = Ω(n²)), and more generally, for graphs where F^* = Õ(m/n). At the heart of our incremental algorithm is the residual graph sparsification technique of Karger and Levine [SICOMP '15], originally designed for computing exact maximum flows in the static setting. Our main contributions are (i) showing how to maintain such sparsifiers for approximate maximum flows in the incremental setting and (ii) generalizing the cut sparsification framework of Fung et al. [SICOMP '19] from undirected graphs to balanced directed graphs.},
  author       = {Goranci, Gramoz and Henzinger, Monika H and Räcke, Harald and Sricharan, A.},
  booktitle    = {52nd International Colloquium on Automata, Languages, and Programming},
  isbn         = {9783959773720},
  location     = {Aarhus, Denmark},
  pages        = {91:1--91:20},
  publisher    = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik},
  title        = {{Incremental approximate maximum flow via residual graph sparsification}},
  doi          = {10.4230/lipics.icalp.2025.91},
  volume       = {334},
  year         = {2025},
}

@inproceedings{21281,
  abstract     = {A strategy profile in a multi-player game is a Nash equilibrium if no player can unilaterally deviate to achieve a strictly better payoff. A profile is an ε-Nash equilibrium if no player can gain more than ε by unilaterally deviating from their strategy. In this work, we use ε-Nash equilibria to approximate the computation of Nash equilibria. Specifically, we focus on turn-based, multiplayer stochastic games played on graphs, where players are restricted to stationary strategies - strategies that use randomness but not memory.
The problem of deciding the constrained existence of stationary Nash equilibria - where each player’s payoff must lie within a given interval - is known to be ∃ℝ-complete in such a setting (Hansen and Sølvsten, 2020). We extend this line of work to stationary ε-Nash equilibria and present an algorithm that solves the following promise problem: given a game with a Nash equilibrium satisfying the constraints, compute an ε-Nash equilibrium that ε-satisfies those same constraints - satisfies the constraints up to an ε additive error. Our algorithm runs in FNP^NP time.
To achieve this, we first show that if a constrained Nash equilibrium exists, then one exists where the non-zero probabilities are at least an inverse of a double-exponential in the input. We further prove that such a strategy can be encoded using floating-point representations, as in the work of Frederiksen and Miltersen (2013), which finally gives us our FNP^NP algorithm. 
We further show that the decision version of the promise problem is NP-hard. Finally, we show a partial tightness result by proving a lower bound for such techniques: if a constrained Nash equilibrium exists, then there must be one where the probabilities in the strategies are double-exponentially small.},
  author       = {Asadi, Ali and Brice, Leonard and Chatterjee, Krishnendu and Thejaswini, K. S.},
  booktitle    = {45th Annual Conference on Foundations of Software Technology and Theoretical Computer Science},
  isbn         = {9783959774062},
  location     = {Pilani, India},
  pages        = {9:1--9:17},
  publisher    = {Schloss Dagstuhl - Leibniz-Zentrum für Informatik},
  title        = {{ε-stationary Nash equilibria in multi-player stochastic graph games}},
  doi          = {10.4230/lipics.fsttcs.2025.9},
  volume       = {360},
  year         = {2025},
}

@unpublished{21309,
  abstract     = {The polarization of light is a critically under-utilized, rich source of information in astronomy. For stars in particular, surface magnetism polarization that can be detected and measured with spectro-polarimetry. Many questions about these surface fields remain unanswered due to a lack of dedicated instruments capable of probing weak and strong surface magnetic fields for the entire mass range of stars, from M-dwarfs (and even substellar objects) to massive O-type stars at different evolutionary stages and metallicities. These questions range from the origin of these fields to their true incidence rate throughout the stellar population and the dependence on metallicity. Magnetic fields, although currently often excluded from stellar evolution models, play an important role in stellar evolution. Connecting the surface fields to internal fields through asteroseismology will instigate a new era of understanding stellar evolution and the transport of angular momentum and chemical elements throughout stellar interiors, also impacting our understanding of star-planet interactions and stellar remnants. Polarimetry is also an under-utilized tool to observationally constrain the mode identification of nonradial oscillations, which lies at the basis of accurate asteroseismic parameter estimation at percentage-level for stellar radii, masses, ages, internal rotation, and magnetic field strengths. Combining strong constraints on mode identification and surface magnetic properties through the acquisition of time-resolved, high-resolution and high-signal-to-noise (S/N) spectro-polarimetry and spectroscopy promises to bring leaps forward in our understanding of stellar structure, particularly when combined with long-term space photometric data from past, current, and future missions.},
  author       = {Vandersnickt, J. and Armenta, R. Ochoa and Vanlaer, V. and A. David-Uraz, A. David-Uraz and Aerts, C. and Das, S. B. and Bouret, J. -C. and Bowman, D. M. and Bugnet, Lisa Annabelle and Khalack, V. and J. Labadie-Bartz, J. Labadie-Bartz and Mathis, S. and Nazé, Y. and Neiner, C. and Petit, P. and Petit, V. and K. Thomson-Paressant, K. Thomson-Paressant and Doorsselaere, T. Van and Vanrespaille, M.},
  booktitle    = {arXiv},
  title        = {{Expanding stellar horizons with polarized light}},
  doi          = {10.48550/arXiv.2512.15170},
  year         = {2025},
}

@article{21317,
  abstract     = {Accreting white dwarfs (WDs) in close binary systems, commonly known as cataclysmic variables (CVs), with orbital periods below the canonical period minimum (≈80 minutes) are rare. Such short periods can only be reached if the donor star in the CV is either significantly evolved before initiating mass transfer to the WD or is metal-poor. We present optical photometry and spectroscopy of Gaia19bxc, a high-amplitude variable identified as a polar CV with an exceptionally short orbital period of 64.42 minutes—well below the canonical CV period minimum. High-speed photometry confirms persistent double-peaked variability consistent with cyclotron beaming, thus indicating the presence of a magnetic WD. Phase-resolved Keck/Low-Resolution Imaging Spectrometer (LRIS) spectroscopy reveals strong hydrogen and helium emission lines but no donor features, indicating the accretor is a magnetic WD and the donor is hydrogen-rich, but cold and faint. The absence of a detectable donor and the low inferred temperature (≲3500 K) disfavor an evolved donor scenario. Instead, the short period and the system’s halo-like kinematics suggest Gaia19bxc may be the first known metal-poor polar. Because metal-poor donors are more compact than solar-metallicity donors of the same mass, they can reach shorter minimum periods. Gaia19bxc is one of only a handful of known metal-poor CVs below the canonical period minimum and has the shortest period of any such magnetic system discovered to date.},
  author       = {Galiullin, Ilkham and Rodriguez, Antonio C. and El-Badry, Kareem and Caiazzo, Ilaria and Szkody, Paula and Nagarajan, Pranav and Whitebook, Samuel},
  issn         = {2041-8213},
  journal      = {The Astrophysical Journal Letters},
  number       = {2},
  publisher    = {IOP Publishing},
  title        = {{Optical spectroscopy of the most compact accreting binary harboring a magnetic White Dwarf and a hydrogen-rich donor}},
  doi          = {10.3847/2041-8213/adff82},
  volume       = {990},
  year         = {2025},
}