Atmospheric and Oceanic Physics
Sensitivity of the ECMWF seasonal forecast model to CO2 and anthropogenic aerosol forcings: Experimental design and impact on climate trends
Michael Mayer, Daniel J. Befort, Jacob Maddison et al. (+1 more)
Detection and attribution studies typically rely on free running
climate models with modified anthropogenic forcings, yet they fail to reproduce key observed decadal trends. Despite reduced biases, higher predictive skill, large ensembles, and improved trends through frequent reinitialization, seasonal forecast models have not been used for this purpose. We introduce a new set of counterfactual seasonal hindcasts using the ECMWF coupled seasonal
forecasting system based on alternative forcing scenarios by modifying atmospheric forcing and ocean and sea ice initial conditions. An observation based estimate of the forced ocean temperature signal is derived to amplify or remove this signal from the ocean initial conditions. Retrospective forecasts include a control configuration together with enhanced and reduced forcing experiments in which either CO2 increases together with doubled anthropogenic ocean warming or CO2 is fixed and the anthropogenic ocean-warming signal is removed. Additional experiments isolate aerosol forcing. The counterfactual hindcasts substantially alter long term temperature trends while largely preserving seasonal prediction skill, interannual variability, and model drift. Enhanced forcing strengthens several observed
climate trends underestimated by the control, including top of atmosphere radiative fluxes and aspects of tropical Pacific atmospheric circulation. However, the coupled atmosphere ocean system fails to sustain the strengthened tropical Pacific temperature gradient through Bjerknes feedbacks, suggesting a fundamental model limitation. Aerosol forcing has little impact, likely because indirect aerosol effects are omitted. These results establish counterfactual seasonal hindcasts as a powerful tool for dynamic attribution and diagnosing model deficiencies in responses to anthropogenic
climate forcing.
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All authors Michael Mayer, Daniel J. Befort, Jacob Maddison, Antje Weisheimer
High Energy Astrophysical Phenomena
Multi-zone Modeling of Blazar Jets: Constraints from GeV-Optical Correlation and Short-Timescale Variability
Arit Bala, Kaustav Mitra and Ritaban Chatterjee
We have developed a multi-zone model of blazar jet emission, in which the emission region contains many
cells with individual
magnetic fields and electron energy distributions. Nonthermal emission from
radio to $\gamma$-rays is generated by electrons accelerated by shocks passing through the region via synchrotron and inverse-Compton (IC) processes. The optical and GeV variability at days-to-months time-scale simulated from our model are strongly correlated with no significant time lag, as observed in most blazars and indicated by the standard shock-in-jet model. However, the mechanism of the shorter time-scale variability has been less explored, although such fluctuations at X-rays, $\gamma$-rays and optical bands have been observed regularly in recent years. In our model, the hr time-scale variability of the synchrotron radiation is due to the spatial fluctuation of the
magnetic field in the emission region. We found that to reproduce the short-timescale variability of the observed synchrotron emission in blazars, the required fluctuations of the
magnetic field are in the range $1-2\%$ to $25-30\%$. Similar variability of the IC emission, which does not depend on the
magnetic field, may be reproduced in our model by implementing equipartition of energy between the
magnetic field and particles. We found that orphan
flares in the optical or GeV band, or optical-GeV correlation with a significant time delay, as observed occasionally, may be reproduced in certain special conditions related to the orientation of the
magnetic field in the
cells.
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Strongly Correlated Electrons
Transitions and Critical Divergences in Periodically Hopping Modulated Su-Schrieffer-Heeger Chains
Surajit Mandal and Satyaki Kar
We use a
curvature renormalization group (CRG) approach to study the topological phase transitions in a Su-Schrieffer-Heeger chain and its extensions coming from periodic hopping modulations. A
curvature function is defined in terms of system parameters near high-
symmetry points where the divergence of this function at critical points, in analogy to usual phase transitions, signals a topological phase transition. According to this theory, the phase transition line for the two-site Su-Schrieffer-Heeger (SSH) model is visible at the critical line \Delta = 0 where the
curvature function diverges. Our study involves this model and also the modulated one with periodicity of four
lattice spacing where the
curvature function not only diverges at the topological phase transition point (Dirac-like) |\Delta/t| = \sqrt(2) but also shows faster divergence at the non-topological gapless point \Delta = 0. We further notice faster divergence of correlation length for \Delta -> 0 as compared to that for the |\Delta/t| -> \sqrt(2) resulting in two different sets of critical exponents making them lie in different universality classes. The edge state exhibits very slow decay into the bulk near the \Delta = 0 point while a much quicker decay from edge into bulk is discernible around the |\Delta/t| = \sqrt(2) point. We also continue similar analysis for a SSH model with hopping periodicity of eight
lattice spacing.
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High Energy Physics (Phenomenology)
Implications of $B\to \chi_{c1}\pi K$ data for an isovector $G$-odd $D^\ast\bar D^\ast$ molecular virtual state
Jun-Zhang Wang
Establishing the near-threshold
spin-isospin multiplet spectrum of $D^{(\ast)}\bar D^{(\ast)}$ systems is central to testing molecular interpretations of the $X(3872)$, $Z_c(3900)$, and $Z_c(4020)$. The isovector channels are particularly important in this context, as the associated structures would have a clear exotic character. In this work, we analyze the BaBar and Belle data on $B\to\chi_{c1}\pi K$ to search for possible isovector $D^\ast\bar D^\ast$ molecules with $J^{PC}=0^{++}$ and $2^{++}$. The three-body decay amplitude includes an effective nonresonant term, intermediate kaon resonances, and $\chi_{c1}\pi$–$D^\ast\bar D^\ast$ coupled-channel rescattering. For each data set, the $\chi_{c1}\pi$ and $K\pi$ invariant-mass distributions are fitted simultaneously under three scenarios: without rescattering and with either $J=0$ or $J=2$ rescattering. We then analytically continue the fitted coupled-channel $T$
matrices to search for poles. For the case of $J^{PC}=0^{++}$, the BaBar and Belle fits yield virtual poles at $-2.15^{+2.10}_{-6.41}$ MeV and $-18.40^{+8.58}_{-13.70}$ MeV, respectively, relative to the $D^\ast\bar D^\ast$ threshold. For $J^{PC}=2^{++}$, the corresponding virtual poles are located at $-3.42^{+2.37}_{-4.29}$ MeV and $-4.26^{+1.34}_{-1.69}$ MeV, respectively. The tensor virtual-state pole is consistent with a prediction from
chiral effective field theory, which also predicts the existence of $W_{c1}$, an isospin partner of $X(3872)$. Since the invariant-mass distributions alone cannot distinguish total
spin $J$, we also predict angular distributions. The $\cos\theta_{\chi_{c1}\pi}$ distribution provides a direct
spin discriminator, while the $\cos\theta_{K\pi}$ distribution further tests the rescattering contribution. The measurements of these predictions would help establish the $D^{(\ast)}\bar D^{(\ast)}$ molecular multiplet spectrum in the future.
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Quantum Physics
An ultracompact dilution refrigerator for fast quantum device characterization
Clḿent Geffroy, Dorian Nicolas, Eric Eyraud et al. (+10 more)
Rapid thermal cycling is a central bottleneck in the development of superconducting
quantum devices: conventional dilution refrigerators require cooldowns of a day or more and substantial cryogenic infrastructure, which throttles the fabricate-measure-redesign loop. We present an ultracompact dilution refrigerator (3 kg in mass and 100 mm in diameter) that completes a full cooldown-warm-up cycle to a base temperature of 70 mK in 1.2 hours when unloaded, and in 2.1 hours when fully equipped with the microwave wiring required for
qubit measurements, while delivering 20 microW of cooling power at 100 mK. We validate the platform through a complete characterization of a two-fluxonium device: we extract the full
circuit Hamiltonian by two-tone spectroscopy, measure energy-relaxation and coherence times, and
benchmark single-
qubit control. Although the relaxation time is limited by the base temperature of the system, we reach a single-
qubit gate fidelity of up to 99%, at the coherence limit set by our operating temperature. These results demonstrate that compact, fast-cycling dilution refrigeration can support state-of-the-art
quantum-device characterization without sacrificing measurement quality, offering a practical route to high-throughput
quantum-hardware development.
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All authors Clḿent Geffroy, Dorian Nicolas, Eric Eyraud, Shelender Kumar, Supriya Mandal, Julien Jarreau, Laura Kowalski, Laurent Del-Rey, Didier Dufeu, Nicolas Roch, Wolfgang Wernsdorfer, Quentin Ficheux, Matias Urdampilleta
Solar and Stellar Astrophysics
A generalized quadratic balance relation for nonradial nonadiabatic pulsations
Jan Zalewski
We derive a generalized quadratic balance relation for linear nonadiabatic, nonradial
stellar pulsations, starting from a sesquilinear amplitude analogue of the pressure-volume-rate work. The derivation requires neither weak nonadiabaticity nor averaging over a pulsation cycle. The relation is expressed in terms of work, generalized norm and boundary contributions and is subsequently recast into kinetic-energy-power form $\mathcal{P}+\Delta B=2\Re(\sigma)E_{\rm kin}$. The volume power is decomposed into a thermodynamic exchange term and response terms associated with compression, horizontal-area deformation and gravitational stratification effects. The equivalent forms of the relation provide diagnostics for checking the computed eigenfrequencies and estimating mode excitation rates. The properties of the balance relation for various types of modes in an envelope of a model AGB
star are examined. We analyze the terms entering the power $\mathcal{P}$ for radial and nonradial p-modes, strange modes as well as examples of low frequency outer-envelope
gravity modes and thermal modes. The results show that the magnitude of mode driving is not determined solely by the thermodynamic work term.
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Optics
Nonlinear collective dynamics and microwave comb generation in a diamond maser
Christoph W. Zollitsch, Jonas N. Bach, Christopher W.M. Kay et al. (+1 more)
Optically pumped room temperature masers are a promising platform for driven dissipative
spin photon physics beyond steady state emission. Here we observe a sequence of dynamical thresholds in a room temperature nitrogen vacancy diamond maser as the optical pump is increased above the conventional masing threshold. The first threshold yields narrow-line continuous wave emission, while a second threshold produces a periodic train of microwave pulses whose repetition rate generates a frequency comb spectrum. At higher pump power, a third threshold gives rise to pulses with an oscillatory, frequency chirped decay. Time-resolved measurements link the comb directly to self-pulsing dynamics and
Fourier analysis of individual bursts reveals a broad distribution of frequencies consistent with collective
spin-resonator dynamics in an inhomogeneously broadened ensemble. These results establish the diamond maser as a room temperature platform for nonlinear nonequilibrium light matter dynamics and microwave comb generation.
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All authors Christoph W. Zollitsch, Jonas N. Bach, Christopher W.M. Kay, Jonathan D. Breeze
Astrophysics of Galaxies
The Total and Polarized Radio Emission from the Innermost Jets of a High-Redshift Quasar and a Candidate at Parsec-Scale Resolution
Bence Husvéth, Krisztina É. Gabányi, Tao An et al. (+4 more)
High-frequency very long baseline interferometry (VLBI) polarimetry probes synchrotron-emitting
plasma closer to the central engines of
radio-loud active
galactic nuclei (AGNs), but observations above 43 GHz are technically demanding. We present 22-GHz European VLBI Network observations of the $z=4.31$
quasar J1510+5702 and J1606+3124, whose published spectroscopic
redshift, $z=4.56$, is uncertain; a photometric estimate gives $z_{\rm phot}=0.9\pm0.1$. For the published $z>4$
redshifts, 22 GHz corresponds to rest-frame frequencies above 118 GHz. Polarized emission is detected in J1510+5702, and a low-level polarized signal is recovered from the brightest feature of J1606+3124. Adopting $z=4.56$, that feature has a brightness temperature of $T_{\mathrm{b,VLBI}}=(7.4\pm0.8)\cdot10^{10}$ K, allowing a mildly Doppler-boosted interpretation, while the young compact-source scenario also remains viable. The core of J1510+5702 has $T_{\mathrm{b,VLBI}}=(1.08\pm0.15) \cdot10^{12}$ K, implying a Doppler factor of ${\sim}22$ under the equipartition assumption. This component has a ${\sim}3.5$ % fractional polarization. These observations show that cm-wavelength VLBI can access rest-frame millimeter-band polarization in bright $z>4$ jets.
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All authors Bence Husvéth, Krisztina É. Gabányi, Tao An, Sándor Frey, Jun Yang, Iván Agudo, Yingkang Zhang
Nuclear Theory
Toward testing antinucleon$\unicode{x2013}$nucleus optical potentials with antineutron scattering lengths
Hiroyuki Fujioka and Sayaka Ishii
The antineutron$\unicode{x2013}$
nucleus scattering length is currently known only indirectly, via antiproton$\unicode{x2013}$
nucleus optical potentials fitted to level shifts and widths of antiprotonic atoms. The antineutron$\unicode{x2013}$
nucleus and antiproton$\unicode{x2013}$
nucleus potentials are related to each other through charge
symmetry. We calculate the scattering length from optical potentials proposed for antiprotonic atoms using nucleon density distributions as input. We find that the scattering length for an $N>Z$ nuclide is largely affected by the poorly constrained
neutron density distribution and by a possible isovector interaction, one of the mechanisms introduced to reproduce the isotope dependence of antiprotonic $^{40,48}\mathrm{Ca}$ data. For $^{48}\mathrm{Ca}$, the isovector term modifies the scattering length by $0.3\unicode{x2013}0.4\,\mathrm{fm}$ ($0.4\unicode{x2013}0.5\,\mathrm{fm}$) for the real (imaginary) part, an order of magnitude beyond the uncertainty propagated from the isoscalar potential. As no antineutron$\unicode{x2013}$
nucleus scattering data are available below $76\,\mathrm{MeV}/c$, a direct measurement with recently proposed low-energy antineutron beams would provide the first access to the antinucleon$\unicode{x2013}$
nucleus interaction in the $s$-wave regime.
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Quantum Physics
Experimental zero-added-loss multiplexing Bell-pair source for long-haul quantum networks
Yoshiaki Tsujimoto, Daiki Ichii, Rikizo Ikuta et al. (+4 more)
Boosting the communication rate of
quantum networks is a central challenge in
quantum information science. Recently, an efficient
entanglement distribution scheme employing quasi-deterministic Bell-pair sources based on time-frequency multiplexing, referred to as zero-added-loss multiplexing~(ZALM), has been proposed. Its implementation, however, requires high-fidelity
entanglement swapping across densely multiplexed time-frequency modes, which has remained an experimental challenge. Here we demonstrate
entanglement swapping across 16 parallel frequency modes with a high average fidelity of 93.9$\pm$\SI{1.4}{%}. Notably, polarization-entangled
photon pairs in each frequency mode are spectrally single-mode using only off-the-shelf 50-GHz dense wavelength-division multiplexing~(DWDM) filters, eliminating the need for additional narrowband filtering. Furthermore, in order to fully exploit the temporal degree of freedom, the pump pulse is operated with a repetition frequency of \SI{3.0}{GHz}. By combining the frequency and time multiplexing, the total swapping rate reaches 5.38$\pm$0.17\,\si{pairs\,s^{-1}}, which corresponds to the ZALM Bell-pair rate of \SI{8.2e2}{pairs\,s^{-1}}. Our results establish the key experimental capabilities required for ZALM and demonstrate a scalable route toward practical high-rate
quantum repeaters and long-haul
quantum networks.
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All authors Yoshiaki Tsujimoto, Daiki Ichii, Rikizo Ikuta, Mikio Fujiwara, Masahiro Takeoka, Go Kato, Kentaro Wakui
Quantum Physics
Quantum-Logic Tsetlin Machines: Interpretable Quantum Machine Learning with Commuting Projector Clauses
Krishna Bhatia
Tsetlin Machines (TMs) learn interpretable Boolean clauses using finite-state automata. We introduce the
Quantum-Logic Tsetlin Machine (QL-TM), which replaces Boolean literals with
quantum propositions represented by projectors while retaining classical include/exclude automata. Clauses are restricted to commuting measurement contexts and activate through the Born probability of their joint projector. We prove an exact reduction to ordinary Boolean TM clauses in diagonal computational-basis contexts and connect Pauli-projector clauses to stabilizer and syndrome semantics. Controlled experiments on Bell states, phase-flip syndromes, randomized 16-class stabilizer tasks, mixed literal pools, context-budget ablations, and finite-shot noise show that correct non-diagonal contexts recover physically meaningful clauses, while diagonal or wrong contexts lose the relevant phase/syndrome information. The context-budget results closely follow the predicted separability ladder 2^(b-k) as true stabilizer generators are removed. The contribution is a controlled bridge between Tsetlin clause learning and
quantum logic, not a claim of
quantum advantage.
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Plasma Physics
Trapping: The "Waterfall" of Vlasov-Poisson Dynamics and the Post-Transient Emergence of Drift-Independent Hole Structures in Collisionless Plasmas
Hans Schamel
A key aspect of structure formation in collisionless
plasmas is particle trapping or, more precisely, the gap this process leaves in the theoretical description. While the dynamics prior to the onset of trapping are governed by Landau physics and phase mixing, the full effects of nonlinearity only emerge during the trapping phase, for which an explicit description is lacking. Consequently, this gap divides the temporal
evolution into a linear Vlasov-Poisson phase preceding the transition and a post-transient Vlasov-Poisson phase characterized by a wide spectrum of particle trapping scenarios and associated Schamel
equilibria. Metaphorically, this trapping process can thus be compared to a waterfall in fluid dynamics, where, similarly, no explicit dynamic link can be established between the regions above and below the cascade. A second insight is that the Vlasov-Poisson mean-field description fails due to the separatrix singularity, which necessitates a temporary recourse to the BBGKY hierarchy. To resolve this problem of the singularity, an analysis using the method of matched asymptotic expansions is proposed. Applied to the singular boundary of the separatrix zone, this approach employs local smoothing techniques, such as those mediated by the two-particle correlation function. It offers a suitable mechanism for selecting hole
equilibria in the post-transition phase. Furthermore, we report the existence of a spatially periodic Langmuir hole that vanishes if regularity requirements are too stringent, and we demonstrate that self-acceleration, accompanying the transition from a slow electron acoustic hole to a fast Langmuir hole, is driven by the release of particularly deeply trapped electrons.
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General Relativity and Quantum Cosmology
On uniqueness of non-vacuum stationary axisymmetric type D spacetime
Hiroaki Nakajima, Ya Guo and Wenbin Lin
We study a family of the non-
vacuum stationary axisymmetric type D metrics, where the two principal null directions are geodesic and shearfree. It is demonstrated that the conformal-to-Carter metric gives the most general form of this family, without any assumptions which are previously used by Ovcharenko and Podolský to arrive at this conclusion.
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Quantum Physics
(Almost) quadruply optimal unitary designs in 1D
Guoding Liu and Jonas Helsen
We construct $n$-
qubit approximate
unitary $k$-designs in 1D systems, achieving
circuit depth $O(\log(n/\varepsilon) + k\log k)$ with relative error $\varepsilon$ and requiring $O(nk\log k)$ magic gates. This matches existing lower bounds $\Omega(\log(n/\varepsilon) + k)$ for
circuit depth, and $\widetilde{\Omega}(nk)$ for the required number of $T$ gates, up to a $\log k$ factor, achieving simultaneous near-optimality in all parameters. Our construction is based on a combination and refinement of two existing results. We reduce the required magic block size for breaking Clifford
symmetries in the magic-augmented
circuit construction of Zhang et al. from $O(k\log k)$ to $O(\log k)$. We also improve the breakthrough construction of Chen et al. to construct a generating set of 1D local constant-depth
circuits for the
unitary group with a constant spectral gap, making $O(\log k)$-local random
unitaries realizable in depth $O(k\log k)$. As a by-product, we provide a constant-size 1D-local generating set for the Clifford group, which we expect to be of independent interest. Combining the two results with the gluing lemma, we prove the final result.
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Cosmology and Nongalactic Astrophysics
Broadband Chiral Primordial Gravitational Waves from Constant-roll Inflation in Parity-violating Symmetric Teleparallel Gravity
Xu Zhang, Chang Liu and Chengjie Fu
We investigate
primordial gravitational waves (GWs) generated during constant-roll inflation in a parity-violating extension of symmetric teleparallel
gravity. The parity-violating interactions leave the background
evolution and linear scalar perturbations unchanged, while inducing velocity birefringence in the tensor sector. Consequently, one of the two circular polarization states undergoes tachyonic amplification, producing a strongly blue and nearly fully
chiral tensor spectrum from the
cosmic microwave background (CMB) to interferometer scales. We identify viable constant-roll parameter regions consistent with current CMB constraints and determine the largest coupling strength compatible with both CMB B-mode measurements and the LIGO-Virgo-KAGRA (LVK) O1–O4a bound on the
stochastic GW background. The predicted CMB B-mode spectra may be detectable by LiteBIRD, while the enhanced high-frequency signal could be accessible to the LISA–Taiji network and LVK O5 run. The model also predicts nonvanishing TB and EB correlations. These results highlight the potential of combining CMB and multi-band GW observations to test parity-violating
gravity during inflation.
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Quantum Physics
Branching (Almost) Everywhere And All at Once
Alyssa Ney
It is sometimes said that a reason to prefer Everettian
quantum mechanics is that it allows one to avoid the kind of spooky action at a distance that is a consequence of
quantum entanglement according to other approaches. There is a straightforward argument to show EQM has this virtue, however some advocates argue that this requires we see branching as a local causal process. I explain this
reasoning and then show why, given the way Everettians standardly conceive of worlds and branching as emergent phenomena, branching need not be viewed as a causal process for EQM to be relativistically local. Forthcoming in Local
Quantum Mechanics, OUP 2026.
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Fluid Dynamics
Physics-informed neural network for inverse modeling of granular flows
Bing Wan, Bidan Zhao and Junwu Wang
Granular flows are ubiquitous in natural and industrial systems, yet their complex dynamics remain difficult to characterize. For inverse problems involving unknown inlet, outlet, and wall boundary conditions, where CFD simulations are challenging, reconstructing complete flow fields from sparse observations constitutes a challenging inverse problem. In this study, a physics-informed neural network framework driven by both physical mechanisms and measurement data is developed to reconstruct the steady-state full-field distribution of granular flows in a pipe. The proposed approach integrates sparse measurement data with governing equations and constitutive relations and is trained using high-fidelity
datasets generated by CFD solutions of a continuum model. The framework incorporates a dimensionless loss formulation, physics-informed initialization, dynamic global weighting, and a locally weighted granular temperature data-loss strategy. These treatments enable accurate reconstruction of the complete flow-field
evolution. This work establishes a robust methodological framework for flow-field reconstruction in complex granular flow systems.
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Optics
Nonlinear Maxwell's Equations as a Boundary Value Problem in Multilayer Nanophotonics
Ruizhe Gu, Dingyang Zhang and Wenjing Liu
Calculating strong-field, broadband nonlinear phenomena in complex nanophotonic structures remains difficult because it requires simultaneous handling of non-perturbative dynamics, impulsive processes, and structural complexity. Here, we introduce a unified framework that combines the transfer
matrix method with an iterative Green's function approach. The linear multilayer response is incorporated as boundary conditions into a nonlinear boundary value problem, which is then solved self-consistently, naturally accommodating broad spectra and arbitrary nonlinearity. The framework is validated with two examples in the transparent and resonant regimes, respectively. The first demonstrates an impulsive spectral modulation in second harmonic generation that is captured only by a full-structure broadband treatment. The second demonstrates the entire dynamical
evolution of
exciton-polaritons in a pump-probe experiment reproduced by a unified simulation. This framework directly links nanophotonic design with ultrafast nonlinear dynamics.
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Quantum Physics
Exact Matching-Polynomial Solution of the Periodic Baxter-Fendley $Z_N$ Clock Chain
Yuguan Li, D. C. Liu and Murray T. Batchelor
The periodic non-Hermitian Baxter-Fendley $Z_N$ clock chain has lacked a complete finite-size spectral solution, whereas its open-chain counterpart admits a solution in terms of independent quasienergies. For the periodic model we show that the operator-valued matching
polynomial associated with its cyclic Weyl
algebra simultaneously generates a set of conserved quantities, including the
Hamiltonian, and realizes a cyclic $\tau^{(2)}$ Yang-Baxter transfer
matrix. Root-of-unity closure yields a finite system of
polynomial spectral equations in each charge sector, which reproduces the complete finite-size energy spectrum counted with algebraic multiplicity. As a first application of this result, we show that Newton continuation of these equations provides a practical numerical route to the periodic ground-state energy without enumerating the full spectrum. For homogeneous chains the thermodynamic seam response yields a criterion for boundary-induced criticality; for $N=3$ it predicts two reciprocal critical couplings with singular ground-state
curvature, in contrast to the single self-dual open boundary critical point.
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Exactly Solvable and Integrable Systems
Long-time asymptotics of the integrable defocusing Wadati-Konno-Ichikawa equation with a finite-genus algebro-geometric background
Taohua Luo, Zhenya Yan and Guoqiang Zhang
We study the finite-genus algebro-
geometric solutions of the Wadati-Konno-Ichikawa (WKI) equation with the saturable nonlinearity and long-time asymptotic behaviors of their short-range perturbations. First, for both the focusing and defocusing reductions, we formulate the finite-genus Baker-Akhiezer functions as explicitly solvable the
matrix Riemann-
Hilbert (RH) problems on the complex spectral plane and obtain theta-function representations together with the reconstruction formulae for the WKI field and the reciprocal coordinate. We then consider the Cauchy problem of the defocusing WKI equation on a finite-genus algebro-
geometric background. We construct the scattering data and RH problem, and perform a Deift-Zhou nonlinear steepest descent analysis. The space-time plane is divided into two transition regions, a Zakharov-Manakov (ZM) region, and a fast-decay region. The leading term is a phase-shifted finite-genus WKI solution. The transition corrections are governed by a Painlevé-XXXIV model, while the ZM radiation is described by
parabolic-cylinder functions. The reciprocal-coordinate asymptotics are obtained simultaneously.
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Materials Science
Thickness-dependent degradation and optical access in epitaxial 2H-MoTe2 protected by metallic capping layers
Wojciech Ryś, Iaroslav Lutsyk, Michał Piskorski et al. (+13 more)
We investigate degradation and surface protection of epitaxial 2H-MoTe2 films grown by molecular beam epitaxy on GaAs(111)B substrates. Using X-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy, atomic force microscopy (AFM), Kelvin probe microscopy (KPM), Raman spectroscopy, and density functional theory (DFT), we examine the structural, chemical, and electronic
evolution of MoTe2 protected by Co and Ni capping layers. XPS shows that the metallic caps effectively suppress oxidation during short-term air transfer, while revealing a pronounced Te-rich near-surface composition. With time, the caps become increasingly difficult to remove, suggesting gradual interfacial bonding promoted by excess tellurium and defect-rich MoTe2 interfaces. AFM and KPM reveal pronounced thickness-dependent ageing, with ultrathin regions showing markedly different contact-potential
evolution from thicker films. DFT calculations support the sensitivity of work function and density of states to thickness and surface chemistry. Raman measurements through approximately 20 nm thick metallic caps demonstrate partial optical access to the protected material. Additional AFM and Raman observations suggest local formation of Te-rich nanostructures under
laser illumination or near mechanically damaged regions. These results provide practical guidelines for protecting, transferring, delaminating, and optically characterizing air-sensitive MoTe2 and related van der Waals materials.
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All authors Wojciech Ryś, Iaroslav Lutsyk, Michał Piskorski, Maxime Le Ster, Maciej Rogala, Paweł Dąbrowski, Paweł Krukowski, Katarzyna Ranoszek-Soliwoda, Jarosław Grobelny, Zuzanna Ogorzałek-Sory, Bartłomiej Seredyński, Wojciech Pacuski, Janusz Sadowski, Marta Gryglas-Borysiewicz, Karol Szałowski, Paweł J. Kowalczyk
Earth and Planetary Astrophysics
Looking for TRAPPIST-1 external planets' emission in JWST archival data
Louis-Julien Cartigny, Alice Maurel, Elsa Ducrot et al. (+1 more)
The TRAPPIST-1 system has been thoroughly observed with JWST. Unfortunately,
stellar contamination issues strongly limit the interpretation of transit observations. As for emission observations, only the two closest
planets have been observed through five dedicated JWST programs. We gathered all these emission observations and tried to detect the combined emission of the external
planets in previous JWST MIRI observations of TRAPPIST-1; this paper presents our approach and our results. We could not achieve sufficient precision to detect the thermal emission of the outer
planets and to discriminate between an all-bare rocks and an all-atmospheres scenario. However, we show that a~60 hours continuous observations at a specific phase range, when the gradient of thermal flux from the outer
planets is maximum, could allow us to achieve this goal.
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All authors Louis-Julien Cartigny, Alice Maurel, Elsa Ducrot, Taylor J. Bell
Chemical Physics
UBio-MolFM: Enabling Biomolecular Dynamics at DFT Accuracy and $10^5$ Atoms with One Untuned Potential
Lin Huang, Frank Peng, JiaJun Cheng et al. (+8 more)
Ion conduction, membrane permeation and metal recognition hinge on electronic structure, yet first-principles simulation reaches only hundreds of atoms. UBio-MolFM lifts that ceiling: a foundation model trained on 160 million
quantum-chemical labels, its receptive field spanning non-covalent distances at near-linear cost. The barrier is cost, not principle. One untuned potential keeps force error near 20 meV/Å past a thousand atoms, reproduces water's X-ray structure and ion hydration, and holds an RNA Mg$^{2+}$ site without ion-specific parameters. Cyclosporine A pays 3.5 kcal/mol in water for its permeable conformer, gated by one kinetically asymmetric hydrogen bond that a fixed-charge model flattens. In a 108,964-atom KcsA channel on one GPU, the relaxed four-ion column is anhydrous in all five replicas, in direct contact in four—the knock-on geometry ten fixed-charge simulations never form. It remains orders of magnitude costlier. Where electronic structure decides the answer, first-principles simulation is in reach.
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All authors Lin Huang, Frank Peng, JiaJun Cheng, Zion Wang, Hao Yin, Hao Li, Ji Zhang, Jack Jia, Junping Zhao, Arthur Jiang, Jia Zhang
Astrophysics of Galaxies
Hector Galaxy Survey: Falling in Between - Infalling Galaxies in the Midst of the Abell 3667 Merger
Oğuzhan Çak{\i}r, Matt Owers, Gabriella Quattropani et al. (+38 more)
Whether cluster mergers enhance ram pressure stripping (RPS) and accelerate member
galaxy evolution remains an open question. Here, we investigate
galaxy populations in the nearby merging cluster Abell 3667 ($z\simeq0.0553$) using spatially resolved data from the Hector
Galaxy Survey. We define an RPS sample combining Hector-selected
galaxies with ionised gas disturbances (e.g., asymmetric tails or truncated disks) and supplementary, optically identified jellyfish
galaxies lacking Hector data. Most of the RPS sample ($\sim 71^{+10}_{-7}\%$; 20/28) lies within $R_{200}$, where the merger impact is greater. Most asymmetric
galaxies ($\sim 73^{+14}_{-8}\%$; 11/15), especially those with extreme RPS signatures, are concentrated in the inner cluster ($R \lesssim 0.6\, R_{200}$), along the merger axis between two shock-tracing
radio relics. These central asymmetric
galaxies show two spatial and kinematic groups: one at the North-West (NW) subcluster, downstream of its
radio relic in a region of high-velocity intracluster medium (ICM) bulk motion, with blueshifted line-of-sight velocities; and a mostly redshifted population near the main cluster (MC), which also shows a turbulent ICM. Despite their projected association with the MC core and NW substructure, both samples' velocities indicate they are not bound to them. Tail orientations give insight into orbital histories: NW tails point away from the cluster centre and often align with the merger axis, suggesting merger-driven stripping, while MC tails show neither pattern clearly. Tails are broadly westward, with MC tails tracing due west and NW tails shifted northwest, pointing to two distinct filamentary
accretion events for the NW and MC populations. Together, our results indicate enhanced RPS in the heart of A3667, driven mainly by infalling
galaxies accreted along nearby filaments interacting with the merger-driven turbulent environment.
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All authors Oğuzhan Çak{\i}r, Matt Owers, Gabriella Quattropani, Mina Pak, Stefania Barsanti, Joss Bland-Hawthorn, Julia Bryant, Scott Croom, Pratyush Kumar Das, Caroline Foster, Madusha Gunawardhana, Hyunjin Jeong, Jong Chul Lee, Joon Hyeop Lee, Yifan Mai, Kyuseok Oh, Sree Oh, Andrei Ristea, Sarah Sweet, Sujeeporn Tuntipong, Gurashish Bhatia, David Brodrick, Rebecca Brown, Elton Cheng, Robert Content, Fred Crous, Tony Farrell, Peter Gillingham, Ellen Houston, Jon Lawrence, Helen McGregor, Mahesh Mohanan, Seong-Sik Min, Barnaby Norris, Naveen Pai, Ayoan Sadman, Will Saunders, Sudarshan Venkatesan, Adeline Wang, Ross Zhelem, Jessica Zheng
Solar and Stellar Astrophysics
An Empirical Effective-Temperature Calibrations for Galactic B/A Supergiants
N.L.Vaidman, A.S.Miroshnichenko, Sh.T.Nurmakhametova et al. (+9 more)
We present empirical effective temperature Teff calibrations for
Galactic supergiants of spectral types B5-A5 based on optical spectra. The relationships were derived from a reference sample with adopted literature temperatures and use equivalent widths, central line depths, and ratios of selected spectral features as temperature indicators. Quadratic relationships are established for individual diagnostics and their ratios. Collectively, the calibrations span a Teff interval from 8 400 K to 14 700K, while the validity range of each relationships is individually specified. Detailed quantitative atmospheric analyzes remain indispensable for deriving physically consistent
stellar parameters. However, their application to extensive spectroscopic samples is observationally and computationally demanding. The empirical relationships presented here provide a homogeneous and readily applicable temperature scale for the characterization of
Galactic BA supergiants. The complete calibration tables, including fitted coefficients and uncertainty information, together with an interactive Python tool to apply the relationships, are publicly available through Zenodo. The reduced continuum-normalized spectra and associated metadata are published through a VO–compliant service of the Kazakhstan National Virtual Observatory.
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All authors N.L.Vaidman, A.S.Miroshnichenko, Sh.T.Nurmakhametova, S.Danford, S.A.Khokhlov, I.M.Izmailova, Ch.T.Omarov, S.V.Zharikov, D.E.Yakhiya, A.T. Agishev, A.A.Khokhlov, D.T.Agishev
High Energy Astrophysical Phenomena
Hybrid disc geometry for shocked accretion flows: Unveiling QPOs in black hole X-ray binaries
Monu Singh, Sudip Kumar Garain and Santabrata Das
We investigate the efficacy of semi-analytical global
accretion solutions in capturing the flow properties observed in two-dimensional numerical simulations of shocked
accretion onto black holes. A comparative analysis reveals that no single disc geometry adequately matches the simulation profiles across the entire radial domain. The pre-shock region exhibits closer agreement with the conical disc geometry, while the post-shock region is better described by the vertical
equilibrium disc, where enhanced thermal pressure leads to substantial vertical expansion. Motivated by these complementary behaviours, we introduce a hybrid disc geometry in which the pre-shock flow follows the conical solution and the post-shock flow attains vertical
equilibrium. This hybrid model satisfactorily reproduces both dynamical and thermodynamical properties of shocked
accretion flows with the predicted Mach number and temperature profiles closely matching the simulations and the inferred shock location differing by $\sim10\%$. Within this framework, we delineate the shock parameter space spanned by the energy ($\mathcal{E}$) and angular momentum ($\lambda$) of the flow for weakly and rapidly rotating black holes and investigate the possible origin of Quasi-periodic Oscillations (QPOs) in black hole X-ray binaries (BH-XRBs). We constrain flow parameters that reproduce observed QPO centroid frequencies ($\nu_{\rm QPO}$) demonstrating that oscillations of the shock front provide a self-consistent mechanism for both low and high frequency QPOs. Extending the analysis to ten
Galactic BH-XRBs, we demonstrate that the observed $\nu_{\rm QPO}$ are reproduced within physically plausible parameter ranges, which establishes shocked global
accretion solutions as a potentially compelling framework for interpreting
accretion driven temporal variability.
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High Energy Physics (Phenomenology)
Probing Sub-GeV Dark Matter with the Migdal Effect at JUNO
Stefano Scopel and Gaurav Tomar
We discuss the sensitivity of the JUNO
neutrino detector to the Migdal ionization signal triggered by
nuclear scattering events produced by sub-GeV weakly interacting massive particles (WIMPs). Exploiting JUNO's large target mass and the annual modulation effect we find that the aggregate rate from many independent and indistinguishable WIMP events in JUNO's
liquid scintillator can be isolated from the total dark rate of the photomultipliers, potentially providing for
spin-dependent interactions a world-leading sensitivity across the sub-GeV mass range.
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High Energy Physics (Theory)
Entanglement islands and information recovery from near-extremal regular black holes
Ankit Anand, Kimet Jusufi, Amir A. Khodahami et al. (+1 more)
We investigate the Page curve and information recovery in a near-extremal regular black hole inspired by T-duality, in which the central singularity is resolved by a minimal length scale. By integrating the first law of thermodynamics at fixed minimal length, we obtain a black-hole
entropy containing an intrinsically
quantum logarithmic correction, while the area-law contribution vanishes in the extremal limit. Consequently, the extremal remnant carries a finite
entropy of purely
quantum origin. Using the island prescription in the near-horizon regime, we evaluate the generalized
entropy of radiation and compare the standard area functional with an alternative functional constructed from the corrected thermodynamic
entropy of the black hole. In the near-extremal limit, the latter reduces analytically to the classical extremization problem with an effective coupling, and it places the physical island closer to the outer horizon. Although both prescriptions produce a Page transition, they predict different saturation values and Page times. While the standard functional yields a plateau controlled by the area term, the corrected prescription saturates at the full thermodynamic
entropy of the outer horizon and, in the extremal limit, at the logarithmic remnant
entropy. Including evaporation and backreaction, the Page curve develops the expected descending branch and asymptotes to the
entropy of the cold extremal remnant rather than to zero. Our results indicate that a thermodynamically consistent description of information recovery from regular near-extremal black holes requires incorporating the intrinsic
quantum correction to the gravitational
entropy.
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All authors Ankit Anand, Kimet Jusufi, Amir A. Khodahami, Ahmad Sheykhi
Quantum Physics
Inverse Feshbach's problem: Solvability and solutions
Miloslav Znojil
Given a certain specific, $M$ by $M$
matrix form of the Feshbach's effective (i.e., energy-dependent)
Hamiltonian $H^{(M)}_{e\!f\!f}(E)$, the inverse-problem reconstruction of the full-space, $N$ by $N$
matrix Hamiltonian $H^{(N)}$ is considered and reduced to the solution of a coupled set of
polynomial algebraic equations. Using computer-assisted symbolic manipulations, an explicit algebraic reconstruction of $H^{(N)}$ is found feasible at not too large $K = N-M$.
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Quantum Physics
Know Your Qubits, Know Your Users: Personas for Quantum Software
Lukas Schmidbauer, Joshua Ammermann, Laura Schulz et al. (+5 more)
The advancement of
quantum hardware and the intricacies of
quantum computing make well-designed
quantum software increasingly necessary. Due to the interdisciplinarity of the field, it is crucial to understand the perspectives and specific needs of involved stakeholders, for example, to balance the desired level of abstraction with the exposition of (hardware)-specific details. In this work, we conduct a stakeholder-based analysis to identify personas of
quantum software as a means of creating meaningful, user-tailored
quantum software. We conducted an expert focus group at a Dagstuhl seminar in 2024 and qualitative interviews with practitioners at conference IEEE QCE in 2025, from which we derive eleven personas of potential users and stakeholders for
quantum software. We discuss these personas regarding their use cases, interests, constraints and abstraction level.
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All authors Lukas Schmidbauer, Joshua Ammermann, Laura Schulz, Jose Garcia-Alonso, Robert Wille, Sebastian Feld, Ina Schaefer, Wolfgang Mauerer