Instrumentation and Methods for Astrophysics
Improved Modeling for Moving Sources of Radio Frequency Interference and Impact on Flagging Strategies
Jade M. Ducharme, Jonathan C. Pober and Michael J. Wilensky
Radio frequency interference (RFI) is a major challenge for low-frequency
radio experiments targeting the redshifted 21-cm signal from the Epoch of Reionization. Many important RFI sources, including aircraft and satellites, move across the sky during an observation. The averaging of visibilities for such moving sources over a finite correlator integration produces a distinct sinc-like pattern in the interferometric uv-plane, causing the RFI to appear bright on some baselines and strongly suppressed on others. Here, we develop an analytical model for this effect and validate its qualitative behavior against real MWA observations and numerical simulations. Controlled RFI injections into clean MWA data are then used to compare several flagging treatments in the context of EoR power spectrum recovery. These treatments explore the trade-off between per-baseline flagging, which can miss weak but potentially non-negligible contamination on baselines where the integration effect leads to strong suppression, and baseline-aggregated flagging, which removes more faint residual contamination but reduces the total number of usable uv-modes. We find that the preferred strategy depends on RFI brightness and occupancy, but that flagging all frequencies at contaminated time-steps most consistently minimizes excess power for bright or frequent events. However, none of the tested flagging treatments fully recovers the uncontaminated reference spectrum, motivating future work on direct modeling and subtraction of moving RFI sources.
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Quantum Physics
Characterizing quantum precision enhancement for multiple currents in open quantum systems
Khalak Mahadeviya, Sheikh Parvez Mandal, Mahasweta Pandit et al. (+3 more)
The kinetic uncertainty relation (KUR) constrains fluctuations of individual currents in classical nonequilibrium systems in terms of the dynamical activity, which quantifies the average number of transitions per unit of time. Here, we derive a multi-current KUR (MKUR) establishing the precision limit for multiple currents generated in classical
stochastic processes in the nonequilibrium steady state. We then apply our theory to identify
quantum devices whose correlated current fluctuations surpass this classical limit by comparing the
quantum system to a classical emulator with the same average currents in the steady state. In this way, violations of the emulator's MKUR have a clear physical meaning, i.e., that the
quantum-coherent
evolution reduces joint current fluctuations below what is possible for a classical Markovian system with the same energy-level structure and incoherent resources. Since the MKUR incorporates correlations between currents, its violation pinpoints nonclassical fluctuations in parameter regimes where the single-current KUR is satisfied. We illustrate the essential and complementary role of these bounds for characterizing joint current precision with two examples: a coherently driven two-level system and an experimentally motivated model of a three-level heat engine subject to parasitic environmental couplings.
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All authors Khalak Mahadeviya, Sheikh Parvez Mandal, Mahasweta Pandit, Javier Prior, Mark T. Mitchison, Saulo V. Moreira
High Energy Physics (Phenomenology)
Higgs pseudo-observables in $e^+e^-\to h\gamma$
Fausto Boniotti, Gino Isidori, Christiane Mayer et al. (+1 more)
We analyse the process $e^+e^-\to h\gamma$ in the Standard Model (SM) and in generic extensions with heavy new physics, using the framework of
Higgs pseudo-observables. We decompose the one-loop amplitude into separately gauge-invariant
photon-pole, $Z$-pole, and non-pole contributions. For heavy new physics, we show that the leading deviations from the SM are necessarily encoded in the $h\gamma\gamma$ and $hZ\gamma$ on-shell effective couplings. Genuine $e^+e^-h\gamma$ contact interactions arise only at higher orders in a derivative expansion, both in SMEFT and HEFT. Although
Higgs decays constrain the magnitudes of these pseudo-observables, they leave their relative sign undetermined. Measurements of $e^+e^-\to h\gamma$ at different FCC-ee energies can resolve this ambiguity. Deviations incompatible with this description would instead point towards relatively light new degrees of freedom, as illustrated by a simplified $Z'$ model.
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All authors Fausto Boniotti, Gino Isidori, Christiane Mayer, Emanuelle Pinsard
Solar and Stellar Astrophysics
The long period radio transient ASKAP J1448-68 is a cataclysmic variable
Geoffrey Mo, Akash Anumarlapudi, Iris de Ruiter et al. (+8 more)
Wide-field time-domain
radio surveys have recently unveiled a new class of
Galactic radio emitter: long period
radio transients (LPTs). Despite the rapid pace of discovery, their origins remain poorly understood, with two main theories emerging: slowly spinning magnetars or binary white
dwarfs (WDs) with
magnetic interactions. All three LPTs with well-characterised optical counterparts are WDs in binary systems, but even within that class there is diversity, with one accreting and two detached systems. In this Letter, we show that the LPT ASKAP J1448-68 is a cataclysmic variable (CV)—a WD accreting from a low-mass companion—with a spectroscopic orbital period consistent with the
radio pulse period, and specifically, potentially consistent with being a polar. Unlike the other known LPT CV, ASKAP J1448-68 does not exhibit the He II emission that is a hallmark of
magnetic CVs in their high
accretion states. We also present new optical time-series and infrared photometric observations, showing flickering at the 10% level and suggesting a possible period bouncer origin. This identification of ASKAP J1448-68 adds to the small sample of characterised LPT counterparts, and shows that LPTs can arise from WD binaries with a range of
accretion states.
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All authors Geoffrey Mo, Akash Anumarlapudi, Iris de Ruiter, Kareem El-Badry, David L. Kaplan, Antonio C. Rodriguez, Ilaria Caiazzo, Kaitlyn Shin, Anthony L. Piro, Tim Cunningham, Daniel D. Kelson
Earth and Planetary Astrophysics
Toddlers in Resonance I: low masses and eccentricities of the 17 Myr giant planets HIP 67522 bc from transit timing variations
Hannah R. James, Madyson G. Barber, Andrew W. Mann et al. (+28 more)
Infant ($<$100\,Myr) transiting
planet systems provide glimpses into the processes that shape the observed mature
planet population. Masses for these
planets are powerful data points for testing theories of
planet formation and
evolution. Because young systems tend to be in mean-motion resonances (MMR) and show higher rates of transit timing variations (TTVs), we can take advantage of deviations in the expected versus observed transit timings due to gravitational interactions between the
planets to determine the planetary masses and orbital eccentricities. Here we report the TTV analysis of HIP\,67522, a 17\,Myr two-
planet system near a 2:1 orbital resonance. The analysis is based on 55 transit observations (50 epochs) of
planet b and 29 transit observations (22 epochs) of
planet c, taken across 11 facilities. Assuming circular orbits, we determine masses of $M_b=25.0^{+7.6}_{-7.8}M_\oplus$ and $M_c=11.2\pm1.4M_\oplus$. Allowing for eccentric orbits, we find $M_b=23.1^{+15.4}_{-12.4}M_\oplus$ and $M_c=11.8^{+3.0}_{-2.3}M_\oplus$, and low eccentricities ($<0.1$) for both
planets. Adopting a Gaussian prior on $M_b$ from the JWST transmission spectrum tightens the eccentric-solution mass for
planet c to $9.7^{+1.9}_{-1.6}M_\oplus$, which is our recommended solution. The low masses and large radii are consistent with a contracting atmosphere
planet formation model, such as Gas
Dwarf formation. Given the challenge of radial-velocity masses and the high rate of TTVs seen in young systems, TTV-masses will be essential for testing theories of the formation and
evolution of super-Earths and sub-Neptunes and determining the conditions that create the most common types of
planets in the
Galaxy.
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All authors Hannah R. James, Madyson G. Barber, Andrew W. Mann, Pa Chia Thao, Adam L. Kraus, Benjamin M. Tofflemire, Andrew Vanderburg, Lyu Abe, Tristan Guillot, Olga Suarez, Djamel Mekarnia, Amaury H. M. J. Triaud, Vincent Deloupy, Mayuko Mori, Jerome P. de Leon, Norio Narita, Akihiko Fukui, John H. Livingston, George Zhou, Camille M. L. Guenée, Juliette Becker, Ana Isabel Lopez Murillo, Karen A. Collins, Richard P. Schwarz, Chris Stockdale, Thiam-Guan Tan, Keith Horne, Leah J. Boff, Mackenna L. Wood, Nidia Morrell, Luke G. Bouma
Quantum Physics
Chern-number estimation: nearly optimal quantum algorithm and provable quantum speedup
Soichiro Imamura, Shintaro Ae, Kazuki Sakamoto et al. (+2 more)
Topological phases of matter are characterized by global properties of
quantum states beyond conventional local order parameters. The Chern number is a central invariant in this characterization, linking the geometry of
quantum states to robust physical observables and making its determination key to understanding
quantum matter. We construct a nearly optimal
quantum algorithm for estimating the Chern number of a smooth
Hamiltonian family over a two-dimensional parameter
torus with a unique, gapped ground state, including interacting many-body systems. The
algorithm transports and reuses two ground-state copies prepared at a single reference point and uses generalized
quantum signal processing to coherently accumulate
geometric phases. It achieves a
Hamiltonian-oracle
evolution time of $\tilde{O}(L_xL_y/\Delta_{\min}^3)$, where $L_x,L_y$ bound the parameter derivatives of the
Hamiltonian and $\Delta_{\min}$ is a known spectral-gap lower bound. We prove a matching worst-case oracle lower bound, even when the Chern number is promised to be zero or one, establishing optimality up to polylogarithmic factors. For local
Hamiltonian families with an inverse-
polynomial gap and a supplied guiding state, exact Chern-number computation is in $\mathsf{FBQP}$ and is $\mathsf{BQP}$-hard, and merely deciding whether the Chern number is zero or one is already $\mathsf{BQP}$-complete. These results establish how efficiently
quantum computers can estimate a quantized topological invariant and provide evidence for
quantum advantage in characterizing topological phases.
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All authors Soichiro Imamura, Shintaro Ae, Kazuki Sakamoto, Ryu Hayakawa, Chusei Kiumi
Mesoscale and Nanoscale Physics
Topological Band Theory for High-Dimensional Parameter Spaces
Vivek Chakrabhavi, Walt Chavarria, Jonathan J. Heckman et al. (+1 more)
We study the topological band theory of
quantum Hall systems in which the adiabatic flux parameters of an external gauge potential form a high-dimensional
manifold. This situation arises both for strongly correlated matter on spatial Riemann surfaces of genus $g > 1$, as well as in the formal study of matter on compact oriented
manifolds of dimension $4\ell+2 = 2p$ coupled to $p$-form gauge potentials. In these cases, the underlying topological invariants defined over the parameter space are significantly richer than the low-dimensional (i.e., two-dimensional) case and involve both the
curvature (i.e., first Chern class) as well as higher order
curvature invariants. These higher
curvature invariants correspond to topologically protected contributions to Kubo-like formulae, constructed from correlation functions of the physical current operators. We illustrate these general considerations with an explicit example from
hyperbolic band theory based on the genus-two Bolza Riemann surface, a case which has recently been simulated on a synthetic-dimension platform.
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All authors Vivek Chakrabhavi, Walt Chavarria, Jonathan J. Heckman, Steven Rayan
High Energy Physics (Theory)
Helicity-Resolved Constructibility from Unified Ward Identities
Jaehoon Jeong
We show that the large-$z$ behavior of massive higher-
spin particles under all-line transverse shifts is controlled by the helicity magnitude rather than the total
spin. The apparent additional $z$ growth of nonextremal higher-
spin wavefunctions is removed by unified Ward identities acting independently on each vector index. To expose this structure, we embed a four-dimensional massive momentum and its mass into an auxiliary null five-vector, whose fifth-current components characterize the breaking and restoration of the massless Ward identities. These identities determine the fixed-helicity large-$z$ scaling and yield a helicity-resolved constructibility criterion valid for arbitrary
spin. Provided the stripped kinematic tensor remains finite in the massless limit, increasing the total
spin does not by itself worsen constructibility, and amplitudes with nonnegative coupling dimension are constructible for all helicity configurations at five points and beyond.
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Quantum Physics
Deciding the Attainability of the Multiparameter Quantum Fisher Information is NP-Hard
Lorcan O. Conlon, Laura Shou, V Vijendran et al. (+7 more)
The
quantum Fisher information (QFI) sets a fundamental bound on the attainable precision when estimating multiple parameters simultaneously. Incompatibility among the individually optimal measurements can, in some cases, imply that the precision limit set by the QFI is not attainable. In certain special cases, including pure states and full-rank states, the exact conditions for when the precision limit set by the QFI can be saturated are known. However, general conditions for the attainability of the QFI with measurements on individual copies of the
quantum state have long been sought. Indeed, this was recently stated as one of the five problems in
quantum information theory highlighted by [P. Horodecki et al, PRX
Quantum 3, 010101 (2022)]. In this work we prove that exact attainability with individual measurements is NP-hard to decide, even for a restricted set of real, constant-rank
quantum models. The source problem for our proof is the NP-hard problem of deciding whether a given bipartite density
matrix is separable or not. Our result shows that the longstanding difficulty in obtaining general conditions for QFI attainability reflects a fundamental computational obstruction, rather than merely a limitation of existing mathematical techniques: unless P=NP, no efficiently computable necessary-and-sufficient criterion can exist in general.
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All authors Lorcan O. Conlon, Laura Shou, V Vijendran, Kishor Bharti, Aritra Das, Simon K. Yung, Jacob M. Taylor, Alexey V. Gorshkov, Jun Suzuki, Syed M. Assad
Cosmology and Nongalactic Astrophysics
JWST lensed quasar dark matter survey V: Hints of self-interacting dark matter from 29 quadruply imaged quasars
D. Gilman, A. M. Nierenberg, J. Gurian et al. (+21 more)
Theories of self-interacting dark matter (SIDM) predict the eventual core collapse of dark matter
halos, a process that transforms these structures into extremely efficient gravitational lenses. We present a population-level inference on the abundance of core collapsed
halos and subhalos in the mass range $10^6 - 10^{10.7} M_{\odot}$ using 29 quadruply imaged
quasars, drawing on the collective
lensing signal of many low-mass perturbers. Our structure formation model predicts the abundance of collapsed (sub)
halos as a function of
halo mass and
redshift. We quantify how our results are affected by systematic uncertainties, including the abundance of globular clusters (GCs) and subhalos, and the internal structure of deeply collapsed
halos. Our data exhibits a strong preference for core collapsed
halos in the lens model, with Bayes factors disfavoring CDM relative to SIDM ranging from 8:1 to 24:1, depending on the assumed SIDM subhalo abundance and the internal structure of collapsed
halos. Explaining our data without core collapse requires both a GC abundance well above expectations and more subhalos than predicted by $N$-body simulations. These results pose a challenge to the CDM paradigm. We present a particle physics interpretation of these results in a companion paper.
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All authors D. Gilman, A. M. Nierenberg, J. Gurian, H. Paugnat, C. Gannon, M. N. Martinez, T. Treu, K. N. Abazajian, T. Anguita, V. N. Bennert, A. J. Benson, S. Birrer, S. G. Djorgovski, S. F. Hoenig, R. E. Keeley, A. Kusenko, M. Millon, T. Morishita, L. A. Moustakas, P. Mozumdar, D. Paris, W. Sheu, D. Sluse, K. C. Wong
Quantum Physics
One-dimensional quantum Gibbs states in constant circuit depth
Saúl Pilatowsky-Cameo, Georgios Styliaris, Ainesh Bakshi et al. (+1 more)
We prove that the Gibbs state of any
spin chain can be exactly decomposed into a mixture of product states over contiguous blocks of
qubits with bounded length, at any constant temperature. As a consequence, any such Gibbs state can be prepared by local
unitary circuits of constant depth, with efficient classical preprocessing. We place strong limits on the spatial structure of thermal
entanglement: both the
entanglement depth and
entanglement width (measures of multiparticle
entanglement) are bounded by constants, while the localizable
entanglement (the bipartite
entanglement that can be generated with the aid of local measurements and classical communication) vanishes exactly beyond a constant threshold distance. Our result also has implications for
quantum thermalization: for any translation-invariant
spin-chain
Hamiltonian with nondegenerate spectral gaps, typical low-complexity pure states drawn from a maximally entropic ensemble at any constant effective temperature become locally indistinguishable from the Gibbs state upon
unitary evolution. Additionally, we obtain an analogous decomposition for fermionic systems: the Gibbs state of any 1D local fermionic
Hamiltonian is exactly a mixture of constant-depth local fermionic
circuits acting on Gaussian states.
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All authors Saúl Pilatowsky-Cameo, Georgios Styliaris, Ainesh Bakshi, Daniel Malz
High Energy Physics (Phenomenology)
Resummation of Next-to-Leading Non-Global Logarithms in Higgs Production
Thomas Becher, Rebecca von Kuk, Xinyu Qin et al. (+1 more)
We analyze
Higgs production at the LHC with a jet veto at central rapidities and present the first next-to-leading logarithmic resummation of non-global logarithms for this process. The resummation combines one-loop hard and soft matching functions with two-loop anomalous dimensions in the large-$N_c$ limit. To perform the resummation we numerically solve renormalization group equations via the parton-shower framework MARZILI. After matching to fixed order, we perform a detailed study of different sources of uncertainties. We find that the hard matching corrections dominate by far and are substantially larger than in Drell-Yan production. Together with earlier results for Drell-Yan, these are the first resummations of subleading non-global logarithms in
hadron-
collider cross sections, and they provide a
benchmark for logarithmically accurate parton showers.
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All authors Thomas Becher, Rebecca von Kuk, Xinyu Qin, Nicolas Schalch
General Relativity and Quantum Cosmology
Black Hole Quasinormal Mode Resonances and Reconnections in Coupled Systems
Leah Jenks, Hayato Motohashi, Kazufumi Takahashi et al. (+2 more)
Black hole quasinormal modes (QNMs) provide a window into the underlying structure of black holes and the environments in which they arise. QNMs have particularly rich dynamics in coupled systems beyond general relativity, in which they are known to undergo avoided crossings, resonant excitation, and mode reconnections. Recent work has shown that reconnecting QNM trajectories can trace out a distinctive double spiral structure in the complex frequency plane. In this work, we study this phenomenology in a concrete model of perturbed dynamical Chern-Simons (dCS) theory, as well as in a minimal toy model. In the former, we characterize the exceptional points, avoided crossings and reconnections for several values of the perturbation parameters, and find that the limiting frequency of the double spiral endpoints is independent of the perturbation strength. We compute the excitation factors and find that they follow the scaling characteristic of a resonance between the scalar and gravitational modes. To determine whether these phenomena depend on the specific features of dCS, we construct a toy model of coupled degrees of freedom with square potential barriers, and find that we can reproduce the avoided crossings and reconnections, indicating that these phenomena can occur more generally in coupled systems and are highly sensitive to the system parameters.
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All authors Leah Jenks, Hayato Motohashi, Kazufumi Takahashi, Takuya Takahashi, Emanuele Berti
Computation and Language
Causal and Interpretable Structures in LLM Compositional Tasks
Gurbir Arora, Toni J.B. Liu, Jiajun Bao et al. (+2 more)
Large
language models are able to solve tasks whose answers depend on not only individual input
tokens, but also on relations among them. How is such relational information represented and processed across
transformer layers? We study activations from ensembles of
prompts that require inferring relationships between three
tokens corresponding to a cyclic concept (months, hours, weekdays, and musical notes) to correctly predict the next
token. Across model families (Llama, Qwen, Gemma, and Mistral) and cyclic concepts, we find a consistent layerwise progression in how the joint dependence among the
tokens is geometrically organized and causally used: intermediate layers use a joint representation based on the inferred relationship between two
tokens, while later layers use a joint representation associated with all three
tokens to correctly complete the task. We also find other relationships between
tokens that are geometrically structured but remain causally inert in the next-
token prediction. Crucially, when taken together, these
geometric and causal investigations reveal the representation-level mechanism that progressively organizes and composes the relational information to form the answer. More surprisingly, restricting the models to such causally relevant joint representations improves next-
token prediction accuracy.
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All authors Gurbir Arora, Toni J.B. Liu, Jiajun Bao, Raphaël Sarfati, Christopher J. Earls
Astrophysics of Galaxies
The 1.6 $\mu\mathrm{m}$ $\rm{H^{-}}$ bump as a diagnostic of TP-AGB contributions and recent quenching. I. Insights from stellar population models
Pengjun Lu, Song Huang, Shiying Lu et al. (+3 more)
The 1.6 $\mu\mathrm{m}$ $\rm{H^{-}}$ bump arises from a minimum in the opacity of the negative hydrogen ion in cool
stellar atmospheres. Although it is recognized as a common feature in
galaxy spectra, its potential for studying
stellar populations and recent quenching remains little explored. Its enhancement at intermediate ages is strong in some
stellar population models with substantial thermally pulsing asymptotic
giant branch (TP-AGB) contributions but weak or absent in others. This variation makes the feature both a potential age diagnostic and a source of model uncertainty. We use models based on the X-shooter Spectral Library (XSL) and Flexible
Stellar Population Synthesis (FSPS) to examine what drives this behavior and what it can reveal about quenching. Controlled FSPS experiments show that the $\rm{H^{-}}$ bump depends on both the amount of TP-AGB light and the
stellar template used to represent it. The adopted XSL and TP-AGB-on FSPS models predict a transient enhancement following rapid quenching, with a different age response from optical spectral features. Combining these diagnostics can therefore provide additional information about recent quenching, although the interpretation depends on the population model and
star-formation history. An illustrative comparison with existing JWST spectra shows that models including TP-AGB contributions can describe the observed $\rm{H^{-}}$ region reasonably well. These results motivate further use of the $\rm{H^{-}}$ bump to test TP-AGB prescriptions and investigate quenching with current and forthcoming observations.
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All authors Pengjun Lu, Song Huang, Shiying Lu, Meng Gu, Li Shen, Cheng Li
High Energy Physics (Phenomenology)
Constraining dark matter using 20-year INTEGRAL/IBIS observations II: Sub-GeV dark matter
Jordan Koechler and Pedro De la Torre Luque
We present new constraints on sub-GeV dark matter (DM) annihilation and decay using twenty years of diffuse hard X-ray observations from the INTEGRAL/IBIS
telescope. By performing a joint analysis of the spectral and morphological information contained in the IBIS
dataset, we simultaneously fit
Galactic longitudinal profiles and energy spectra, exploiting their complementary signatures to disentangle potential DM signals from the dominant astrophysical backgrounds. We use physically motivated background models combining inverse-Compton (IC) emission from
Galactic cosmic-ray electrons with thermal emission from unresolved accreting white
dwarfs, and consistently include the secondary IC emission generated by DM-induced electron and positron populations propagated through the
Galaxy. We conservatively derive 95% upper limits on the annihilation cross section $\langle\sigma v\rangle$ and decay half-life $\tau$ for the $e^+e^-$, $\mu^+\mu^-$, and $\pi^+\pi^-$ final states across the mass range 1 MeV to 5 GeV. Our constraints are in the range $10^{-28}$ cm$^3$/s $\lesssim \langle\sigma v\rangle \lesssim 10^{-26}$ cm$^3$/s for annihilation and $\tau \gtrsim 10^{25}$ s for decay at DM masses of a few MeV, improving upon existing X-ray limits by up to two orders of magnitude over much of the mass range. Our bounds are translated into constraints on the kinetic mixing parameter $\epsilon$ of a dark
photon and the scalar-
Higgs mixing angle $\sin\theta$, and compared with existing indirect, direct and accelerator limits available, providing a comprehensive picture of the allowed parameter space for light portal DM.
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Earth and Planetary Astrophysics
GameDev: GPU-accelerated model for dust evolution
Jiaqing Bi
Grain growth and fragmentation through
dust collisions in protoplanetary disks are strongly coupled with
dust dynamics. This is because the spatial and velocity distributions of
dust set the collision rates and outcomes, while
dust grain sizes set the aerodynamic coupling with gas. However, existing
dust evolution codes often rely on prescribed
dust velocities and are mostly restricted to one or two spatial dimensions. In this work, we present GameDev, a
dust evolution model accelerated by graphics processing units (GPUs) that couples independently evolved three-dimensional
dust dynamics with Monte Carlo collisional
evolution of
dust. In GameDev, we model
dust as Lagrangian representative particles in a prescribed gas disk. We integrate particle trajectories with the staggered semi-analytic method, which remains accurate for both tightly and weakly coupled
dust grains. We estimate collision rates from each particle's nearest neighbors rather than on a grid, preventing physically close particles from being excluded from collision sampling because they lie across a grid boundary. Most importantly, we sample collision events against neighborhoods that remain frozen over adaptive intervals, enabling massive parallelization across particles. These implementations make GameDev an accurate and efficient tool for studying
dust evolution in protoplanetary disks. GameDev supports both NVIDIA CUDA and AMD ROCm platforms, provides a smaller-scale standalone Eulerian
dust fluid model, and is publicly available on GitHub.
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Instrumentation and Methods for Astrophysics
SIFARI: Self-Supervised Interferometric Fitting for Astronomical Radio Imaging
Shunyuan Mao, Andrea Isella, Paris Perdikaris et al. (+2 more)
Radio-interferometric images are reconstructed from sparsely sampled visibilities, and CLEAN-based imaging can struggle with spatial filtering, complex morphologies, and uncertainty quantification. Alternative methods that fit visibilities directly can address some of these limitations but often require manual choices of image priors and model hyperparameters. We present SIFARI (Self-Supervised Interferometric Fitting for Astronomical
Radio Imaging), a self-supervised neural network workflow that represents sky brightness as a continuous function of position and fits measured visibilities without an external image training set or explicit spatial regularizer. An empirical rule sets the
Fourier feature scale from the visibilities before training, controlling how readily the network fits fine structure. Sampling network weights with
Stochastic Weight Averaging-Gaussian (SWAG) gives approximate brightness uncertainty estimates, which we combine with a thermal-noise floor to construct spatially resolved signal-to-noise maps. In synthetic ALMA tests, SIFARI yields an effective point-source response about eight times narrower than the natural-weighting CLEAN restoring beam and recovers more extended flux than CLEAN when short baselines are missing. It also achieves higher image fidelity than the restored CLEAN images in all three morphology
benchmarks. Applied to ALMA observations of PDS 70, SIFARI recovers the bright outer ring together with faint compact emission in the central cavity. For long-baseline-only WISPIT 2 data, SIFARI supplies a sky model for phase self-calibration where the CLEAN model is inadequate. The restored, self-calibrated SIFARI image has approximately 30% lower RMS noise than the CLEAN image made from the original visibilities without self-calibration.
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All authors Shunyuan Mao, Andrea Isella, Paris Perdikaris, Li-Ta Lo, Hui Li
Computer Vision
Yunzhe Xu and Zhe Liu
Vision-and-
Language Navigation (VLN) has largely focused on a single
agent following a single instruction, yet many real-world applications require teams of
robots to tackle tasks beyond the capabilities of any individual
agent. We present Systematic Multi-
Agent Vision-and-
Language Navigation, providing, to our knowledge, the first systematic formalization of multi-
agent VLN as a constrained coordination problem: each mission consists of subtasks carrying dependency and resource constraints (presence locks and holding chains). A verified four-stage crafting pipeline instantiates the task as MAVLN, comprising 11,724 episodes across 145 scenes with teams of up to four
agents under three instruction regimes, accompanied by tailored constraint-aware metrics. We further present TRISS, a coordination-ready
navigation system coupling an LLM-based subtask scheduler, a shared topological
memory that turns each
agent's exploration into team knowledge, and a conflict-aware execution mechanism that realizes simultaneous intentions as collision-free routes. Extensive experiments establish TRISS as a comprehensive baseline and reveal substantial room for improvement across scheduling, planning, and execution, highlighting the challenges of coordinating under MAVLN task constraints. Project page: https://xyz9911.github.io/mavln.
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Cosmology and Nongalactic Astrophysics
Current and Future Constraints on the Primordial Power Spectrum
Zachary Cheslog, Emily Finson, Amanda MacInnis et al. (+4 more)
The
primordial scalar power spectrum provides a powerful window onto early-universe physics, including a broad class of inflationary scenarios. These models often predict a characteristic scalar spectral index $(n_s)$, nonzero running $(\alpha_s)$, or more general deviations from a pure power-law form. We find that freeing the number of light relic species $(N_{\rm eff})$ and the sum of the
neutrino masses $(\sum m_\nu)$ broadens the $n_s$ error contours enough that key early-Universe models are no longer excluded. In particular, while both Starobinsky inflation and the Bi-thermal Big Bang model are ruled out at about the 95% confidence level in the six-parameter $\Lambda$CDM model, we find that in the nine-parameter $\Lambda{\rm CDM} + \alpha_s + N_{\rm eff} + \sum m_\nu$ model, CMB data from Planck, ACT, and SPT (CMB-PAS) combined with DESI DR2 give $n_s = 0.9758 \pm 0.0064$ and $\alpha_s = 0.0080 \pm 0.0064$, consistent with both models. Future CMB facilities will sharply improve constraints on $n_s$, $\alpha_s$, and, more generally, the binned
primordial power spectrum $\mathcal{P}(k)$. For example, CMB-PAS constrains $e^{-2\tau}\mathcal{P}(k = 0.2\,{\rm Mpc}^{-1})$ to 0.5%, while SO-like and CMB-HD-like surveys would tighten this to 0.1%; CMB-HD would also extend this measurement to smaller, previously unprobed scales, constraining $e^{-2\tau}\mathcal{P}(k = 30\,{\rm Mpc}^{-1})$ to within a factor of ten. We release our forecast code and update the public CMB-HD likelihood and Fisher codes to support CLASS in addition to CAMB.
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All authors Zachary Cheslog, Emily Finson, Amanda MacInnis, Neelima Sehgal, Niayesh Afshordi, Simran K. Nerval, Renée Hložek
High Energy Physics (Theory)
Type IIB supergravity solutions for polarized IKKT
Eric D'Hoker, Michael Gutperle and Christoph F. Uhlemann
The general local solutions to complexified Type IIB supergravity which are invariant under the complex Lie superalgebra $F(4)$, and which were derived and classified in arXiv:2508.14959, are supplemented here by the construction of their flux potentials and field strengths. We then focus on the Type IIB$^\star$ real form of complex Type IIB supergravity, where we obtain solutions with spacetime metric of the warped product form $dS_{1,5}\times S^2\times\Sigma$. We systematically derive boundary and regularity conditions under which the $dS_{1,5}\times S^2\times\Sigma$ solutions can be analytically continued to regular $S^6\times S^2\times\Sigma$ solutions in Euclidean Type IIB supergravity. Using these results, we construct explicit global solutions. These solutions include explicit realizations of recent proposals for a
holographic description of the polarized IKKT model, and we clarify the charges carried by these solutions. We also obtain novel solutions in the same regularity class with different brane charges.
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General Relativity and Quantum Cosmology
Low Frequency Gravitational Wave Detection with Gravito-Magnetism
Reza Ebadi and Surjeet Rajendran
The detection of gravitational waves in the low-frequency band (10 nHz to 1 micro-Hz) using inner
solar system proof masses is severely limited by Newtonian
gravity gradient noise (GGN) sourced by the asteroid belt. In this paper, we propose a novel detection concept that exploits the relativistic nature of gravitational waves to break the degeneracy between the signal and the asteroid GGN background. The non-relativistic motion of asteroids dominantly sources gravito-electric fields, with velocity suppressed gravito-
magnetic components. Relativistic gravitational waves produce gravito-electric and gravito-
magnetic components of equal magnitude. We propose detecting the gravito-
magnetic component of low frequency gravitational waves using the Lorentz acceleration of test bodies. The measurement of this Lorentz acceleration is metrologically possible due to the fact that expected astrophysical sources of low frequency gravitational waves have considerably higher characteristic strains than the strains typically expected at higher frequencies. We show that this measurement allows for unambiguous extraction of the gravitational wave signal from the
gravity gradient noise in a three satellite constellation. The gravito-
magnetic measurement still requires a proof mass that is well isolated from non-gravitational noise. We propose the use of atom interferometers to serve as such a pristine inertial reference.
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High Energy Physics (Theory)
Allowable complex saddles with real charges in the gravitational index
Fabio Billiato and Gianmarco Esposto
We present a new supersymmetric, non-extremal complexification of asymptotically $\mathrm{AdS}$ black holes, characterized by real charges and multiple complex horizons. We investigate whether these solutions define admissible supersymmetric saddles of the gravitational path integral by applying the Kontsevich-Segal-Witten (KSW) criterion, and compare the resulting gravitational constraints with the convergence conditions of the dual superconformal index. For most of the cases studied, the KSW criterion in the asymptotic region agrees with the index convergence, while the full bulk condition is more stringent and excludes saddles whose chemical potentials lie within the index-convergence domain.
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Strongly Correlated Electrons
Advancing Fuzzy-Sphere CFTs: $\mathrm{SO}(3)$-Rotation-Resolving Exact Diagonalization, 3D Ising Heavy Primaries, and Quasi-Hole-Space Projection
Zheng Zhou and Yin-Chen He
Fuzzy-sphere regularization has recently emerged as a powerful framework for studying three-dimensional conformal field theories (CFTs). In this work, we exploit
symmetry and
Hilbert-space structures to substantially advance this framework. We develop an exact-diagonalization
algorithm that resolves the full $\mathrm{SO}(3)$ rotational
symmetry, reducing computational costs by factors of several hundred. For the three-dimensional Ising CFT, we identify around 100 primary operators, including a large number of previously unknown heavy scalar primaries up to scaling dimension $\Delta\approx16.5$. We also resolve the tension between previous fuzzy-sphere and bootstrap results regarding the parity-odd scalar primary. Furthermore, we identify a branch of scalar primaries associated with $\phi^n$ operators in the $\phi^4$ Lagrangian description, beginning with the identity, $\sigma$, $\epsilon$, $\epsilon'$, and $\sigma'$. Their wave functions exhibit a semi-classical structure closely related to states invariant under area-preserving diffeomorphisms of the sphere. Finally, we show that critical points involving fractional
quantum Hall states can be studied within a substantially reduced
Hilbert space spanned by quasi-hole states of the corresponding model
quantum Hall wave functions like the Laughlin state. This suggests a general strategy for exploring CFTs intertwined with topologically ordered phases.
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Solar and Stellar Astrophysics
Discovery of over a thousand variable stars in Terzan 5 and Liller 1 with JWST
Kevin B. Burdge, Ilaria Caiazzo, Malina M. Desai et al. (+18 more)
The Bulge Fossil Fragments Terzan 5 and Liller 1 host some of the densest
stellar environments in the
Galaxy, yet their variable
star populations have remained largely unexplored due to crowding and heavy obscuration. Here, we identify 1,315 variable sources in these two systems in what is to our knowledge the first JWST time-series variability census of a globular cluster-like object. By differencing consecutive non-destructive reads within each NIRCam integration, we transform sample-up-the-ramp imaging into an infrared movie sampled every 21 seconds. More than a century of observations has cataloged 5,604 variables, the majority of them pulsating
stars, across 151
Galactic globular clusters. Our census alone amounts to 23 percent of that total and contains more photometrically variable binaries than had previously been cataloged in all globular clusters combined. The field of Liller 1, with zero previously known variables, now hosts 915, nearly double the count in the runner-up $\omega$ Centauri. We detect dramatic infrared variability from the Rapid Burster, revealing the counterpart sought since 1976 (see Desai et al. 2026), and blindly recover a signal coincident with the prototype redback
pulsar PSR J1748-2446A at its
radio-timed orbital period, identifying the first optical or infrared counterpart to any of Terzan 5's
pulsars. More broadly, we present a technique that recovers group-level time-series photometry from JWST observations, enabling time-domain studies with an observatory whose field of view is naturally matched to the
Galaxy's densest
stellar systems.
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All authors Kevin B. Burdge, Ilaria Caiazzo, Malina M. Desai, Cristina Pallanca, Vera L. Berger, Kaley Brauer, Matteo Correnti, Paul Draghis, Kareem El-Badry, Francesco R. Ferraro, Denis González-Caniulef, Kyle Kremer, Barbara Lanzoni, Dongzi Li, Jessica R. Lu, Geoffrey Mo, Mason Ng, Roger W. Romani, Kaitlyn Shin, Daniel R. Weisz, Giorgia Zullo
High Energy Physics (Theory)
Solver Agent: an Agentic AI Framework for Theoretical Physics Computations Applied to F-theory Uplifts of O3-planes and S-folds
Eliott Morgensztern, Cesar Fierro Cota and Alessandro Mininno
We introduce Solver
Agent, an AI framework based on large
language models for calculations and proofs in mathematics and theoretical physics. The solution process is tracked through a persistent ledger that records assumptions, derivations, and computations. A central
agent delegates tasks to specialized sub-
agents, while independent
agents verify both intermediate steps and the final result. This setup improves the traceability, reproducibility, and verification of computer-assisted calculations. Applying Solver
Agent, we study global F-theory uplifts of Type IIB orientifolds and their S-fold generalizations. We establish sufficient conditions for Weierstrass models over projective threefolds with terminal $\mathbb{Z}_k$ quotient singularities ($k\in\{2,3,4,6\}$) to give $\mathbb{Q}$-factorial projective elliptically fibered Calabi-Yau fourfolds with isolated Gorenstein terminal quotient singularities. These geometries realize O3-planes and S-folds, where local D3-brane probes of the latter yield four-dimensional $\mathcal{N}=3$ superconformal field theories. Using stringy invariants, we derive fixed-point contributions to Hodge data and Euler characteristics, and show that these Euler corrections determine the localized D3-brane charges required for tadpole cancellation. We illustrate these results using toric hypersurface constructions, where a single three-dimensional polytope determines both the Type IIB Calabi-Yau threefold and the F-theory base; here, the orientifold double cover naturally forms a bisection of an alternative genus-one-fibered uplift with discrete $\mathbb{Z}_2$ gauge
symmetry. Finally, we provide methods for toric computations and four-form flux analysis in four-dimensional $\mathcal{N}=1$ compactifications with non-abelian gauge sectors.
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Cosmology and Nongalactic Astrophysics
LIMFAST. V. Probing Reionization with the Synergy Between 21 cm and Photometric Galaxy Surveys
Guochao Sun, Adam Lidz, Tzu-Ching Chang et al. (+4 more)
Cross-correlating the 21\,cm signal from intergalactic neutral hydrogen with the
galaxy distribution is a powerful probe of the Epoch of Reionization and the physical mechanisms driving it. While upcoming surveys with the SKA-Low
radio telescope and the Roman Space
Telescope offer ideal synergies for this measurement, foreground mitigation of 21\,cm data requires exquisite
redshift precision of
galaxies, effectively excluding the rich photometrically selected samples of Lyman-break
galaxies (LBGs) with typical
redshift uncertainties $\sigma_z \gtrsim 0.1$. We overcome this challenge using a squared statistic of the foreground-cleaned 21\,cm signal. Squaring the filtered 21\,cm signal couples surviving high $k_\parallel$ modes into low $k_\parallel$ fluctuations accessible to photometric LBG surveys. This higher-order cross-correlation statistic remains measurable even when direct cross-correlations are strongly suppressed. Applying Fisher
matrix analysis to this LBG–21\,cm$^2$ cross-correlation signal simulated by the LIMFAST code over $6 \lesssim z \lesssim 10$, we investigate the prospects for constraining EoR physics combining SKA-Low 21\,cm measurements and Roman photometric
galaxy samples. For an overlapping survey area covering 10\,deg$^2$, we find that the LBG–21\,cm$^2$ cross-correlation is detectable at high significance across much of the EoR through 1000\,hours of SKA-Low integration with 15\,MHz bandwidth and a Roman photometric
galaxy sample from the High-Latitude Wide-Area Survey (HLWAS) reaching $m_\mathrm{AB,lim}=27$ and photo-$z$ uncertainties of $\sigma_z \sim 0.1$–0.3. The characteristic sign
evolution of the large-scale cross-power spectrum—driven primarily, though not exclusively, by the evolving neutral fraction—provides strong constraints on the physical parameters governing the ionization and thermal history of the IGM.
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All authors Guochao Sun, Adam Lidz, Tzu-Ching Chang, Claude-André Faucher-Giguère, Steven R. Furlanetto, Aritra Kundu, Jordan Mirocha
High Energy Astrophysical Phenomena
Discovery of the Infrared Counterpart of the Rapid Burster with JWST
Malina M. Desai, Kevin B. Burdge, Cristina Pallanca et al. (+8 more)
The Rapid Burster (MXB 1730$-$335) is the only known
neutron star to produce both Type I and Type II X-ray bursts, making it a key system for understanding
accretion physics onto
neutron stars. It resides in Liller 1, a dense, metal-rich
stellar system whose crowded core and $\sim$11 magnitudes of visual extinction have concealed the Rapid Burster's optical/infrared (OIR) counterpart for nearly five decades. Here, we present infrared observations of Liller 1 obtained with JWST/NIRCam that, for the first time, reveal the unambiguous OIR counterpart to the Rapid Burster. Caught in an X-ray active state, the counterpart exhibits dramatic infrared variability, fading by $\sim$ 2.5 magnitudes in JWST's F200W band (1.755$-$2.227 $\mu$m) with strong fluctuations on minute timescales. These observations provide an infrared anchor for the Rapid Burster and open the way for future spectroscopy and simultaneous IR and X-ray monitoring to constrain the donor's spectral type and the system's
accretion physics.
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All authors Malina M. Desai, Kevin B. Burdge, Cristina Pallanca, Saul Rappaport, Francesco R. Ferraro, Barbara Lanzoni, Mason Ng, Paul Draghis, Emma T. Chickles, Ilaria Caiazzo, Deepto Chakrabarty
Computer Vision
HEIR: Learning Human-Entity Interactions with Functional Roles
Di Wen, Wenhao Guo, Yuedong Tan et al. (+15 more)
Understanding human-entity interactions requires recovering each person-action event's participants, roles, and shared identities. This structure can support
embodied agents by clarifying who acts on which entities and how, informing anticipation and coordination in shared environments. Standard HOI metrics score individual links, leaving complete event composition undermeasured. We introduce HEIR (Human-Entity Interactions with Functional Roles), an image
benchmark for complete grounded participant-role sets across object, interpersonal, and self-directed interactions. It contains 18,730 images, six roles, 105 actions, and 437 nouns, with shared entities, role changes, and repeated fillers; 51.6% of images contain multiple actors and 62.1% contain multiple actions. HEIR pairs relation AP with complete-set AP and structural evaluation. We also introduce CoRISP (Compositional Role-aware Interaction Set Prediction), which uses shared entity identities to combine role-conditioned evidence and predict normalized participant-role sets. Cardinality and role-multiplicity potentials couple assignments through event size and role composition, with exact per-event normalization. Across 16 baselines, relation and complete-event rankings diverge even after aligning action weights. CoRISP leads the evaluated systems on repeated-role events and shared-participant images in HEIR by 2.87 and 3.82 Set mAP points, respectively. On V-COCO, CoRISP achieves 73.72/76.23 role AP and 61.06/68.59 complete-set AP on two-slot actions under Scenarios 1/2. These results show the value of learning and evaluating event composition alongside individual relations. The code and
dataset are publicly available at https://github.com/Kratos-Wen/HEIR.
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All authors Di Wen, Wenhao Guo, Yuedong Tan, Yun Huang, Minheng Wu, Zhihang Chen, Haiwen Sun, Fei Teng, Zhiyuan Gao, Yufeng Zhang, Yuanhao Luo, Jingqi Zhang, Yufan Chen, Junwei Zheng, Ruiping Liu, Jiale Wei, Kailun Yang, Kunyu Peng
Machine Learning
ROSS: Relearning from Self-Generated Rollouts through Selective Supervision
Zhiwei Zhang, Huayu Deng, Fei Zhao et al. (+4 more)
Large
language model post-training generates self-generated rollouts through reinforcement learning and on-policy
distillation, yet this experience is often treated as stale once the policy advances. Historical rollouts can remain compatible with a later policy while preserving behaviors that the policy no longer expresses reliably. However, they may also contain mistakes, abandoned attempts, and redundant actions that should not be imitated, motivating finer-grained selective supervision. We introduce ROSS (Relearning from Self-Generated Rollouts through Selective Supervision), which preserves the full historical trajectory as context while applying loss only to selected model-generated continuations. Across domain-specific reinforcement learning, multi-teacher on-policy
distillation, and agentic reinforcement learning, ROSS consistently improves upstream checkpoints and outperforms baselines across mathematics, code generation, instruction following, and software engineering. On Qwen3.6-35B-A3B, ROSS improves the six-
benchmark MOPD average from 58.40% to 62.20% and SWE-bench Verified from 64.20% to 68.40%. These results show that self-rollout training leaves behind reusable behavioral experience that can yield further gains through offline supervised fine-tuning (SFT), without additional policy rollouts.
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All authors Zhiwei Zhang, Huayu Deng, Fei Zhao, Jiayan Fu, Bin Liang, Kam-Fai Wong, Mu Chuan