Quantum Physics
Near-Optimal Separations of Certificate Complexity from Randomized and Quantum Query Complexity
Andris Ambainis, Jānis Iraids and Martins Kokainis
We study how large the certificate complexity ${C}(f)$ of a total Boolean function can be relative to its randomized and
quantum query complexities. We construct a total Boolean function $f$ whose randomized query complexity with one-sided error satisfies ${R}_1(f) = \Theta(\sqrt{{C}(f)})$. This separation is optimal even when two-sided error is allowed. From this construction, we obtain another total Boolean function $F$ with bounded-error
quantum query complexity ${Q}(F) = \widetilde O({C}(F)^{1/4})$, attaining the general quartic bound up to polylogarithmic factors. For the same function, both exact and zero-error
quantum query complexities are $\widetilde O(\sqrt{{C}(F)})$. We also prove matching lower bounds for these two measures on $F$.
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Physics Education
Questioning your brilliance in physics: Differential shifts in fixed mindsets by grade and gender
Fargol Seifollahi, Christian D. Schunn and Chandralekha Singh
Students' domain-specific mindsets and their beliefs about their capacity to improve through effort play a crucial role in shaping their experiences and decisions to persist in STEM disciplines. Physics is generally seen as a field requiring innate brilliance, which can reinforce fixed mindsets, particularly after initial setbacks in performance that are common in introductory university courses. In this study, we examine changes in fixed mindsets and potential gender differences in an introductory calculus-based physics course. Our sample consisted of 508 students with an average age of 18, predominantly White, with men comprising the majority. Based upon survey response distributions, three distinct mindset categories were identified: Hesitant, Hopeful, and Confident, describing how strongly students rejected a fixed mindset in physics. The results suggested large gender differences in distributions at the high and low-end groups. We also found an overall decline toward fixed mindsets across the course, and logistic regressions controlling for initial mindsets showed that women were significantly more likely than men to shift away from the Confident category. While the majority of men tended to stay within the Confident category, the majority of women moved away from it. Particularly, this differential shift was seen among students receiving Bs or Cs, the most commonly awarded grades in this course. Furthermore, there were relatively small differences in the probability of change within men as a function of grades received, whereas women showed marked declines toward fixed beliefs with either a B or C. Our findings provide empirical evidence for the dynamic, grade-sensitive nature of students' mindsets in a calculus-based physics course.
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Astrophysics of Galaxies
The atomic multiphase interstellar medium of galaxies in the COLIBRE simulations
Moa Huppenkothen, Sylvia Ploeckinger, Joop Schaye et al. (+7 more)
We analyse the neutral ISM of
galaxies at
redshift z=0 in the COLIBRE hydrodynamical simulations and investigate the conditions under which these two gas phases coexist in a narrow range of thermal pressures. COLIBRE
galaxies are selected based on the
metallicity of their ISM. The median and mass-weighted distributions of thermal pressures of the multiphase ISM are analysed and compared to thermal
equilibrium models and observations. The ISM in
galaxies with gas
metallicities similar to
solar values exhibits a clear multiphase structure with a warm and cold phase coexisting in a certain range of thermal pressures. The pressures at which the ISM is multiphase depend on the gas
metallicity. For COLIBRE
galaxies with lower
metallicities ($Z_{\mathrm{ISM}}\lesssim0.1\,\mathrm{Z}_{\odot}$), this multiphase structure largely disappears, partly due to resolution. The thermal pressures weighted by the HI mass of the neutral phases in COLIBRE
galaxies are lower than, but still comparable to, some theoretical works and observational estimates. The thermal pressures show a strong dependence on the weighting scheme. If weighted by the
star formation rate or CI mass, the thermal pressures of the cold phase match those derived from observations. The resulting pressures depend on a combination of the assumed radiation field strength,
dust abundance, limited resolution and the weighting scheme. The strong dependence of the thermal pressures on the weighting scheme indicates observational tracers used to estimate the thermal pressure are biased towards high-pressure regions.
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All authors Moa Huppenkothen, Sylvia Ploeckinger, Joop Schaye, Alejandro Benítez-Llambay, Evgenii Chaikin, Filip Huško, Alexander J. Richings, James W. Trayford, Alvaro Hacar, Juan D. Soler
Cosmology and Nongalactic Astrophysics
TDCOSMO XXXI: New techniques in line-of-sight studies of time delay lenses
Daniel Johnson, Devon Williams, Chris Fassnacht et al. (+5 more)
The distribution of matter along the same line of sight but external to the main lens, quantified by $\kappa_\mathrm{ext}$, is a key source of uncertainty in time delay cosmography and other applications of strong
lensing, and must be independently estimated to avoid biasing the inferred value of the Hubble constant ($H_0$). We present advancements and standardisations in the weighted number counts techniques used to constrain $\kappa_\mathrm{ext}$, in particular the use of the Euclid Flagship Simulation and a breakdown of the line-of-sight contributions between the observer, lens and source. As part of the TDCOSMO 2026 milestone analysis, we apply this updated method to the sample of 11 time delay lenses used in that study. Our estimates for certain systems are sensitive to these methodological changes, but are nonetheless consistent within $1\sigma$ for all but one of the systems which had been studied previously, with the median $\kappa_\mathrm{ext}$ across those systems changing from $-0.002$ to $-0.006$ following this new analysis. This work represents the first estimate of $\kappa_\mathrm{ext}$ values which includes the contribution of the observer-lens and lens-source terms, and largest standardised analysis of time delay lens environments to date.
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All authors Daniel Johnson, Devon Williams, Chris Fassnacht, Patrick Wells, Pierre Fleury, Allan Schweinfurth, Martin Millon, Aymeric Galan
High Energy Physics (Theory)
Effective Dynamics of Inflationary End-of-the-World Branes in AdS$_3$
Kosei Fujiki, Michitaka Kohara, Jason Kristiano et al. (+2 more)
We develop an effective description of a two-dimensional cosmological end-of-the-world brane embedded in AdS$_3$, with a scalar field localized on the brane. Integrating out bulk degrees of freedom, especially in the small-gradient regime, the effective action reduces to a Liouville-like theory coupled to the brane scalar. We then construct brane trajectories whose induced geometry realizes slow-roll inflation and reconstruct the associated scalar profile and potential. We also study regular Euclidean brane geometries that admit a smooth continuation to Lorentzian de Sitter and inflationary universes, and evaluate the semiclassical on-shell action for the de Sitter solution. Finally, we analyze linearized inhomogeneous perturbations and find no exponentially growing mode within the regime of validity of the approximation.
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All authors Kosei Fujiki, Michitaka Kohara, Jason Kristiano, Yu-ki Suzuki, Tadashi Takayanagi
High Energy Physics (Phenomenology)
Distinguishing a pseudoscalar from a vector $t\bar t$ resonance with top-quark spin correlations at the HL-LHC
Ahmed Bellagroudi and Farida Fassi
Top-
quark spin correlations provide a direct probe of the
quantum numbers of a resonance decaying to $t\bar t$. We compare a CP-odd type-II two-
Higgs-doublet-model pseudoscalar $A$ with a
spin-1 leptophobic topcolor $Z'$ in the dilepton channel. The two hypotheses differ in the parton-level helicity correlation by $\Delta c_{\rm hel}\simeq0.43$, nearly independently of mass, and
neutrino-weighted reconstruction preserves this separation with an effective dilution factor of about 0.66. At 400 and 800 GeV, the pseudoscalar normalization is anchored to CMS HIG-22-013 coupling limits, while the $Z'$ rate is matched to the pseudoscalar so that the comparison primarily tests
spin structure. The leading-order $t\bar t$-only projection gives expected separations of 2.27 and 2.74 standard deviations at $3000\,{\rm fb}^{-1}$. Equalizing the selected signal yields gives pure
spin-shape separations of 1.86 and 2.70 standard deviations. Profiling a Gaussian-constrained Standard Model $c_{\rm hel}$-shape nuisance gives 2.07 and 2.63 standard deviations for an optimistic sideband
benchmark, or 1.67 and 2.26 for a weaker constraint. A local fixed-template extrapolation corresponds to five-standard-deviation discrimination at couplings about 22% and 16% above the reference values. A 1500 GeV $g=1$ point is shown separately. The reach is limited by the sub-percent signal fraction and control of the mass-dependent Standard Model
spin shape, rather than by the intrinsic resonance-
spin separation.
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Materials Science
High-throughput thermodynamic screening of oxide-scale adhesion across the CoCrFeMnNiAl high-entropy alloys
Dennis Boakye and Chuang Deng
One significant benefit of reactive element (RE) additions is the colossal improvement in
oxide-scale retention during high-temperature oxidation. Selecting optimal RE dopants in high-
entropy alloys remains empirical because the relevant thermodynamic landscape is inaccessible to first-principles at the required compositional resolution. Here we apply the macroscopic atom model, coupled with McLean isotherm and Guttmann models, to screen adhesion across nine CoCrFeMnNiAl sub-families at \ce{Cr2O3} and \ce{Al2O3} interfaces, ranking five REs (Hf, Y, Zr, La, Ti) for segregation, adhesion enhancement, and sulfur displacement. The screening reveals an
oxide-dependent ranking inversion, with Hf dominating at \ce{Cr2O3} and La dominating at \ce{Al2O3}, driven by the interplay between RE–O and RE–
matrix interaction enthalpies. Mn-containing
alloys exhibit intrinsic sulfur resistance, consistent with their experimentally observed oxidation characteristics. A sulfur immunity phase diagram identifies compositions with Al~+~Mn~$\gtrsim$~25~at% as thermodynamically immune to S-induced adhesion loss. All crossover concentrations collapse onto a universal exponential governed by the segregation enthalpy difference, providing a transferable design rule. Inverse design identifies \ce{Co16Cr16Fe16Ni16Al35} as the optimal S-immune composition with $W_\text{sep} = 5.95$~J/m$^2$ without RE doping.
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Quantum Physics
Certifying Adversarial Robustness of Quantum Classifiers under Known-Readout Query Access
Ji Guan and Mingyu Huang
A
quantum classifier assigns labels by evolving an input
quantum state and measuring the output, so repeated executions reveal only a distribution over labels. We study certified
adversarial robustness for such classifiers under known-readout query access (KRQA), where an evaluator can prepare inputs, knows the
quantum measurement, and observes finite-shot outcomes but cannot inspect the internal
evolution, parameters, or gradients. We give a measurement-only framework that returns two complementary guarantees for each input: a lower bound ruling out untargeted errors within a radius, and an attack-independent upper bound witnessing an
adversarial state within a radius. Both are estimable from the known readout measurement and sampled outcomes, require no
tomography or
circuit description, and have finite-sample control of probability-estimation error. The upper bound uses gap operators induced by the
quantum measurement; the lower bound relaxes state-space search to an efficient optimization over outcome distributions with operator-spectrum constraints, yielding certificates that are never weaker than prior probability-only certificates and can be strictly stronger when the spectral constraints are active. On tractable instances, we compare the lower bound with numerical white-box reference estimates; across multiple classifiers, the upper bound remains informative when standard attacks fail. We further demonstrate real-device feasibility on IBM
Quantum hardware: from 40 executions of two 8-
qubit quantum neural networks, our method estimates both bounds, with the expected lower-upper ordering on every tested input. Taken together, these results show that robustness claims for
quantum classifiers can be audited directly from observable statistics under KRQA.
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Quantum Physics
Quantum-hardware spectral co-design framework for multifrequency Rydberg electrometry
Song Huang, Guibin Tian, Fernando Quijandría et al. (+4 more)
Engineering electromagnetic hardware to satisfy discrete
quantum-defined spectral constraints constitutes a general spectral co-design problem for
quantum systems. Here we address this challenge in multifrequency Rydberg electrometry by directly coupling a fabrication-constrained simultaneous perturbation
stochastic approximation (SPSA)–Adam optimizer to full-wave finite-element eigenmode simulations. Requiring neither analytical nor adjoint gradients, the method operates over a discrete design space containing approximately $10^{300}$-configurations and yields a novel multimode electrometry architecture that simultaneously aligns four high-$Q$ eigenmodes with four selected Cs Rydberg transitions. The optimized design remains highly robust to fabrication imperfections, achieving a relative frequency error as low as $8.42\times10^{-7}$ while reducing the device length by a factor of $1.75\times10^{2}$, thereby overcoming the difficulty of simultaneous multimode spectral matching encountered in conventional design. For a comparable simulation budget, the proposed co-design framework achieves frequency-matching errors approximately 10 and 41 times smaller than those of covariance
matrix adaptation
evolution strategy and discrete simulated annealing, respectively. The electrometry is predicted to provide an average input-power-sensitivity enhancement of approximately $4.04\times10^{3}$, demonstrating
quantum–hardware spectral co-design as a general route toward compact hardware for multichannel
quantum sensing.
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All authors Song Huang, Guibin Tian, Fernando Quijandría, Zhengjiang Li, Zhimin He, Franco Nori, Yong Lu
Atomic Physics
Impact of Raman lasers beam profile inhomogeneities on a spaceborne quantum accelerometer
Benoit Kaczmarczuk, Gabriel Ducasse, Louis Pagot et al. (+2 more)
We report on the study of the impact of
laser beam profile inhomogeneities on the acceleration measurements of a
quantum accelerometer in space. This sensor uses a low ballistic expansion source based on delta-kick collimated Bose-Einstein condensates, and an interferometer configuration based on a sequence of Raman double diffraction beamsplitters, best suited to the microgravity environment. We characterize both phase and intensity fluctuations in terms of power spectral densities and calculate their impact on the interferometer phase, averaging over all trajectories of the atoms, via numerical simulations based on randomly drawn
laser profiles as well as via analytical treatments. We show that high quality optics, such as those realized for gravitational wave detectors, combined with large initial size atomic sources, will allow to reduce interferometer phase bias and fluctuations to the order of 1 mrad corresponding to accelerations in the low 10 -12 m.s -2 range.
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All authors Benoit Kaczmarczuk, Gabriel Ducasse, Louis Pagot, Quentin Beaufils, Franck Pereira dos Santos
Mesoscale and Nanoscale Physics
Phase-Controlled Majorana Zero Modes in Altermagnetic Topological-Insulator Josephson Junctions
Hao Dong, Xun-Jiang Luo, Xiao-Hong Pan et al. (+1 more)
We exploit facet-dependent Andreev phase shifts to control topological superconductivity with a phase bias in a three-dimensional altermagnetic topological-
insulator Josephson junction. In the weak link between two conventional $s$-wave
superconductors, the $d$-wave altermagnetic order produces anisotropic momentum shifts of the surface Dirac cones. The resulting net momentum of the states involved in Andreev reflection generates additional propagation phases that differ between facets. Consequently, the facet-resolved Andreev spectra exhibit gap closings at distinct phase biases, giving rise to topological superconducting regimes that host Majorana zero modes (MZMs). We further show that the spatial locations of the MZMs can be controlled by the phase bias. Moreover, these topological superconducting transitions are only weakly affected by moderate variations in the chemical potential, obviating the need for fine-tuning to the Dirac point. Our results establish a platform for realizing and spatially controlling MZMs by tuning the superconducting phase bias in altermagnetic topological-
insulator Josephson junctions.
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All authors Hao Dong, Xun-Jiang Luo, Xiao-Hong Pan, Xin Liu
Fluid Dynamics
Surface gravity wave-mean flow interaction with comparable spatial scales. Part II: two-way coupling and wave-wave interactions
Basile Gallet
We consider narrow-band deep-water surface
gravity waves propagating above a background flow whose spatial scale is comparable to the wavelength. We focus on the regime where the background-flow speed is comparable to the Stokes drift of the waves to derive a two-way coupled model between the fast waves and the slow background flow. Nonlinear wave interactions arise at the same asymptotic order as the two-way coupling and must therefore be included in the derivation. The resulting model consists of a nonlinear version of the reduced wave equation obtained in part I, coupled to a Craik-Leibovich equation governing the
evolution of the background flow. The model describes the
evolution of the wave field and background flow over the slow turnover frequency of the background flow, thus saving the computational burden of temporally resolving the fast wave frequency. The inviscid model exactly conserves wave action, mechanical energy and horizontal momentum, while the viscous model exactly conserves horizontal momentum. The coupling terms are cast in compact form for ease of physical interpretation and numerical implementation.
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Mathematical Physics · Cross-listed from math.PR
Precise Delocalisation and Gumbel Laws for Eigenvectors of Wigner Matrices
Mohammed Osman
We prove a delocalisation bound for eigenvectors of Wigner
matrices with the precise relationship between the size of the largest entry and the decay exponent of the probability. We also prove that the largest entry of an individual eigenvector and the largest entry of all eigenvectors are both Gumbel distributed. The proof is based on the inclusion-exclusion principle, the small probability comparison of Erdős–Xu, and partial diagonalisation of Gaussian divisible
matrices.
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High Energy Astrophysical Phenomena
One Precessing Jet Pair, Diverse Core-Collapse Supernova Remnant Morphologies
Jessica Braudo and Noam Soker
We produce a diverse set of observed core-collapse
supernova (CCSN)-type morphologies using a precessing pair of opposite jets within the jittering-jets explosion mechanism (JJEM) framework. We conduct a three-dimensional hydrodynamical simulation of a precessing pair of jets that explode a massive
star, and find that a single precessing pair of opposite jets can generate S-shaped structures, pipe-spout-blowout features as observed in the Cygnus Loop, multiple apparent pairs of opposite protrusions similar to some morphological features in S147, and H-shaped structures with a prominent bar, similar to the one observed in the 3C 397 remnant. At small scales, the jets form clumps and filaments, resulting from instabilities and
vortices that the jets induce in the ejecta as they interact with the
stellar material. We did not aim the simulation to reproduce any particular CCSN remnant, but rather to explore the resulting morphological features. Our finding of simulated features similar to observed ones supports the role of jets in exploding CCSNe and, in turn, supports the claim that the JJEM is the primary explosion mechanism of CCSNe.
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Plasma Physics
Physics-Informed Neural Networks to Infer the Perpendicular Energy Conductivity in the Scrape-Off Layer of Stellarator Devices
J. Gallego, P. Protopapas, A. Bustos et al. (+6 more)
In this work, we develop an inverse Physics-Informed Neural Network (PINN) framework to infer the dependence of the scrape-off layer (SOL) perpendicular heat conductivity on
plasma density and temperature, $\kappa_\perp(n,T)$. The method combines radial profile measurements of electron density and temperature with the residual of a reduced one-dimensional SOL transport equation, so that the inferred conductivity is constrained by both the measurements and the underlying transport model. Three neural networks are trained simultaneously: two reconstruct the temperature and density profiles as functions of the radial coordinate and transported power, while a third represents the effective conductivity as a function of the local density and temperature. The framework is first validated using synthetic data generated from a prescribed conductivity function, allowing the inferred $\kappa_\perp(n,T)$ to be compared directly with the ground truth. The model recovers the imposed functional dependence with errors below $10~\%$ in the data-constrained region. Bootstrap resampling is shown to provide a practical indicator of prediction reliability and consistency. A scan in the number of
plasma profiles used for training and the number of radial measurement positions per profile identifies a practical trade-off between reconstruction accuracy and data availability. Finally, the method is applied to an experimental
dataset from the TJ-II stellarator obtained with the helium-beam diagnostic. This exploratory application provides an initial estimate of the effective SOL conductivity and illustrates the potential of inverse PINNs for extracting transport information from
plasma edge measurements.
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All authors J. Gallego, P. Protopapas, A. Bustos, A. Alonso, S. Barquero, A. Baciero, I. Rivera, J. A. Moríñigo, R. Mayo-García
Quantum Physics
Quantum models of interaction Hamiltonians and their paradoxes
Nicolas Gisin, Serge Massar, Jef Pauwels et al. (+1 more)
In
quantum physics it is commonplace to model the interaction of remote systems with a many-body
Hamiltonian. Taking such an action-at-a-distance description à la lettre leads to various paradoxes related to faster-than-light communication and apparent inconsistencies in local energy accounting. It also neglects residual effects, such as
entanglement between the remote systems and the mediator that implements the interaction, or the decoherence that arises when the remote systems undergo local
evolution. We study simple microscopic
quantum models that respect the light cone by design and reproduce two-body
Hamiltonians. For these models we quantitatively analyze the residual effects of the microscopic mediator on the remote systems, including dressing of stationary states, and decoherence in the presence of fast local control. We show how the models resolve the paradoxes.
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All authors Nicolas Gisin, Serge Massar, Jef Pauwels, Pavel Sekatski
High Energy Physics (Experiment)
Projected Sensitivity to Slow Muonphilic Dark Matter with Accelerator Muon Beams
Rongfeng Zhang, Cheng-en Liu, Ruihu Zhu et al. (+9 more)
The nature of dark matter (DM) remains one of the most enduring open questions in modern physics, and muonphilic DM has emerged as a promising scenario that complements traditional DM candidates. Following the recently established
cosmic-ray
muon scattering approach, we investigate the sensitivity for probing slow muonphilic DM with accelerator
muon beams. A Geant4-based simulation framework is developed, incorporating the detector geometry from the PKMu
muon tomography system and a dedicated elastic $\mu$-DM scattering process. The projected sensitivity is found to be largely insensitive to both the beam energy and the transverse beam size when the beam is fully contained within the detector acceptance. For a
benchmark beam intensity of $10^5/\rm{s}$, the simulated pure-
muon beam surpasses the existing
cosmic-ray limit of $1.61\times10^{-17}$ cm$^2$ at $m_{\rm DM}=1$ GeV within approximately 11 seconds. A realistic
muon beam phase-space distribution based on simulations for the High Intensity heavy-ion Accelerator Facility (HIAF) is also implemented, yielding projected limits that improve upon the
cosmic-ray results by nearly two orders of magnitude in a one-day exposure. These results demonstrate that a beam-
muon scattering experiment offers a robust and promising route toward significantly improved sensitivity to slow muonphilic DM.
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All authors Rongfeng Zhang, Cheng-en Liu, Ruihu Zhu, Yu Xu, Zijian Wang, Leyun Gao, Xueheng Zhang, Qite Li, Liangwen Chen, Chen Zhou, Qiang Li, Zhiyu Sun
Instrumentation and Detectors · Cross-listed from eess.SP
Multi-Threshold Sampling: Signal Space, Sampling Operators, and First Recorded Crossing-Time Distributions
Ao Qiu and Qingguo Xie
Multi-threshold (MT) sampling records crossing times at selected thresholds for parameter estimation and waveform reconstruction. We develop a mathematical framework that defines the signal space and sampling operators and maps the signal distribution to the distribution of recorded crossings. The framework distinguishes model mismatch, signal noise, threshold mismatch, and threshold noise. Finite point measures accommodate variable crossing counts and preserve multiplicity after time quantization.
Stochastic crossing, timing, and selection operators and their associated Markov kernels describe the sampling process. For nonhomogeneous Poisson
photon arrivals and deterministic MT sampling, we derive the exact cumulative distribution function (CDF) of the first recorded crossing time at a specified threshold within a recorded-time interval. Under additional regularity and local monotonicity conditions, this CDF admits a one-dimensional
Fourier representation. For a scintillation pulse model, numerical CDFs and standard deviations of the first recorded crossing time agree with independent Monte Carlo simulations, providing a quantitative basis for comparing threshold settings. The framework provides a foundation for MT performance evaluation, parameter estimation, waveform reconstruction, and sampler design.
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High Energy Astrophysical Phenomena
Probing the details of relativistic electrons with multifrequency observations of M87 black hole
J.G.J. Keuper and M. Moscibrodzka
Beginning in March 2026, the Event Horizon
Telescope (EHT) conducted a two-month observing campaign aimed at obtaining the first time-resolved sequence of images of the black hole M87* at the center of the Virgo A
galaxy. The primary scientific objectives of this campaign are to constrain the black hole
spin and to investigate the temporal variability of the
magnetic field and
plasma properties within the horizon-scale jet-launching region. In this work, we present theoretical predictions for the spectral index maps expected from these observations. Our predictions are based on Magnetically Arrested Disk simulations performed with the EBHLIGHT code and post-processed using the IPOLE general relativistic ray-tracing code. We investigate the temporal
evolution of the spectral index for a range of electron distribution models and five different black hole
spin values. The analysis includes both frequency bands currently present within the EHT and neighboring frequencies proposed for future extensions of the EHT array. In addition to extending previous studies to a broader range of observing frequencies, our work systematically investigates the time variability of the predicted spectral index maps. In purely thermal electron models, the temporal variability of the spectral index maps closely traces variations in the
magnetic field strength and electron temperature in the immediate vicinity of the event horizon. By contrast, models incorporating a non-thermal electron population exhibit substantially weaker spectral index variability, owing to the contribution of a power-law component with a fixed spectral slope. Our numerical results are consistent with theoretical expectations. Finally, a comparison with the recently measured integrated spectral index of the M87* enables us to place preliminary constraints on the model parameters.
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Instrumentation and Methods for Astrophysics
An RFSoC-based Backend and Timing System for the Balloon-borne Very Long Baseline Interferometry Experiment
Mayukh Bagchi, Felix M. Thiel, Laura M. Fissel et al. (+13 more)
We present the design and performance characterization of the digital backend and precision-timing system for the Balloon-borne Very Long Baseline Interferometry Experiment (BVEX), a pathfinder for high-frequency stratospheric VLBI at 22 GHz. The backend uses one of the four 14-bit analog-to-digital converter inputs on an AMD-Xilinx RFSoC 4x2. Although the converters support sampling rates up to 5 GSPS, the flight configuration digitizes the 2-4 GHz intermediate frequency at 4.096 GSPS. CASPER firmware provides both a high-resolution spectrometer for pointing and receiver verification, and a VLBI acquisition chain with two-bit requantization that records at a rate of about 8.2 Gbps. The timestamped data packets are sent over 100 Gigabit Ethernet (GbE) to a 16 TB NVMe array in a storage computer that draws approximately 70-80 W. The timing chain uses a Rakon oven-controlled
crystal oscillator as a timing reference while a time-interval counter measures its drift relative to a GPS reference with approximately 60 ps resolution. This is the first deployment of an RFSoC-based VLBI backend and precision-timing system on a stratospheric balloon. Ground tests validated the backend, spectrometer, and timing chain. The August 2025 CSA STRATOS flight ended before reaching the target float altitude because of a balloon failure, and as a result no science observations were obtained. For the planned 2027 reflight, we are developing a conduction-cooled data storage computer with 24 TB of NVMe capacity and a direct data path from the 100 GbE interface to the NVMe array.
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All authors Mayukh Bagchi, Felix M. Thiel, Laura M. Fissel, Maggie Oxford, Lindy Blackburn, Rafael Costa, Vincent L. Fish, Daryl Haggard, Michael D. Johnson, Dominic W. Pesce, Ganesh Rajagopalan, Javier L. Romualdez, Aarchi Shah, Adrian K. Sinclair, Stephanie St-Jean, Terry Yang
High Energy Physics (Phenomenology)
Collinear fragmentation of pseudoscalar quarkonia from NLO NRQCD
Francesco Giovanni Celiberto and Francesca Lonigro
We discuss a new family of publicly available collinear fragmentation functions (FFs) for pseudoscalar quarkonia, the NRFF1.0 set. It builds upon the Heavy-
Flavor Non-Relativistic
evolution (HF-NRevo) scheme, designed to describe heavy-
hadron formation through leading-power fragmentation at moderate and large transverse momentum. Heavy-quarkonium production naturally involves both perturbative and non-perturbative QCD dynamics, from the production of the heavy $Q\bar{Q}$ pair to its formation into a physical bound state. Within NRFF1.0, Non-Relativistic
Quantum Chromodynamics (NRQCD) provides the theoretical framework for calculating the FF inputs at the initial scale, which are subsequently evolved through the HF-NRevo scheme. This setup provides a precision baseline for investigating the underlying partonic hierarchy and jet structure across the moderate- to high-transverse-momentum regime. The explicit treatment of partonic channels and heavy-
flavor thresholds makes this framework particularly suitable for exploring quarkonium-in-jet fragmentation, jet-quenching sensitivity, energy-loss mechanisms, and the emergence of medium-modified fragmentation patterns in the
quark-
gluon plasma.
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Mathematical Physics
On asymptotic expansions of the density of states for Poisson distributed random Schrödinger operators
Jan Fischer, David Hasler and Jannis Koberstein
We study a random Schrödinger operator with a potential distributed according to a Poisson process. Asymptotic expansions for traces of resolvents in the limit of small disorder are derived. Explicit estimates for the expansion coefficients are given and we show that their infinite volume limits are finite as the spectral parameter approaches the spectrum of the free
Laplacian. As an application we derive bounds on the integrated density of states.
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Chemical Physics
Breaking Water at Graphene Defects
Samuel G. H. Brookes, IniOluwa C. Popoola, Fabian Berger et al. (+3 more)
Water dissociation at solid surfaces underpins processes ranging from corrosion and catalysis to electrochemistry and photovoltaics. Defects often serve as reactive sites for dissociation, yet how solvation influences water dissociation at such sites remains poorly understood. Here, we use state-of-the-art machine-learned interatomic potentials to explore water dissociation at defective
graphene-water interfaces. We show that solvation qualitatively changes the reaction mechanism at a
graphene single vacancy (SV), opening pathways that are absent for an isolated water molecule. Whereas the gas-phase process proceeds via a single concerted channel, the solvated SV splits water through two competing pathways: a basic route forming SV-H and OH-(aq), and an acidic route forming SV-OH and H3O+(aq). These lower-barrier pathways produce distinct chemisorbed intermediates that enhance
graphene-water adsorption. Accordingly, even a simple carbon vacancy gives rise to unexpectedly rich interfacial chemistry, coupling surface chemistry to interfacial charge and wettability, with implications for carbon functionalization and nanofluidic transport.
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All authors Samuel G. H. Brookes, IniOluwa C. Popoola, Fabian Berger, Kara D. Fong, Angelos Michaelides, Christoph Schran
High Energy Physics (Phenomenology)
Cosmic ray boosted dark matter with momentum dependent interactions can explain the LZ 248 keV event
Matti Heikinheimo and Niklas Zimmermann
The LZ experiment has recently reported an observation of a single event with characteristics of a
nuclear recoil at a high
recoil energy of 248 keV, where no background events are expected. We show that such
nuclear recoil event could be caused by high velocity dark matter particles originating from interactions with energetic
cosmic rays. We analyze the expected
recoil spectrum due to
cosmic ray boosted dark matter within the non-relativistic effective theory formalism, and show that momentum-dependent operators, such as $\mathcal{O}_6$ and $\mathcal{O}_{10}$, can produce a spectrum that peaks at the observed energy.
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Quantum Physics
Dissipative Quantum Battery from Many-Body Scars
Jinglin Liu, Yiming Liu, Mingdi Xu et al. (+1 more)
We propose an autonomous
quantum-battery protocol based on dissipatively selected
quantum many-body scars. Using an
embedding-type
spin chain with an exact scar tower and a generalized interacting $J_1$–$J_2$ chain, we show that engineered local bond dissipation can drive the system from a passive state into a high-energy scar-supported
manifold with large extractable work. The resulting charged states exhibit single-copy ergotropy close to the
entropy-matched thermodynamic work bound while retaining the coherent structure associated with the scar ladder. Because the ideal scar
manifold also supports nondecaying peripheral modes, we introduce weak local dephasing to obtain a stable charging protocol and find a broad regime in which the charging time is reduced without substantially degrading the stored work. Finally, an explicit scar-breaking perturbation produces a correlated loss of scar support and extractable work, demonstrating that the favorable battery performance is tied to the nonthermal scar structure rather than merely to the preparation of a generic excited state. Our results establish dissipatively stabilized many-body scars as a promising resource for autonomous and robust
quantum energy storage.
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All authors Jinglin Liu, Yiming Liu, Mingdi Xu, Lei Pan
Instrumentation and Methods for Astrophysics
Towards First Light for MICADO: Validation of the PSF-R service with real data
Matteo Simioni, Luca Cortese, Roland Wagner et al. (+12 more)
MICADO, one of the ELT first-light instruments, will rely on point-spread-function reconstruction (PSF-R) to meet scientific requirements, especially for SCAO observations of targets that lack bright reference
stars nearby. PSF-R will be performed in post-processing using only AO telemetry, recorded simultaneously with the science data. For SCAO observations, both on- and off-axis PSFs will be delivered. We present the current status and results from an ESO TTR campaign begun in 2023, targeting a sparse three-
star asterism under varying conditions with the ERIS instrument at VLT. Reconstructed PSFs reach ~10% accuracy in Strehl ratio and FWHM at separations up to half the size of the isoplanatic patch. The current results suggest the telemetry-driven approach can reproduce not only the core PSF structure but also the extended wings, which are essential for reliable photometry and morphological analysis of bright extended sources. The obtained results also corroborate the key role of wind as a limiting factor of the method, reducing the amount of recovered information on specific directions.
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All authors Matteo Simioni, Luca Cortese, Roland Wagner, Carmelo Arcidiacono, Andrea Grazian, Marco Gullieuszik, Elena Masciadri, Elisa Portaluri, Benedetta Vulcani, Anita Zanella, Richard Davies, Johanna Hartke, Roberto Piazzesi, Stefan Raffetseder, Piero Vaccari
Instrumentation and Methods for Astrophysics
The MICADO first light imager for the ELT: the PSF Reconstruction Software
Andrea Grazian, Fernando Pedichini, Matteo Simioni et al. (+14 more)
The MICADO instrument for the ESO ELT will provide Adaptive Optics (AO) diffraction-limited NIR imaging and spectroscopy. A critical component of MICADO is the Point Spread Function Reconstruction (PSF-R) Software, which is designed to perform a blind reconstruction of the PSF for all observations using AO telemetry data only, both with the Single Conjugate (SCAO) and Multi-Conjugate Adaptive Optics (MCAO) modes of MICADO. The SCAO PSF-R Pipeline is currently being completed, and validation with ERIS at VLT and SOUL+LUCI at LBT has demonstrated high accuracy, of percent-level on-axis and 5-20% off-axis. Initial scientific simulations confirm that the PSF-R software meets the necessary precision for high-quality analysis, securing its role for MICADO's first light and future ELT operations.
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All authors Andrea Grazian, Fernando Pedichini, Matteo Simioni, Jani Achren, Carmelo Arcidiacono, Luca Cortese, Ric Davies, Marco Gullieuszik, Johanna Hartke, Hanindyo Kuncarayakti, Roberto Piazzesi, Elisa Portaluri, Stefan Raffetseder, Piero Vaccari, Benedetta Vulcani, Roland Wagner, Anita Zanella
Strongly Correlated Electrons
Robust Spin-1 Haldane Topology under Itinerant Doping
Satoshi Nishimoto
We study itinerant hole doping of the
spin-$1$ Haldane
symmetry-protected topological (SPT) phase in two $t$–$J$ chains coupled by
ferromagnetic (FM) Hund exchange. Density-
matrix renormalization group calculations show that string order, a finite
spin gap, and the Haldane
entanglement structure coexist over a broad doping range. Combined with
entanglement-
entropy scaling consistent with a single gapless charge mode, these results support a metallic doped Haldane SPT with a $C1S0$ low-energy description. At low doping, short-range charge correlations reduce the density of
spin-$1/2$ defect rungs, whereas at larger doping their positions become nearly uncorrelated while their
spins are collectively incorporated into the correlated
spin sector. The doped Haldane SPT terminates in a fully
spin-polarized FM phase, which forms a reentrant pocket at high doping in the global phase diagram. Dilute-limit analyses trace the two FM boundaries to
spin–charge factorization at weak Hund coupling and to rung-triplet binding with reduced pair mobility at strong Hund coupling. Our results show how mobile carriers reorganize the Haldane
spin structure while preserving its characteristic signatures.
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Fluid Dynamics
Surface gravity wave-mean flow interaction with comparable spatial scales. Part I: reduced wave equations
Basile Gallet and Alexandre Tlili
We consider deep-water surface
gravity waves propagating above a background flow whose spatial scale is comparable to the wavelength, focusing on the regime where the flow is slow compared to the group velocity of the waves. We introduce an "equivalent solvability condition" method to construct reduced equations, demanding that, upon multiple-timescale expansion, the reduced equations share the same leading-order solution and first solvability condition as the original system. This approach turns the full 3D problem into a 2D reduced equation for the wave field. We derive such reduced equations for broad-band waves above a depth-invariant background flow, and for narrow-band waves above a fully 3D background flow. In the latter case the reduced equation takes the form of a Schrodinger equation involving the near-surface vorticity of the background flow only, with the impact of the near-surface horizontal flow divergence shown to be subdominant. Beyond the reduction in spatial dimensionality, the latter reduced equation describes the
evolution of the wave field over the slow advective timescale of the background flow, thereby eliminating the computational burden of time-resolving the fast wave period. We illustrate the capabilities of the reduced equations through an analytical solution for the weak scattering of a wave packet by a patch of organized flow, followed by numerical solutions for stronger scattering of a wave packet by a patch of disorganized flow.
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Optics
Heterogeneously Integrated Efficient and Widely Tunable Lasers at 795 nm for Rubidium-Based Quantum Technologies
Max Kiewiet, Stijn Cuyvers, Tom Reep et al. (+8 more)
Scaling
quantum processors and optical atomic clocks fundamentally requires orders-of-magnitude reductions in the size, weight, power, and cost of optical control systems. Photonic integration of
lasers is critical to fulfill these requirements. At the near-infrared wavelengths required for atomic clocks and
quantum computing through manipulation of rubidium atoms,
laser integration is hindered by difficulty in light coupling and poor heat dissipation. Here, we introduce a wafer-scalable method utilizing micro-transfer printing to integrate GaAs-based amplifiers in etched recesses, directly butt-coupled to silicon nitride waveguides. We demonstrate extended-cavity single-mode
lasers using this integration approach. Our compact microgear
laser achieves a narrow 3 kHz fundamental linewidth at an on-chip output power of >22 mW – a record for a single-mode heterogeneously integrated
laser in the 780-800 nm band – with a wall-plug efficiency of 9.4%, showcasing the high-power and efficiency potential of this integration approach. Additionally, we demonstrate a widely tunable
laser leveraging Vernier filters to achieve lasing with 9 nm coarse tuning, a quasi-continuous fine-tuning range exceeding 140 GHz, and a mode-hop-free tuning range of 45 GHz. Our scalable integrated
laser toolkit shows great promise for replacing macroscopic external-cavity diode
lasers in next-generation
quantum technologies and optical atomic clocks.
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All authors Max Kiewiet, Stijn Cuyvers, Tom Reep, Konstantinos Akritidis, Gaudhaman Jeevanandam, Manuel Reza, Roelof Jansen, Pol Van Dorpe, Günther Roelkens, Kasper Van Gasse, Bart Kuyken