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Physics

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Wednesday 8 July

General Relativity and Quantum Cosmology

Hierarchy of Angular Instabilities in Scalarized Black Holes

Jose Luis Blázquez-Salcedo, Luis Manuel González-Romero, Fech Scen Khoo et al. (+2 more)

We investigate the stability of scalarized black holes in Einstein-scalar-Gauss-Bonnet-Ricci theory along their fundamental branches. We show that initially stable solutions first lose nonspherical stability in the eikonal regime, while lower multipoles remain stable. As the branch is continued, instability extends systematically toward lower multipoles, forming an ordered hierarchy of deformation instabilities extending down to the quadrupole mode, while the dipole sector remains stable. The instability thresholds obey a common scaling law and approach finite eikonal limits, defining the boundary of the angularly stable region. We demonstrate that the previously identified quadrupole and angular-Laplacian instabilities are connected by a continuous hierarchy of instability thresholds spanning the angular sectors of the theory. This hierarchy is distinct from radial stability, which changes only at branch turning points, and reveals a previously unexplored angular organization of instabilities in scalarized black holes.
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All authors Jose Luis Blázquez-Salcedo, Luis Manuel González-Romero, Fech Scen Khoo, Jutta Kunz, Pablo Navarro Moreno

Astrophysics of Galaxies

From 2D to 3D: Recovering Turbulent Density Dispersions from Noisy Data

Luz L. Jimenez Vela, Christoph Federrath, David C. Collins et al. (+1 more)

Turbulence plays a central role in shaping the structure and dynamics of the interstellar medium (ISM), governing the star formation rate (SFR) and the initial mass function (IMF). A key consequence of turbulence is the generation of density fluctuations, which regulate the amount of dense gas available for star formation. Accurate measurements of the three-dimensional (3D) turbulent density dispersion are therefore essential for understanding molecular-cloud structure and star formation. However, observations typically provide only two-dimensional (2D) column densities and are often affected by measurement/detector noise. The Brunt method estimates the 3D density dispersion from 2D column-density maps, but it does not account for finite signal-to-noise ratio (SNR). Here, we extend the method to recover the 3D turbulent density dispersion from noise-contaminated observations. Using numerical simulations spanning a range of density perturbation amplitudes and noise types, we identify a characteristic noise wavenumber, k_noise, corresponding to the intersection of the signal and noise spectra. Restricting the Brunt reconstruction to wavenumbers below k_noise yields a denoised density-dispersion estimate that closely reproduces the noise-free result. We provide a practical prescription to determine k_noise directly from the measurement SNR and image resolution. Alternatively, if the noise spectrum is known, it can be subtracted directly from the observed spectrum, eliminating the need to estimate k_noise. The proposed correction recovers the noise-free density dispersion with errors of <~5% for SNR>=3 and <~15% for SNR>=1, enabling substantially more reliable estimates of turbulent density fluctuations from noisy column-density data.
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All authors Luz L. Jimenez Vela, Christoph Federrath, David C. Collins, Seth Davidovits

Quantum Gases

Wall tension of a Bose-Einstein condensate: Effects of quantum fluctuations and finite-range interactions

Pham Duy Thanh and Nguyen Van Thu

We investigate the effects of quantum fluctuations (QFs) and finite-range interatomic interactions on the ground state and wall tension of a Bose-Einstein condensate (BEC) at zero temperature by means of modified Gross-Pitaevskii equations. The QFs are shown to stiffen the condensate near the hard wall, narrowing the density profile and raising the wall tension above its mean-field value by an amount proportional to square-root of the gas parameter. Finite-range corrections always reduces the wall tension relative to the QFs correction value regardless of the effective range. We find the ordering $\gamma_0 < \gamma_{\rm II} < \gamma_{\rm I}$ in the dilute regime and identify a crossover condition under which the two beyond-mean-field contributions mutually cancel. These results provide an experimentally accessible way for probing beyond-LHY physics through precision measurements of the wall tension in ultracold Bose gases.
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High Energy Astrophysical Phenomena

X-ray Spectral Properties of Four Classical TeV Blazars using Simultaneous Observations from NICER and NuSTAR

Riya Bhowmick and Alok C. Gupta

We present a detailed study of X-ray spectral properties observed in 4 classical TeV (tera-electron volt) photon-emitting high synchrotron-peaked BL Lacertae objects using the simultaneous data of NICER and NuSTAR satellites. We analyzed 13 spectra in total from four BL Lacertae objects: Mrk 421, Mrk 501, PG 1553+113, and PKS 2155-304. We fitted all the spectra using the absorbed Log-Parabolic (LP) model first. While 7 spectra were fitted well using the absorbed LP model, we observed that 4 spectra of Mrk 421 and 2 spectra of Mrk 501 were not fitted satisfactorily using the absorbed LP model. The investigation of the flux states of the sources revealed that Mrk 421 was in a moderate to low-flux state during the 4 epochs and Mrk 501 was in a low-flux state during the 2 epochs. We concluded that there was a contribution from the disk in these 6 spectra. The moderate to low-flux state can justify the contribution of disk emission in the X-ray spectra. In the case of 4 spectra of Mrk 421, we observed a Gaussian feature between 1.42 and 1.70 keV.
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High Energy Astrophysical Phenomena

Multi-band optical photometric variability of the blazar OJ 287 from 2015 to 2025

Alok C. Gupta, Karan Dogra, Mark Kidger et al. (+101 more)

We present the most densely sampled multi-band optical photometric observations of the peculiar BL Lacertae object OJ 287 from 2015 to 2025 with a focus on its optical activity on diverse timescales. We present a total of 2296, 10927, 11484, and 2982 data points in B, V, R, and I bands, respectively. The densely sampled observations allow us to keep track of the source evolution that it has exhibited since the start of the predicted major optical flaring activity at the end of 2015. The study reveals clear and persistent bluer when brighter trends in both the long-term and short-term variations. Different bands were cross-correlated with discrete correlation functions, which peak at zero lag, implying co-spatial emission. Using eight optical spectra in the low flux states of OJ 287 taken from 2017 October 21 to 2017 November 22, from Steward Observatory, we estimate the central black hole mass to be at least 3.89 $\times \ \rm{10}^{9} \ \rm{M}_{\odot}$ from the [O III] line width. The emission mechanism of the binary black hole blazar, and its possible implication in various aspects of multi-messenger astronomy are briefly discussed.
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All authors Alok C. Gupta, Karan Dogra, Mark Kidger, Mauri J. Valtonen, Paul J. Wiita, Pankaj Kushwaha, Sergey S. Savchenko, Sofia O. Kurtanidze, Svetlana G. Jorstad, Alan P. Marscher, Katsura Matsumoto, Lang Cui, Shao Ming Hu, Goran Damljanovic, Rumen Bachev, O. Vince, Mai Liao, Zhongxiang Wang, A. Darriba, S. Haque, F. S. Alfaro, J. B. Amatller, J. M. F. Andujar, S. Arnold, T. Arranz, M. Bachini, C. L. Barcelo, S. Boeva, G. A. Borman, D. Boyd, D. Buczinski, J. D. Casal, X. Chen, J. M. Cores, F. C. Cucarella, P. U. Devanand, V. Dhiman, L. T. Espasa, J. H. Fan, R. G. Farfan, J. R. Fernandez, F. Garcia, R. C. Garcia, H. Gaur, J. C. Gomez, J. L. S. Gonzalez, J. L. Gonzalez-Carballo, T. S. Grishina, F. H. Grondona, M. F. Gu, H. Guo, V. A. Hagen-Thorn, G. Hurst, S. Ibryamov, R. Z. Ivanidze, N. James, B. Jardine, S. Johnstone, M. D. Jovanovic, N. Kalita, S. Karge, S. Kishore, E. N. Kopatskaya, O. M. Kurtanidze, A. Kurtenkov, E. G. Larionova, E. R. Lorenz, J. Lozano, E. F. Mananes, F. L. Martinez, M. Mobberley, M. Morales-Aimar, D. A. Morozova, M. G. Nikolashvili, Y. Nikolov, R. N. Nogues, P. A. Novikova, L. M. Penas, A. E. Perez, C. Perello, R. Pickard, F. G. Pinilla, G. Poyner, F. Rahmatullaeva, B. Rajkumar, N. G. Ribes, E. Semkov, E. V. Shishkina, M. Stojanovic, A. Strigachev, T. Tripathi, Yu. V. Troitskaya, I. S. Troitskiy, J. Valero, A. A. Vasilyev, B. Villarroel, A. E. Volvach, L. N. Volvach, S. J. Wagner, Z. R. Weaver, Wen-Xin Yang, Z. Zhang, A. V. Zhovtan, W. Zuo

High Energy Astrophysical Phenomena

Detection of Quasiperiodic Oscillations in the Blazar PKS 0735+178 with TESS

Shubham Kishore, Alok C. Gupta, Paul J. Wiita et al. (+2 more)

We report here the detection of signatures of a quasiperiodic oscillation (QPO) and a short flare in the optical light curve of the blazar PKS 0735+178, observed in two sectors, 71 and 72, spanning around 49 days with the Transiting Exoplanet Survey Satellite. The modest flare in sector 71 lasted ~4.3 days and appears as a combination of two sub-flares. In sector 72, a transient QPO with a period ~11.2 hours is detected at local and global significance levels of 4.11$\sigma$ and 3.06$\sigma$, respectively. We used weighted wavelet z transform, Lomb-Scargle periodogram, and phase dispersion minimization analysis techniques to look for and confirm the QPO feature. We also performed a segment-wise statistical inspection of these light curves and discuss here possible mechanisms that could explain the observed flux behavior.
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All authors Shubham Kishore, Alok C. Gupta, Paul J. Wiita, Sandeep K. Mondal, M. Vivek

Strongly Correlated Electrons

Floquet-Weyl states at one-photon resonances in three-dimensional topological insulators

Keiya Uehara, Ryo Okugawa, Takami Tohyama et al. (+1 more)

Quantum materials exhibit exotic phases and electronic responses under irradiation by circularly polarized light, which breaks time-reversal symmetry and generates Floquet replica bands. Recently, Floquet topological states arising from direct resonances have attracted much attention, e.g., the emergence of Floquet-Weyl points at a one-photon resonance, rather than topological features within the modulated original bands via high-frequency expansion. In this study, we investigate the effects of a one-photon resonance in a representative three-dimensional topological insulator, Bi$_2$Se$_3$, applying Floquet theory under circularly polarized light. We find that four pairs of Floquet-Weyl points emerge in the intermediate-frequency regime, mediated by hybridization between the original and one-photon-resonant Floquet bands, preserving the threefold rotational symmetry of the crystalline structure. Our numerical calculations demonstrate that tuning the chemical potential via hole doping yields a large anomalous Hall conductivity, directly associated with these Floquet-Weyl points. This work provides a highly accessible route toward the experimental realization of one-photon-resonant Floquet-Weyl semimetals.
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All authors Keiya Uehara, Ryo Okugawa, Takami Tohyama, Shun Okumura

High Energy Physics (Phenomenology)

Inclusive Charmless Non-Leptonic B Decays at NLO within and beyond the Standard Model

Stefan Meiser, Pol Morell, Angel Picazo et al. (+1 more)

We calculate the full set of BSM contributions to the inclusive non-leptonic $B$-meson lifetime from charmless final states within the framework of the Weak Effective Theory up to next-to-leading order in QCD and to leading power in the heavy-quark expansion. We do so by computing cut diagrams and the corresponding phase space integrals. This involves calculating current-current, penguin-penguin, penguin-dipole and dipole-dipole diagrams with two-, three- and four-particle cuts. We describe the technical difficulties of the computation. We then discuss how our results can be used to constrain new physics scenarios related to the anomalies observed in semi-leptonic and charmless non-leptonic decays.
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All authors Stefan Meiser, Pol Morell, Angel Picazo, Javier Virto

Quantum Physics

Analytical Landscape of Maximal Magic for Two-Qutrit States and Beyond

Marco Knipfer, Alexander Roman, Katia Matcheva et al. (+1 more)

Achieving a genuine quantum advantage relies on two distinct non-classical resources that restrict efficient classical simulation: entanglement and magic (nonstabilizerness). We investigate the interplay between these resources by characterizing the Pareto frontiers of extreme magic at fixed entanglement for systems of two qutrits ($d=3$) and two ququints ($d=5$). Unlike the case of two qubits, the Schmidt spectrum for two qutrits features two independent entanglement parameters, resulting in two-dimensional Pareto surfaces. For the lower frontier, we recast the minimal magic as a compact function of concurrence and negativity, with a maximal value of $\ln 2$. For the upper frontier, we determine the maximal stabilizer Rényi entropy to be $M_2 = \ln(81/17) \approx 1.561$, which tightens the previous theoretical bound of $\ln 5\approx 1.609$ and improves on earlier numerical estimates. The maximum magic is achieved at eighteen distinct maxima categorized into three families of six permutation-equivalent spectra. We provide analytical expressions for the maximal magic in the neighborhood of each maximum and for the corresponding maximally magical states which turn out to be Weyl-Heisenberg-covariant fiducial states for mutually unbiased bases. Finally, numerical analysis of two ququints ($d=5$) reveals six permutation-inequivalent maxima with a peak magic value of $M_2 = \ln(625/49) \approx 2.546$. Based on these findings, we conjecture that the maximal magic for a bipartite system of two qudits with prime dimension $d$ is given by $\ln [ d^4 / (2d^2 - 1) ]$, which reproduces the previously known value for qubits, as well as the values derived here for qutrits and ququints.
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All authors Marco Knipfer, Alexander Roman, Katia Matcheva, Konstantin T. Matchev

Fluid Dynamics

Elastic pseudoturbulence induced by low-Galilei settling spheres

Ludovico Fossà, Michele Macaluso, Luca Brandt et al. (+1 more)

In this Letter, we show how a suspension of light solid spheres settling through a polymer solution results in a chaotic and highly-intermittent state. By leveraging particle-resolved direct numerical simulations, we investigate the effect of increasing polymer relaxation time and Deborah number $De$ on viscoelastic sedimentation at a low density ratio $\rho_s/\rho_f=5$ and a low Galilei number $Ga=3.16$. Even at moderate $De$, the spheres form gravity-aligned clusters and settle faster, while the polymer stresses energize the large scales of motion. The onset of elastic turbulence and intermittency is signaled by a $-4$ spectral scaling in the high-wavenumber range and by nonlinear high-order exponents of the velocity structure functions. These results indicate that viscoelastic effects induce pseudoturbulence in the presence of viscous-dominated sedimentation.
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All authors Ludovico Fossà, Michele Macaluso, Luca Brandt, Marco Edoardo Rosti

High Energy Physics (Phenomenology)

Higgs boson mass and thermal wino dark matter from Starobinsky supergravity with the MSSM

Daniel Frolovsky, Alexander Belyaev and Sergei V. Ketov

We propose a framework connecting cosmic microwave background (CMB) observables with high-energy particle phenomenology, based on Starobinsky supergravity coupled to the Minimal Supersymmetric Standard Model (MSSM). Cosmic inflation and supersymmetry (SUSY) breaking occur within the hidden sector emerging from Starobinsky supergravity. The inflationary scale sets the hidden-sector mass scale and, via gravitational mediation of SUSY breaking, the MSSM soft terms. The same hidden sector can also dynamically generate a high-scale $\mu$ term. The resulting MSSM spectrum fixes the high-scale threshold corrections and the boundary conditions for the renormalisation-group (RG) evolution of the Higgs quartic coupling. Three-loop RG evolution of the Higgs quartic coupling gives a Higgs boson mass consistent with the measured value within the theoretical and experimental uncertainties, thereby linking the amplitude of primordial scalar perturbations to the Higgs boson mass. With conserved R-parity, the lightest supersymmetric particle is stable, and the minimal framework developed here points to a nearly pure neutral wino as the dark-matter (DM) candidate. In the thermal-relic scenario, the observed abundance selects a wino mass of about $3$ TeV. Recent gamma-ray analyses exclude it as the sole DM component, even for conservative cored Galactic profiles. Alternatives include a subdominant wino fraction or late entropy dilution. Its loop-induced spin-independent wino-nucleon scattering cross section lies below current LUX-ZEPLIN sensitivity but within reach of next-generation liquid-xenon detectors. Electroweak corrections generate a small charged-neutral wino mass splitting, producing a long-lived charged wino and disappearing-track signature. A future $100$ TeV proton collider can discover the corresponding pure-wino signal or exclude the scenario independently of its cosmological abundance.
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Biological Physics · Cross-listed from q-bio.BM

Enhanced sampling and cryo-EM data resolve magnesium binding to RNA

Olivier Languin-Cattoën, Elisa Posani and Giovanni Bussi

Magnesium ions are essential for RNA structure but difficult to model due to slow binding kinetics and experimental limitations. We present an enhanced-sampling strategy that accelerates Mg$^{2+}$ inner-shell binding by orders of magnitude, enabling quantitative exploration of ion-binding motifs in a large ribozyme. The method combines a barrier-flattening bias with Hamiltonian replica exchange to efficiently sample multiple equivalent binding sites, and builds on an approach that achieved top performance in the CASP16 blind assessment of RNA solvation structure. Using cryo-electron microscopy maps for validation, we introduce a local analysis framework that infers the population of individual binding motifs from their agreement with experimental density, enabling site-by-site validation. We find that insufficient sampling of inner-shell binding leads to significantly poorer agreement with experiment, whereas force fields predicting different inner/outer binding equilibria remain largely indistinguishable at the current experimental resolution. These results highlight the dominant role of sampling in modelling divalent ion binding and provide a general strategy for integrating simulations with experimental data in complex biomolecular systems.
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Instrumentation and Methods for Astrophysics

A search for narrowband technosignatures from LTT 3780 with the Allen Telescope Array and the Karl G. Jansky Very Large Array

Chenoa D. Tremblay, Sofia Z. Sheikh, Vishal Gajjar et al. (+9 more)

The LTT3780 system hosts two known exoplanets-LTT3780b, a rocky super-Earth, and LTT3780c, a temperate sub-Neptune-orbiting a nearby M dwarf on opposite sides of the radius valley. LTT3780c has been proposed as a candidate Hycean world, making the system an important target for astrobiological investigation, particularly in light of recent JWST atmospheric observations. Although biosignature and technosignature searches both seek evidence of life beyond Earth, these approaches have historically been pursued independently. Well-characterized exoplanet systems provide an opportunity to combine these complementary search strategies. In this work, we conducted radio technosignature observations of the LTT3780 system using both the Allen Telescope Array (ATA) and the Karl G. Jansky Very Large Array (VLA). The two facilities provide complementary observational capabilities, with the ATA optimized for wide-band multi-beam post-processing analyses and the VLA enabling high-sensitivity real-time interferometric searches. Across approx 30 hr of total observing time, we searched for narrowband Doppler-drifting signals in the frequency range approx 1–10 GHz. After applying comprehensive radio-frequency interference mitigation and multi-beam consistency tests, no candidate signals consistent with astrophysical or technosignature origins were identified. We place minimum detectable effective isotropic radiated power limits of 4.7 X 10^12–3.6 X 10^13W across the observed bands and facilities. Although no technosignatures were detected, this work demonstrates how complementary observation and analysis strategies can be applied to exoplanets of astrobiological interest and serves as a pathfinder for future combined biosignature and technosignature investigations.
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All authors Chenoa D. Tremblay, Sofia Z. Sheikh, Vishal Gajjar, Nikku Madhusudhan, Isabel Gerrard, Daniel Czech, Talon Myburgh, David E. MacMahon, Ross A. Donnachie, Andrew P.V. Siemion, Matthew Lebofsky, Alex W. Pollak

Lattice Field Theory

The large-$N$ Yang–Mills $\Lambda$-parameter from step scaling

Claudio Bonanno, Jorge Luis Dasilva Golán, Margarita García Pérez et al. (+1 more)

We use the step-scaling method and results obtained at $N = 3, 5$ and $8$ to determine the $N$-dependence of the dynamically generated scale $\Lambda$ of $\mathrm{SU}(N)$ Yang–Mills theories. We implement the step-scaling method in a suitable finite-volume renormalization scheme based on twisted boundary conditions, introduced to effectively achieve large-$N$ volume independence, and on a coupling defined through the gradient flow. In the $\overline{\mathrm{MS}}$ scheme, we obtain the following values in terms of the gradient flow scale $t_0$: $\sqrt{8t_0}\Lambda_{\scriptscriptstyle{\overline{\mathrm{MS}}}} = 0.577(23)$, $0.632(32)$, and $0.611(43)$ for $N=3,5$ and $8$, respectively. They extrapolate to a large-$N$ value of: $\sqrt{8t_0}\Lambda_{\scriptscriptstyle{\overline{\mathrm{MS}}}} (N=\infty) = 0.639(36)$, and the $N$-dependence is given by $\sqrt{8t_0}\Lambda_{\scriptscriptstyle{\overline{\mathrm{MS}}}}(N)=0.639(36)[1-0.85(62)/N^2+\mathcal{O}(1/N^4)]$. This work represents the first calculation of the Yang–Mills $\Lambda$-parameter in the large-$N$ limit that does not rely on asymptotic scaling strategies.
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All authors Claudio Bonanno, Jorge Luis Dasilva Golán, Margarita García Pérez, Andrea Giorgieri

High Energy Physics (Theory)

Formation of holographic vortex in a rotating shell-shaped superfluid

Chang-Xu Yan, Hao-Ran Chang, Meng Gao et al. (+2 more)

We investigate the holographic superfluid dynamics subjected to external rotation on a spherical geometry. Through a linear perturbation analysis, we identify several dynamically unstable phases in the phase diagram, each characterized by distinct unstable modes. Employing fully nonlinear numerical simulations, we further demonstrate that these unstable modes generically drive the system into vortex-antivortex configurations with definite winding numbers, determined by the symmetry of the corresponding unstable modes.
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All authors Chang-Xu Yan, Hao-Ran Chang, Meng Gao, Yu Tian, Hongbao Zhang

Quantum Physics

Macroscopic position-position entanglement by photon recoil in Rydberg atoms

Xiao-Feng Shi

Entanglement between two spatially separate matter particles can be generated via many means and often resides in the internal states of particles. Here, via Rydberg blockade in two spatially separate neutral atoms, we find that the photon recoil in Rydberg excitation can push one atom microns away provided the other atom exerts a state-dependent Rydberg-mediated blockade. When the atoms are recaptured by optical traps, a position-position entangled state between two spatially separate atoms can emerge. This realizes a Bell state of two atoms, where the entanglement exists in the position of each atom and the distance between the two possible locations of each atom can be in the hundred-micron regime.
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Superconductivity

Emergent superconductivity upon disordering a topological insulator

Carlos Eduardo S. P. Corsino, Hermann Freire and Anurag Banerjee

We study the emergence of superconductivity in a quantum spin Hall insulator and identify a disorder-driven enhancement of pairing arising from quantum geometry. Using sign-problem-free quantum Monte Carlo simulations of the attractive Bernevig-Hughes-Zhang (BHZ) Hubbard model, we obtain a quantum phase transition as a function of interaction strength for different impurity densities. In the clean limit, the system develops bulk superconductivity for Hubbard interaction $\vert U \vert$ above a finite critical strength. Interestingly, strong impurities significantly reduce such $\vert U \vert$ required for the onset of superconductivity. Our calculations indicate that Cooper pairing first nucleates in subgap ring states surrounding the impurities and then evolves into a globally coherent superconducting phase. Our results demonstrate that impurity-generated bound states can promote superconductivity in systems with strong quantum geometry. This mechanism is expected to be relevant in nearly flat-band systems like moiré materials where quantum geometry plays a dominant role.
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High Energy Astrophysical Phenomena

Weakly supervised machine learning for model-agnostic searches of new phenomena in the $\gamma$-ray sky

Michael Krämer, Silvia Manconi and Kathrin Nippel

The $\gamma$-ray sky, as observed by the Fermi Large Area Telescope, contains a significant number of unassociated sources that may point to new astrophysical populations or more exotic phenomena. Machine-learning methods are widely used for source classification and searches for new physics, but most existing approaches rely on fully supervised training and therefore on explicit signal models. We explore weakly supervised classification as a less model-dependent strategy for analysing $\gamma$-ray source spectra. In a background-versus-mixture setup, classifiers are trained on samples with different signal admixtures rather than on fully labelled signal and background events. We study three representative scenarios: pulsar-active galactic nuclei separation as a controlled benchmark, the identification of dark-matter subhalos, and spectral irregularities induced by axion-photon oscillations. In each case we investigate the impact of signal fraction and sample composition on classification performance. Our results show that weak supervision can identify anomalous or signal-like subsets of data while reducing the reliance on detailed signal templates during training. In favourable cases, the method approaches the performance of fully supervised classifiers, while remaining applicable in situations where the signal model is uncertain or only partially specified. Weakly supervised learning therefore provides a complementary candidate-selection and anomaly-ranking strategy for $\gamma$-ray data analysis and searches for new phenomena.
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Physics and Society · Cross-listed from math.OC

Link-Based Multimodal Traffic Dynamics Model in Continuous-Time Framework

Ning Xie, Lei Wei, Nikola Bešinović et al. (+1 more)

Computationally efficient models for multimodal traffic flows with inter-modal interactions are foundational for coordinated traffic management. However, such models are lacking in the current literature. This study introduces a multimodal link transmission model (M-LTM) accommodating both continuous road traffic and discrete tramway traffic at the network level. M-LTM builds on a link model that captures the inter-modal interactions through the moving bottleneck theory. We further develop node models describing the flow transfer, tram operations, and mode interactions at tram stops and intersections. Specifically, the tram dwell process and dwell-induced congestion of road traffic are simulated at the stop node, and the intersection node model can reproduce queue spillback and tram priority. Case studies are conducted on two synthetic one-node networks, a synthetic arterial network, and the real network of Dresden to demonstrate the predictive power and the applicability of the proposed model in network traffic analysis and management. The GEH statistics of road traffic are below 4, and the average tram arrival time absolute errors are less than 10 seconds.
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All authors Ning Xie, Lei Wei, Nikola Bešinović, Meng Wang

Lattice Field Theory

Hints for string breaking in QCD

P. Cea, V. Chelnokov, L. Cosmai et al. (+1 more)

We present results for the chromo-electric field generated by a static quark-antiquark pair at nearly zero temperature in lattice QCD with 2+1 dynamical staggered fermions at physical quark masses. We investigate the evolution of the flux-tube structure as the distance between the static color charges increases. We find hints that string breaking occurs at a distance in the range $0.963 \; \text{fm} \; \lesssim \; d^* \lesssim \; 1.156 \; \text{fm}$.
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All authors P. Cea, V. Chelnokov, L. Cosmai, A. Papa

Nuclear Theory

Hadronic and partonic composition of QCD matter across the crossover

Artemiy Lysenko, Mark I. Gorenstein, Marek Gazdzicki et al. (+2 more)

We construct a simple equation of state of strongly interacting matter at zero chemical potentials that provides a unified description of lattice QCD thermodynamics in terms of hadronic and partonic degrees of freedom. The hadronic phase is described by the quantum van der Waals hadron resonance gas, extended by excluded-volume repulsion between mesons, while the quark-gluon plasma is modeled as an ideal gas of quarks and gluons supplemented with a phenomenological interaction term proportional to $T^3$. The two regimes are connected by a smooth crossover switching function. The three model parameters - the meson hard-core radius, the strength of the partonic interaction term, and the switching temperature - are determined from a fit to lattice QCD results for the trace anomaly. The resulting equation of state reproduces the lattice data on the pressure, entropy density, energy density, and speed of sound in the temperature range $T=100$-$500$ MeV. The fit yields a meson hard-core radius $r_M \simeq 0.2$ fm, a partonic interaction scale $A \simeq 600$ MeV, and a switching temperature $T_0 \simeq 216$ MeV, substantially exceeding both the pseudocritical temperature of the QCD chiral crossover and the chemical freeze-out temperature. This finding suggests that the transition from hadronic to partonic degrees of freedom is considerably more gradual than indicated by the chiral pseudocritical temperature alone, with hadronic states remaining an important component of strongly interacting matter up to temperatures of about $250$ MeV, well above the QCD chiral crossover.
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All authors Artemiy Lysenko, Mark I. Gorenstein, Marek Gazdzicki, Roman Poberezhniuk, Volodymyr Vovchenko

Quantum Physics

Dynamical structure factor with a pumping approach on a trapped-ion quantum computer

Etienne Granet, Keisuke Murota, Henrik Dreyer et al. (+3 more)

Dynamical structure factors (DSF) measured with neutron-scattering experiments provide key insights into the structure of materials. Their computation requires both the preparation of an equilibrium state and the implementation of Hamiltonian dynamics. We demonstrate the feasibility of computing DSF on the Quantinuum Reimei trapped-ion quantum computer, comparing the DSF of 1D Heisenberg model on $20$ sites, and that of the copper sulfate crystal. To that end, we introduce a pumping approach for computing the DSF $S(q,\omega)$ on quantum computers that enables targeting specific arbitrary values of frequencies $\omega$. This method time-evolves the initial state using a time-dependent Hamiltonian perturbed by a source term oscillating at the target frequency $\omega$. When targeting only a few frequency values, this approach provides a significant reduction in shot overhead compared to previous methods.
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All authors Etienne Granet, Keisuke Murota, Henrik Dreyer, Kentaro Yamamoto, Juan Pedersen, Hidemaro Suwa

General Relativity and Quantum Cosmology

Naked Singularities beyond Spherical Symmetry: Singular Inner Cauchy Horizons for the Einstein-Scalar Field System

Xinliang An and Shengrong Wu

In this work, we investigate the formation of naked singularities for the $3+1$-dimensional Einstein-scalar field system without symmetry assumptions. We generalize the spherically symmetric and self-similar naked-singularity solution constructed by Christodoulou in [4] by prescribing non-spherically symmetric initial data along both incoming and outgoing initial null hypersurfaces. We then establish global existence for the resulting solutions and analyze the singular structure of the inner Cauchy horizon. Our construction is based on employing a notion of four-type differences and designing a system of scale-invariant weighted norms to control the corresponding geometry. We show that the constructed spacetimes retain a global naked-singularity structure, characterized by an incomplete future null infinity and a singular inner Cauchy horizon. Moreover, we derive detailed asymptotics near the inner Cauchy horizon and prove the desired $C^{1, \frac{\kappa}{1-\kappa}+}$ inextendibility of these solutions, where $\kappa\in (0,1/3)$ is the self-similar parameter. This indicates a connection between weak and strong cosmic censorship: for the class of non-spherically symmetric solutions constructed here, the failure of weak cosmic censorship in its strict formulation is accompanied by a quantitative inextendibility mechanism at the inner Cauchy horizon.
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Materials Science

Interplay of Umklapp scattering and Sb-Au hybridization in surface-reconstructed Sb/Au(111)

Zhe Zheng, Celine Wassenberg, Stefanie Hilgers et al. (+2 more)

Surface reconstructions induced by atomic adsorption can strongly reshape metallic surface states, providing a direct pathway to tune their electronic structure. Using angle-resolved photoemission spectroscopy, we investigate the electronic structure of Sb/Au(111) during the coverage-driven evolution from the clean Au(111) surface to the $(14\times14)$ and Rec$(3\times\sqrt{3})$ phases. In the Rec$(3\times\sqrt{3})$ phase, triangular Fermi pockets emerge at the Brillouin-zone boundary. Their momentum positions are consistent with a reciprocal-space folding construction, but their reduced size near the Fermi level indicates a modification of the Au-derived $sp$ dispersion. The substantial modifications of deeper Au $d$-derived bands observed in ARPES further indicate significant mixing between Sb $p$ orbitals and Au $d$ states. These results show that the electronic structure of Sb/Au(111) is governed by the interplay between reconstruction-induced Umklapp scattering and interfacial orbital hybridization, highlighting adsorbate-substrate hybridization as a key mechanism for tuning and engineering surface electronic structures.
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All authors Zhe Zheng, Celine Wassenberg, Stefanie Hilgers, Carsten Westphal, Mirko Cinchetti

Chemical Physics

Plasmonic Cavity Quantum Dynamics under Linear Vibronic Coupling

Mohammad Shams, Kimia Kargar, David Mendive-Tapia et al. (+3 more)

Modeling the quantum dynamics of plasmonic excitations – collective oscillations of free electrons interacting with light – remains a significant theoretical challenge, particularly due to the need to accurately describe their quantum nature and the role of non-radiative decay channels. At the same time, a reliable theoretical framework is essential for advancing applications ranging from materials design to the development of new quantum optical platforms for quantum technologies. In this work, we address these challenges by introducing a Hermitian formalism based on the linear vibronic coupling (LVC) model for the description of plasmonic excitations in metallic nanostructures. This is parameterized through first-principles calculations – including but not limited to, the full DFT ground state with tight-binding excited states – and machine learning techniques using a newly implemented automated platform named Python Plasmonic Cavity (PyPC). The effectiveness of this workflow is demonstrated by successfully reproducing the experimental absorption spectra and vibronic broadening of plasmonic silver nanoparticles containing more than a hundred atoms. Additionally, the population dynamics of plasmonic states are investigated, showing that the LVC model accurately predicts ultrafast lifetimes for bright states and effectively captures the dynamics of dark states.
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All authors Mohammad Shams, Kimia Kargar, David Mendive-Tapia, Fatemeh Khalili, Oriol Vendrell, Zahra Jamshidi

Lattice Field Theory

Weight-Space Physics: Interpretable Hypernetworks for Lattice Quantum Field Theories

Tobias Göbel, Julian R. Ebelt, Zier Mensch et al. (+2 more)

Lattice field theory is the workhorse of non-perturbative physics, used to simulate phenomena from the strong nuclear force to critical phenomena in materials. Its Boltzmann distributions are parametrized analytically by coupling constants, but these bare parameters are weak predictors of observables – extracting physics typically requires extensive simulation. While normalizing flows have emerged as effective samplers at fixed couplings, it remains difficult to interpret what these networks have learned. This raises a natural question: can the physics be read off directly from the flow network parameters themselves, and can those parameters be generated for unseen theories? We propose lattice field theory as a testbed for neural network interpretability: because the target physics is qualitatively well-understood and smoothly varying, it provides ideal synthetic data with known ground truth. To this end, we introduce JEPAWG, a Joint-Embedding Predictive Architecture-based Weight Generator that maps couplings directly to flow weights via a learned latent space. On a scalar theory at lattices of size $6^2$ to $11^2$, the JEPAWG latent space recovers the correct intrinsic dimension of the underlying manifold, locates the phase transition, and encodes a finite-size shift aligned with the 2D Ising exponent $\nu \approx 1$, allowing us to uncover physical structure by studying the network weights alone. This suggests the fascinating idea of treating the network weights as a new type of physical observable. As a generator, JEPAWG also interpolates and extrapolates to unseen couplings effectively and remains robust to weight-space discontinuities introduced by multi-seed training data, outperforming PCA, AE, and VAE baselines.
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All authors Tobias Göbel, Julian R. Ebelt, Zier Mensch, Mathis Gerdes, Miranda C.N. Cheng

Atomic Physics

Density effects in precision laser spectroscopy of exotic helium atoms

Hubert J. Jóźwiak, Dimitar Bakalov, Michał Przybytek et al. (+2 more)

Exotic helium atoms act as unique atomic traps for heavy, negatively charged particles, protecting them from nuclear annihilation and nuclear capture on timescales long enough to enable high-precision laser spectroscopy. Such measurements serve as stringent tests of three-body quantum electrodynamics and offer a direct route to determining fundamental particle masses. Motivated by upcoming spectroscopic efforts targeting pionic ($\pi^{-\,4}\mathrm{He}^+$) and kaonic ($K^{-\,4}\mathrm{He}^+$) helium, we present a rigorous theoretical evaluation of the collisional and density effects governing these systems. Using an ab initio potential energy surface and coupled-channel quantum scattering calculations, we study the collisional stability of the candidate metastable states against inelastic quenching in a cryogenic helium buffer gas. Furthermore, we provide theoretical reference values for the pressure broadening and pressure shift coefficients of the targeted transitions. These results establish an essential benchmark for future experiments, paving the way for refined determinations of the pion and kaon masses.
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All authors Hubert J. Jóźwiak, Dimitar Bakalov, Michał Przybytek, Michail Stoilov, Piotr Wcisło

Quantum Physics

Room-temperature inversionless diamond nitrogen-vacancy electronic spin maser

Ali Fawaz and Sarath Raman Nair

We propose a method to create a room-temperature maser operating at approximately 2.9~GHz frequency using an ensemble of negatively charged nitrogen-vacancy electronic spins (NV) in diamond, without requiring population inversion. Our method considers a DC magnetic field of a few milli-Tesla (mT) applied along the perpendicular direction of an ensemble of NV spins aligned along a common axis. This perpendicular magnetic-field creates superposition states of $|m_{\mathrm{s}}=-1\rangle$ and $|m_{\mathrm{s}}=+1\rangle$ of the NV spin's ground state triplet levels and thereby makes it possible to drive all three transitions in the NV spin ground state. We model the system by including optical pumping of the NV spins, near-resonant driving of two transitions, and coupling the third transition to a near-resonant microwave resonator. Numerical estimates using experimentally realizable parameters show that inversionless masing can be achieved inside the microwave resonator using our method. As an application, we show that the output intensity of an inversionless maser ($1.1\times10^{14}$ spins) can be used for magnetic field sensing with a DC sensitivity on the order of a hundred pT/$\sqrt{\mathrm{Hz}}$. Our study opens a new direction in room-temperature diamond NV maser devices for quantum technological applications without the requirement of a strong bias magnetic field, as in conventional NV diamond masers.
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Astrophysics of Galaxies

The MAGPI Survey: Evidence for Non-Universal Resolved Dust Attenuation Relations Beyond the Local Universe

A. Mailvaganam, T. Zafar, P. Corcho-Caballero et al. (+39 more)

We study the spatially resolved relation between dust attenuation ($A_V$) and star formation rate surface density ($\Sigma_{\mathrm{SFR}}$) in galaxies from the MAGPI survey ($0.25 < z < 0.42$). Using Balmer-decrement-based attenuation maps for 178 galaxies, we investigate whether the locally calibrated resolved $A_V$–$\Sigma_{\mathrm{SFR}}$ relation remains valid at intermediate redshift by comparing MAGPI with the local relation measured from MaNGA. We find a clear positive correlation between $A_V$ and $\Sigma_{\mathrm{SFR}}$ in MAGPI, with systematically higher attenuation than in MaNGA at fixed $\Sigma_{\mathrm{SFR}}$. After matching galaxies in stellar mass ($M_{*}$) and offset from the star-forming main sequence ($\Delta$SFMS), MAGPI galaxies remain more attenuated than MaNGA galaxies at fixed $\Sigma_{\mathrm{SFR}}$. The attenuation excess is strongest for galaxies below the SFMS ($\Delta A_V \sim 0.40$ mag), weaker for galaxies on the SFMS ($\Delta A_V \sim 0.28$ mag), and minimal for galaxies above the SFMS ($\Delta A_V \sim 0.07$ mag). The dependence of the offset on $\Delta$SFMS suggests that nebular attenuation on kpc scales is regulated not only by local star formation activity, but also by the global evolutionary state of the host galaxy. Together, these results indicate that the resolved $A_V$–$\Sigma_{\mathrm{SFR}}$ relation is not universal, and that locally calibrated attenuation relations may not fully describe galaxies at intermediate redshift. This highlights the need for attenuation calibrations that account for galaxy population and redshift when interpreting spatially resolved galaxy properties.
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All authors A. Mailvaganam, T. Zafar, P. Corcho-Caballero, S. Salim, Y. Koyama, K. E. Harborne, C. D. P. Lagos, J. T. Mendel, E. Wisnioski, I. U. Aalia, S. Ayyappan, S. Barsanti, A. J. Battisti, J. Bland-Hawthorn, I. Breda, S. Carlson, Q.-H. Chen, B. Courtney-Barrer, S. M. Croom, S. Ellis, C. Foster, E. Gjergo, K. Grasha, S. Gurung-Lopez, S. Mobina Hosseini, S. Jeon, X. Lyu, T. Mukherjee, M. Mun, Hye-Jin Park, Y. Peng, L. A. Porta, J. Prathap, A. Raidani, R. S. Remus, B. S. Salmasi, G. Sharma, Sarah M. Sweet, Dian P. Triani, L. M. Valenzuela, G. van de Ven, Bodo L. Ziegler

Astrophysics of Galaxies

Vortex-reconnection energy bounds in Bose-Einstein-condensed and superfluid dark matter halos

Kaz{\i}m Yavuz Ekşi

Bose-Einstein-condensed (BEC) and superfluid dark-matter (SFDM) halos can contain coherent, wave-supported cores whose angular momentum is carried by quantized vortices. When vortices form a tangle, reconnections convert part of the vortex kinetic energy into dark phonons, density waves, Kelvin waves, and vortex loops, providing a microscopic channel by which vortex structure can affect halo-core evolution. We estimate the dynamical importance of this channel by combining the local Gross-Pitaevskii (GP) reconnection law with a halo-scale vortex-line density calibrated against Schrödinger-Poisson (SP) simulations. Vortex reconnections cannot appreciably restructure a standard SP halo core under the fiducial assumptions: for a $m=10^{-22}$ eV, $r_c=1$ kpc soliton and a one-percent energy-transfer efficiency per event, an unforced network transfers at most $1.3\%$ of the core virial energy in 10 Gyr. Reconnection converts ordered vortex energy into sound and smaller-scale excitations; we bound the cumulative transfer using a spectral scale measured in published SP halo simulations. To connect the result with measured systems, we match the standard soliton profile to half-light masses derived with a single mass estimator for eight classical Milky Way dwarf spheroidals. Assigning the measured aperture mass to the soliton gives ceilings of $0.98-4.52\%$ at the Mocz line-density reference and $0.061-3.19\%$ for a modest-rotation normalization. The largest value is a factor of 22 below the core virial-energy scale and limits the fixed-structure velocity change to $2.3\%$. The spectral reference represents fewer than one projected vortex crossing, so these are continuum upper limits; a vortex-free core has no reconnection heating. Reconnections remain worth testing because they are unavoidable when a tangle exists.
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