Quantum Physics
Causal-Class Hierarchies in Coherence-Constrained Channel Transformation
Lin Zhu, Benchi Zhao, Xuanqiang Zhao et al. (+3 more)
Higher-order
quantum transformations allow multiple channel uses to be combined through different causal architectures, from parallel and fixed-order sequential networks to general higher-order processes. Whether this causal freedom improves channel transformation when the higher-order operation is also constrained by a resource theory remains largely unexplored. We study this question in the dynamical resource theory of coherence using a unified semidefinite-programming framework. For two
qubit amplitude-damping channels and the identity target, we prove a strict causal hierarchy at every nontrivial damping strength under both maximally incoherent superchannels (MISC) and dephasing-covariant incoherent superchannels (DISC). In contrast, mixed-Pauli channels admit a common teleportation simulation that transfers the channel dependence to Bell-diagonal program states prepared in parallel. The remaining processing can then be absorbed into a single
quantum operational, so parallel, fixed-order sequential, and general higher-order strategies achieve the same optimal error for any target. These results identify free program-state parallelisation as a structural obstruction to causal enhancement.
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All authors Lin Zhu, Benchi Zhao, Xuanqiang Zhao, Ranyiliu Chen, Xin Wang, Shenggen Zheng
Quantum Physics
Finite-size Entanglement Certification via Third-Order Local Randomized Measurements
Giovanni Scala, Corrado Cosimo Mattiacci, Dorota Pietryka et al. (+1 more)
Certifying
entanglement in high-dimensional systems usually requires full state
tomography, whose cost grows rapidly with the system dimension. Local randomized measurements offer a scalable alternative, but existing tests based on second-order correlations access only limited information about the state. Here, we derive a finite-size
entanglement certificate that extends local randomized measurements to third order. The additional third-order information reveals
entanglement that remains undetected at second order, while a dimension-independent concentration bound provides rigorous control of finite-sample errors. Our result opens a practical route to extracting stronger
entanglement information from experimental platforms without the dimension-dependent overhead of state
tomography.
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All authors Giovanni Scala, Corrado Cosimo Mattiacci, Dorota Pietryka, Gniewomir Sarbicki
Materials Science
Pulse-Burst Excitation Reveals Time-Dose Reciprocity Breakdown in Mixed-Halide Perovskites
Alexandr Marunchenko, Shivam Singh, Daniel Lizotte et al. (+3 more)
Time-dose reciprocity, commonly associated with the Bunsen-Roscoe law, states that the response of a photosensitive system depends only on the total exposure dose, regardless of how that energy is delivered over time. Light-sensitive processes in mixed-halide perovskites, such as photoinduced halide segregation, often exhibit threshold-like behavior that may violate this principle and enable material-state control by
photon timing. We test this using pulse-burst excitation, which introduces an additional temporal control dimension beyond conventional parameters such as pulse fluence, repetition rate, and average power. By redistributing the same
photon dose over microsecond-to-millisecond timescales, we create distinct nonequilibrium excitation conditions and show that mixed-halide perovskites can evolve into different metastable states, revealing a breakdown of time-dose reciprocity in the combined processes of halide segregation and remixing. This additional temporal degree of freedom not only enables control of the material state but also provides a new experimental framework for disentangling the competing processes underlying photoinduced halide redistribution. Our findings establish
photon timing as a control parameter for perovskite photochemistry and open additional opportunities for optical
memory and neuromorphic photonic applications.
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All authors Alexandr Marunchenko, Shivam Singh, Daniel Lizotte, Bhaskar De, Yana Vaynzof, Ivan G. Scheblykin
Nuclear Theory
The Interplay of Symmetry Energy Uncertainties, Nonlinear $\sigma-\delta$ Coupling, and Dark Matter in Neutron Star Macroscopic Properties
Zhaohui Feng, Xiaoxuan Zhai, Shuangxuan Chen et al. (+1 more)
The poorly constrained density dependence of the
nuclear symmetry energy introduces significant uncertainties in the equation of state (EOS) of dense
nuclear matter and, consequently, in
neutron-
star properties. We systematically investigate how uncertainties in the
symmetry energy $E_{\rm sym}$ and its slope $L$ at saturation density $n_0$ affect NS properties within the relativistic mean-field (RMF) framework, including the effects of nonlinear $\sigma$-$\delta$ coupling and possible admixture of dark matter(DM) . For fixed $E_{\rm sym}(n_0)$ and $L(n_0)$, we find that the $\sigma$-$\delta$ coupling with $g_{\sigma\delta}=-0.004$ induces an abnormal softening of the EOS, which simultaneously increasing the maximum NS mass and reducing the
stellar radius and
tidal deformability. A similar behavior is found in the presence of DM with
Fermi momentum $k_F^{\rm DM}=50~\mathrm{MeV}$ at $E_{\rm sym}(n_0)=36~\mathrm{MeV}$. In this case, the RMF EOS satisfies the
tidal-deformability constraint from GW170817. We further find that the surface
curvature of NSs is strongly correlated with the stiffness of $E_{\rm sym}$, with softer
symmetry energy corresponding to larger surface
curvature. Our results also indicate that the behavior of $E_{\rm sym}$ around $n_0$ is mainly governed by isoscalar rather than isovector parameters.
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All authors Zhaohui Feng, Xiaoxuan Zhai, Shuangxuan Chen, Defu Hou
Earth and Planetary Astrophysics
XUE. ProDiMo models of internally and externally irradiated planet-forming disks around 0.3-4.0 solar mass stars (The IRIS project I)
Jenny Frediani, Konstantin V. Getman, Peter Woitke et al. (+18 more)
Most
stars and
planets form in massive
star-forming regions, where disks are exposed to external far-ultraviolet (FUV) radiation from nearby O- and B-type
stars. The combined effects of
stellar irradiation and external FUV fields on terrestrial
planet-forming regions (< 10 au) across
stellar masses remain unclear. We investigate how internal UV and X-ray irradiation and external FUV fields affect mid-infrared (mid-IR) gas emission and the atmospheric carbon-to-oxygen (C/O) ratios inferred in T Tauri and Herbig Ae/Be disks. We compute disk structures with ProDiMo and synthetic spectra with FLiTs, convolved to a representative JWST/MIRI-MRS resolution (R$\sim$2680). (1) We present the Internal and external irRadIation of diSks (IRIS) grid: four model sets spanning
stellar masses of 0.3-4.0
solar masses, including
stellar X-ray
flares and an external FUV field of 1e4 G0 (Habing units). (2) We predict increasing flux densities with
stellar mass for key atomic and molecular mid-IR tracers. (3) External FUV irradiation enhances CH3+ and H2 emission, whereas FUV-induced disk truncation yields inner disk chemistry resembling that of disks irradiated only by their host
stars. (4) Mid-IR H2O, CO2, and C2H2 line ratios imply carbon-rich compositions (C/O$\sim$1-10) in the warm emitting layers of T Tauri and Herbig Ae/Be disks, primarily reflecting
stellar irradiation, with little sensitivity to external FUV irradiation. The IRIS grid provides a flexible framework for interpreting JWST and future Extremely Large
Telescope (ELT) infrared disk observations across a broad range of
stellar properties and irradiation conditions. Future models should include FUV-driven photoevaporative winds, X-ray radiative transfer, and time-dependent X-ray irradiation.
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All authors Jenny Frediani, Konstantin V. Getman, Peter Woitke, Bayron Portilla-Revelo, Eric D. Feigelson, Christian Rab, Arjan Bik, María Claudia Ramírez-Tannus, Rens Waters, Thomas Henning, Inga Kamp, Germán Chaparro, Sebastián Hernández, Simón Rodríguez, Pablo Cuartas-Restrepo, Andrew Winter, Thomas J. Haworth, Thomas Preibisch, Sierk E. van Terwisga, Veronica Roccatagliata, Alexis Brandeker
Accelerator Physics
Flexible Spectral-Normalized Neural Gaussian Process for Dynamic Aperture Prediction
Yousra El-Bachir, Frederik Van der Veken, Davide di Croce et al. (+4 more)
We address the challenge of scalable uncertainty quantification in large-scale scientific applications, where complex state-of-the-art machine learning methods are often computationally infeasible. Our primary contribution is a simple yet effective empirical Bayes method for automatically tuning the hyperparameters of a flexible, heteroscedastic Spectral-normalized Neural Gaussian Process. This approach retains the expressiveness and uncertainty-awareness of semi-
Bayesian neural models while significantly reducing the computational burden by integrating hyperparameter learning directly into the training loop. We demonstrate the practical impact of our method on the task of estimating the dynamic aperture in circular particle accelerators, a fundamental problem in high-energy physics
colliders and storage rings, using simulation data from the case of the Large
Hadron Collider at CERN. Traditional approaches to DA estimation require extensive particle-tracking simulations, which are prohibitively time-consuming and resource-intensive. Our results show that the proposed method achieves competitive predictive performance and well-calibrated uncertainty estimates at much lower computational cost than state-of-the-art approaches. We stress that, beyond this application, the proposed empirical Bayes framework offers a general solution for training heteroscedastic neural models in situations where manual hyperparameter tuning is impractical. Accordingly, we anticipate that this framework can be applied to other domains that encounter comparable computational limitations.
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All authors Yousra El-Bachir, Frederik Van der Veken, Davide di Croce, Carlo Emilio Montanari, Massimo Giovannozzi, Ekaterina Krymova, Tatiana Pieloni
Atmospheric and Oceanic Physics
Neptune: An AI model for Global Ocean Subseasonal Prediction
Davide Donno, Italo Epicoco, Massimo Cafaro et al. (+8 more)
Subseasonal-to-seasonal (S2S)
forecasting is societally critical, supporting decision-making in sectors ranging from water and agricultural management to disaster risk reduction, energy planning, and insurance. Achieving reliable predictions at these timescales requires representing the ocean and its dynamics, but traditional physics-based Ocean General Circulation Models (OGCMs), are computationally expensive and difficult to develop and improve because of the code complexity. In this work, we propose Neptune, an end-to-end data-driven framework for global ocean and sea-ice components emulation tailored for S2S timescales, up to 60 days. Neptune combines Convolutional Neural Networks (CNNs) and Spherical
Fourier Neural Operators (SFNOs) to effectively capture local features and global cross-scale interactions, thereby obtaining a coherent representation of the ocean state. Forced by prescribed daily atmospheric fields, Neptune emulates ocean state variables, from temperature and salinity, to zonal and meridional currents, from sea surface height to sea ice thickness and concentration, with daily outputs at the ocean surface and through the water column. Specifically, we propose two variants of Neptune, Neptune-1 and Neptune-025, capable of emulating the ocean state at 1{\deg} and 0.25{\deg} resolution, respectively. Evaluated against a suite of metrics, including statistics (RMSE, CRPS and ACC), physical coherency (Ocean Heat Content, Eddy Kinetic Energy and Ice Brier Score) and
climate indices (ENSO and Z20 metric, IOD), Neptune successfully reproduces the spatio-temporal
evolution of the oceanic fields up to 60 days, and is stable over long timescales. Neptune provides compelling evidence that end-to-end data-driven ocean emulators can become a powerful component of next-generation S2S
forecasting systems, emulating ocean state at high spatio-temporal resolution.
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All authors Davide Donno, Italo Epicoco, Massimo Cafaro, Gabriele Accarino, Mohammad M. Amirian, Viviana Acquaviva, Paola Nassisi, Doroteaciro Iovino, Annalisa Bracco, Simona Masina, Pierre Gentine
Instrumentation and Methods for Astrophysics
A Missing Tool for Calculating Auto/Cross-correlation Function under Nonuniform Sampling Observations
Chen-Ran Hu, Yong-Feng Huang, Jin-Jun Geng et al. (+10 more)
Nonuniform sampling presents a long-standing challenge in astrophysical time-domain analysis, invalidating the standard autocorrelation and cross-correlation functions and forcing researchers to adopt ad-hoc methods like interpolation or binning, which introduce unquantified biases and lack rigorous error estimation. Here we introduce a new method for calculating the nonuniform autocorrelation function (NUACF) and nonuniform cross-correlation function (NUCCF) for irregularly sampled time series. Instead of relying on interpolation, it naturally evaluates the correlation function by incorporating time-interval weights and misalignment penalties. Monte Carlo simulations provide confidence bands for significance assessment and a complete error budget for the time delays that accounts for both flux uncertainties and sampling irregularity (essential but generally absent from existing methods). Through extensive simulations, we demonstrate our method outperforms traditional methods across various conditions, from strictly periodic to complex repeating variability patterns (e.g., intermittent but aperiodic). Its effectiveness is demonstrated via various real astrophysical data sets, revealing repetitive variability in
stellar light curves, measuring time delays for multi-band disc reverberation in the AGN Fairall 9, and providing model-independent validation of time delays for the gravitationally lensed
quasar HE 0435-1223. The method provides a rigorous and general solution to the ubiquitous problem of nonuniform sampling, positioning it as a useful tool for large-scale time-domain survey data analysis. The framework is also directly applicable to emerging time-domain phenomena such as fast
radio bursts (FRBs), enabling, e.g., the study of correlations between persistent
radio source luminosity and repeating FRB activity, or among the multi-parameter variability curves of FRB emission itself.
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All authors Chen-Ran Hu, Yong-Feng Huang, Jin-Jun Geng, Orkash Amat, Ze-Cheng Zou, Chen Deng, Fan Xu, Xiao-Fei Dong, Chen Du, Nurimangul Nurmamat, Pei Wang, Lang Cui, Cheng-Ming Li
Materials Science
Polymorph Engineering of the Layered Rare-Earth Magnet GdAlGe
Dmitry V. Averyanov, Ivan S. Sokolov, Alexander N. Taldenkov et al. (+7 more)
The recent advances in research on layered magnets have established them as invaluable materials for spintronic applications and precursors to 2D magnets. The problem is that the number of such materials available for experimentation is still low. To tackle the problem, one may employ phase engineering; in particular, the interplay between the phase stability and dimensionality provides great opportunities for design of layered magnets. Here, this interrelation is harnessed to produce epitaxial films of an overlooked layered polymorph of GdAlGe. The compound is formed by alternating triangular Gd and honeycomb AlGe
lattices. It is stable in ultrathin films, up to 5 monolayers. In thicker films, an additional unwanted phase emerges. The structural quality of the ultrathin films is witnessed by electron and X-ray diffraction as well as electron microscopy. Magnetization measurements detect an anisotropic
ferromagnetic state. The GdAlGe magnetism is corroborated by a study of electron transport revealing the anomalous
Hall effect and negative magnetoresistance. The material is naturally integrated with Ge, a technological
semiconductor, which should facilitate applications. The present study can serve as a blueprint for design of layered magnets via polymorph engineering.
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All authors Dmitry V. Averyanov, Ivan S. Sokolov, Alexander N. Taldenkov, Oleg E. Parfenov, Alexey N. Mihalyuk, Ivan A. Yakovlev, Igor A. Karateev, Oleg A. Kondratev, Andrey M. Tokmachev, Vyacheslav G. Storchak
Quantum Physics
Fisher-Information Recovery in Superconducting-Qubit Magnetometry with Squeezed-Microwave Readout
M.-R. Yun, Y.-J. Qu, Zheng Shan et al. (+3 more)
The performance of superconducting-
qubit magnetometers depends not only on
magnetic-field encoding during Ramsey interrogation, but also on how efficiently the encoded information is recovered during readout. Squeezed microwaves provide a promising route to improve information extraction by suppressing readout noise, yet how such readout enhancement translates into accessible information for
magnetic-field estimation remains unclear. Here we develop an effective detected-mode framework linking projected quadrature noise, state-assignment error, and the classical Fisher information accessible from binary readout outcomes. A finite mismatch between the squeezed quadrature and the discrimination axis produces an optimal squeezing strength through the competition between squeezed and anti-squeezed fluctuations. We further show that squeezed readout improves the readout-limited
magnetic-field sensitivity by recovering information otherwise lost during state assignment, with the enhancement remaining robust against quadrature mismatch, transmission loss, and added noise. These results establish a quantitative connection between squeezed-microwave readout and measurement-stage information recovery in superconducting
quantum sensing.
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All authors M.-R. Yun, Y.-J. Qu, Zheng Shan, L.-L. Yan, Yu Jia, S.-L. Su
Materials Science
The Hidden Cost of Alloying: Disorder-Driven Transport Collapse in TMDs
Michele Pisarra, Clara Rebanal, Enrique Arévalo Rodríguez et al. (+19 more)
Alloying in two dimensional
semiconductors is widely used to tune bandgaps, yet its implications for charge and energy transport remain poorly understood. Here, we investigate MoS2xSe2(1-x)
alloys as a model system to study the interplay between composition, thickness, and disorder. Optical transitions and valence band dispersions evolve continuously with both stoichiometry and number of layers, with negligible bandgap bowing and a composition dependent attenuation of thickness driven renormalization. In contrast, time resolved spatial mapping of photoexcited carriers reveals a pronounced and asymmetric collapse of carrier diffusivity at intermediate compositions, which cannot be accounted for by changes in effective mass or band
alignment, and instead emerges from strong real space fluctuations in the local energetic landscape generated by random chalcogen substitution. Microscopic simulations reproduce the experimental trends and show that the character of disorder depends critically on the direction of alloying, producing either scattering barriers or deep trapping sites. Together, these results demonstrate that transport in TMD
alloys is governed by disorder physics, overlooked by conventional optical and photoemission probes at
equilibrium. Our findings establish transport as a stringent metric of electronic quality and high-light intrinsic limitations in the usage of TMD
alloys for layered
semiconductor devices.
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All authors Michele Pisarra, Clara Rebanal, Enrique Arévalo Rodríguez, Marc Meléndez, Elena Blundo, Giacomo Amadore, Jonathan J. Finley, Fabián Calleja, Marc G. Cuxart, Jesús Álvarez, Ma-ría José Capitán, Fernando J. Urbanos, Julia García Pérez, Ramón Bernardo Gavito, Daniel Granados, Ji Dai, Massimo Tallarida, Antonello Sindona, Fernando Martín, Ferry Prins, Iolanda Di Bernardo, Amadeo L. Vázquez de Parga
Computational Physics · Cross-listed from cs.LG
Structured Multi-Level-Set Inversion for 3-D Electromagnetic Inverse Scattering
Yutong Du, Zicheng Liu, Bo Qi et al. (+3 more)
Many dielectric targets encountered in 3-D electromagnetic inverse scattering exhibit piecewise-homogeneous material distributions, which provide useful structural information for inversion. To exploit this property, this paper proposes a structured multi-level-set inversion (SMLSI) method within a physics-driven neural network (PDNN) framework. Instead of directly parameterizing the contrast distribution, SMLSI represents it in terms of object support and material distribution. Multiple level-sets are mapped to soft-support functions and combined through a soft-union operation to construct the object support. The normalized contributions of these soft-support functions, together with trainable complex relative permittivities, determine the material distribution within the support. The level-set residuals are parameterized by a coordinate-based neural network, and the trainable parameters are optimized from scattered field data. Structure-aware regularization terms are introduced to promote binary object support and spatially coherent material regions while reducing material mixing and redundant activation of level-set supports. Adaptive regularization weighting is further employed to reduce the dependence on manual parameter tuning. Numerical experiments demonstrate that SMLSI improves reconstruction accuracy over direct contrast parameterization and enables the recovery of irregular 3-D geometries, closely spaced objects, and multiple material regions. Compared with CSI and $L_{2/3}$-FBE-WCIE, SMLSI achieves more accurate reconstructions on representative synthetic targets. Experimental validation using 3-D Fresnel data further demonstrates its applicability to measured scattering data.
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All authors Yutong Du, Zicheng Liu, Bo Qi, Yali Zong, Xin Li, Peixian Han
Quantum Physics
Multimode squeezed light generation and characterization
Alexander Chudakov, Vladislav Severin, Anastasia Poshevkina et al. (+5 more)
Nowadays, the realization of
quantum computations and communications based on continuous variables has attracted a significant
attention due to a substantial expansion of the system dimensionality. The main progress in this area is attributed to the implementation of multimode systems based on squeezed states of light. One of the simplest ways to generate such states relies upon their producing in a single-pass optical parametric amplifier (OPA) using ultrafast pumping. However, for homodyne detection of such multimode states, the profile of the local oscillator (LO) must perfectly match the profile of the measured mode. Usually, this is not the case; therefore a proper treatment of multimode squeezing is required. In this work, we study both theoretically and experimentally the multimode squeezed light generated in type-0 and type-II OPA. We characterize such sources and investigate the degree of squeezing in dependence on the LO spectral profile, employing a pulse shaping technique. The theoretical analysis is performed using the Schmidt-mode theory. This work might have a significant impact on the realization of multimode
quantum protocols
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All authors Alexander Chudakov, Vladislav Severin, Anastasia Poshevkina, Danil Malyshev, Kirill Kuznetsov, Olga Tikhonova, Dmitry Kalashnikov, Polina Sharapova
Earth and Planetary Astrophysics
Radial velocity follow-up of Gaia astrometric substellar companions: six confirmed brown dwarfs and 13 impostor binaries
Marcus L. Marcussen, Simon H. Albrecht, Kamil K. Kalinowski et al. (+7 more)
With microarcsecond precision,
Gaia has made the astrometric discovery of substellar companions feasible. However, follow-up observations are needed to check on orbital solutions and rule out astrophysical false positives. We validate and characterise a sample of 20
Gaia Data Release 3 (DR3) astrometric candidates for substellar companions, with the dual goal of identifying false positives and deriving robust physical parameters for genuine companions. We performed high-resolution spectroscopy using FIES, NIRPS, and NEID at the Nordic Optical
Telescope, the ESO 3.6m
telescope, and the WIYN
Telescope, respectively. Double-lined spectroscopic binaries were identified as false positives, and surviving systems were characterised through joint
Gaia astrometry and radial velocity modelling. Thirteen of the candidates proved to be near-twin binary
stars for which the astrometric motion of the center of light is small enough to mimic that of a single
star in response to a substellar companion. We confirm that six companions are brown
dwarfs with masses in the range ${\sim}26$–$68\,M_\mathrm{Jup}$, two of them for the first time. In contrast to earlier studies of lower-mass
Gaia candidates, we find that the astrometric orbital solutions are generally reliable to within the stated uncertainties.
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All authors Marcus L. Marcussen, Simon H. Albrecht, Kamil K. Kalinowski, Joshua N. Winn, Gu{\dh}mundur Stefánsson, Jens Reersted Larsen, Julie Gadeberg, Evan Fitzmaurice, Kevin Schlaufman, Suvrath Mahadevan
High Energy Physics (Theory)
Gravitational decoherence from soft-graviton $S$-matrix
Hiroki Matsui
We revisit gravitational decoherence of matter superpositions using the leading soft sector of the graviton $S$-
matrix. Starting from Weinberg's soft
theorem and the overlap of coherent radiation states, we derive, for branch configurations with the same total four-momentum, a gauge-invariant, nonnegative leading-soft decoherence exponent and evaluate the polarization sum and angular integrals exactly at this order. In the
vacuum, coherence between branches with distinguishable soft radiation vanishes as the infrared cutoff is removed. The leading nonrelativistic term is purely quadrupolar as a consequence of energy–momentum conservation. We extend the analysis to single- and two-mode squeezed graviton states, including the two-mode case motivated by inflation. Squeezing can enhance or suppress decoherence depending on the relative phase, while phase averaging gives an enhancement governed by the graviton occupation. For a phase-averaged relic background with an approximately flat energy-density spectrum over the relevant soft frequency band, the sharp-cutoff identification of the infrared scale with the inverse observation time gives a contribution that grows with the gravitational-wave energy density and with the fourth power of the observation time. These results connect soft-graviton scattering, infrared
quantum information, and decoherence in nonvacuum gravitational backgrounds.
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Strongly Correlated Electrons
Magnetic phases of Kondo lattice materials Ce$_5$RhGe$_2$ and Ce$_5$IrGe$_2$
Jiawen Zhang, Yanan Zhang, Mingyi Wang et al. (+5 more)
Single
crystals of Ce$_5$RhGe$_2$ and Ce$_5$IrGe$_2$ have been systematically investigated by electrical resistivity, specific heat, and magnetization measurements. Together with Ce$_5$CoGe$_2$, all three compounds crystallize in the orthorhombic Pnma structure, with the
lattice parameters increasing monotonically from Co to Rh to Ir, consistent with the effect of negative chemical pressure. Magnetization measurements along the three principal crystallographic axes identify the a axis as the easy magnetization direction throughout the series. Ce$_5$RhGe$_2$ exhibits
ferromagnetic ordering with a Curie temperature of approximately 11.5 K and shows
magnetic behavior closely resembling that of Ce$_5$CoGe$_2$. In contrast, Ce$_5$IrGe$_2$ undergoes two successive
magnetic transitions at $T_{\rm M1}=12.7$ K and $T_{\rm M2}=11.8$ K, and there are multiple metamagnetic transitions under
magnetic fields, giving rise to magnetization plateaus at fractions of the saturation magnetization $M_{\rm s}$ of approximately $M_{\rm s}/5$ and $M_{\rm s}/3$. The low-field metamagnetic transition along the easy axis shifts to lower field with decreasing temperature, and eventually a pronounced hysteresis loop is observed about zero-field, establishing that Ce$_5$IrGe$_2$ exhibits a ferrimagnetic ground state at the lowest measured temperatures.
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All authors Jiawen Zhang, Yanan Zhang, Mingyi Wang, Ye Chen, Yu Liu, Yongjun Zhang, Michael Smidman, Huiqiu Yuan
High Energy Physics (Phenomenology)
Free $\mu^{+}\mu^{-}$ and bound-free $e^{+}e^{-}$ pair production in relativistic heavy-ion collisions
Melek Yilmaz Şengül
In our previous studies, we calculated the cross-section for the production of free $\mu^{+}\mu^{-}$ pairs using a probability function dependent on the impact parameter, and also, we computed bound-free $e^{+}e^{-}$ pair production cross section. In this study, unlike the others, we obtained the cross section for the production of bound-free $e^{+}e^{-}$ pairs using the probability function dependent on the impact parameter. Here also, we simultaneously calculated the cross sections for producing free $\mu^{+}\mu^{-}$ with bound-free $e^{+}e^{-}$ pairs in relativistic $Pb+Pb$ collisions at the LHC with Lorentz factors at $\gamma=1500$ and $\gamma=3000$ reported in the literature. Our calculation is based on second-order perturbation theory, implemented by using Monte Carlo integration techniques. We present impact parameter dependent pair production probabilities for free $\mu^{+}\mu^{-}$ and bound-free $e^{+}e^{-}$ pair production processes. Notably, the bound-free $e^{+}e^{-}$ pair production was evaluated by using a formalism adapted from that of free $\mu^{+}\mu^{-}$ pair production. Our results obtained here for the free $\mu^{+}\mu^{-}$ with bound-free $e^{+}e^{-}$ pair production cross sections are compared with those from other theoretical methods available in the literature. This study aims to provide predictions that can be tested against future experimental data, thereby offering a valuable check for
quantum electrodynamics (QED) in strong electromagnetic fields.
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Cosmology and Nongalactic Astrophysics
Harnessing stellar kinematics to constrain dark energy with the double-source-plane gravitational lens SDSS J0946+1006
Daniel J. Ballard, Wolfgang J. R. Enzi, Thomas E. Collett et al. (+6 more)
SDSS J0946+1006 is an attractive target for measuring cosmological parameters through lens modelling. It is the best-studied
galaxy-scale strong gravitational lens with multiple sources whose
redshift separations are well-suited to constraining the dark energy equation of state. However, multi-plane lens models with free cosmological parameters risk a multi-plane mass-sheet degeneracy, although this can be lifted by a non-
lensing deflector density profile tracer. We simultaneously reconstruct near-infrared and near-ultraviolet HST imaging whilst including a velocity dispersion measurement from VLT-MUSE to constrain the foreground deflector. Imaging is reconstructed faithfully regardless of whether the inferred kinematics are realistic, though we find the kinematic constraint essential for shifting the preferred cosmology into a region not in significant tension with other dark energy probes. Deflector density profile perturbations, via substructure and multipolar
halo shape deformations, have only a modest effect on inferred cosmology. Combining our fiducial model with Planck CMB data yields $w=-1.01^{+0.08}_{-0.13}$; or, combined with Pantheon SNe Ia, $w=-0.99^{+0.13}_{-0.15}$. We further show that this system proves a remarkably valuable complementary probe in the $w_{0}$-$w_{a}$ plane of an evolving dark energy model, and that the DESI BAO tension with $\Lambda$CDM seen when combined with other
datasets is not reproduced when combined with this lens, yielding $(w_{0}, w_{a})=(-0.87^{+0.10}_{-0.11}, -0.22^{+0.28}_{-0.25})$. The system's third source, visible with MUSE, only weakly constrains $w$CDM but may strengthen $w_{0}w_{a}$CDM constraints, though further mass-model complexity along its line of sight is required. Overall, kinematics-informed multi-plane lens modelling is a robust route to competitive dark energy constraints, even with a single system.
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All authors Daniel J. Ballard, Wolfgang J. R. Enzi, Thomas E. Collett, Coleman M. Krawczyk, Giovanni Granata, Tian Li, Geraint F. Lewis, Karl Glazebrook, Huimin Qu
Superconductivity
Fabrication And Characterization Of High-Quality Nb/Al-AlO$_x$/Nb Cross-Type Josephson Tunnel Junctions Utilising CMP-based Planarisation Techniques
Alexander Stoll, Andreas Reifenberger, Daniel Hengstler et al. (+2 more)
Josephson tunnel junctions (JJs) are the fundamental building blocks of today's most advanced superconducting electronic components, such as
qubits and superconducting
quantum interference devices (SQUIDs). Given the ongoing demand for scalability of these devices on the wafer-scale, it is crucial to control the fabrication process as precisely as possible to ensure uniform quality and reproducibility. Today, window-type JJs are often used in the production of DC SQUIDs and while they are reliable and reproducible, they suffer from
alignment inaccuracies caused by photolithography and unavoidable parasitic capacitances, thus limiting the energy sensitivity of DC SQUIDs. These problems can be circumvented by producing JJs with cross-type geometry, which allows for smaller junction areas and eliminates parasitic capacitances. Here we discuss the fabrication of Nb/Al-AlOx/Nb-based cross-type JJs, where the trilayer is embedded in sputter-deposited SiO$_2$ to allow for planarisation of the structures and to ensure the reliable insulation of the sidewalls of the bottom electrode. Instead of lift-off processes that require a lot of time and potentially leave unwanted wings along the edges of microstructures behind that might compromise subsequent layers, we use chemical-mechanical polishing (CMP) for the removal of excess SiO$_2$. This is not only much faster, but produces smooth and uniform surfaces, which in turn effectively improves the reliability of our JJ production process resulting in a high yield of over $90\,\%$ on wafer-scale. In addition, we discuss the influence of fabrication details on the quality and electrical properties of our JJs with different junction areas down to $1\,\mathrm{\mu m} \times 1\,\mathrm{\mu m}$ distributed across the wafer and extract the junction specific quality parameters from their IV-characteristics and their Fraunhofer patterns.
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All authors Alexander Stoll, Andreas Reifenberger, Daniel Hengstler, Andreas Fleischmann, Christian Enss
Optics
Encoding Propagation Invariance into Light
Wenxiang Yan, Tianyue Li, Zhuolin Wu et al. (+6 more)
Diffraction governs the axial
evolution of optical fields, whereas conventional
holographic synthesis primarily controls their transverse structure. Here we add axial diffraction management as an additional design freedom to the transverse_field programmability of holography, enabling the transverse optical function and its diffraction-driven axial
evolution to be co_designed. By incorporating established propagation_invariant dynamics into computer_generated hologram and meta_hologram synthesis, we realize task_selectable axial responses in user_defined monochromatic, full-colour and vectorial fields. On a spatial light modulator, the same scalar user_defined field is configured either for a rapidly evolving 1.2_cm depth of field or for an approximately 75_cm propagation_invariant range. Millimetre_scale metasurfaces further enable metre_scale refocusing_free full_colour projection and vectorial colour fields with polarization textures preserved over more than 30 cm. This transverse_axial co_design framework extends
holographic field synthesis beyond transverse programmability, providing a broadly compatible route towards task_configurable optical systems and compact multidimensional photonics.
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All authors Wenxiang Yan, Tianyue Li, Zhuolin Wu, Yiyu Zhao, Zhi-Cheng Ren, Xi-Lin Wang, Hui-Tian Wang, Shuming Wang, Jianping Ding
Earth and Planetary Astrophysics
MAD-LEO: A Maneuver-Annotated Orbital Dataset for LEO Satellites with Tiered Multi-Source Evidence
Zhixin Guo, Qi Shi, Xiaofan Xu et al. (+6 more)
With the rapid development of aerospace technology and the large-scale deployment of low Earth orbit (LEO) constellations, the risk of orbital collisions has increased, creating a growing demand for reliable observations of satellite maneuvers. However, public
datasets containing real maneuver records remain scarce. We present MAD-LEO, a Maneuver-Annotated orbital
Dataset for LEO satellites. The mission-reported subset contains 1,134 maneuver events from eleven geodetic and altimetry satellites spanning 1992 to 2026, with labels taken directly from mission-published maneuver histories. Each event is checked against two-line element (TLE) data, precise orbit products, and satellite
laser ranging (SLR) observations, with evidence tiers assigned according to data availability. The operational subset pairs operator-published ephemerides for 6,785 Starlink satellites with cataloged TLE records over a continuous 107-hour period. Technical validation across seven machine-readable experiment suites confirms the cross-source consistency of the labels and the evidence products.
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All authors Zhixin Guo, Qi Shi, Xiaofan Xu, Linqiang Ge, Hua Zhu, Liyan Ben, Bendian Nie, Yuanrui Zhao, Xiaohan Li
Quantum Physics
Kinematic Control and Dephasing Dynamics of Quantum Resources in $e^{+}e^{-}\to\tau^{+}\tau^{-}$
Elhabib Jaloum, Omar Bachain, Mohamed Amazioug et al. (+1 more)
We characterize several
quantum resources carried by the
spins of the $\tau^{+}\tau^{-}$ pair produced in $e^{+}e^{-}$ annihilation. At the Belle-II energy, $\sqrt{s}=10.579\,\mathrm{GeV}$, Bell nonlocality, steerability,
entanglement of formation, and coherence are governed by the production angle and are largest for transverse emission, $\vartheta=\pi/2$. Their common kinematic origin is exposed by expressing the
spin state as a velocity and angle-dependent mixture of a separable contribution and a maximally entangled component. Within the physical production domain, this representation connects the weakly correlated threshold state at $\sqrt{s}=2m_{\tau}$ to the Bell-state limit approached at ultrarelativistic energies. We then propagate the two-
spin state through a phenomenological correlated-dephasing channel to determine how environmental
memory and inter-channel classical correlations affect the available resources.
Memory effects generate collapses and revivals that are absent from the monotonic Markovian
evolution. The analysis therefore separates the kinematic mechanism that creates the
spin correlations from the noise properties that control their subsequent survival.
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All authors Elhabib Jaloum, Omar Bachain, Mohamed Amazioug, Rachid Ahl Laamara
Optics
Universal Broadband Linear Optical Transformations by an Interlaced Structured Integrated Photonic Processor
Ilya V. Kondratyev, Kseniia N. Urusova, Artem S. Argenchiev et al. (+8 more)
Reconfigurable photonic integrated
circuits enable applications in a wide range of fields. They represent a powerful platform for signal processing due to the ability to perform parallel computations. In this work, we demonstrate a photonic processor based on a six-channel universal chip fabricated by femtosecond
laser writing with an interlaced architecture comprising multiport beam splitters. We exploit and enhance a previously demonstrated calibration procedure for a single building block, and extend it to a complete six-channel interferometer, reconstructing the corresponding interferometer models over a broad spectral range. We validate them by measuring a set of 100 Haar-random
unitary matrices, achieving mean amplitude fidelities of 95.9 %, 98.0 %, and 96.0 % for radiation wavelengths 910, 945, and 980 nm, respectively, without on-device optimization. Furthermore, we experimentally realize spectral demultiplexing and multiplexing at these wavelengths, yielding routing fidelities ranging from 90.1 % to 96.5 % and total crosstalk values ranging from -9.6 to -14.4 dB, confirming the applicability of the fabricated photonic processor to practical wavelength-routing tasks.
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All authors Ilya V. Kondratyev, Kseniia N. Urusova, Artem S. Argenchiev, Sergei A. Zhuravitskii, Nikolay N. Skryabin, Alexander D. Golikov, Vadim V. Kovalyuk, Gregory N. Goltsman, Ivan V. Dyakonov, Stanislav S. Straupe, Sergei P. Kulik
Plasma Physics
Demonstration of a 10-metre-long discharge plasma source for plasma wakefield acceleration
C. Amoedo, N. Lopes, N. E. Torrado et al. (+13 more)
The AWAKE experiment at CERN uses high-energy
proton bunches to drive
plasma wakefields capable of accelerating electron bunches up to hundreds of GeV in a single
plasma. Realising this potential requires a
plasma source that can extend to tens of metres while maintaining high longitudinal uniformity and reproducibility. Towards this goal, we report on the first experimental characterisation and beam-based validation of a 10-metre-long pulsed-DC discharge
plasma source (DPS) used as an alternative to the
laser-ionised rubidium vapour
plasma source (VPS). The DPS reliably delivered
plasma densities in three noble gases (He, Ar, Xe) at electron densities between 10$^{14}$ and 10$^{15}$ cm$^{-3}$.
Proton bunch self-modulation was observed with all three gases, and the resulting modulation frequency was used as a beam-based diagnostic of the
plasma density, showing good agreement with laboratory interferometry measurements. The event-to-event modulation frequency was demonstrated to be reproducible to within 0.63%, comparable to that of the VPS. These results establish the DPS as a valid alternative
plasma source for beam-driven wakefield experiments, and support its further development towards longer
plasma lengths. The present design is tailored to AWAKE requirements, but the underlying discharge concept provides a route to long, reproducible
plasma sources with straightforward density control through discharge-beam timing for other beam-
plasma experiments.
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All authors C. Amoedo, N. Lopes, N. E. Torrado, F. Silva, P. Muggli, L. Verra, M. Turner, G. Zevi Della Porta, M. Bergamaschi, A. Clairembaud, J. Mezger, F. Pannell, N. Z. van Gils, E. Gschwendtner, A. Sublet, the AWAKE Collaboration
Strongly Correlated Electrons
Schwinger boson perturbation theory for spin-$S$ Kitaev-Heisenberg magnets: phase diagram and dynamical response near Kitaev spin liquids
Daiki Sasamoto and Joji Nasu
We develop a Schwinger
boson perturbative framework for the
spin-$S$ Kitaev-Heisenberg model. The
spin-
liquid saddle point of the pure Kitaev model is used as the unperturbed state, and
magnetic instabilities and dynamical
spin correlations are evaluated around this saddle point. We decompose the
Hamiltonian exactly into two parts by exploiting the Klein duality intrinsic to the Kitaev-Heisenberg model. We perform the random-phase approximation by taking the part invariant under the duality transformation as the unperturbed term and treating the remaining term, which changes sign under it, as the perturbation. We determine the phase boundaries separating the
quantum spin-
liquid regimes from the adjacent magnetically ordered phases for $S=1/2$, $1$, $3/2$, and $2$. The
spin-
liquid regions shrink rapidly with increasing $S$ and become very narrow at $S=2$. We also compute the
spin dynamics of the
spin-$S$ Kitaev-Heisenberg model, focusing on $S=1$, and find that the dressed dynamical
spin structure factor retains a broad two-spinon continuum at finite energies, while the low-energy spectral weight softens at the ordering wave vectors of the adjacent
magnetic phases. Our framework thus enables thermodynamic-limit calculations of
spin dynamics near
magnetic instabilities.
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Mesoscale and Nanoscale Physics
Equivalent Circuit Representation and Thermodynamic Limitations of Non-Adiabatic Spin-Transfer Torque effect
Wataru Koshibae
We present an equivalent
circuit representation of the Thiele equation for the current-driven domain walls. We show that the non-adiabatic
spin-transfer torque (\beta-term) cannot be represented by passive elements alone (such as resistors, inductors, and capacitors) and necessarily requires active elements, corresponding to negative dissipation. Consequently, assuming that the driving current is the only power source for the texture dynamics, directly incorporating the \beta-term introduces a fundamental contradiction with thermodynamic principles. This equivalent
circuit theory indicates that the interpretation of experiments solely through the \beta-term does not fully capture the underlying physics, highlighting the need to account for effects distinct from the
spin dynamics.
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Astrophysics of Galaxies · Cross-listed from cs.SC
Physical Law Ecology: mapping multi-mechanism ecologies as the zeroth step of data-driven scientific discovery
Xiongheng Bian, Xiangyu Cui, Ma Feng et al. (+1 more)
Every data-driven equation discovery method assumes (implicitly and without verification) that the target system obeys a single governing law ($K{=}1$). Here we show that this assumption is the primary bottleneck limiting scientific discovery in multi-mechanism systems, and introduce Physical Law Ecology, a framework that makes $K^*$ (the number of coexisting independent mechanisms) itself the first quantity to be determined from data. The framework automatically mines a pool of topologically distinct candidate equations, constructs a continuous dominance weight field across parameter space, and discovers analytic
evolution laws governing mechanism succession—with optional monotonicity constraints encoding irreversible physics. Across four unrelated systems (elastomer mechanics, pool boiling,
galactic dynamics, and droplet evaporation), BIC consistently identifies $K^*{=}3$ independent governing
topologies. Applied to 163 SPARC
galaxies (3,269 spatially resolved measurements), the framework autonomously recovers three gravitational laws whose coexistence provides evidence against the single-universal-acceleration hypothesis of MOND ($p<10^{-34}$). In engineering applications, multi-law weighted prediction reduces error by 67-72% over single-equation baselines while retaining full interpretability. By establishing the determination of $K^*$ as the zeroth step of scientific discovery-prior to and independent of equation search—this work opens a direction orthogonal to existing symbolic regression: not finding better equations, but mapping the ecology of mechanisms that govern complex systems.
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All authors Xiongheng Bian, Xiangyu Cui, Ma Feng, Xiaoyan Shen
Mesoscale and Nanoscale Physics
Memory Control of Ice Growth During Non-Equilibrium Freezing of Water
Abhigyan Hazarika, Sudeep N. Punnathanam, Biman Bagchi et al. (+1 more)
Freezing of supercooled water is a classic non-
equilibrium problem, yet the influence of thermal history on crystallization remains unclear. Using molecular dynamics simulations with the TIP4P/Ice model, we investigate how the initial temperature $T_i$ shapes freezing following rapid quenching to 250 K. By monitoring the
evolution of hydrogen-bonded ring structures, we find a non-monotonic dependence of the freezing time $t_F$ on $T_i$, with the slowest crystallization occurring near 300 K. Remarkably, this means that initially hotter water can freeze faster than cooler water, a molecular-scale analogue of the Mpemba effect. A non-stationary generalized Langevin equation framework shows that two-time
memory kernels retain information about the system's thermal past, directly influencing crystallization dynamics. Structural analysis further reveals that five-membered rings act as kinetic traps, while correlations among ring types regulate the accessibility of ice-like motifs. These results uncover a molecular origin of
memory-driven freezing and establish structural
memory as a key driver of non-
equilibrium phase transitions.
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All authors Abhigyan Hazarika, Sudeep N. Punnathanam, Biman Bagchi, Prabal K. Maiti
High Energy Astrophysical Phenomena
Nuclear equation-of-state effects on the two-dimensional post-outburst thermal evolution of magnetized neutron-star crusts
Wei-Feng Zhang, Zhi-Fu Gao, Wen-Qi Ma et al. (+2 more)
We present a controlled two-dimensional study of
nuclear-equation-of-state (EOS) effects on the post-outburst thermal relaxation of magnetized
neutron-
star crusts. Six EOS models are evolved at a fixed gravitational mass of $1.4 M_{\odot}$ with EOS-specific TOV backgrounds, crust compositions, and transport inputs under identical
magnetic-field and heating prescriptions. Our analysis combines self-consistent multi-EOS
evolution with a BSk-family factorization that separates structural, microphysical, and interaction contributions, together with an accepted-step energy ledger and a numerical-sensitivity budget. The models show EOS-dependent changes in both the early response and the later redistribution of heat between the surface, crust, and inner boundary; light-curve crossings near $10^2$ days demonstrate that the EOS effect is not a simple luminosity rescaling. By 1000 days the cumulative surface-
photon energy fraction differs by less than one percentage point, whereas the internal energy partition differs much more strongly. The updated sensitivity tests show that the late-time luminosity differences and the largest peak contrasts exceed the corresponding BSk24 numerical-sensitivity scales, while the smallest early peak contrast remains less securely resolved. The calculations are intended as a reproducible EOS-sensitivity
benchmark rather than an observational fit.
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All authors Wei-Feng Zhang, Zhi-Fu Gao, Wen-Qi Ma, Na Wang, Yan-ling Liu
Mathematical Physics
The phase coordinates transformation in Moyal noncommutative framework 2-dimensional harmonic oscillator and Painlevé second equation
Irfan Mahmood
This work aims to explore the physical application of Moyal noncom- mutative formalism with the the presentation of new transformations which connect the old canonical coordinates to purly noncommuting phase coordi- nates through the parameters describe the Moyal noncommutative deforma- tion. These transformations are consistent with the Moyal noncommunica- tive brackets and build sixteen components traceless anti-symmetric tensor. This formalism incorporates space-space and space-momentum noncommu- taivity rather then noncommutativity (Heisenberg
quantum commutation ) only for the canonical coordinates. The transformations imply to construct noncommutative analogs of 2-dimensional harmonic oscillator with its superintegrability and Painlevé second equation. The associated deformed
Hamiltonians additionally involve some extra
symmetries and reveal a deep physical understanding of about the additional
symmetries with noncommunicative structure. The Painlevé second noncommutative coordinates transformation are also efficiently applied to generate the first Yablonskii Vorobev
polynomial with Painlevé second parameter transformation.
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