Instrumentation and Methods for Astrophysics
The Roman Coronagraph Community Participation Program: data reduction pipeline design and implementation
Jason J. Wang, Maxwell A. Millar-Blanchaer, Marie Ygouf et al. (+39 more)
The Roman Space
Telescope Coronagraph Instrument will demonstrate a series of technologies and techniques to enable the direct detection of reflected-light
planets with space-based observatories. To characterize and validate the performance of the Coronagraph Instrument, the Community Participation Program is developing corgidrp, an open-source Python-based data reduction pipeline. The pipeline can process data from the required and best-effort observing modes and their associated calibration sequences into calibrated science-ready data products. We present the software design and implementation of corgidrp and the motivation behind specific design decisions. We describe the software architecture, data flow, processing steps, automation tools, testing framework, and development philosophy. We also outline future development plans in preparation for on-sky data.
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All authors Jason J. Wang, Maxwell A. Millar-Blanchaer, Marie Ygouf, Julia Milton, Jürgen Schreiber, Kevin J. Ludwick, Ellis Bogat, Amanda Chavez, Eric Shen, Aneesh Baburaj, Ramya Anche, Toshiyuki Mizuki, Taichi Uyama, Ezar Shinbaro, Alexis Lau, Neil T. Zimmerman, Sophie Noiret, William Balmer, Ben J. Sutlieff, Adrien Maillard, Matthias Samland, A J Eldorado Riggs, Clarissa Do Ó, Jingwen Zhang, Giovanni M. Strampelli, Lisa Altinier, Michael Liang, Jessica Gersh-Range, Kylee Fluckiger, John Livingston, Malachi Noel, Dmitry Savransky, Michele Woodland, Tsutsumi Nagai, Justin Hom, Al Niessner, Cynthia Wong, Eric J. Cady, Vanessa P. Bailey, Guillermo Gonzalez, Alexandra Z. Greenbaum, Enrico Biancalani
High Energy Astrophysical Phenomena
The X-Ray Continuum Emission Region in the Lensed Quasar SDSS J133907.23+131038.6 is Much Smaller than the Accretion Disk
Christopher W. Morgan, James B. Margeson, Gilberto Garcia et al. (+4 more)
We analyze microlensing variability in 15 seasons of optical monitoring data and 4 epochs of new X-ray observations of the doubly-imaged gravitationally lensed
quasar SDSS J133907.23+131038.6 to place empirical constraints on the size and structure of that system's X-ray and optical continuum emission regions. Employing a
Bayesian Monte Carlo method, we analyzed ground-based optical light curves to constrain the half-light radius of the far-UV source $\log(r_{\rm 1/2, FUV}/{\rm cm})=15.78^{+0.26}_{-0.28}$ at 193 nm, the rest-frame center of the r-band, assuming a $60^\circ$ inclination angle. This size corresponds to $\sim100\,{\it r}_{\rm g}$ for a $4.0 \times 10^{8} \: {\rm M_{\odot}}$ black hole. We measured the half-light radius of the full band ($0.2-8.0 \: {\rm keV}$) X-ray continuum emission region $\log(r_{\rm 1/2, X_{full}}/{\rm cm})=14.32^{+0.23}_{-0.31}$, a size measurement that is consistent with the radius of the innermost stable circular orbit (ISCO) in the Schwarzschild metric.Two shifted Fe K$\alpha$ lines caused by microlensing are detected in the stacked spectrum of image A at 5.9 and 8.9~keV at $>99\%$ significance.
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All authors Christopher W. Morgan, James B. Margeson, Gilberto Garcia, Xinyu Dai, Luis J. Goicoechea, Vyacheslav N. Shalyapin, George Chartas
Mesoscale and Nanoscale Physics
Local magnetic resonance of scalar spin chirality
Mar Ferri-Cortés and Joaquin Fernández-Rossier
Quantum states with finite scalar
spin chirality carry an orbital
magnetic moment that has eluded direct measurement. We show that a local drive breaks the cyclic
symmetry and activates chirality-changing transitions. We propose two complementary probes: direct chirality resonance and chirality-resolved
spin resonance. Lindblad simulations demonstrate their feasibility in locally addressable
spin platforms, including scanning tunneling microscopy, silicon donors, and
quantum dots.
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Solar and Stellar Astrophysics
Tracking nonlinear solar-wind dynamics over three solar cycles using Wind observations
Dario Javier Zamora and Facundo Maximo Abaca
The
solar wind is a turbulent, weakly collisional
plasma characterized by non-Gaussian fluctuations, long-range correlations, and multifractal dynamics. We investigate the long-term
evolution of these properties using hourly
proton density measurements obtained directly by the Wind spacecraft over 1995–2025. The use of a single-spacecraft
dataset provides an independent test of previous results derived from the multi-spacecraft OMNI database. The three components of the nonextensive $q$-triplet are estimated within one-year sliding windows shifted monthly: $q_{stat}$ from the distribution of density increments, $q_{rel}$ from the decay of the autocorrelation function, and $q_{sens}$ from the multifractal spectrum. Their mean values, $q_{stat}=1.71\pm0.07$, $q_{rel}=4.62\pm0.52$, and $q_{sens}=-0.45\pm0.27$, confirm the persistent presence of heavy-tailed statistics, slow relaxation, and weakly chaotic multifractal dynamics. The parameters nevertheless exhibit distinct temporal variability and relationships with
solar activity. The
Fourier spectrum of $q_{stat}$ contains a dominant period of approximately $10.1$ years, while its correlation with the sunspot number is positive and moderate ($r=0.611$). Correlation and mutual-information analyses show that $q_{stat}$ is primarily associated with
solar proxies, whereas $q_{sens}$ displays stronger relationships with geomagnetic indices and $q_{rel}$ exhibits weaker dependencies. An anomalous enhancement of $q_{stat}$ around 2004 coincides with a sequence of intense interplanetary disturbances, although possible effects related to Wind's orbital transition must also be considered. These findings demonstrate the robustness of the nonextensive description and show that the statistical and dynamical properties of
solar wind
proton density show evidence of modulation by
solar activity.
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Computational Physics
Validating direct solvers for Newton's gravitational N-body problem, and the systematic comparison between IEEE floating point and Posits
Simon Portegies Zwart
We present a systematic comparison between arbitrary precise arithmetic and integration, IEEE-754 compliant floating point arithmetic (fp16, bfp16, fp32, double precision fp64, and quadruple precision fp128), and two implementations of Posits (type III unum) for solving Newton's chaotic N-body problem. Each implementation is benchmarked with arbitrary precise calculations to objectively evaluate their performance in precision as well as speed. We rely on hardware and compiler implementations for fp64, and software implementations for arbitrary-precision arithmetic and Posits. Half precision arithmetic (fp16, bfp16, and Posits$<16,1>$) are insufficiently precise for solving Newton's equations of motion. Single precision (fp32, and Posits$<32,2>$) could be used for statistical ensemble calculations, but lead to relatively large errors in any individual strong encounter. All 64-bit implementations fp64 as well as Posits (Posits$<64,3>$) experience difficulty in our tests. One of the implementations of Posits (Universal) gives precision comparable to fp64 but is slow (by at least an orders of magnitude compared to fp64 after correcting for the more efficient hardware support for the latter). The other (CPPPosits) has a speed comparable to fp64 but has systematically larger errors (by about an order of magnitude compared to fp64 with excesses exceeding two orders of magnitude). As a consequence, this implementation leads to a systematic drift in the result space and has difficulty resolving close encounters. Posits and fp64 have difficulty when integrating a dynamical system in a moving reference frame; testing Galileo invariancy. In their current implementation, Posits do not seem to be the ideal alternative for fp64 when integrating chaotic or stiff ordinary differential equations, such as Newton's equations of motion.
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Optics
Erbium-implanted tellurite waveguides with low-temperature post-implantation activation and signal enhancement
Yuxuan Gao, Batoul Hashemi, Bruno L. Segat Frare et al. (+7 more)
In this paper, we demonstrate erbium ion implantation and signal enhancement in tellurium
oxide hybrid waveguides. Silicon nitride strips with a width of 2 $\mu$m and a height of 100 nm were clad with a 110-nm-thick tellurium
oxide layer to form hybrid waveguides, followed by erbium ion implantation at an energy of 200 keV and a dose of $1\times10^{15} ions/cm^{2}$, with a projected peak implantation depth of approximately 50 nm into the tellurium
oxide layer. After low-temperature annealing at 150 {\deg}C for 30 minutes, the propagation loss decreased from 1.7 to 0.9 dB/cm, while the erbium lifetime increased from 40 $\mu$m to over 800 $\mu$m. We measure a small-signal enhancement of 9 dB in an 11-cm-long waveguide at a wavelength of 1550 nm. These results demonstrate progress towards a low-temperature post-ion implantation process for incorporating erbium and other rare earth ions into tellurium
oxide films for integrated photonic applications.
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All authors Yuxuan Gao, Batoul Hashemi, Bruno L. Segat Frare, Niloofar Majidian Taleghani, Pooya Torab Ahmadi, Henry C. Frankis, Ponnambalam Ravi Selvaganapathy, Jonathan D. B. Bradley, Peter Mascher, Andrew P. Knights
Quantum Physics
Eigenframe Synchronization in Disordered Driven Quantum Ensembles
Saipriya Satyajit, Zechuan Yin, Jner Tzern Oon et al. (+5 more)
Periodic driving underlies many forms of
quantum control, including
spin-based
quantum sensing. However, in an ensemble sensor, one waveform must act on
spins with different detunings, drive amplitudes, hyperfine environments, and local fields. Existing robust-control approaches to such disorder are usually framed in terms of coherence, effective
Hamiltonians, filter functions, or refocusing. Here we identify a complementary
geometric requirement for collective ensemble Floquet control: disorder realizations must share a common Floquet eigenframe. When this condition is met, initialization, protection, signal coupling, and readout are defined in one dressed basis, so the ensemble responds as a collective Floquet sensor rather than as an average over inequivalent driven members. We make this condition measurable with an eigenvector-based synchronization order parameter and a complementary fragmentation metric that quantify the
alignment and spread of Floquet quantization axes across the ensemble. As one realization of this framework, we use a continuous counterdiabatic Floquet drive to derive synchronization criteria and predict resonance-governed breakdown at the first two low-order commensurabilities between the engineered Floquet gap and the drive modulation, with detuning and amplitude disorder producing distinct breakdown channels. Experiments on a nitrogen-vacancy (NV) ensemble in diamond verify the synchronized regime through long-lived collective oscillations, a two-dimensional disorder-robustness map, and breakdown resonances that shift with the modulation rate. Finally, we demonstrate a harmonic-free continuous-drive AC magnetometry protocol whose collective single-tone response is enabled by the synchronized Floquet eigenframe. These results establish Floquet eigenframe synchronization as a measurable condition for disorder-resilient collective control and
quantum sensing.
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All authors Saipriya Satyajit, Zechuan Yin, Jner Tzern Oon, Katrijn Everaert, Smriti Bhalerao, John W. Blanchard, Christopher Jarzynski, Ronald L. Walsworth
Quantum Physics
Hardware-Aware Compilation and Execution of Bivariate Bicycle Codes on Neutral-Atom Systems
Jason Ludmir, Aditya Ranjan, Nicholas S. DiBrita et al. (+2 more)
Quantum computers are noisy; without
quantum error correction (QEC), deep programs fail as
qubits lose information due to decoherence. Among QEC approaches, bivariate bicycle (BB) codes offer low overhead and constant-depth syndrome extraction, while neutral-atom arrays provide scalable, reconfigurable
qubit layouts. However, executing BB-code primitives on neutral-atom systems requires a hardware-aware mapping that respects movement, zoning, and interaction constraints. We present Park-n-Ride, a system for compiling and executing the BB code on neutral-atom processors. Park-n-Ride introduces a module layout and movement model aligned with neutral-atom constraints, exposes a compact BB-native logical interface for compilation, and integrates scheduling mechanisms that enable efficient execution on zoned architectures. By co-designing BB-code abstractions with hardware execution, Park-n-Ride provides a practical path from qLDPC primitives to resource-efficient, high-throughput execution on reconfigurable neutral-atom arrays.
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All authors Jason Ludmir, Aditya Ranjan, Nicholas S. DiBrita, Jason Han, Tirthak Patel
Quantum Physics
Multi-purpose quantum laboratories from superconducting circuits
Arpit Arora, Emily M. Been, William Munizzi et al. (+4 more)
Superconducting
circuits (SCs) are the cornerstone of modern
quantum technology, enabling scalable computing through coherent control of macroscopic
quantum states. Through a legacy that predates modern
quantum computing, SCs have emerged as high-precision instruments for discovery. In this review, we highlight the role of SCs as general-purpose
quantum laboratories, outlining the emerging landscape of correlated matter-
circuit science. We review and unify the capabilities of superconducting
quantum hardware across condensed matter, high energy and
quantum information sciences. We trace the technical
evolution of these architectures, illustrating how their foundational development has culminated in a toolkit for resolving the complexities of macroscopic
quantum states.
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All authors Arpit Arora, Emily M. Been, William Munizzi, Joel Wang, Taylor L. Patti, Aaron Chou, Prineha Narang
Earth and Planetary Astrophysics
Understanding the Energy Input Required for Methane Emission on CWISEP J193518.59-154620.3: A Comprehensive Analysis
Kayla J. Smith, Mark S. Marley, Tommi T. Koskinen et al. (+1 more)
The Y
dwarf WISE 1935 exhibits a thermal inversion in its radiative atmosphere, producing methane emission features in its JWST spectrum, but the physical mechanism responsible for this inversion remains unknown. Using the open-source radiative–convective
equilibrium code PICASO, we model atmospheric heating with Chapman energy deposition profiles to reproduce the observed thermal inversion and methane emission feature. Our models require heating rates of approximately 10^5-10^6 erg cm^-2 s^-1. We show that the atmospheric response depends primarily on the integrated heating deposited in the observable atmosphere, revealing a degeneracy between heating magnitude, vertical extent, and emitting surface fraction. Disequilibrium chemistry lowers the required energy input by lowering CH$_4$ opacity and strengthening the inversion. Comparison with recent electron-beam heating models indicates that reproducing the thermal inversion in W1935 requires substantially greater energy deposition than currently predicted for brown
dwarf auroral heating, while the observed methane emission favors energy deposition near 10^-3-10^-2 bar. Our models also predict a prominent methane emission feature near 7.8 microns, along with energy-sensitive ammonia features near 6 microns, implying a bolometric luminosity greater than that yet measured. Finally, we investigate potential sources of the inferred upper-atmospheric heating. We find that Joule heating would require a strong
magnetic field and large electron densities, the latter supported by external ionization from an unidentified source. We also consider cometary impacts as a possible source of atmospheric heating.
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All authors Kayla J. Smith, Mark S. Marley, Tommi T. Koskinen, James Mang
General Relativity and Quantum Cosmology
Astrophysical Graviton Squeezing Can Be Hidden in the Far-Field
Cheng-Jun Fang, Zong-Kuan Guo, Zhen-Hong Lyu et al. (+3 more)
While localized astrophysical sources can generate macroscopic graviton squeezing, their observable
quantum signatures at far-field detectors remain unresolved. In this work, we investigate the propagation dynamics of the squeezed states using spatial
quantum optics methods to evaluate correlation functions accessible to a local observer. Crucially, we reveal a severe kinematic conflict in same-cone measurements, which highly suppresses local
quantum coherence. Consequently, these macroscopically squeezed states appear classically thermal to a single detector. Our results demonstrate that global squeezing does not guarantee local observability, and the measurable
quantum signatures may be significantly weaker than what would be expected from the overall squeezing parameter of the state.
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All authors Cheng-Jun Fang, Zong-Kuan Guo, Zhen-Hong Lyu, Jing Shu, Yu-Heng Sun, Zi-Zheng Zhou
Astrophysics of Galaxies
Measuring Simulated Circumgalactic Medium Turbulence with Emission-Weighted Projected Velocity Structure Functions in FOGGIE
Helena Bouchereau, Cassandra Lochhaas, Jake S. Bennett et al. (+1 more)
The spatially-resolved kinematics of line emission from the circumgalactic medium (CGM) of a
galaxy can contain information about the CGM
turbulence, which may play an important role in
galaxy evolution. Due to the region's diffuse nature, there have been limited observations of low-
redshift CGM emission until recent efforts that use spatially-resolved emission line kinematics to probe CGM
turbulence. We use velocity structure functions (VSFs) as a measure for the properties of
turbulence using the high-resolution cosmological zoom-in FOGGIE simulations. We focus on the location of the "turnover" in the VSF slope, often used as a measurement of the
turbulence driving scale, and study how resolution, measurement area size, projection effects, and gas temperature influence the inferred CGM
turbulence driving scale. We find that projection significantly lowers the VSF normalization but we do not find significant differences in the slope between 3D VSFs and emission-weighted projected 2D VSFs. We find that the size of the area used to measure the VSF, which can be thought of as the size of the emission nebula for a given instrument sensitivity, correlates directly with the turnover location in the VSF. These dependencies should be considered when using VSFs to interpret CGM
turbulence from emission data, as projection, resolution and sensitivity constraints, and the temperature of the gas probed will all have a measurable effect on the VSF structure and the corresponding inferred turbulent properties.
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All authors Helena Bouchereau, Cassandra Lochhaas, Jake S. Bennett, Mandy C. Chen
High Energy Physics (Theory)
Yu-Ping An, Peng-Bo Ding, Zhen-Han Jin et al. (+1 more)
A long-standing obstacle in
quantum turbulence has been the difficulty of sustaining robust statistical steady states, preventing unambiguous identification of universal
vortex organization and kinetic scaling. We construct such a steady state in two-dimensional
holographic superfluid
turbulence by continuous Landau-instability driving, sustaining ${\sim}2500$
vortices free from transient artifacts. The topological charge structure factor $S_c(k)$ reveals Class I disordered hyperuniformity with $S_c(k)\propto k^{\alpha>1}$ as $k\to0$, where $k$ is the wavenumber. This constitutes the strongest long-range order of its kind and its first observation in a strongly driven, far-from-
equilibrium quantum fluid with topological defects as the organizing principle, establishing a novel non-
equilibrium vortex phase. Exploiting this platform, we resolve the scaling controversy: the apparent $k^{-5/3}$ signature in the kinetic energy spectrum is a narrow crossover between the $k^{-1}$ single-
vortex and $k^{-3}$ core regimes, not a genuine Kolmogorov inertial range. The real-space second-order structure function provides decisive evidence via $S_2(r)\propto \ln r$ where $r$ is the spatial separation, with no $r^{2/3}$ Kolmogorov scaling, ruling out a true inertial cascade. These findings reveal that strongly coupled
quantum turbulence lacks an inverse cascade due to the absence of macroscopic Onsager clusters, demonstrating energy transport fundamentally distinct from weakly coupled superfluids.
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All authors Yu-Ping An, Peng-Bo Ding, Zhen-Han Jin, Li Li
Astrophysics of Galaxies
The VariableTNG project: Unveiling the physical drivers of galaxy quenching
Ignacio G. Alfaro, Antonio D. Montero-Dorta, Hong Guo et al. (+4 more)
Understanding the physical processes that regulate
galaxy quenching is a key challenge in
galaxy formation and
evolution. The VariableTNG (VTNG) project provides a laboratory to investigate these processes, as it systematically varies eight parameters of
galaxy formation while keeping the initial conditions fixed, allowing the effects of individual feedback prescriptions to be isolated. We use interpretable machine-learning techniques as a tool to identify the parameters that most strongly regulate the quenched
galaxy fraction. Our goal is to quantify the relative importance of the
galaxy formation and feedback parameters that regulate the quenched
galaxy fraction at z=0, determine how their influence changes across
stellar mass and environment. We compute the quenched
galaxy fraction for 26 VTNG boxes as a function of
stellar mass, black hole mass, and gas mass, considering both the total
galaxy population and separate samples of central and satellite
galaxies. We train Random Forest regressors to predict the variation of the quenched fraction relative to the TNG100-1 model and use SHAP values to quantify both the magnitude and direction of the influence of each parameter. Our analysis reveals that only a small subset of the VTNG parameters dominates the variance of the quenched fraction. The
stellar feedback wind parameter is the primary driver at low
stellar masses, while its importance gradually shifts toward AGN-related parameters at higher masses. The
supernova temperature also plays an important role at both extremes of the
stellar-mass range. This transition persists when the
galaxy population is divided into central and satellite systems. Comparisons with observational measurements further suggest that variations in these feedback parameters may contribute to the discrepancies between the fiducial TNG100-1 model and the observed passive
galaxy population.
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All authors Ignacio G. Alfaro, Antonio D. Montero-Dorta, Hong Guo, Catalina Riveros-Jara, Kexin Liu, Yikai Liu, Luis C. Ho
Instrumentation and Methods for Astrophysics
A novel technique for reflection coefficient measurement in precision cosmology
Adarsh Kumar Dash, Yash Agrawal, Somashekar R. et al. (+7 more)
The detection of the global 21-cm signal from the
Cosmic Dawn and Epoch of Reionisation remains a challenge to experiments worldwide. Emitted at a rest-frame frequency of 1420.405~MHz, this signal from the early Universe is redshifted to 40-200~MHz with a maximum brightness temperature of a few 100~mK. Efforts to detect this sky-averaged signal include experiments such as the Shaped
Antenna measurement of the background
RAdio Spectrum (SARAS) and Probing ReionizATion of the Universe using Signal from Hydrogen (PRATUSH). Detecting this faint signal requires precise calibration of the
antenna, which includes a high-precision measurement of its reflection coefficient. This measurement must be performed in situ at the observation site, as the
antenna characteristics vary significantly with the environment. PRATUSH, a space-based radiometer, faces the additional challenge of structural distortions induced by thermal cycling, necessitating multiple measurements of the reflection coefficient. This work highlights the development of an in situ Vector Network Analyser, which utilises a novel noise source-based calibration scheme and a cross-correlation spectrometer to perform magnitude and phase measurements of the complex reflection coefficient of the
antenna. Further, we demonstrate the performance of the designed network analyser using independent measurements from a precision network analyser and reflection coefficient modelling of the device under test. We find the level of non-smooth calibration systematics, which need critical control for 21-cm signal detection, to be about $10^{-5}$. Finally, we study the impact of reflection coefficient correction on sky measurements, highlighting its usability for precision 21-cm observations.
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All authors Adarsh Kumar Dash, Yash Agrawal, Somashekar R., Jayadev Ashok T., Keerthipriya S., Vishwapriya Gautam, Saurabh Singh, Mayuri Sathyanarayana Rao, Girish B. S., Srivani K.S
Materials Science
PowderLine: a programmatic powder diffraction analysis application
Adam A. Corrao, Jennifer A. Perez, John D. Langhout et al. (+3 more)
Whole-pattern fitting methods, such as Rietveld refinement, excel at extracting detailed structural, chemical, and microstructural information from powder diffraction data. Obtaining reliable results requires both considerable expertise and software-specific knowledge, and applying these methods at scale typically relies on custom scripts written for each application. High-throughput experiments and autonomous self-driving laboratories increasingly utilize powder diffraction analysis to proceed programmatically and to return structured, machine-readable results. Here, we introduce PowderLine, a Python application that encapsulates a complete refinement into a single declarative recipe, validates that recipe against a versioned schema, and executes it through refinement software to return structured results. The refinement recipe is an all-inclusive, machine-readable and -writable description of either Rietveld or single peak analysis that users, scripts, and automated
agents can specify and run in the same way. As a result of PowderLine's composability, it naturally fits into interactive, scripted, and autonomous workflows alike.
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All authors Adam A. Corrao, Jennifer A. Perez, John D. Langhout, Megan M. Butala, Thomas A. Caswell, Daniel Olds
Earth and Planetary Astrophysics
SCExAO/CHARIS High-Contrast Pre-Launch Vetting of Roman Coronagraph Technology Demonstration PSF Reference Stars
Thayne Currie, Jie Li, Mona El Morsy et al. (+9 more)
We present deep, SCExAO/CHARIS high-contrast integral field spectroscopy and archival imaging of four candidate Roman Coronagraph PSF reference
stars within/near the Roman Continuous Viewing Zone and potentially suitable for the Coronagraph's key technology demonstration targets HIP 71618 and HIP 54515. For CHARIS data, we achieve 5-$\sigma$ contrasts down to $\sim$1.4$\times$10$^{-5}$, $\sim$6$\times$10$^{-6}$, and 10$^{-6}$ to 4$\times$10$^{-7}$ at 0\farcs{}16, 0\farcs{}25, and 0\farcs{}5 to 1\arcsec{}. Companion mass limits rule out brown
dwarfs at $\rho$ $\sim$ 0\farcs{}15–0\farcs{}25 and massive
planets at wider separations around all targets. More critically, for three of the four references our analysis disfavors companions with $V$ band contrasts brighter than 10$^{-8}$, 10$^{-9}$, and $10^{-10}$ at 0\farcs{}15, 0\farcs{}3, and 1$\arcsec{}$. Unless these targets have faint substellar companions within $\rho$ $\sim$ 0\farcs{}15, they likely lack background
stars or companions that could corrupt the Roman Coronagraph's dark hole digging to preclude detecting reflected-light
planets. For $\alpha$ Cep, our limits are a factor of $\sim$10 worse but still meet the TTR5 limit of 10$^{-7}$ beyond $\rho$ $\sim$ 0\farcs{}25: beyond 0\farcs{}4, they exclude a Jupiter-twin reflected-light companion (10$^{-9}$). Archival Keck/NIRC2 data likewise find no substellar companions with $\Delta$V $>$ 10$^{-8}$ at wider separations. Finally, we assess the observability of HIP 71618 and HIP 54515 – updated for Roman's launch date of August 30, 2026. Adding $\gamma$ Boo – not currently in the Roman CPP team reference-
star list – would improve schedulability for the tech demo's key targets.
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All authors Thayne Currie, Jie Li, Mona El Morsy, Olivier Guyon, Julien Lozi, Erica Dykes, Danielle Bovie, Sebastien Vievard, Garima Singh, Kyohoon Ahn, Vincent Deo, Yoshito Ono
Lattice Field Theory
Computing the Critical Temperature of the Affine-Transformed $D=3$ Ising Model Using Masked Autoregressive Flow
Kai Svenson, George T. Fleming, Richard C. Brower et al. (+2 more)
The simple Ising model provides a rich environment to build and study
lattice field theories. As part of an ongoing project to construct a conformal field theory (CFT) on an arbitrarily curved
manifold, in this work we develop methods to measure the critical temperature $\beta_c$ of the affine-transformed Ising model on the face-centered cubic (FCC)
lattice. The main challenge in this endeavor is finding a computationally efficient and accurate method of interpolating and extrapolating Monte Carlo observables with respect to coupling coefficients and temperature. Herein, we compare two such methods. A traditional statistical approach uses the multiple histogram (MH) method, while a newer machine learning approach uses a masked autoregressive flow (MAF) to estimate the underlying probability density function of a set of observables. While the MH method is specifically designed to interpolate and extrapolate Monte Carlo observables, we find that MAF is a viable alternative for measuring $\beta_c$ with a computational cost that scales more favorably. Furthermore, we comment on additional advantages of MAF relevant to our work, such as extrapolating in system volume.
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All authors Kai Svenson, George T. Fleming, Richard C. Brower, Nobuyuki Matsumoto, Rohan Misra
Quantum Physics
Sound and Efficient Certification of High-Quality Qubit Operations: Theory and Experiment
Nikolai Miklin, Jan Nöller, José Martínez et al. (+4 more)
Can a high-quality
quantum gate be certified when uncharacterized state-preparation and measurement errors are dominant? Can this be achieved with low experimental overhead? Here, we introduce a sound black-box certification protocol for a single-
qubit gate based on a small set of fixed, deterministic sequences. From the data, the protocol derives finite-sample bounds on the gate's rotation
eigenvalue, a gauge-invariant property. Its phase reveals the accuracy of the rotation angle, while its modulus quantifies the loss of coherence under repeated gate applications. We implement the protocol on a $^{40}\mathrm{Ca}^{+}$ trapped-ion processor and certify the $\sqrt{\mathrm{X}}$-gate rotation
eigenvalue using $22\,000$
circuit executions, and demonstrate the robustness of certification to state-preparation and measurement errors by deliberately degrading the readout. Finally, we prove that these spectral constraints imply, up to a physically meaningful
unitary change of basis, a rigorous average gate-fidelity lower bound for every time-independent
qubit model compatible with the data. In both readout settings, the spectral bounds yield the same fidelity certificate of $99.94(3)\%$ with $99\%$ confidence. Our results establish a new standard for
quantum-gate certification by combining soundness and experimental efficiency without requiring trusted reference operations, randomized
circuits, or model fitting.
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All authors Nikolai Miklin, Jan Nöller, José Martínez, Lucas B. Vieira, Ulrich Poschinger, Ferdinand Schmidt-Kaler, Mariami Gachechiladze
Earth and Planetary Astrophysics
A Statistical Mechanics Model for Stable Rings Outside the Roche Limit
Jack T. Dinsmore
Stellar occultations have revealed two rings around the
dwarf planet Quaoar outside the Roche limit. Simulations suggest that the rings are sustained by large velocity dispersions. We present the first analytical, first-principles theory that extends the Roche limit to describe planetary rings with large velocity dispersion. The underlying principle is an analogy between a
liquid/gas phase transition and the moon/ring transition: just as high temperatures can boil a
liquid under pressure, high velocity dispersions can stabilize ring systems beyond the Roche limit. We employ statistical mechanics to derive a modification to the Roche limit that treats rings with nonzero velocity dispersion. We demonstrate the new model's consistency with previous simulations of Quaoar's outermost ring. We also note that dense regions of the ring experience negative pressure, which would cause them to shrink over time if the assumptions of the model continue to hold. This could help explain the rings' azimuthal asymmetry.
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High Energy Astrophysical Phenomena
Extreme-Mass-Ratio Inspirals in Gaseous Disks
Alexander J. Dittmann, Abhishek Hegade K. R. and Callum W. Fairbairn
Gravitational waves from extreme mass ratio inspirals (EMRIs) are precise probes of the environment of the supermassive black holes (SMBHs) they orbit. If an SMBH is actively accreting, the surrounding gaseous disk can impart hydrodynamic torques on and assist the formation of EMRIs within it. Such disk-EMRI interactions could leave measurable imprints on future observations by the
Laser Interferometer Space
Antenna (LISA), and potentially provide a route to constrain disk properties using gravitational wave observations. We present herein a detailed relativistic analysis of these hydrodynamic interactions using linear theory. We first derive a Lagrangian governing the
evolution of spiral density waves in the disk and use it to formulate a balance law for the transfer of angular momentum between the EMRI and disk. We then develop a stable numerical scheme which can be used to treat corotation resonances and find modal solutions in thin disks up to very large azimuthal numbers. Using this numerical scheme, we explore how SMBH
spins, EMRI semi-major axes, disk scale heights, sound speed gradients, and surface density gradients affect the interaction between
accretion disks and circular EMRIs. Our results show that relativistic effects substantially alter disk-EMRI interactions once the secondary orbit is within $\mathcal{O}(25)$ Schwarzschild radii from the SMBH. Comparing our numerical results with recent analytical models suggests that the impact of pressure gradients and softening of the gravitational potential is important for disks with finite thickness and cannot be captured by tuning the torque cutoff parameters in the analytical models. The framework provided here will help analyze the formation scenarios of EMRIs and build relativistically accurate waveform models of disk-EMRI interactions.
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Cosmology and Nongalactic Astrophysics
Spectral Fingerprints Beyond Degeneracies in Primordial Gravitational-Wave Sources
Subhasis Maiti
Stochastic gravitational-wave backgrounds from different
primordial mechanisms can exhibit identical peak frequencies and amplitudes, leaving their origin degenerate. We show that this degeneracy can be broken by the broadband spectral response of the gravitational-wave source. By comparing scalar-induced and gauge-field-induced gravitational waves with the same
primordial spectral profile and cosmological
evolution, we isolate the imprint of the tensor-source dynamics. Although both mechanisms exhibit the same infrared scaling, they develop distinct spectral shapes near the peak and different ultraviolet asymptotes. The local spectral index $n_{\rm gw}$ and its running $\alpha_{\rm gw}$ further characterize this source-dependent
evolution, providing a spectral fingerprint beyond the peak observables. These results show that broadband, multi-frequency observations can probe the production mechanism of a
primordial gravitational-wave background even when its peak frequency and amplitude are degenerate.
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Solar and Stellar Astrophysics
Sr and Ba yields of the First Generation(s) of stars: Constraints from metal-poor stars
Sarah Hughes, Anna Frebel, Xiaowei Ou et al. (+6 more)
We present our chemical abundance analysis of ten new extremely metal-poor
stars with $-4.05\leq\mbox{[Fe/H]}\leq-2.33$, based on high-resolution (R $\sim28,000$) Magellan/MIKE spectra. Eight of our
stars have low heavy-element abundances of $\mbox{[Sr/H]}<-4.5$ and $\mbox{[Ba/H]}<-4.0$, making them Small Accreted
Stellar System (SASS)
stars. Four are hyper
neutron-capture-element poor with $\mbox{[Sr/H]}<-5.0$, including
Gaia DR3 5729400267359655680, which sets a new record for the lowest detected Sr abundance of $\mbox{[Sr/H]} =-6.4$. We identify four distinct [Sr/Ba] groups within the wider SASS
star population which span a large range from $\mbox{[Sr/Ba]} =-2.0$ to +1.6, pointing to multiple types of progenitor events and different nucleosynthesis processes/sites. To explore the origins of this large [Sr/Ba] range, we adopt site-agnostic Sr yields of $\mbox{[Sr/H]}=-6$, $-5.75$, $-5.42$, and $-4.93$ for the four groups. Applying those yields suggests that the majority of SASS
stars formed from gas enriched by $\sim$1-10 progenitor events, consistent with expectations from their extremely metal-poor nature. We thus attribute the [Sr/H] abundance scatter to intrinsic variations in the Sr yield per nucleosynthesis site/event. Our proposed Sr yields for each [Sr/Ba] group and associated nucleosynthesis origin are a reasonable and representative approximation, good to within a factor of a few, and can constrain future theoretical heavy element nucleosynthesis calculations in early core-collapse
supernovae.
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All authors Sarah Hughes, Anna Frebel, Xiaowei Ou, Alexander Yelland, Felicia Xiao, Jorian Benke, Kali Kraus, Reidyn Wingate, Mohammad Mardini
High Energy Astrophysical Phenomena
Broadband emission of microquasar remnants
Leandro Abaroa, Gustavo E. Romero and Valentí Bosch-Ramon
Microquasar remnants (MQRs), the long-lived cocoons inflated by extinct microquasar jets, have recently been proposed as hidden
Galactic PeVatrons capable of producing ultra-high-energy gamma rays without an active central engine. While hadronic interactions can account for bright gamma-ray emission from nearby clouds, the direct detection of MQRs remains challenging because their intrinsic emission is expected to be extended and of low surface brightness. In this work, we explore the broadband emission of MQRs by focusing on the leptonic component confined within the cocoon and on particle interactions in the shocked shell surrounding it. We model the injection and time-dependent transport of relativistic particles, including
stochastic re-acceleration driven by internal
turbulence, treated as a second-order
Fermi process. We consider sub-Eddington and super-Eddington microquasar systems and compute the resulting non-thermal emission from
radio to gamma-ray energies, together with the thermal soft X-ray emission produced in the shocked shell. In the super-Eddington case, the intrinsic emission reaches peak values of $\nu L_\nu \sim 10^{35}-10^{36}\,{\rm erg\,s^{-1}}$, whereas sub-Eddington remnants are typically several orders of magnitude fainter. At 1.3 GHz, the modeled cocoon surface brightness is of order $\Sigma_\nu \sim 10^{-19}\,{\rm W\,m^{-2}\,Hz^{-1}\,sr^{-1}}$ for young powerful remnants and decreases rapidly as the remnant evolves. We find that the direct detectability of MQRs is therefore controlled mainly by surface brightness rather than by integrated luminosity. Powerful remnants may be detectable as extended synchrotron
radio cocoons and shell-dominated soft X-ray structures, whereas sub-Eddington remnants are expected to be much harder to identify directly. Our results suggest that MQRs may constitute a hidden population of extended
Galactic non-thermal sources.
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High Energy Physics (Phenomenology)
Quadruple-Higgs boson production at the high-luminosity LHC
Andreas Papaefstathiou and Gilberto Tetlalmatzi-Xolocotzi
We investigate the production of four
Higgs bosons via
gluon fusion at the high-luminosity LHC. We construct a phenomenological analysis of the eight-$b$-jet final state and use a multivariate analysis to derive expected simultaneous constraints on the triple and quartic
Higgs boson self-coupling modifications. At 95% confidence level, the resulting region projects onto $-10.3<c_3<11.2$ and $-222<d_4<234$, where $c_3=\kappa_3-1$ and $d_4=\kappa_4-1$. We also examine how quadruple-
Higgs boson production can enter a triple-
Higgs boson signal region requiring at least six $b$-tagged jets. In addition, we consider two extensions of the Standard Model scalar sector: a one-real-singlet extension yielding the direct resonant process $pp\rightarrow S\rightarrow hhhh$, and a two-real-singlet extension yielding the cascade $pp\rightarrow h_3\rightarrow h_2h_2\rightarrow (hh)(hh)$, where $S$, $h_2$ and $h_3$ are new scalar resonances. For these processes, we derive expected upper limits on the quadruple-
Higgs boson production cross sections as functions of the new scalar masses.
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High Energy Physics (Theory)
Who Writes the Gravitational Second Law of Thermodynamics?
V. R. Shajiee, M. M. Sheikh-Jabbari and V. Taghiloo
We define gravitational
entropy as the manifestly integrable surface charge associated with local transverse Lorentz boosts, entirely bypassing the conventional reliance on spacetime diffeomorphisms. Any notion of
entropy must satisfy the second law. To answer the question posed in the title, an analogy with Newtonian classical mechanics is instructive: Newton's second law of motion is written by inertial observers who are defined by the first law of mechanics. We show that the second law of gravitational thermodynamics is written by free-fall observers with path parameterization in which the non-affinity of the geodesics is equal to the expansion of their velocity vector field. We then provide a proof of the local second law by studying variations in
entropy as viewed by this class of covariantly-defined causal free-fall observers. We show that the
entropy variation is strictly non-decreasing, provided the matter sector satisfies the integrated strong energy condition along the observer path.
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Astrophysics of Galaxies
Diverse ionized gas conditions in a dynamically hot, interacting galaxy at $z = 9.31$ revealed by JWST/NIRSpec IFU
Ryota Ikeda, Takahiro Morishita, Massimo Stiavelli et al. (+1 more)
We present a spatially and spectrally resolved study of an interacting
galaxy, Gz9p3 at $z=9.31$, using the James Webb Space
Telescope NIRSpec/G395H IFU observation with high-spectral resolution ($R\approx 2700$) mode. Gz9p3 consists of two sub-regions (`core' and `tail'), which show stark contrast in their physical properties. The HII regions in the core are characterized by high electron density ($n_{e}\gtrsim2900$ cm$^{-3}$), low gas-phase
metallicity ($0.25$ dex below the mass-
metallicity relation), and yet relatively low specific
star formation rate (sSFR) among the system. On the other hand, the tail exhibits low electron density ($n_{e}<70$ cm$^{-3}$), relatively high gas-phase
metallicity that is consistent with the mass-
metallicity relation, and high sSFR. The integrated spectrum thus shows the properties inbetween these two regions. No evidence of ordered rotation in ionized gas is found, suggesting that Gz9p3 is a dynamically hot system. Finally, we find ionized gas
outflows characterized by the secondary [OIII]5007 line component throughout most of the system. The
outflow velocity is below the escape velocity, making Gz9p3 one of the first
galactic systems experiencing a
galactic fountain. Overall, our findings indicate that this system is in a phase in which the pristine gas is falling efficiently into the core, diluting the gas
metallicity, and enhancing
star formation and
outflows after the
galaxy interaction.
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All authors Ryota Ikeda, Takahiro Morishita, Massimo Stiavelli, Antonello Calabrò
Quantum Physics
Andrew C. Yuan and Nouédyn Baspin
We generalize the unified framework in [Phys. Rev. A 113, 022438 (2026)] to accommodate arbitrary stabilizer codes (referred as non-CSS for emphasis). The generalization has immediate consequences in areas including logical measurement,
quantum weight reduction and Euclidean
embedding. For example, currently CSS (pure $X,Z$-type) logical measurements are well-understood based on the (height-1) cone, while non-CSS (e.g., $Y$-type) logical measurements are ad hoc (e.g., rely on local Clifford transform). Similarly,
quantum weight reduction and optimal Euclidean
embeddings only exist for CSS input codes. Here, we show that our generalized framework addresses this issue, and thus many constructions, including qLDPC surgery, Layer Codes and
quantum weight reduction generalize to non-CSS codes in a relatively straightforward fashion. The previously mentioned examples are derived in detail for clarity.
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Quantum Physics
Basis-update and Galerkin time integration in canonical matrix-product-state form
Maximilian Fröhlich, Richard M. Milbradt, Martin Eigel et al. (+3 more)
Matrix product state
algorithms must enlarge their bond spaces as
entanglement grows and compress them to control cost. We formulate basis-update and Galerkin (BUG) time integration as a sequence of canonical MPS sweeps for
Hamiltonians represented as
matrix product operators. We show when two natural basis updates produce the same trial space and when transporting coefficients between successive bases preserves the represented state. Under these conditions, the existing first-order error bound for uncompressed tree-tensor-network BUG also applies to the alternating-endpoint MPS schedule. We verify the uncompressed implementation against an independent six-site calculation. We then compare BUG with two-site TDVP for 16-site transverse-field Ising and Haldane-Shastry dynamics. At matched timestep and truncation settings, BUG performs fewer local exponential actions and has lower runtime. These settings do not produce equal accuracy. The runtime versus accuracy curves cross for the Ising model and are close for the Haldane-Shastry model. The comparison therefore identifies model-dependent trade-offs rather than a general advantage for either method.
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All authors Maximilian Fröhlich, Richard M. Milbradt, Martin Eigel, Aaron Sander, Robert Wille, Christian B. Mendl
Astrophysics of Galaxies
Interacting stellar winds feeding Sgr A*: from the system of mass-losing stars to the binary IRS 16SW
Diego Calderón, Jorge Cuadra, Christopher M. P. Russell et al. (+3 more)
The discovery of cold structures around Sgr A* has challenged our understanding of the gas dynamics and thermodynamic state of the
plasma in its vicinity. This work aims to constrain the conditions for the formation of such structures, namely the cold disc-like structure and the recently discovered G-1-2-3 complex. We conduct hydrodynamic simulations of the observed Wolf-Rayet
stars feeding Sgr A*. Our simulations show that the
plasma chemical composition is crucial for determining the medium properties. We demonstrate that the formation of a cold disc is possible for chemical compositions that are consistent with observational constraints. However, it is not possible to reproduce all the properties of the observed disc which might suggest the interaction with another structure. Additionally, we present our first results on the hydrodynamic modelling of IRS 16SW as a colliding-wind binary. This is the first step to develop a realistic model on the formation of the G-1-2-3 complex.
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All authors Diego Calderón, Jorge Cuadra, Christopher M. P. Russell, Andreas Burkert, Stephan Rosswog, Mayura Balakrishnan