Nuclear Theory
Proton and Neutron Elastic Scattering on He Targets from $\textit{Ab Initio}$ SA-NCSM Optical Potentials
Darin C. Mumma, Matthew B. Burrows, Kristina D. Launey et al. (+2 more)
We construct and discuss $\textit{ab initio}$ nucleon-
nucleus optical potentials at low energies for $^{3,4,6}$He targets. In this work, we use the $\textit{ab initio}$ SA-NCSM/GF approach that combines the $\textit{ab initio}$
symmetry-adapted no-core shell model with the Green's function technique to construct optical potentials, and extend this formulation to
proton scattering and targets with nonzero
spin. We show that these optical potentials reproduce experimental differential cross sections and phase shifts for
proton and
neutron elastic scattering remarkably well. The $\textit{ab initio}$ SA-NCSM/GF approach provides nonlocal, energy dependent and dispersive optical potentials, suitable for the astrophysically relevant regime of low energies and for exotic
nuclei, where experiments are difficult and data is often unavailable.
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All authors Darin C. Mumma, Matthew B. Burrows, Kristina D. Launey, Daniel Langr, Tomas Dytrych
High Energy Physics (Experiment)
A homodyne detection scheme for all-optical photon-photon scattering experiments using 2D detectors
Timo Pohle, Leonard Doyle, Paul Ihde et al. (+3 more)
Low signal-to-noise ratios are a common problem in experiments attempting to measure
photon-
photon scattering. In the optical regime, where petawatt
lasers with femtosecond pulse durations are used, the large beam sizes cause the major contribution of the background to be spread over up to 100 ps in arrival time, whereas the signal is confined to the femtosecond scale. We present a balanced homodyne measurement scheme, which exploits this property to suppress the background. By interfering the signal with a short reference pulse, the measurement becomes effectively gated to the pulse duration and is therefore only sensitive to the co-timed part of the light, reducing the effective background by 3-4 orders of magnitude. Additionally, increasing the reference pulse energy increases the amplitude of the measured quantity without changing the intrinsic signal-to-noise ratio. Using this property, other external noise sources can be made negligible by boosting the measured quantity above the noise floor. Using two-dimensional detectors further enhances the scheme by improving sensitivity and enabling self-referenced single-pulse measurements. In addition, an evaluation procedure based on maximum-likelihood estimation is presented and demonstrated. The robustness and performance of this scheme are demonstrated on simulated data, where a more than 100-fold reduction of measurement time compared to conventional
photon-counting methods under realistic conditions is found.
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All authors Timo Pohle, Leonard Doyle, Paul Ihde, Felix Karbstein, Jörg Schreiber, Matt Zepf
Optics
Collective emission of subwavelengths atom-like emitter arrays in the presence of inhomogeneous broadening
Uri Israeli, Shahar Levi, Sagi Ben-Avi et al. (+4 more)
Quantum metasurfaces comprised of subwavelength atomic arrays emerged as a promising platform for enhanced atom-
photon interaction. However, realizing such a system with solid-state emitters has been considered impractical due to strong inhomogeneous broadening, which was expected to suppress the
photon-mediated interactions that underpin collective emission. Here we report the observation of collective emission from subwavelength arrays of silicon-vacancy centres in diamond – solid-state emitters whose inhomogeneous broadening exceeds the natural linewidth by two orders of magnitude – demonstrating that collective effects such as resonance shifts, modified decay rates and directional coherent emission survive this disorder. A crucial enabling element is the implantation of a high density of silicon ions at each array site. This creates so-called superatoms, local ensembles that probabilistically achieve frequency matching across the array and enhance the collective response. We support our observations with a theoretical analysis explaining the mechanisms that preserve the collective effects even in the presence of inhomogeneity. These observations have direct implications for the realization of subwavelength arrays in any solid-state system, paving the way for
quantum-emitter metasurfaces that are naturally integrated into nanophotonic environments.
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All authors Uri Israeli, Shahar Levi, Sagi Ben-Avi, Ada Kransnovsky, Daniel Silvian, Shlomo Winberg, Rivka Bekenstein
High Energy Astrophysical Phenomena
The Western Jet of SS 433/W50: Hard X-ray Emission, Spectral Evolution, and Comparison to the Eastern Jet
Brydyn Mac Intyre, Samar Safi-Harb, Dmitry Khangulyan et al. (+5 more)
The W50 nebula powered by the microquasar SS 433 is a unique laboratory for exploring several fundamental astrophysical phenomena. This study presents observations from NuSTAR and XMM-Newton, concentrating on the western lobe of W50. Detection of hard non-thermal X-ray emission is reported, extending up to approximately 30 keV. This emission originates from a compact, knotty area referred to as the "Head", located at approximately 17 arcmin (equivalent to 26.5 pc at an assumed distance of 5.5 kpc) to the west of SS 433, and characterized by a power-law spectrum with a hard
photon index of 1.55 +/- 0.07 (0.5-30 keV). Moving westward from SS 433, the
photon index gradually steepens, ultimately reaching a
photon index of 2.10 +/- 0.05 in the "w2" region centered at approximately 35 arcmin or approximately 56 pc from SS 433. The distinct hard X-ray
knots observed serve as clear markers for sites of particle acceleration within the western jet. The synchrotron radiation from the "Head" region implies equipartition
magnetic field strength B of approximately 15 microG. Notably, these properties (western "Head" location, unusually hard spectral index, inferred
magnetic field, and spectral
evolution away from SS 433) are very similar to what has been observed in the eastern lobe, supporting a symmetric jet-driven origin. Finally, the broadband spectral energy distribution (SED) and X-ray morphology are modeled using semi-analytic jet models, exploring different jet velocity and
magnetic field configurations. The results favor a scenario in which in-situ particle acceleration and synchrotron emission dominate, with implications for understanding particle transport, jet dynamics, and W50's role as a
Galactic PeVatron.
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All authors Brydyn Mac Intyre, Samar Safi-Harb, Dmitry Khangulyan, Shuhan Zhang, Kaya Mori, Naomi Tsuji, Felix Aharonian, Laura Olivera-Nieto
Astrophysics of Galaxies
Polarized and unpolarized synchrotron emission from dark matter in extragalactic targets
Javier Reynoso-Cordova, Catherine Gibson and Stefano Profumo
We compute 95% confidence-level upper limits on the dark matter annihilation cross section and decay rate from both total-intensity and polarized synchrotron emission in five extragalactic targets: M31, the Large Magellanic Cloud (LMC), the Draco and Sculptor
dwarf spheroidal
galaxies, and the Coma cluster. Using Planck maps at 30, 44, and 70 GHz, we solve the
diffusion-loss equation for dark-matter-produced electrons and positrons numerically with DRAGON and integrate the resulting synchrotron emission along the line of sight with HERMES, computing both total-intensity and polarized-intensity maps for each target with target-specific
magnetic-field, gas, and radiation-field environments. The 30 GHz channel yields the most stringent constraints in all cases, and limits on annihilation or decay into $e^+e^-$ are stronger than those for $b\bar{b}$ due to the harder injected spectrum. For most targets the total-intensity and polarized limits are broadly comparable; the LMC is an exception, where Faraday depolarization in the turbulent disk suppresses the polarized signal relative to total intensity, making total intensity the primary
estimator. Our results are robust against the choice of flux
estimator and coordinate uncertainty. This work demonstrates that microwave polarimetry provides a complementary and largely independent probe of dark matter synchrotron emission in extragalactic targets.
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Optics
Optical Poling Reveals Hidden Molecular Restructuring in Multimode Fibers, Unlocking Ultra-Efficient Third-Order Nonlinearities
Maxime Jonard, Thomas Larqué, Dan-Esli Bouyou Bouyou et al. (+10 more)
Optical poling is a well-established technique for inducing \chi^{(2)} nonlinearity, yet its impact on silica's molecular structure remains unexplored. Here, we report the first direct observation of molecular restructuring in large-core graded-index multimode fibers (MMFs) induced by optical poling, transforming the silica tetrahedral ring network. Through coherent light beating, this process converts large rings of more than four SiO_4 tetrahedra into smaller ones, altering both linear and nonlinear optical susceptibilities. Contrary to the assumption that poling efficiency stems solely from charge displacement, we show that structural modifications dominate, leading to record enhancements in third-order nonlinear processes, including
geometric parametric instabilities (GPIs) and Kerr self-cleaning, despite a low modification of the Kerr coefficient. High-energy poling acts as an in situ annealing process, dynamically modulating the refractive index for unprecedented spatiotemporal light control. These findings provide fundamental insights into silica's molecular dynamics under intense optical fields and open avenues for ultra-efficient nonlinear optical devices, enabling next-generation fiber-based photonics for high-power
lasers, broadband light generation, and all-optical signal processing.
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All authors Maxime Jonard, Thomas Larqué, Dan-Esli Bouyou Bouyou, Tigran Mansuryan, Alessandro Tonello, C. Sandt, Jean-René Duclère, Julie Cornette, Yago Arosa, Marc Fabert, Claire Lefort, Vincent Couderc, Maggy Colas
Soft Condensed Matter
Flow of deformable droplets: self-pinned glasses and string-like flow
Achille Quarante, Michael Chiang, Davide Marenduzzo et al. (+1 more)
We investigate, through numerical simulations, the rheology of a dry suspension of deformable droplets under pressure-driven flow. The system exhibits two force-driven dynamical transitions. At low forcing, the suspension behaves as a yield-stress material: below a critical force, droplets remain arrested in an amorphous solid-like state. Our simulations suggest that yielding is controlled by droplet contacts and predict that the critical force strongly depends on deformability. Above yielding, the suspension does not flow steadily but rather enters an intermittent, stick-slip regime characterised by long-lived caging and non-Gaussian velocity fluctuations. This state can be interpreted as a "self-pinned” glass, in which slowly evolving droplet overlaps generate an effective rugged energy landscape that dynamically traps droplets and produces intermittent rearrangements reminiscent of near-critical dynamics in depinning models. At larger forcing, droplets deform sufficiently to continuously exchange neighbours, progressively annealing the overlap structure and driving a dynamic transition to a string-like, flowing state. Our results identify the restructuring of overlap networks as a generic mechanism which controls flow in driven suspensions of deformable particles.
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All authors Achille Quarante, Michael Chiang, Davide Marenduzzo, Giuseppe Negro
Mathematical Physics · Cross-listed from math.QA
Defects in skein theory and TQFT
Patrick Kinnear and Ingo Runkel
Given a 3-
manifold $M$ with a network of line and point defects in its boundary, we define the skein module of this configuration, generalizing the well-studied case of 3-
manifolds which only admit point defects in the boundary. We prove that when all defects are labelled by semisimple data, our skein module is isomorphic to the state space of $\partial M$ in the defect version of the Reshetikhin-Turaev TQFT constructed by Carqueville-Runkel-Schaumann. Our defect skein modules follow naturally by globalizing the graphical calculus of module categories and functors thereof, and generalize the possible defect data considered in the defect TQFT beyond the semisimple case.
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High Energy Physics (Phenomenology)
Interpolation between Sudakov and BFKL rapidity evolutions for TMD factorization at small $x$
Ian Balitsky
Within the framework of rapidity-only small-$x$ TMD factorization, the
evolution with respect to the rapidity cutoff is initially governed by Sudakov double logarithms and subsequently by BFKL/BK single logarithms. The
evolution equation proposed in this paper correctly reproduces both the Sudakov and BFKL limits, while providing a consistent interpolation between these two regimes.
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Quantum Physics
Srinivasan Arunachalam and Arkopal Dutt
We give a general framework for
tomography of states that have bounded-extent with respect to a structured class of states. Let $\textsf{C}$ be a family of $n$-
qubit states such that: $(i)$ $\textsf{C}$ is succinctly representable and $(ii)$ there is a weak agnostic learner of $\textsf{C}$. We give a
tomography protocol for an unknown state $|\psi\rangle$ that is promised to admit a decomposition of the form $|\psi\rangle = \sum_i c_i |\phi_i\rangle$, where $|\phi_i\rangle \in \textsf{C}$ with bounded $\ell_1$-norm of the coefficients (which we call extent). Our main contribution is to show that a weak agnostic learner for $\textsf{C}$ can be boosted into a
tomography algorithm for states with bounded extent with respect to $\textsf{C}$. Our reduction is black-box and applies broadly across model classes. As an application, when $\textsf{C}$ is the class of stabilizer states, we obtain
tomography algorithms for states with stabilizer extent $\xi$ up to trace distance $\varepsilon$, in time $\textsf{poly}(n,(\xi/\varepsilon)^{\log(\xi/\varepsilon)})$, which is improvable to $ \textsf{poly}(n,\xi,1/\varepsilon)$ assuming the algorithmic
polynomial Freiman-Ruzsa
conjecture in the high-doubling regime. When the unknown state $|\psi\rangle$ is arbitrary, we give an algorithmic decomposition result in the spirit of a weak regularity lemma for
quantum states with respect to $\textsf{C}$ and show that the structure in $|\psi\rangle$ that is explainable by $\textsf{C}$ can be efficiently learned. Our main conceptual message is that agnostic learning of a structured base class automatically yields learnability of its low-complexity linear span.
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Astrophysics of Galaxies
Dust in the very metal-poor galaxy Sextans A with JWST. I: Characterizing the evolved stellar population of Sextans A based on JWST observations and stellar evolution models
C. Gavetti, F. Dell'Agli, E. Tarantino et al. (+22 more)
The nearby
star-forming
dwarf galaxy Sextans A offers a unique window into
galaxy evolution in the early Universe, owing to its extremely low
metallicity (about 1-7% Zsun). Recent JWST imaging of Sextans A spanning 1-21 micron enables a detailed characterization of its dusty
stellar populations and interstellar medium. In this work, we compare the observed JWST color-magnitude distributions of evolved
stars with
stellar evolution and
dust-formation models to characterize the properties of the asymptotic
giant branch (AGB) population, including progenitor mass, formation epoch,
metallicity, and
dust production. Evolutionary tracks for 0.8-7 Msun
stars with
metallicity Z=10^-3 provide good agreement with the overall distribution of AGB
stars in Sextans A. More than 90% of the AGB population occupies a nearly vertical sequence in the color-magnitude diagrams, corresponding to
stars spanning a wide range of masses and ages but exhibiting little or no circumstellar
dust. This sequence appears to be dominated by oxygen-rich (M-type) AGB
stars and reveals that the F444W flux is a robust luminosity diagnostic. A small subset of sources displays strong infrared excesses and is dominated by carbon
stars descending from 1.25-1.5 Msun progenitors that formed about 2-3 Gyr ago and are currently in the final AGB phases. Their MIRI colors imply very low
metallicities, consistent with estimates from the red
giant branch morphology (about 1-2% Zsun). Finally, we show that the JWST/NIRCam F277W-F444W color serves as an effective proxy for the
dust production rate, with models predicting rates up to 10^-7 Msun/yr for the reddest sources in Sextans A.
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All authors C. Gavetti, F. Dell'Agli, E. Tarantino, M.L. Boyer, I. McDonald, J.Th. Van Loon, D.A. Garcia-Hernandez, M.A.T. Groenewegen, A. Nanni, J.A.D.L. Blommaert, R.D. Gehrz, L.M. Gerlach, S. Goldman, M. Marengo, K.B.W. McQuinn, J.M. Oliveira, J. Roman-Duval, R. Sahai, E.D. Skillman, B.F. Williams, A. Javadi, O.C. Jones, F. Kemper, F. La Franca, G. C Sloan
Statistical Mechanics
Fermion sign problem and the structure of Lee-Yang zeros. II. Finite temperature results for a model system without interactions
Ran-Chen He, Jia-Xi Zeng, Shu Yang et al. (+3 more)
Beyond the analysis of the Lee-Yang (LY) zero of $\xi$ at $0$ K presented by our previous work [He et. al. Phys. Rev. E 113, 24115 (2026)], it is important but intricate to understand how these zeros evolve with temperature ($T$). Here, we use an analytically solvable noninteracting one-dimensional particle-on-a-ring model to address this. We determine the trajectories of these zeros and analyze how their
evolution with $T$ reshapes the analytic structure of the partition function. In particular, the zero originating from $\xi=-1$ at $T=0$ remains close to $-1$ at low $T$, where it governs the sign factor and strongly constrains continuation along the real $\xi$ axis. This explains why both direct extrapolation and implicit schemes such as contour-based fitting can fail in the low-$T$ regime, even at high fitting order, while becoming reasonable again once the relevant zeros move away at higher $T$s. Furthermore, based on the
polynomial structure of the partition function, we propose a new fitting strategy for low-$T$ fermionic properties. The key is to first obtain reliable high-$T$ fermionic properties by continuing sign-problem-free data in $\xi\in[0,1]$ to $\xi=-1$, and then extend this information toward lower $T$ through $T$-fitting of the $\xi$-independent remainder $\phi(\beta)=Z_{\text{F}}$. These results provide a solvable
benchmark for diagnosing the validity of analytic continuation and suggest a possible route toward treating more realistic interacting fermionic systems.
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All authors Ran-Chen He, Jia-Xi Zeng, Shu Yang, Cong Wang, Qi-Jun Ye, Xin-Zheng Li
High Energy Physics (Phenomenology)
Two-Pole Structure of $\Lambda(1405)$ with Temporal Evolution and Spatial Distribution
Yu Zhuge and Zhan-Wei Liu
The $\Lambda(1405)$ is a special
hadron resonance associated with two poles of the scattering amplitudes, and its nature remains under debate since its discovery before the birth of the
quark model. In this work we study the structures of these two poles and their temporal
evolution, including their difference, interference, and synergy. Each pole can usually be represented by the Gamow vector $|\psi^{\rm Gamow}\rangle$ in the complex momentum space $|\vec p e^{-i\theta}\rangle$. We construct its representation $|\psi^{\rm phys}\rangle$ in the real momentum space $|\vec p\rangle$ through the analytic continuation of the Gamow wavefunction, which also satisfies the
Hamiltonian eigenvalue equation with the assistance of a virtual state vector. Both the decreasing behavior of the resonance and the production of the decayed scattering states can be simultaneously described by the temporal
evolution $|\psi^{\rm phys},t\rangle=\exp(-iH t) \, |\psi^{\rm phys}\rangle$. The state $|\psi^{\rm phys},t=0\rangle$ gives the finite-range confinement of the resonance while $|\psi^{\rm phys},t\to \infty\rangle$ provides a Breit-Wigner-like distribution of the final scattering states whose appearance probability is nonzero as $r\to \infty$. In the two-channel system $\pi\Sigma$-$\bar{K}N$, we first dynamically generate the two poles of $\Lambda(1405)$ and then discuss their temporal evolutions and spatial distributions which can produce results consistent with experimental measurements such as the $\pi\Sigma$ invariant-mass spectrum and provide a new path to study
hadron resonances.
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Materials Science
Near-room-temperature magnetoelectric coupling engineered through inversion-breaking tilts in a bulk perovskite polytype
Struan Simpson, Urmimala Dey, Martin R. Lees et al. (+3 more)
Systematic strategies to design properties such as ferroelectricity or magnetoelectric coupling are well established in simple perovskite materials, but they remain scarce in more complex framework structures. Using a hexagonal polytype of the ternary manganite AMnO3 (A = Ba, Sr, Ca) as a model system, we introduce a
symmetry-guided design principle in which an inversion-breaking rigid-unit mode (RUM) serves as a single structural instability generating both polar and
ferromagnetic orders within a bulk material.
Symmetry analysis and first-principles calculations reveal that co-operative tilts of the Mn2O9 bioctahedral dimers generate both a spontaneous polarization and a
ferromagnetic moment. High-resolution diffraction and
magnetic susceptibility measurements show the structural and
magnetic orders persist as high as 450 K and 280 K, respectively, highlighting the untapped potential of framework structures which deviate from simple perovskite motifs to be designed to host useful ferroic properties. Our approach establishes a transferable
symmetry-based framework to engineer ferroelectric and magnetoelectric states across chemically diverse framework architectures.
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All authors Struan Simpson, Urmimala Dey, Martin R. Lees, Ivan Da Silva, Nicholas C. Bristowe, Mark S. Senn
High Energy Physics (Phenomenology)
Correlating lepton flavor violating $b \to s$ and leptonic decay modes in a minimal abelian extension of the Standard Model
Davide Milillo
We examine possible correlations between $b \to s \ell_1^- \ell_2^+$ transitions – both in the
lepton flavor conserving ($\ell_1=\ell_2$) and violating case ($\ell_1 \neq \ell_2$) – and purely leptonic
flavor violating decays within the ABCD model [1], a minimal abelian extension of the Standard Model (SM) introducing a new $\text{U}(1)'$
symmetry. The associated neutral $Z'$
boson has generation-dependent,
flavor non-universal couplings to SM
fermions, governed by three rational parameters $\epsilon_{1,2,3}$, which sum to zero to ensure gauge anomaly cancellation. Each $\epsilon_i$ is common to all
fermions of a given generation, thus inducing correlations among
quark and
lepton observables. For
lepton flavor conserving (LFC) processes, only small deviations from SM predictions were found [2], reflecting the mutual constraints between the
quark and
lepton sectors, which preclude large discrepancies. On the other hand, the model allows tree-level
lepton flavor violating (LFV) decays, yielding correlations between LFV $b\to s$ transitions and charged
lepton decays. The analysis of such correlations shows that the current experimental upper bounds for the rates of $\tau^- \to \mu^-\mu^+\mu^-$, \ $\mu^-\to e^- \gamma$, \ $\mu^- \to e^- e^+e^-$ and $\mu^- \to e^-$ conversion in
nuclei constrain branching ratios of LFV $B_{(s)}$ decays in hierarchical order [2].
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Materials Science
Scalable Prediction of Complex Surface Reconstructions under Operating Conditions via Harmony-Search-Based Global Optimization
Shi-Yang Chen and Xiao-Ming Cao
The dynamic structural
evolution of catalyst surfaces under operating conditions dictates catalytic performance, yet capturing these reconstructions atomically remains challenging. Global optimization based on machine learning interatomic potentials (MLIPs) is promising, but scaling to large-scale, low-
symmetry operando systems is hindered by expansive search spaces and potential energy surface (PES) inaccuracies. Herein, we present Harmony-search-based Atomic Structural Global Optimization (HASGO), a framework integrating universal MLIPs with a harmony search
algorithm. HASGO overcomes the problem of PES softening by incorporating a multi-head replay fine-tuning protocol. Moreover, the
stochastic structural perturbation step in its
algorithm offers a fault-tolerant strategy to enhance the robustness of global convergence. These enable HASGO to identify intricate surface
oxide overlayers that align with atomic-resolution microscopy, thereby resolving the square-pyramidal subsurface O5 motif on Ag(100) during ethylene epoxidation. This scalable framework provides a robust approach for uncovering operando structures, accelerating the rational design of industrial catalysts.
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Mesoscale and Nanoscale Physics
Polar and quadratic magneto-optical Kerr effects in nonmagnetic/ferromagnet bilayers for spin-orbit torque measurements
Yukihiro Marui, Masashi Kawaguchi, Kohji Nakamura et al. (+1 more)
Recent studies have revealed that
spin Hall magnetoresistance (SMR) contributes to both the anomalous and planar
Hall resistances in nonmagnetic metal (NM)/
ferromagnetic metal (FM)
bilayers. This effect becomes pronounced when the NM layer exhibits a large
spin Hall angle, as in W/CoFeB
bilayers. In such systems, the ratio of planar to anomalous
Hall resistances, normally small in single CoFeB layers, can approach unity. This unusually large ratio complicates the determination of
spin-torque efficiency using harmonic
Hall voltage measurements. To overcome this limitation, magneto-optical Kerr effect (MOKE) measurements have been proposed as an alternative approach. Here, we investigate the polar and quadratic MOKE components, which correspond to, respectively, the anomalous and planar
Hall resistances in the low-frequency limit to clarify whether the MOKE measurements are suitable for characterizing the
spin-torque efficiency. We find that the ratio of quadratic to polar MOKE signals in NM/FM
bilayers is significantly smaller than the corresponding
Hall resistance ratio, indicating that SMR contributes negligibly to the MOKE response in the visible range. Consequently, the
spin-torque efficiency extracted from MOKE measurements agree well with those expected from the
spin Hall angle of the NM layer. These results clarify the reason why MOKE measurements provide reliable determination of the
spin-torque efficiency.
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All authors Yukihiro Marui, Masashi Kawaguchi, Kohji Nakamura, Masamitsu Hayashi
Cosmology and Nongalactic Astrophysics
Mass-Varying Neutrinos from an Inverse Symmetron
Mainak Baidya, Øyvind Christiansen, Vitor da Fonseca et al. (+2 more)
Neutrinos enter cosmology in different ways and are constrained by distinct observational probes across different epochs: as a relativistic species at high
redshift, as a massive but clustering-suppressing component at low
redshift, and as a particle physics observable in laboratory experiments. Low (verging on negative) bounds on
neutrino mass from
galaxy surveys motivate exploration of models where
neutrinos may couple to dark energy, causing their mass to vary over
cosmic evolution. If the coupling involves an inverse phase transition (
symmetry broken, rather than restored, as
neutrinos become nonrelativistic) this can tame instabilities in
neutrino growth, appear as a lower
neutrino mass in
galaxy surveys, and add extra suppression to the matter power spectrum. We find that the late-time decoupling shuts down the fifth force and inhibits the excessive growth of
neutrino perturbations, thereby eliminating linear-regime instabilities. The model may potentially address the Hubble tension via an early dark energy component localized around the time of recombination.
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All authors Mainak Baidya, Øyvind Christiansen, Vitor da Fonseca, Eric V. Linder, David F. Mota
Astrophysics of Galaxies
ALMAGAL IX. The chemical complexity of AG318.9477-00.1960: A line-identification template for ALMAGAL
J. Allande, M. T. Beltrán, V. M. Rivilla et al. (+36 more)
We present a detailed molecular line analysis of one of the most chemically rich cores in the ALMAGAL sample, the high-mass core~9 in the AG318.9477-00.1960 clump (AG318-c9), located at a heliocentric distance of \sim 10.4\,\rm kpc. We further assessed whether the emission of selected COMs, that is, ethylene glycol ((CH_2OH)_2; EG), glycolaldehyde (CH_2(OH)CHO; GA), and methyl formate (CH_3OCHO; MF), can be used to trace the innermost regions of hot molecular cores (HMCs). We analysed ALMA Band~6 observations (\sim 217-221GHz). Spectral line identification and local thermodynamic
equilibrium modelling were performed using the software MADCUBA. We derived the physical parameters, including the column density (N), excitation temperature (Tex), velocity, line width, and molecular abundances relative to H_2, for all detected species. The chemical inventory of AG318-c9 was compared with that of the HMC G31.41+0.31 (G31). In addition, we performed a pixel-by-pixel analysis of EG, GA, and MF to generate spatially resolved N and Tex maps and corresponding radial profiles.
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All authors J. Allande, M. T. Beltrán, V. M. Rivilla, Á. López-Gallifa, C. Y. Law, Á. Sánchez-Monge, C. Battersby, M. Benedettini, H. Beuther, C. L. Brogan, L. Bronfman, S. D. Clarke, L. Colzi, D. Elia, F. Fontani, G. A. Fuller, T. R. Hunter, P. T. P. Ho, K. G. Johnston, B. M. Jones, K. -T. Kim, P. D. Klaassen, R. S. Klessen, R. Kuiper, D. C. Lis, C. Mininni, S. Molinari, T. Möller, L. Moscadelli, A. Nucara, S. Pezzuto, P. Schilke, E. Schisano, F. van der Tak, Y. Tang, A. Traficante, S. Walch, Q. Zhang, T. Zhang
Chaotic Dynamics
Unified Geometry-Guided ML-FTLE for Tracking Transient Chaos from Scalar Time Series
S. V. Manivelan, Andrei Velichko and I. Manimehan
Detecting transient chaos from scalar observations without governing equations represents a fundamental challenge in nonlinear dynamics. We propose a geometry-guided machine learning framework that unifies predictive trajectory divergence with macroscopic attractor morphology to track abrupt regime shifts. The methodology extracts a local instability scale via out-of-sample k-nearest neighbor forecast errors to establish the ML-FTLE
estimator, subsequently mapping this temporal divergence onto a structural closeness
matrix derived from a minimal dictionary of Poincare occupancy grids. By employing partial least squares regression, we extract a latent
geometric component calibrated directly to the empirical finite-time Lyapunov spectrum, yielding the Poincare-based
geometric-guided FTLE. Validation against analytical QR-FTLE baselines confirms that fusing topological state spaces with predictive divergence systematically improves continuous transition tracking. The Structural Similarity Index optimally resolves gradual damping, while Hausdorff Distance exhibits extreme resilience during abrupt phase-space collapses. Furthermore, macroscopic spatial discretization acts as a robust topological regularizer against additive Gaussian noise, preserving deterministic signatures even at moderate signal thresholds. This equation-free framework provides a highly accurate, noise-resilient diagnostic for monitoring structural transitions in complex non-stationary systems.
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Soft Condensed Matter
Hydrogel mechanics below swelling equilibrium
A. Chao Correas, Y. Feng, R. W. Style et al. (+1 more)
Hydrogels are versatile soft materials whose behavior arises from complex
polymer-network-fluid interactions. Combining theory and experiments, we show that their mechanics simplify greatly below swelling
equilibrium. In this regime, mixing and pore pressures effectively control local hydration, relegating
polymer-network elasticity to accommodate the deformed shape. This mechanical hierarchy renders partially-dried hydrogels analogous to incompressible solids with environment-driven target volumes, enabling a staggered mechanical description that accurately captures their state and behavior.
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All authors A. Chao Correas, Y. Feng, R. W. Style, D. S. Kammer
Statistical Mechanics
Topologically Enforced Lifshitz Multicriticality in One Dimension
Kuang-Hung Chou and Xue-Jia Yu
Recent advances have revealed that
topology can further enrich the universality classes of
quantum phase transitions, thereby extending beyond the traditional paradigms of statistical and condensed matter physics. However, multicriticality between topologically distinct
quantum critical lines remains insufficiently explored. In this Letter, we systematically construct and investigate a novel class of topologically enforced Lifshitz multicritical points in one dimensional
chiral symmetric fermionic systems. Such multicriticality is driven solely by changes in the
topology of neighboring critical lines, beyond previously recognized multicritical points that are typically induced by changes in critical exponents. More importantly, the topologically enforced multicriticality identified here can host robust topological degeneracies while surprisingly exhibiting a breakdown of the Li Haldane bulk boundary correspondence-a phenomenon we elucidate through a simple physical picture.
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Quantum Physics
Ferroelectrical Switching as a Probe of Quantum Damping in Magnetic Spin Systems
Yuefei Liu, Anna Delin, Olle Eriksson et al. (+3 more)
While damped
spin dynamics is important for the understanding of
magnetic materials, clear signatures of
quantum corrections to the Gilbert damping mechanism remain elusive. We propose a route to distinguish
quantum and classical Gilbert
spin damping using ferroelectric control of a
magnetic dimer. Ab initio calculations for dimers on ferroelectric substrates show that polarization reversal switches the inter-
spin exchange between
ferromagnetic and
antiferromagnetic regimes. We formulate a magnetization-based diagnostic that relates magnetization traces to
entanglement dynamics, which enables ferroelectrical on/off control of dimer
entanglement. Material-informed
quantum Landau-Lifshitz-Gilbert simulations illustrate how the signature of magnetization dynamics can, in principle, be used to infer the existence of
quantum Gilbert
spin damping. This minimal and non-volatile platform connects first-principles modeling to experimentally accessible observables and provides a starting point for voltage-controlled
quantum entanglement in
magnetic spin networks.
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All authors Yuefei Liu, Anna Delin, Olle Eriksson, Erik Sjöqvist, Kaiyou Wang, Qirui Cui
Quantum Physics
Coherent versus stochastic error injection on a repetition-code logical qubit in superconducting hardware
S. L. M. van der Meer, M. Serra-Peralta, Y. Xin et al. (+5 more)
The performance of
quantum error correction (QEC) codes is limited by the underlying physical noise. Theoretical studies show that coherent and
stochastic noise have different effects when performing QEC with either surface or repetition codes. We use the bitflip repetition code, realized in a transmon
quantum processor, as a testbed to experimentally study the impact of injecting coherent versus
stochastic errors on the logical performance. We adapt a scalable free-
fermion simulator to simulate the experiments and we modify a subset sampling technique to efficiently sample
stochastic noise in the
quantum circuit. In the experiment, we do not observe the difference in logical fidelity predicted by simulation for either the distance-3 or distance-5 repetition codes. We hypothesize that this discrepancy could be explained by small drifts in
qubit frequencies, which introduce phase-coherent noise that `stochastifies' the injected coherent errors. Our work contributes to advancing an understanding of how coherent errors affect experimental QEC.
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All authors S. L. M. van der Meer, M. Serra-Peralta, Y. Xin, M. Finkel, H. M. Veen, M. W. Beekman, L. DiCarlo, B. M. Terhal
Quantum Physics
Measurement circuit ansatz: Naimark versus quantum neural-network measurements
Sung Won Yun, Thi Ha Kyaw and Joonwoo Bae
In this work, we present constructions of
quantum circuits to implement general measurements on
quantum hardware. Firstly, we investigate a
quantum circuit ansatz by following the Naimark extension with a universal set of gates, such as controlled-NOT and single-
qubit gates; we call it a Naimark measurement. We present a
circuit ansatz framed by the Naimark extension, leaving single-
qubit gates with parameters, and apply a classical optimizer to determine their parameters to approximate a desired
quantum measurement. Secondly, we relax the Naimark measurement with
quantum neural-network (QNN)
circuits, employing parameterized
quantum circuits. We present hybrid Naimark-QNN measurements by incorporating QNN
circuits into Naimark measurements. Thirdly, we also consider fully QNN measurements with shallow parameterized
circuits. Then, we compare the constructed measurement
circuits, Naimark, hybrid Naimark-QNN, and fully QNN measurements, for strategies of state discrimination, such as minimum-error and maximum-confidence measurements. We demonstrate that QNN
circuits can efficiently and effectively achieve near-optimal
quantum measurements with fewer training iterations.
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Soft Condensed Matter
Resolving Light-Induced Structural Rearrangements in Responsive Microgels
Fabrizio Camerin, Megha Emerse, Gianpaolo Gallo et al. (+6 more)
Optically-responsive microgels offer a versatile platform for designing adaptive soft materials with coupled light and thermal responsiveness. Control over the crosslinking degree is particularly appealing as it can regulate not only particle size but also stiffness, thereby enabling remote tuning of key material functionalities. However, the internal structural changes that couple molecular photoresponsive mechanisms to mesoscopic properties remain poorly resolved. Here, we investigate different light-responsive microgels containing covalently incorporated coumarin moieties, which impart optical sensitivity through UV-induced cycloaddition, by combining dynamic light scattering, small-angle
neutron scattering, and molecular dynamics simulations. We show that light irradiation alters not only particle size but also the internal
polymer density distribution and subsequent thermal response. Before irradiation, the microgels exhibit a
star-like architecture with a dense core and extended polymeric arms. After irradiation, the network evolves toward a markedly more compact structure. This transformation cannot be rationalized simply as an equivalent to an increase in crosslinking density during synthesis, as observed in the thermal response, revealing light as a powerful tool to regulate microgel architecture and multifunctional responsiveness.
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All authors Fabrizio Camerin, Megha Emerse, Gianpaolo Gallo, Najet Mahmoudi, Gregory Smith, Emanuela Zaccarelli, Lucio Isa, Marco Laurati, Jacopo Vialetto
Astrophysics of Galaxies
Origin of monolithic high-z galaxies and UV luminosity of mergering high-z galaxies in the cosmological model with non-standard spectrum of density perturbations
Yu.N. Eroshenko, V.N. Lukash, E.V. Mikheeva et al. (+2 more)
The James Webb Space
Telescope (JWST) has detected an unexpectedly large number of
galaxies at
redshifts $z\geq 10$ compared to the predictions of the standard $\Lambda$CDM model. One of possible explanations is the presence of an excess (bump) in the power spectrum of perturbations at the mass scale of these
galaxies, which is about $10^{10}M_\odot$. This excess simultaneously shifts the epoch of
cosmic reionization to significantly earlier times, in contradiction with observations. Here we show that this defect of the bump model can be avoided if the perturbation spectrum has a cutoff (suppression) at smaller scales, which can be realized by lowering the amplitude of the
primordial perturbation spectrum or by considering warm dark matter. With a cutoff present, fewer low-mass
halos form and, consequently, fewer
stars producing ionizing UV radiation. We also derive the
halo merger-rate distribution in the presence of a bump using the extended Press–Schechter (EPS) theory, and verify this distribution against direct $N$-body simulations. Based on this distribution, and under the assumption that mergers trigger starbursts, we compute the UV luminosity function of early
galaxies and demonstrate its agreement with available observational data. In the model under consideration, the fraction of early
galaxies forming via the monolithic mechanism (through a single large-scale collapse) is significantly increased in comparison with the standard $\Lambda$CDM model, and the first
stars appear directly in
halos with masses $\geq10^8M_\odot$. We refer to such
stars with
primordial chemical composition as “Population~IV
stars,” to distinguish them from the evolutionary different
stellar populations.
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All authors Yu.N. Eroshenko, V.N. Lukash, E.V. Mikheeva, S.V. Pilipenko, M.V. Tkachev
Quantum Physics
Tests of constructor theory
Chiara Marletto, David Deutsch and Vlatko Vedral
Constructor theory is a proposal to extend
quantum information theory beyond both
quantum theory and computation, to cover more general machines than programmable computers – called constructors. It consists of newly conjectured physical principles that can be expressed as constraints on what tasks are possible, what are impossible, and why. These principles also determine the repertoire of the universal constructor, which is a programmable machine that can perform all physically possible tasks. The principles of constructor theory have novel physical content that supplements current dynamical laws, leading to new predictions for experimental tests. In this paper, we review the main experimental proposals to test the principles of constructor theory and discuss their implications for existing theories of physics and for their successors.
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Chemical Physics
Correcting basis-set errors due to the absence of the electron-electron cusp using an adiabatic correction
Anthony Scemama and Andreas Savin
This article proposes an analytical method to address the slow convergence of electronic structure calculations caused by the inability of finite one-particle basis sets to describe the electron-electron cusp. An equivalence is established between a calculation using a finite basis set with the physical Coulomb interaction and a calculation using a complete basis set with a model interaction (specifically, the error-function screened Coulomb potential characterized by a range-separation parameter $\mu$). By leveraging the adiabatic connection formalism, a simple, parameter-free correction formula is derived. It depends only on the on-top pair density and a locally defined range-separation parameter ($\mu$) derived from the basis set itself. This `adiabatic connection based basis-set error correction' (ABC) is derived from the asymptotic expansion of the wave function at large $\mu$ for small inter-electronic distances. Therefore it is applicable to both ground and excited states without the restriction imposed by the Hohenberg-Kohn
theorem. Numerical tests illustrate that the method achieves chemical accuracy using smaller basis sets than typically required.
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Strongly Correlated Electrons
Direct High-Magnetic-Field Coupling to Stripe Order in a Cuprate Superconductor
Leonardo Martinelli, Izabela Biało, Jens Oppliger et al. (+47 more)
Superconductivity in cuprates emerges out of a complex normal state that hosts density waves, pseudogap physics, and strange metal properties. Here, we access this normal state by synchronizing free-electron
laser x-rays with high-
magnetic-field pulses up to 44 T. We observe a linear increase in charge order amplitude and correlation length that persists far above the
vortex melting transition. This behavior is incompatible with standard phase competition between charge order and superconductivity. By means of conventional hard x-ray diffraction and magnetostriction, we show that applied fields also enhance monoclinic
lattice distortions. However, this magnetoelastic response is weaker and an epiphenomenon of the stripe order enhancement. Combined with recent observations of field-linear
spin freezing, our results point to a direct coupling between
magnetic field and the
spin component of stripe order in the high-field normal state – a mechanism independent of superconductivity suppression that has so far remained hidden from scattering probes.
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All authors Leonardo Martinelli, Izabela Biało, Jens Oppliger, Julia Küspert, Orion Gerguri, Sandro Brunner, Benedikt Eggert, Mark H. Fischer, Jochen Geck, Marein Rahn, Ellen Fogh, Jaewon Choi, Atsuhiko Miyata, Oleksandr Prokhnenko, Zahirul Islam, Fernando Igoa Saldaña, Martin v. Zimmermann, Rachel Nickel, Kurt Kummer, Nicholas B. Brookes, Adheena Painganoor, Paola Caterina Forino, Rasmus Toft-Petersen, Niels Bech Christensen, Xunyang Hong, Qisi Wang, Tohru Kurosawa, Naoki Momono, Migaku Oda, Dmitri V. Novikov, Azat Khadiev, Thomas Herrmannsdörfer, Ana Kurtanidze, Katharina Ollefs, Zuzana Konôpková, Michał Andrzejewski, Minxue Tang, Ulf Zastrau, Alexander Pelka, Hauke Höppner, Jolanta Sztuk-Dambietz, Vratko Rovensky, Torsten Laurus, Erik Brambrink, Björn Näser, Marcin Sikora, Cornelius Strohm, Carsten Baehtz, Shingo Yamamoto, Johan Chang