Earth and Planetary Astrophysics
The exozodi spectral effect: Residual habitable zone dust may bias exoEarth characterization
Miles H. Currie, Christopher C. Stark, Eleonora Alei et al. (+1 more)
All exoplanetary systems are expected to host exozodiacal
dust, or exozodi, originating from planetesimals. For many
stars, exozodi will likely be the largest source of astrophysical noise in direct observations of terrestrial
exoplanets. Nearby Sun-like systems likely have $\gtrsim3$x more habitable zone (HZ)
dust than our
solar system, which must be removed from direct images and spectra to reveal
exoplanet signals. The albedo of this micron-sized
dust varies smoothly over VIS – NIR wavelengths, but exozodi can be composed of different materials that can impact its color. If left unsubtracted, exozodiacal light will add cloud-like continuum emission to extracted spectra, potentially biasing characterization studies by reducing the apparent absorption depth of spectral features. To quantify these effects, we simulate exoEarth systems with a range of exozodi densities and compositions, and apply an atmospheric
retrieval tool to synthetic Habitable Worlds Observatory (HWO) spectra. We find that exozodi at levels similar to the
solar system (i.e., 1 zodi) can reduce the apparent depth of visible wavelength molecular absorption features by up to 50%, an effect that worsens at longer wavelengths. To measure molecular abundances, significant post-processing may be required to remove exozodi to a fractional residual that tightens with
dust density. However, targeting a binary detection result for an absorbing species instead relaxes this requirement by an order of magnitude, especially at higher spectral resolution. Understanding and mitigating the effects of exozodi in extracted exoEarth spectra is critical to characterize HZ
exoplanet environments with HWO and ultimately to search for signs of habitability and life.
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All authors Miles H. Currie, Christopher C. Stark, Eleonora Alei, Aki Roberge
Earth and Planetary Astrophysics
Helium escaping from the atmosphere of a nearby rocky exoplanet orbiting in a habitable zone
Collin Cherubim, Shreyas Vissapragada, Tim Cunningham et al. (+13 more)
Observations of highly irradiated gas
giant exoplanets have shown helium escaping from their atmospheres. There is limited evidence for atmospheres on rocky
exoplanets, perhaps because they have already escaped. We report spectroscopic observations of LHS 1140b, a rocky
exoplanet that orbits in the habitable zone of a nearby low-mass
star. The near-infrared transit spectra show absorption by helium escaping from the
planet's atmosphere. Helium absorption is detected in 2024 but not in 2025, indicating time-variable atmospheric escape. We interpret these results as indicating an upper atmosphere dominated by helium and depleted in hydrogen, with other volatile species trapped at lower altitudes, consistent with atmospheric fractionation models. No helium absorption is detected for LHS 1140c, a smaller and more heavily irradiated
exoplanet in the same system.
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All authors Collin Cherubim, Shreyas Vissapragada, Tim Cunningham, Annabella G. Meech, David Charbonneau, Robin Wordsworth, Aaron Householder, Johanna Teske, Leonardo A. Dos Santos, Nicole L. Wallack, William Misener, Zifan Lin, Andrew McWilliam, Michael Zhang, Jason A. Dittmann, Mercedes López-Morales
Optics · Cross-listed from cs.NI
Transition-Aware Routing in Hybrid Hollow-Core/Single-Mode Fiber Networks: A Cost–Throughput Investigation
Md Ghulam Saber and Zhiping Jiang
Incremental deployment of hollow-core fiber (HCF) in single-mode-fiber (SMF) networks introduces a routing tradeoff: reducing HCF-SMF transitions can improve physical-layer feasibility, but overly transition-averse routing incurs harmful path detours. We study this tradeoff using a common event-driven simulator that compares six protected routing schemes spanning fiber-blind, generalized signal-to-noise ratio (GSNR)-aware, and explicitly transition-aware designs on hybrid HCF/SMF
topologies. The model includes a per-transition GSNR penalty and an exploratory splice-failure availability term. Across six reference
topologies, five HCF deployment fractions, and dynamic loads at 300 Erlang, the strongest transition minimizers, transition-penalty-aware routing (TPAR) and the GSNR/fiber-transition joint scheme (GFJ), halve the mean transition count at a 20-25% carried-traffic penalty. Among the intermediate designs, GSNR- maximal routing with transition-aware reranking (GMR-T) cuts transitions by approximately 22% relative to distance-adaptive routing and spectrum assignment (DA-RSA) at a 3% throughput cost, while bounded-detour TPAR (BD-TPAR) cuts transitions by approximately 11% at only a 1% cost. Deployment pattern also matters: contiguous HCF rollout lowers transitions by approximately 40% on average while improving carried traffic, reducing the benefit of aggressive transition-aware routing. These results support BD-TPAR as a practical default under fragmented deployment, GMR-T as a lower-complexity alternative, and TPAR or GFJ only where the external cost of transitions is high.
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Earth and Planetary Astrophysics
Tidal evolution of packed moon systems around an Earth-mass planet
Alan Briseño, Billy Quarles and Marialis Rosario-Franco
While missions have long targeted terrestrial
exoplanets within the habitable zone of their host
stars, the number of exomoon candidates is expected to grow as next generation space-based observatories achieve the photometric sensitivity required to detect their transit signals. Constraining the stability limits of tightly packed moon systems is therefore essential for transit searches and predicting the number of moons around terrestrial
planets. In our
Solar System, only three moons orbit the terrestrial
planets, motivating the question of whether Earth-mass
exoplanet systems can sustain long-lived, tightly packed satellites. We investigate the stability limits of an Earth-mass
planet orbiting a Sun-mass
star, where the
planet hosts multiple moons. We use the REBOUND N-body integrator along with the tides_
spin module in REBOUNDx to assess the stability of tightly packed systems of Luna-, Pluto-, and Ceres-mass moons across a range of
tidal dissipation parameters, up to $10^{7}$ dynamical orbits of the innermost moon. We find that an Earth-mass
planet can stably host up to two Luna-mass moons, three Pluto-mass moons, or five Ceres-mass moons. Under Earth-like dissipation, the Luna, Pluto, and Ceres packed systems survive within narrow regions of orbital spacing. These results imply that long-lived multi-moon systems around Earth-mass
planets are possible but strongly depend on
tidal dissipation; for these architectures to exist on billion-year timescales, tides must be weaker than those of the present-day Earth-Moon system.
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Fluid Dynamics
Interfacial-Thermo-Fluid-Adhesion Dynamics of Evaporating Capillary Bridges between Curved Surfaces
Arnov Paul, Subhadeep Mondal and Purbarun Dhar
We probe the evaporation mechanism, and the associated adhesion dynamics of
liquid capillary bridges connecting two curved, solid substrates. The coupled thermo fluid species transport and the transient
evolution of capillary adhesion during evaporation are systematically examined. An accurate, fully coupled transient numerical framework is developed, wherein the
equilibrium capillary profiles are first determined from level set method. Next, the evaporation is simulated via Arbitrary Lagrangian Eulerian ALE framework to accurately track the moving
liquid vapor interface. The combined influence of substrate
curvature, surface wettability, and solid thermal conductivity on evaporation and capillary adhesion character is comprehensively analysed. The simulation methodology is robustly validated against published literature for capillary profiles, evaporation rates, and capillary forces, demonstrating good agreement. Our results reveal that the evaporation characteristics of both hydrophilic and superhydrophobic SH
liquid bridges are strongly governed by substrate
curvature and thermal conductivity, and increasing values pose favourable condition for augmented interfacial mass transfer rate. The innately non uniform vapour flux generates spatially varying evaporative cooling, producing surface tension gradients that drive internal thermo capillary circulation. A non dimensional scaling analysis shows that Marangoni flow dominates buoyancy induced flow throughout. Also, increasing substrate
curvature decreases the overall capillary force, owing to the reduced
curvatures of the
liquid bridge, while the temporal
evolution of the adhesion force is strongly influenced by both substrate
curvature and wettability.
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Quantum Physics
Towards a monolithic platform for coupling superconducting circuits to low-loss microwave phonons in AlScN on 4H-SiC
Yuanchen Deng, William W. Roberts, Sueli Skinner-Ramos et al. (+12 more)
Hybrid superconducting-
phonon quantum processing is promising for cavity QED, measurement-based
quantum computing, and other
quantum applications. Relative to microwave
photons at the same frequency,
phonons can provide ultra-compact footprints, extremely low losses, and greater connectivity.
Phonons can also couple strongly to superconducting
circuits through the piezoelectric effect. However, this promise rests on scalable platforms that achieve these benefits without degrading superconducting
circuit performance. This motivates a monolithic platform combining low phononic loss, strong electromechanical coupling, and superconducting-
circuit compatibility without requiring suspended phononics. Here, we characterize a monolithic
quantum acoustic platform combining aluminum superconducting
circuits on exposed silicon carbide (SiC) with piezoelectric aluminum scandium nitride (AlScN) on SiC for integrated phononics. This architecture is enabled by selective removal of AlScN from selected chip regions, allowing aluminum superconducting microwave resonators to be fabricated directly on the SiC while preserving adjacent AlScN-on-SiC regions for
phonon transduction. The resulting Al-on-SiC resonators exhibit a coherent lifetime of 2.9 {\mu}s, demonstrating compatibility with aluminum superconducting
quantum devices. In parallel, cryogenic surface acoustic delay-line measurements on the retained AlScN-on-SiC regions show low phononic propagation loss at 4.05 GHz, corresponding to an estimated
phonon lifetime of 7.6 {\mu}s. Together with a previously demonstrated electromechanical coupling coefficient of about 4.3% and a theoretical upper bound of 8%, these results establish Al-on-SiC/AlScN-on-SiC as a promising monolithic platform for integrating superconducting microwave
circuits with piezoelectric phononic components for
quantum acoustic networking and hybrid
quantum systems.
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All authors Yuanchen Deng, William W. Roberts, Sueli Skinner-Ramos, Dalton Anderson, Katherine Hewey, Xingyu Du, Michael Miller, Brandon Smith, Hwijong Lee, Pingping Chen, Charles Thomas Harris, Roy H. Olsson III, Lisa Hackett, Rupert Lewis, Matt Eichenfield
High Energy Astrophysical Phenomena
Einstein Probe Fast X-ray Transients Extend the Physical Parameter Space of Relativistic Jets
Connery Chen, Yihan Wang and Bing Zhang
Fast X-ray Transients (FXTs) detected by the Einstein Probe (EP) mission possess exceptionally low spectral peak energies compared to typical long (Type II) GRBs. Some of these extragalactic transients show phenomenological similarities to X-ray flashes (XRFs), but the physical origins of FXTs remain uncertain. In this work, we investigate EP-detected FXTs using various jet structures relevant to Type II GRBs and test the hypothesis that these FXTs belong to the intrinsically same population of known GRBs but viewed at large angles from the jet axis. We apply detectability estimates to evaluate their distribution in the observed E_iso-E_p plane. We find that standard single- and multi-component jet structures can reproduce the energetics of off-axis events such as GRB 170817A and low-luminosity GRBs (llGRBs), while also yielding energetics consistent with XRFs at the lower end of the E_iso-E_p continuum for moderately off-axis observers. However, viewing-angle effects of standard Type II GRBs alone cannot account for the E_p values observed in some energetic FXTs. This tension suggests that EP-detected FXTs are unlikely to be explained solely as classical GRBs viewed off-axis, and may instead probe relativistic explosions in a previously underexplored region of parameter space. In particular, these transients may be associated with lower Lorentz factors, reduced angular momentum in the collapsing core, or alternative jet structures and emission mechanisms. Our results motivate further studies to test these scenarios and constrain the physical properties of FXT progenitors and their
outflows.
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Mathematical Physics · Cross-listed from math.AP
Semiclassical measures through Coulomb collisions
Nicholas Lohr
We prove that $\mu$ is a semiclassical measure associated to a sequence of eigenfunctions of energy $E<0$ of the attractive Coulomb operator if and only if $\mu$ is a probability measure on the energy (hyper)surface $\Sigma_E$ invariant under the regularized Kepler flow due to Moser. The converse was shown in recent work by the author, and the present article proves the other direction (as well as an independent proof of the converse). We prove the main
theorem for a general symbol class allowing certain non-decay at infinity, which implies that semiclassical measure mass entirely reflects off of the origin. In the special case of semiclassical measures of sequences of eigenfunctions of the exact Coulomb operator, this article solves an open problem posed by Keraani. The main tools include the celebrated Moser-Fock map along with a technical operator extension lemma in $\Psi_{\hbar}^0(\mathbb{S}^d)$, which utilizes standard eigenfunction concentration bounds.
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Quantum Physics
General theory of monitored Quantum Reservoir Computing
Oriol Morguí-Sancho, Gonzalo Manzano, Gian Luca Giorgi et al. (+1 more)
Quantum reservoir computing (QRC) provides a powerful framework for processing temporal data using
quantum dynamics, but incorporating measurements into the reservoir remains a fundamental challenge and distinctive feature with respect to classical settings. The induced back-action can vary from a source of disturbance to a computational resource, as measurement deeply modifies the dynamics underlying temporal processing. Existing approaches have treated specific monitoring schemes independently, missing the common physical principles governing online
quantum reservoirs. Here we develop a general theory of monitored
quantum reservoir computing based on indirect
quantum measurements, which unifies projective, weak, partial, and dissipative monitoring protocols within a single operational framework. Measurement back-action can serve as a controllable resource, providing the effective dissipation and non-unital dynamics required for successful QRC, even when the underlying unmonitored
evolution is unsuitable. We derive general criteria under which monitored dynamics satisfy the echo-state property, fading
memory, and input separability, including a necessary and sufficient condition for emergent strict contractivity. By comparing different monitoring schemes under a common reference dynamics, we show that these protocols are not interchangeable parameterizations to be optimized for peak performance, but rather constitute qualitatively distinct routes to computational capability, each enabled by the interplay between information extraction and measurement-induced disturbance – a trade-off that can be further shaped through time multiplexing. Our results provide a unified theoretical foundation for online monitored
quantum reservoir computing and establish
quantum measurement engineering as a systematic approach for designing reservoir architectures across different
quantum platforms.
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All authors Oriol Morguí-Sancho, Gonzalo Manzano, Gian Luca Giorgi, Roberta Zambrini
Quantum Physics
An end-to-end quantum algorithm for weakly nonlinear plasma physics with superquadratic speedup
Bjorn K. Berntson, David Jennings, Matteo Lostaglio et al. (+1 more)
Nonlinear kinetic
plasma simulation is high-dimensional and classically demanding, while
quantum algorithms face different bottlenecks:
embedding nonlinear dynamics into a linear computation, loading dense field-interaction data, and efficiently extracting information. We present an end-to-end
quantum algorithm, with rigorous convergence guarantees, for a weakly nonlinear kinetic
plasma model. The system describes a 3D electron-ion
plasma with adiabatic electrons, kinetic ions, Debye screening, and Krook relaxation. After
Fourier-Hermite truncation, the dynamics reduces to a high-dimensional quadratic ordinary differential equation. To tackle
quantum bottlenecks we combine three key ingredients. First, we use a
plasma free energy to identify a Lyapunov transform under which a Carleman linear
embedding converges exponentially in the truncation order within a certified weakly nonlinear regime. Second, we develop a hierarchical block-encoding protocol for dense
matrices, exploiting the spatial decay of the field to avoid
polynomial overhead from sparse access encodings. Third, we introduce a subroutine for information extraction that exploits nonlinear components encoded in the full Carleman history state to improve the estimation of linear observables. We construct a
quantum algorithm to estimate the spacetime-averaged kinetic energy using $\widetilde{O}\!\left( N_F N_H^{1/2} \operatorname{polylog}\!\left(\frac{T}{\epsilon}\right)\frac{1}{\epsilon}\right)$ gates and $\widetilde{O}\!\left(\log\!\left(N_F N_H^{1/2}T\right)\log\!\left(\frac{1}{\epsilon}\right)\right)$
qubits, where $N_F$ and $N_H$ are the
Fourier and Hermite cutoffs. Relative to a
Fourier-Hermite spectral solver, this yields exponential
memory savings and superquadratic improvements in time. Together, these results establish a controlled nonlinear
plasma benchmark for
quantum simulation.
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All authors Bjorn K. Berntson, David Jennings, Matteo Lostaglio, Scott Parker
Solar and Stellar Astrophysics
Positive superhumps in high mass ratio cataclysmic variables driven by apsidal disk precession
Rebecca G. Martin, Stephen H. Lubow, David Vallet et al. (+1 more)
Previously it has been assumed that a cataclysmic variable (CV) disk can only become eccentric and display superhumps if the 3:1 resonance is located within the disk. This requires the binary mass ratio to be $q=M_2/M_1\lesssim 0.33$, where $M_1$ is the mass of the white
dwarf and $M_2$ is the mass of the companion
star. However, several systems with higher mass ratios have been observed to exhibit positive superhumps, posing a challenge to this picture. We present the first 3D hydrodynamic simulations to show that eccentricity growth can occur in CV disks even when the resonance radius lies outside the disk. The finite width of the 3:1 resonance extends into the outer parts of the disk and drives eccentricity. While high mass ratio CVs more commonly show negative superhumps, our linear analysis reveals that the direction of apsidal precession is highly sensitive to the disk outer radius and surface density distribution. Smoothed particle hydrodynamic simulations tend to suppress eccentricity gradients and favor prograde precession. These results provide a natural explanation for positive superhumps in high mass ratio CVs and show that disk structure, rather than the resonance location alone, controls the emergence of superhumps.
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All authors Rebecca G. Martin, Stephen H. Lubow, David Vallet, Stephen Lepp
Physics Education
Assessing AI in Introductory Physics Problem Solving
Amir Bralin and N. Sanjay Rebello
Reasoning or inference-scaling models are the new generation of Large
Language Models (LLMs) capable of complex problem solving. To investigate their problem-solving capability in physics, we evaluated model o4-mini by OpenAI on solving traditional, end-of-chapter problems from Halliday and Resnick's "Fundamentals of Physics," spanning core topics in the undergraduate physics curriculum. Performance was analyzed across modality and problem difficulty. The model solved the problems with overall accuracy of about 90%, but performance depended strongly on representation: accuracy was much higher on text-only problems (96%) than on problems requiring coordinated interpretation of text and images (79%). Accuracy also declined significantly as the problem difficulty increased from low to medium to high. These results show that state-of-the-art LLMs can solve much of the standard introductory physics problems, but that their performance remains uneven and constrained by problem modality and problem difficulty.
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High Energy Physics (Phenomenology)
Production Effects and Final-state Interactions in $\pi_1 \to 3\pi$
D. Winney, S. Gonzàlez-Solís, M. Mikhasenko et al. (+8 more)
We investigate the $\pi_1(1600)$ signal channel of $3\pi$ in the $J^{PC} = 1^{-+} \,[\pi\pi]_{1^{--}}\pi~P$-wave. This channel has recently been analyzed by the COMPASS collaboration using the “freed-isobar" technique which provides direct experimental access to the lineshape modifications of the $P$-wave $\pi\pi$ sub-channel arising from both final state interactions and production processes such as the Deck mechanism. We motivate a unified formalism combining production effects and final state interactions using the Khuri-Treiman formalism, which is consistent with low-energy unitarity, analyticity, and crossing
symmetry, seeded by an initial production amplitude. We demonstrate that the precise lineshape of the $\pi\pi$ mass spectrum can be used to determine the relative strength and complex phase of different production mechanisms contributing to the $3\pi$ final state. We conduct a global fit of the $\pi_1$ freed-isobar data set, yielding a multi-dimensional parameterization of the $\pi_1\to3\pi$ decay amplitude at COMPASS as a function of both decay and production variables. We identify the contributions from short-range production and the Deck mechanism and extract the total $3\pi$ invariant mass dependence which will be important for a future extraction of the $\pi_1$ pole position in the $\rho\pi$ channel.
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All authors D. Winney, S. Gonzàlez-Solís, M. Mikhasenko, Ł. Bibrzycki, C. Fernández-Ramírez, V. Mathieu, G. Montaña, A. Pilloni, L. Qiu, A. Rodas, A. P. Szczepaniak
Fluid Dynamics
Orientation Dynamics of Rigid Fibers in a Microfluidic Burgers-like Vortex
Marine Aulnette, Mathis Coutadeur, Clément Bielinski et al. (+2 more)
Fiber suspensions are common in biological and environmental flows and are widely used in industrial applications. Fiber transport and orientation dynamics are affected by interactions with the surrounding fluid and strongly depend on the nature of the flow. The complexity of realistic flows, which are often heterogeneous or time-dependent, hinders a full understanding of fiber dynamics. In this study, we combine microfluidic experiments, theory and numerical simulations to investigate the orientation dynamics of rigid neutrally buoyant fibers in a well-controlled model system, a streamwise stationary
vortex at moderate Reynolds number. Despite the three-dimensional nature of the flow, the orientation dynamics are remarkably simple: the fiber orientation is accurately described by Jeffery equations coupled with the Burgers-
vortex model over a large range of particle Reynolds number. We show that fibers undergo uniform precession about the
vortex axis driven by fluid vorticity while simultaneously aligning with the latter due to strain in the
vortex core. These two motions are decoupled, with the
alignment timescale determined by the local strain rate and the fiber aspect ratio. Finite particle size and inertia induce weak deviations from the base flow streamlines while leaving the orientational dynamics largely unaffected. These results establish a simple framework for understanding the behavior of elongated particles in stretched
vortex flows, which constitute key building blocks of
turbulence.
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All authors Marine Aulnette, Mathis Coutadeur, Clément Bielinski, Blaise Delmotte, Anke Lindner
Quantum Physics
Disorder-enhanced compressibility of Floquet random quantum circuits
Francesca De Franco, Dante M. Kennes, David J. Luitz et al. (+2 more)
Current
quantum hardware is limited by noise and decoherence, which restrict the depth of
unitary circuits that can be implemented with high fidelity. We investigate how the compressibility of time-
evolution operators depends on the dynamical regime of the underlying many-body system. As a testbed, we study a one-dimensional Floquet random
circuit with a tunable competition between interactions and on-site disorder. Using tensor-network simulations, we characterize operator growth through the operator-
entanglement entropy of the Floquet
unitary as well as of out-of-time-ordered correlators (OTOCs). We find rapid operator scrambling at weak disorder, while strong disorder leads to slow OTOC-front propagation and logarithmic or near-logarithmic operator-
entanglement growth over the accessible time window. We then optimize shallow brickwall
circuits to approximate the Floquet
evolution and show that strong-disorder
circuits can be compressed to substantially smaller depths than weak-disorder
circuits at fixed logarithmic fidelity density. These results suggest that localized or slowly scrambling dynamics provide a favorable regime for compressed
quantum simulation on noisy devices.
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All authors Francesca De Franco, Dante M. Kennes, David J. Luitz, Matteo Rizzi, Markus Schmitt
Instrumentation and Methods for Astrophysics
Enhancing WISE Infrared Imaging to Spitzer Resolution Using Deep Learning Super-Resolution
Saeed Rezaee, Shoubaneh Hemmati, Bahram Mobasher et al. (+5 more)
We present a deep-learning framework that performs 4.6x spatial super-resolution from WISE W1 (3.4 micron) toward Spitzer IRAC Ch1 (3.6 micron), and characterize its behavior on the COSMOS field. We train on ~390,000 paired cutouts drawn uniformly within the WISE/Spitzer overlap and report all metrics on a held-out test set of 83,592 cutouts. The framework uses a convolutional neural network trained with a loss function that emphasizes accurate recovery of sources in crowded fields. The model recovers the total flux of the central source in a fixed aperture to a median relative error of 11%, a factor of ~2 better than the interpolation baselines; the gain reaches ~3x on the faintest quartile. The brightness dependence is monotonic: the aperture integrated flux error decreases from 13% on the faintest quartile to 8% on the brightest. At the 3-5 arcsec separations where WISE blends sources that Spitzer separates, the model recovers 35% of the source peaks detectable in the Spitzer truth compared with 9% for interpolation. The characteristic failure mode is oversmoothing of source profiles, which biases integrated flux measurements upward; this pattern is qualitatively similar to that of the interpolation baselines but is quantitatively smaller for the trained model. These results suggest genuine resolution enhancement and source deblending, providing a path toward applying super-resolution across the all-sky area that Spitzer could not cover. An appendix replicates the analysis at W2 -> IRAC Ch2 with consistent results; the trained model and code are publicly available.
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All authors Saeed Rezaee, Shoubaneh Hemmati, Bahram Mobasher, Naveen A. Reddy, Tara Fetherolf, Alexander de la Vega, Negin Moharrami Allafi, Sina Miri
Solar and Stellar Astrophysics
Preferential alignment of Class 0, Class I protostellar disks in multiple systems across nine nearby molecular clouds
Cheng-Han Hsieh, Aleksey Generozov, Stella S. R. Offner et al. (+6 more)
Protostellar disk orientations in multiple systems provide critical insights into the primary mechanisms that govern the formation of multiple-
star systems, their subsequent dynamical
evolution, and their impact on
planet-forming disks. We present a disk
alignment study of 512 Class 0, Class I, and flat-spectrum protostars across nine nearby molecular clouds within 500 pc, utilizing data from the CAMPOS and VANDAM surveys. Our sample includes 74 binaries and 31 high-order multiple systems. We find that multiple systems with projected pair separations up to 6000 au exhibit preferential disk
alignment with respect to each other across all evolutionary classes, deviating significantly from the random distribution predicted by turbulent fragmentation models. This suggests that the formation of multiple systems cannot be explained by turbulent fragmentation alone. Disk
alignment on scales of a few thousand au is also difficult to explain by disk fragmentation as the dominant origin. We further find that the degree of nearest-neighbor disk
alignment in higher-order multiples is comparable to that in binaries. Finally, we identify a significant deficit of flat-spectrum protostellar disks in high-order multiple systems as compared to younger Class 0 and Class I phases. The decline is consistent with rapid dynamical
evolution, in which most higher-order systems dissolve by the end of the Class I phase.
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All authors Cheng-Han Hsieh, Aleksey Generozov, Stella S. R. Offner, Héctor G. Arce, Jaime E. Pineda, Michael M. Dunham, Diego Mardones, Dominique Segura-Cox, Bethany Grimm
Quantum Physics
Real-Time Detection of Charge Jumps in Superconducting Qubits with a Convolutional Neural Network
Daniel Gaytan-Villarreal, Peter Meiring, Daniel Baxter et al. (+6 more)
Ionizing radiation from
cosmic rays and gammas can induce discontinuous jumps in the environmental charge of superconducting
qubits (charge jumps), causing correlated errors that challenge fault-tolerant
quantum computing while simultaneously providing a detection signature for
quantum sensing applications. Current detection methods operate offline, introducing latency incompatible with in-the-loop
qubit control. In this paper, an online detector of charge jumps for superconducting
qubits, based on a dilated causal convolutional neural network (DCCNN) designed for in-the-loop deployment on the
Quantum Instrumentation Control Kit (QICK) platform, is presented. The network is trained on synthetic Ramsey
tomography scans generated from
qubit templates measured at the Northwestern Experimental Underground Site (NEXUS) at Fermilab, and translated to FPGA firmware via hls4ml with ap_fixed$\langle 16,6 \rangle$ quantization, reaching a per-inference latency of $ 32.0 \mu$s on the Zynq UltraScale+ RFSoC ZCU216. At this operating point the DCCNN matches the detection efficiency of the established offline $\chi^2$
algorithm ($0.843 \pm 0.022$ vs. $0.868 \pm 0.007$ on $|\Delta q| \in [0.1, 0.5] e$ at matched false-positive rate), while requiring no per-
qubit hyperparameter tuning. This shifts charge-jump detection from a post-hoc diagnostic to a control-loop primitive, enabling adaptive protocols that respond to radiation-induced events in situ, with applications to
quantum-computing error mitigation and to the use of superconducting
qubits as particle detectors.
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All authors Daniel Gaytan-Villarreal, Peter Meiring, Daniel Baxter, Daniel Bowring, Grace Bratrud, Matteo Cremonesi, Giuseppe Di Guglielmo, Grace Wagner, Bowen Xiao
Instrumentation and Methods for Astrophysics
Expanding the SPISEA Stellar Population Synthesis Software to the Substellar Regime
Caitlin Begbie, Rachel Street, Katarzyna Kruszynska et al. (+4 more)
We present an extension of the SPISEA
stellar population synthesis framework that adds brown
dwarfs to the existing range of
stellar mass objects, enabling physically consistent modeling of brown
dwarfs within synthetic
star clusters. Previous versions of SPISEA included limited substellar support, relying on outdated initial mass functions and incomplete atmospheric and evolutionary coverage below the hydrogen-burning limit. This was addressed through the implementation of a modern substellar initial mass function based on robust observational constraints, the introduction of merged atmospheric grids that smoothly transition between
stellar and brown
dwarf regimes, and the construction of unified evolutionary tracks spanning the lowest-mass brown
dwarf objects through massive
stars at
solar metallicity. The updated framework was validated by comparing simulated color-magnitude diagrams to observational data from the Pleiades, Upper Scorpius, and M44 clusters using
Gaia, UKIDSS, and 2MASS photometry. The new models allow for generation of user-specified isochrones and clusters that reproduce observed
stellar behaviors while enabling realistic population synthesis in the brown
dwarf regime. This work extends SPISEA's applicability to substellar science cases, including young cluster studies and microlensing simulations, and provides a foundation for future incorporation of planetary-mass objects and non-
solar metallicities.
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All authors Caitlin Begbie, Rachel Street, Katarzyna Kruszynska, Jessica Lu, Matthew Hosek Jr., Natasha Abrams, Macy Huston
Instrumentation and Detectors
Comprehensive study of timing resolution in plastic scintillator detectors with wavelength-shifting fiber and silicon photomultiplier readout
Haohui Che and Guang Yang
We present a comprehensive study of the timing resolution achievable in plastic scintillator detectors read out through wavelength-shifting (WLS) fibers coupled to silicon photomultipliers (SiPMs), combining a semi-analytical framework, toy Monte Carlo validation, and full Geant4 optical
photon simulation. The analytical model traces the complete
photon detection chain: scintillation emission, WLS fiber re-emission, optical transit time dispersion, SiPM single-
photon time resolution, and electronics quantization. It expresses the timing resolution $\sigt$ as a function of the detected photoelectron yield $\Npe$, scintillator decay constants ($\taur$, $\taud$), WLS re-emission time ($\tauwls$), fiber numerical aperture, detector geometry, and readout electronics parameters. The analytical predictions are validated at two levels. First, toy Monte Carlo simulations ($2\times 10^5$ events per parameter point across 80 grid points spanning 8 fiber types and $\Npe$ from 5 to 200) achieve analytical-to-MC agreement of \add{$1.0000 \pm 0.0018$}. Second, full Geant4 optical
photon simulations track the entire scintillation, wavelength-shifting, and fiber transport chain in realistic detector geometries, confirming the analytical timing predictions\add{ to within 10–20% for $\Npe \gtrsim 10$} and providing first-principles photoelectron yield calibration. A comprehensive parameter scan covering 7 scintillator materials, 8 WLS fiber types, 5 SiPM models, 5 electronics configurations, 3 readout
topologies, and 3 boundary conditions produces quantitative design maps and lookup tables for detector optimization.
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High Energy Physics (Theory)
Dynamical Entropy Is a Noether Charge
V.R. Shajiee, M.M. Sheikh-Jabbari and V. Taghiloo
Black hole thermodynamics for generic dynamical, non-
equilibrium regimes remains a fundamental challenge. We establish dynamical
entropy as the Noether charge associated with a generic evolving null surface subject to Dirichlet boundary conditions. We specify the
symmetry generator associated with the dynamical
entropy, which is a null vector on the null surface, upon requiring physically motivated
geometric conditions that yield a notion of “dynamical zeroth law.” We prove that this Noether charge density satisfies the second law of thermodynamics strictly at each instant in time, bypassing the teleological final conditions traditionally required by event horizons. Thus, we extend and generalize the notion of dynamical
entropy introduced in \cite{Hollands:2024vbe}, in some different ways: We do not impose background stationarity; our dynamical
entropy and the associated second law are local in time and work for generic dynamical gravitational systems.
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Computational Physics · Cross-listed from math.NA
A structure-preserving Numerical Method for the Compressible Resistive-Hall-MHD System
Murtazo Nazarov, Rafael Rodriguez-Velasco and Ignacio Tomas
In this paper, we present a structure-preserving method for the compressible resistive
Hall-magnetohydrodynamics (MHD) model. The differential operator is split into two parts: a hydrodynamic part consisting of the compressible Euler equations, and a
magnetic part consisting of a system coupling the Lorentz force and the induction equation. The method uses continuous Lagrange elements for the Euler part and a curl-conforming finite element space for the
magnetic part. The hydrodynamic part preserves the positivity of the density and internal energy, the conservation of total energy, and the minimum principle for the specific
entropy. Owing to the choice of finite elements, the
magnetic part preserves the divergence involution constraint. The fluid part is solved using explicit strong-stability-preserving Runge-Kutta (SSP-RK) methods, whereas the
magnetic part is solved by Crank-Nicholson method, which requires using Newton's method. Coercivity estimates for the Jacobian of the corresponding Newton iteration are presented. We introduce a high-order artificial resistivity to improve the conditioning of the nonlinear residual and the invertibility of the Jacobian. Several challenging
benchmarks, including a smooth whistler wave, the Orszag-Tang
vortex for comparing resistive MHD with resistive
Hall-MHD, and a
magnetic reconnection problem, are solved to validate the robustness and accuracy of the method.
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High Energy Physics (Theory)
Non-Hermitian Holographic Flows to Little Rip Cosmologies
Daniel Arean, David Garcia-Fariña and Juan F. Pedraza
Spacelike singularities supported by matter satisfying the null energy condition (NEC) are expected to fall within the Belinski–Khalatnikov–Lifshitz (BKL) paradigm. We show that controlled violations of the NEC in holography can lead to different black hole interiors. In a
holographic model dual to a strongly coupled non-Hermitian $\mathcal{PT}$-symmetric QFT, we uncover a novel non-Kasner regime within its real, $\mathcal{PT}$-restored phase. The deep-interior geometry describes an isotropic FLRW cosmology undergoing super-accelerated expansion and approaching a Little Rip. This regime leaves a characteristic imprint on two-sided heavy-operator correlators, allowing it to be distinguished from a standard Kasner interior. Our construction provides a concrete
holographic realization of a Little Rip cosmology and lays the groundwork for a Little Rip/CFT correspondence, in which such cosmological regimes can be explored through observables in a non-Hermitian
quantum field theory.
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Optics
High-resolution single-molecule mass measurement of megadalton assemblies in solution
Tereza Roesel, Evangelos Efraimidis, Niklas Hansen et al. (+5 more)
Resolving heterogeneity in megadalton assemblies requires precise single-molecule mass measurements in solution. Mass photometry infers mass from individual molecular surface-landing events, and event-to-event measurement variability limits precision. Nanofluidic scattering microscopy overcomes this limitation by continuously tracking molecules in motion, enabling repeated sampling and temporal averaging of these fluctuations. Benchmarking with 4.5 MDa DNA origami demonstrates up to a fourfold improved resolution, approaching the performance of ensemble-averaged native mass spectrometry.
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All authors Tereza Roesel, Evangelos Efraimidis, Niklas Hansen, Yulia Yancheva, Miroslav Hekrdla, Katarzyna M. Tych, Vladimira Petrakova, Barbora Spackova
Quantum Physics
Worldline-Susceptibility Scheduling for Quantum Annealing Beyond Local-Adiabatic Evolution
Suraj Singh, Lakshya Nagpal, Vikas Chauhan et al. (+1 more)
The performance of
quantum annealing depends critically on how the available annealing time is distributed along the
evolution. Although the Roland Cerf local adiabatic schedule is theoretically optimal, it requires complete knowledge of the instantaneous spectral gap, making it impractical for large optimization problems. We propose a computationally inexpensive surrogate schedule based on the worldline magnetization susceptibility measured during simulated
quantum annealing. The susceptibility is obtained directly from
equilibrium Monte Carlo sampling and identifies the critical region of the anneal without requiring spectral information. Using exact diagonalization of Sherrington Kirkpatrick
spin glass instances as ground truth, we show that the resulting schedule consistently outperforms conventional linear annealing and, for a substantial fraction of instances, also surpasses the exact Roland Cerf schedule. We demonstrate that this unexpected behaviour originates from two finite time failure modes of exact local adiabatic scheduling a boundary gap trap, in which the minimum spectral gap occurs at the end of the anneal, and an oscillatory instability caused by excessively localized time allocation around an interior minimum gap. These results suggest that robust scheduling based on inexpensive
equilibrium observables can outperform exact spectral gap based strategies under realistic finite time conditions. The complete methodology is implemented in the open source Qanneal framework.
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All authors Suraj Singh, Lakshya Nagpal, Vikas Chauhan, S.R. Hassan
General Relativity and Quantum Cosmology
Acceleration radiation and HBAR thermodynamics for atoms falling into a BTZ black hole: A CQM quantum-optics approach
H. E. Camblong, A. Chakraborty, C. R. Ordóñez et al. (+3 more)
Atoms falling freely into a Bañados-Teitelboim-Zanelli (BTZ) black hole in a Boulware-like
vacuum are shown to emit radiation with a Planck spectrum at the Hawking temperature $T_{H}$. This leads to thermal Hawking-like radiation for a cloud of falling atoms prepared with random initial times. Moreover, the radiation is related to the relative equivalence principle, with the
vacuum field modes accelerated with respect to the falling atom. The physics of the atom-field interactions is most easily described within a
quantum optics approach, where each atom can be interpreted as a detector. Despite the topological nature of
gravity in $(2+1)$ dimensions, the thermodynamic and radiation properties of BTZ black holes are still universally governed by the same near-horizon conformal
quantum mechanics (CQM) applicable to higher-dimensional
gravity. This universal conformal behavior is exhibited by all fields in the background of generic black holes, and generates an HBAR
entropy $S_{\mathcal P}$ associated with the
photon radiation field that mimics the Bekenstein-Hawking
entropy $S_{\mathrm{BH}}=A/4$, proportional to the black-hole horizon area, and with the correct $1/4$ proportionality factor.
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All authors H. E. Camblong, A. Chakraborty, C. R. Ordóñez, M. O. Scully, G. Valdivia-Mera, H. Wang
Cosmology and Nongalactic Astrophysics
Cosmological $\gamma$-$\gamma$ Pair-Production Background
Mika A. Gelowicz, Thomas Siegert, Saurabh Mittal et al. (+10 more)
The origin of positrons is one of the unsolved puzzles in astrophysics as the majority of sources are still unidentified. The
Cosmic Photon Background (CPB) is the isotropic radiation spanning the entire electromagnetic spectrum. Interactions of the CPB with itself may pose a promising source of positrons and secondary emission. We calculate the electron-positron pair production rate from the $\gamma$-$\gamma$ pair-production of the CPB with itself for
redshifts $z \leq 10$, and determine the annihilation spectrum, Inverse Compton emission, and bremsstrahlung. The CPB is decomposed into a sum of gray body functions, of which each is being evolved according to source type luminosity functions and
redshift. We compute the pair-production rate by integrating the angle- and energy-dependent cross section over the evolving CPB. The pairs produced at each
redshift are then propagated towards $z=0$, taking into account a cosmological, intergalactic, energy loss function. The
photon emission is calculated per
redshift and then line-of-sight integrated towards a contribution of the
Cosmic Gamma-Ray Background (CGB) today. The resulting pair-production emissivity increases steeply from $z=0$ of about $2 \times 10^{-36}$ to a peak of $1.8 \times 10^{-31}\,\mathrm{e^\pm\,cm^{-3}\,s^{-1}}$ at $z=2.7$, then declines again. This yields a total
cosmic pair-production rate on the order of $10^{54}\,\mathrm{e^\pm\,s^{-1}}$ up to
redshift $10$. The secondary emission of pairs experiencing Inverse Compton scattering off the CPB results in a sizable contribution to the CGB. The pairs from cosmological $\gamma$-$\gamma$ absorption provide a minimum level of secondary emission which needs to be taken into account for any CGB study. Especially in the range from 1 MeV to 1 GeV, this background can make up 20% of the total CGB emission and may substantially reduce the gap between MeV observations and models.
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All authors Mika A. Gelowicz, Thomas Siegert, Saurabh Mittal, Laura Eisenberger, Dimitris Tsatsis, Niklas C. Bauer, Rudi Reinhardt, Patrik Ehrmann, Manja L. Zimmerer, Hiroki Yoneda, Tomohiko Oka, Tristan Bouchet, Manuel R. H. W. Skalka
Cosmology and Nongalactic Astrophysics
Misalignment production of isotropized vector dark matter?
Chong-Bin Chen
We present dark matter production by the misalignment mechanism of a multi-vector condensate through kinetic coupling during inflation. We impose isotropized background vector fields to release the model from the stringent constraint of anisotropy. However, it turns out that the constraints imposed by non-Gaussianity and isocurvature fluctuations are incompatible with each other, regardless of whether the fluctuations are in the weak-mixing or strong-mixing regime.
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Strongly Correlated Electrons
AutoHF: a general Hartree-Fock solver utilizing direct energy minimization with automatic differentiation
Ryan Levy, Brandon Eskridge, Lukas Weber et al. (+2 more)
We present autohf, a general, easy-to-use mean-field solver for
quantum many-
fermion Hamiltonians. It allows the user to bypass the process of deciphering the mean-field form for each many-body
Hamiltonian $H$ and thus avoid setting up a tailored program for each $H$. Rather, autohf finds the optimal Slater determinant $|\Psi\rangle$, written in terms of orbital coefficients and subject to
symmetry constraints, by directly minimizing the variational energy $\langle H \rangle$. By embracing this variational approach, autohf makes use of the growing power of automatic differentiation and optimization tools developed by the machine learning community.
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All authors Ryan Levy, Brandon Eskridge, Lukas Weber, Miguel A. Morales, Shiwei Zhang
Quantum Physics
Emulation of Entanglement Distribution Networks on a Quantum Computer
Ashley N. Tittelbaugh, Jerry Horgan, Rohan Bali et al. (+4 more)
We investigate how
quantum computers can be used to emulate
quantum networks and study their performance under practical impairments. In particular, we evaluate how degraded
entanglement and communication latency affect teleportation-based distributed multipartite-
entanglement-state construction. We model imperfect Bell-pair sources using depolarizing noise channels and classical communication delays using thermal relaxation. We implement the depolarization using Stinespring dilation, randomly applied Pauli errors, and quasi-probability decompositions, evaluating the latter two on IQM
quantum hardware and all three in simulation. We then study the performance of the
entanglement distribution under noise generated by the aforementioned models. Although these noise models are mathematically equivalent, we find that hardware constraints result in profound differences in the corresponding results, highlighting the importance of careful experiment design.
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All authors Ashley N. Tittelbaugh, Jerry Horgan, Rohan Bali, Marco Ruffini, Daniel C. Kilper, Shelbi L. Jenkins, Boulat A. Bash