Quantum Physics
The Infinitesimal Structure of Quantum Information
Luca Barbieri-Viale
This paper establishes a rigorous, unified
geometric framework for
quantum state spaces by constructing smooth, regular
embeddings into higher-order dual number
algebras $\mathcal{Q}_N \equiv \mathbb{R}[\varepsilon]/(\varepsilon^{N^2-1})$, wherein every
quantum state is faithfully represented as a non-reduced scheme-theoretic point. We show that under this unified family of truncated rings, the non-linear
matrix commutators governing the Liouville-von Neumann dynamics map globally onto flat, linear, and rigid algebraic flows, establishing nilpotent dual
algebras as a pristine
geometric landscape for higher-dimensional
quantum kinematics. As $N \to \infty$, this family converges to a Cauchy-complete power series ring $\mathcal{Q}_\infty$, where non-Archimedean completion linearizes the phase space, aligning the Fubini-Study geometry with the classical Fisher-Rao
manifold.
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High Energy Astrophysical Phenomena
Machine Learning Detection of Non-Axisymmetric Fast Flavor Instabilities in Compact Objects
Madhurima Chakraborty, Sajad Abbar, Meng-Ru Wu et al. (+2 more)
Neutrinos in dense astrophysical environments such as core-collapse
supernovae (CCSNe) and
neutron star mergers (NSMs) can undergo FFCs, which could develop on extremely small scales. A necessary condition for the occurrence of FFCs is the presence of a zero crossing in the electron
lepton number (ELN) angular distribution of
neutrinos. In this work, we explore machine learning (ML) approaches to detect non-axisymmetric ELN crossings in these environments, based on input features of the $\nu_e$ and $\bar\nu_e$ zeroth and first angular moments. Overall, the ML models demonstrate relatively good generalizability for most of the unseen test
datasets generated by various methods that do not assume the same underlying angular distributions as used in the training set. Interestingly, while the model's performance is mediocre for an axisymmetric distribution
dataset derived by solving the discretized Boltzmann transport equation under 1D CCSN background, imposing an artificial non-axisymmetry substantially improves the performance. We also find that for the
flavor-equilibrated angular distributions, although our ML model trained based solely on ELN inputs performs poorly when the true crossings depend on the post-equilibrated angular distributions of heavy
lepton neutrinos and antineutrinos, which become different, it delivers strong performance in detecting ELN crossings when the heavy-
lepton neutrino and antineutrino distributions are artificially removed. This highlights the need for additional input features to further improve the model. This is a crucial step toward successfully integrating FFCs into large-scale CCSN and NSM simulations.
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All authors Madhurima Chakraborty, Sajad Abbar, Meng-Ru Wu, Francois Foucart, Zewei Xiong
High Energy Physics (Phenomenology)
High Energy Evolution of Dipole Gluon Distribution Beyond Eikonal Approximation
Ming Li
At high energy, the dipole
gluon distribution is described at eikonal order by the Wilson-line dipole correlator, whose high-energy
evolution is governed by the Balitsky-Kovchegov equation. Going beyond the eikonal approximation, we identify the subeikonal operator representing the dipole
gluon distribution, consisting of a Wilson line with a single insertion of the light-cone chromoelectric field, and derive its high-energy
evolution equation in the large-$N_c$ limit under the single-logarithmic approximation. The resulting nonlinear
evolution is coupled to the Wilson-line dipole correlator and incorporates
gluon saturation effects. In the dilute limit, the subeikonal distribution grows as a power-law of the energy with exponent $\alpha_s N_c/2\pi$, less than one fifth of the eikonal value, while in the saturation regime it obeys the same Levin–Tuchin law as the eikonal correlator. These results constitute the first closed nonlinear
evolution equation for the dipole
gluon distribution at subeikonal order, a step toward precision small-$x$ phenomenology and toward connecting small-$x$ physics with the moderate-$x$ dynamics.
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High Energy Physics (Phenomenology)
CP violation induced by the real part of the interference term in $\rho^0 - \omega$ mixing
Jin-Zhao Guo, Gang Lü and Zhen-Hua Zhang
To circumvent the severe numerical cancellations in the standard integrated CP asymmetry ($A_{CP}$) near the $\omega$ mass $m_\omega$, we propose a modified CP-violating observable, $A_{CP}^{\Re}$, which explicitly highlights the contribution of the real part of the interference term. Subsequently, we employ the three-body hadronic decay $B^{-} \rightarrow \pi^{+} \pi^{-} \pi^{-}$ within the Perturbative QCD (PQCD) approach as a primary case study to validate this theoretical framework. Furthermore, this method naturally eliminates the smooth, sign-preserving continuum background originating from broad scalar resonances like the $f_0(500)$. This generalized framework provides clean and robust theoretical guidance for recovering localized CP-violation signals that might otherwise be masked by coarse experimental binning at future high-luminosity
colliders.
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Mesoscale and Nanoscale Physics
Effect of the local field and dipole-dipole interaction on the spontaneous ordering of dipole moments in bismuth monolayers with an orthorhombic structure
D. V. Ponkratova, I. V. Zagorodnev and V. V. Enaldiev
Using two complementary approaches, the instability of bismuth monolayers with an orthorhombic structure with respect to the emergence of spontaneous electric dipole moments at the
crystal lattice sites has been studied. The first approach, based on determining the dipole moments of
lattice sites through the polarizability of bismuth atoms and taking into account the local Lorentz-Lorenz field, suggests the possibility of the existence of several antiferroelectric and ferroelectric phases in orthorhombic bismuth monolayers. Using the second approach, the vibrational spectrum of a nonpolar symmetric
lattice has been analyzed, and two types of soft optical modes corresponding to the ferroelectric and antiferroelectric instabilities of the monolayers have been revealed. The relationship of the Born effective charges to the polarization direction in the ferroelectric phase, as well as their role in the reduction of the frequency of the polar optical
phonon, which characterizes the
lattice deformation in the ferroelectric phase due to the dipole-dipole interaction, has been shown.
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Strongly Correlated Electrons
Research on topological materials using ultrafast spectroscopy
Hao Liu and Jian-Qiao Meng
Topological materials, characterized by
symmetry-protected nontrivial band structures such as Dirac cones and Weyl nodes, host diverse
quantum phenomena, with potential applications in
quantum transport, spintronics, and nonlinear optics. Ultrafast pump-probe spectroscopy has emerged as a powerful tool for exploring nonequilibrium dynamics in these systems. Its femtosecond resolution allows charge,
spin, orbital, and
lattice interactions to be tracked on their intrinsic timescales, thereby revealing key coupling mechanisms in topological phases. This review summarizes progress in ultrafast spectroscopic studies of topological
insulators, topological semimetals, and
magnetic topological materials. We first discuss the relaxation pathways of photoexcited surface and bulk electronic states, emphasizing electron-
phonon scattering, surface-bulk charge transfer, and ultrafast
spin conversion. We then examine population inversion in Dirac and Weyl semimetals,
spin-polarization dynamics associated with tilted Weyl bands, and the effects of
magnetic order on topological states, including coherent
phonon and
magnon excitations, magnetically driven topological transitions, and terahertz emission. We further review photoinduced topological phase transitions driven by electronic correlations,
lattice distortions, and
magnetic order under intense optical excitation, highlighting routes toward nonthermal control of
quantum phases. Finally, we outline future directions that combine multidimensional ultrafast spectroscopy with temporal, energy, momentum, and
spin resolution and advanced theoretical modeling to establish a unified picture of nonequilibrium topological states. This review aims to provide a useful reference for ultrafast studies of topological
quantum materials and to advance their applications in high-speed, low-power information processing, spintronics, and
quantum technologies.
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Mathematical Physics
A canonical two-scale Sonine fractional calculus induced by the Tricomi function
Ivano Colombaro and Marc Tudela-Pi
We introduce a Tricomi-type generalized fractional calculus in the Sonine kernel framework. The key result is that the Tricomi branch is a Stieltjes function in the admissible parameter range, so its reciprocal is a complete Bernstein function. This fact induces a Sonine fractional calculus together with the canonical Tricomi integral and the associated Riemann–Liouville-type and Caputo-type derivatives. We also prove that, within the Kummer class, the Tricomi branch is the unique Stieltjes representative, once the natural asymptotic normalization is fixed, and we derive the corresponding Lévy–Khintchine representation, Volterra formulation, and scalar Cauchy problem. A distinctive feature of the resulting operators is the emergence of two independent asymptotic orders.
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Atomic Physics
Optically Derived Radio-Frequency Benchmark in Methanol: A Sub-kHz Reference for Astrophysical Tests of Fundamental Physics
Frank M. J. Cozijn, Arthémise Altman, Alexandr S. Bogomolov et al. (+8 more)
Methanol
radio lines observed in space provide sensitive probes of whether the
proton-to-electron mass ratio has changed over
cosmic time, but such tests require laboratory rest frequencies with very high accuracy. Here we determine the frequency of the astrophysically important 12.2 GHz $3_{-1}$E – $2_{0}$E transition of CH$_3$OH by measuring near-infrared rovibrational transitions rather than the microwave line directly. Using wavelength-modulated NICE-OHMS locked to an ultra-stable optical frequency comb and referenced via a fiber link to a hydrogen-maser frequency standard, we measure Lamb-dip frequencies near 1.4 $\mu$m (216 THz) with 10 Hz statistical reproducibility and absolute uncertainties as low as 130 Hz. Pairs of optical transitions sharing common upper levels form a triangulation scheme that yields the ground-state rotational combination difference. We obtain 12 178 596.415(135) kHz, improving on earlier molecular-beam microwave spectroscopy by a factor of 20 and agreeing with a recent free-induction-decay measurement. This result establishes a sub-kHz laboratory
benchmark for a key
radio-astronomical methanol line and demonstrates that optical triangulation can be extended to non-
chiral molecules with internal rotation.
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All authors Frank M. J. Cozijn, Arthémise Altman, Alexandr S. Bogomolov, Alexis Libert, Simon Collignon, Erik Dierikx, Jeroen C. J. Koelemeij, Boy Lankhaar, Isabelle Kleiner, Clément Lauzin, Wim Ubachs
Quantum Physics · Cross-listed from cs.LO
Quantum Weakest Preconditions Revisited: Pre-expectations for Expected Runtime Analysis
Christina Gehnen, Dominique Unruh and Joost-Pieter Katoen
Quantum weakest preconditions are a fundamental tool for program verification of
quantum programs. Many variations have been reported in the literature. We revisit
quantum weakest preconditions from the perspective of expected runtime analysis of
quantum programs and introduce a novel pre-expectation framework that enables to reason about the preconditions of
quantum programs without the need of an upper bound. This is particularly interesting for
quantum programs involving reward statements. The overall goal is to analyze runtime behavior even in the case of programs with potentially infinite expected runtime. This paper presents several ways to do so, e.g., a program transformation such that the expected runtime of a
quantum program can be expressed using the weakest pre-expectation calculus with rewards.
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High Energy Astrophysical Phenomena
Photometric and Spectroscopic Studies of Type Ic Supernovae SN 2020akf and SN 2021mxx
Mulchand Kurre, K. R. Sahu, Shrutika Tiwari et al. (+8 more)
We present a comprehensive analysis of optical photometry and medium-resolution spectroscopy for Type Ic
supernovae (SNe) SN 2020akf and SN 2021mxx. Our study covers the
evolution of SN 2020akf from -5 to 109 days and SN 2021mxx from -3 to 115 days relative to their B-band maximum. Their peak quasi-bolometric luminosities are estimated at logL_bol = 42.37 +- 0.02 and 42.21 +- 0.02 erg/s, respectively. The velocities of the ejecta, derived from the Fe II 5169 A line at maximum light, are approximately 15000 km/s for SN~2020akf and about 10000 km/s for SN~2021mxx, which are consistent with those observed in other Type~Ic SNe. Using the semianalytical Arnett model, we estimate that SN 2020akf has a kinetic energy of E_k = 6.33 (+0.68)(-0.62) x 10^51 erg and an ejected mass of M_ej = 4.71 (+0.50)(-0.46) M_sun, while for SN 2021mxx, we get E_k = 0.54 (+0.08)(-0.12) x 10^51 erg and M_ej = 0.90 (+0.14)(-0.18),M_sun. The mass of Ni56 synthesized in the explosion is estimated at 0.10 +- 0.02 M_sun for SN 2020akf and 0.05 +- 0.01 M_sun for SN 2021mxx. The
metallicities of the host
galaxies near the SN regions are ~0.81 Z_sun for SN 2020akf and ~0.76 Z_sun for SN 2021mxx, where Z_sun indicates
solar metallicity. Our detailed analysis suggests that SN 2020akf falls into the category of a transitional Type Ic SN, having spectral properties between normal and broad-line Type Ic SNe, while SN 2021mxx is a normal Type Ic SN with an extremely low value of the M_ej / E_k ratio.
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All authors Mulchand Kurre, K. R. Sahu, Shrutika Tiwari, Yogita Patel, N. K. Chakradhari, D. K. Sahu, Rishabh Singh Teja, G. C. Anupama, Mridweeka Singh, Anirban Dutta, Anjasha Gangopadhyay
Atomic Physics
Coherence enhancement of Rydberg polaritons
Xiao-Feng Shi, Yan Lu, Yuechun Jiao et al. (+1 more)
Quantum nonlinear optics by Rydberg polaritons can enable single-
photon transistor and switch, single-
photon source, and deterministic
quantum information processing. A major hindrance in this study is the fast motional decoherence. Here, we devise a scheme to significantly enhance the coherence of Rydberg polariton by letting the atoms remember their velocities, or, alternatively, by changing the phase of Rydberg polariton according to its storage time. After the Rydberg polariton is prepared with a Rydberg state $|r_1\rangle$, i.e., during the storage time, two
laser fields induce a transition between $|r_1\rangle$ and a nearby Rydberg state $|r_2\rangle$ via a low-lying intermediate state $\lvert f\rangle$ which is largely detuned. In particular, we find that either a $2\pi\mathbb{N}$ protocol, a $\pi$-wait-$\pi$ protocol, or a wait-$\pi$ protocol, along with an appropriate choice of $\lvert f\rangle$ can lead to a phase-coherent Rydberg polariton upon its
retrieval. Importantly, the coherent transition between $|r_1\rangle$ and $|r_2\rangle$ ensures that the Rydberg polariton can block the Rydberg excitation of nearby atoms as in usual applications of Rydberg polaritons. Numerics show that the theory can nearly completely eliminate the motional dephasing, leaving Rydberg-state decay as the only fundamental channel of decoherence. This sheds light on a broad application of Rydberg-mediated
quantum nonlinear optics.
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All authors Xiao-Feng Shi, Yan Lu, Yuechun Jiao, Jianming Zhao
Plasma Physics
First reduced model for integrated computations of helicon wave heating and current drive in magnetic fusion plasmas
Zi-Chen Kan, Lei Chang, Zhen-Yu Wang et al. (+9 more)
Fast predictive modelling of
radio-frequency heating and current drive is important for integrated tokamak scenario design, yet kinetic calculations of helicon-wave absorption remain too computationally expensive for large-scale parameter scans. We present a reduced model for helicon-wave heating and current drive that retains the dominant parallel electron Landau-damping channel. The wave response is evaluated on the cold-
plasma dispersion root, and a single-Landau-pole correction is introduced to obtain compact expressions for the local damping rate and current-drive efficiency. The model is benchmarked against the Chiu-Chan heating model using approximately 1.6 million samples covering representative conditions of EAST, HL-3, DIII-D and KSTAR. The reduction error is found to be governed primarily by the electron Landau parameter and electron beta. Within an identified sub-lower-hybrid-frequency validity window, results from different devices collapse onto a common error curve, which enables an empirical correction that is further tested using ITER-like and BEST-like extrapolation cases. Near and above the lower-hybrid frequency, the agreement deteriorates rapidly owing to changes in the cold-dispersion root structure and the breakdown of the single-branch WKB description. When coupled to a reduced current-drive source, the corrected heating model gives a median deviation of 10.8 percent from the Landau-channel Ehst-Karney reference and reproduces published CFETR current-density profiles. The resulting model provides a computationally efficient reduced closure for helicon-wave heating and current-drive calculations, together with physically interpretable limits on its range of validity.
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All authors Zi-Chen Kan, Lei Chang, Zhen-Yu Wang, Hua-Sheng Xie, Ping-Wei Zheng, Lai Wei, Qi-Bin Luan, Xue-Mei Zhai, Zhao-Qing Hu, Zheng-Xiong Wang, Matthew Hole, Zhi-Song Qu
Lattice Field Theory
Haobo Yan
This thesis develops
lattice-QCD methods for studying
hadron structure, scattering, and decays, with particular emphasis on multi-
hadron resonances. The Mathematica package OpTion is developed to automate the construction of
lattice multi-
hadron operators. Finite-volume spectra are related to infinite-volume amplitudes through quantization conditions. For coupled-channel $D\pi$ scattering, the pion-mass dependence of the pole trajectories and the scattering length are determined, and the results support a two-pole structure for the $D_0^*(2300)$. The thesis then studies the three-pion decay of the $\omega(782)$. Two- and three-body spectra are calculated, and three-body quantization conditions and effective field theory descriptions are developed. The extracted resonance pole, extrapolated to the physical point, gives a mass and width consistent with experiment and establishes a practical first-principles procedure for interacting three-body systems. These methods are further applied to the $\pi(1300)$, providing, for the first time, first-principles predictions of its resonance pole at several pion masses and revealing significant three-body effects. Finally, radiative and semileptonic decays of charmed
mesons are investigated, and a model-independent method is developed to extract transition form factors with improved precision. These results advance the first-principles study of coupled-channel and three-body
hadron resonances and provide new insight into their structure and decays.
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Data Analysis and Statistics · Cross-listed from stat.ME
Symbolic Weak-form Recovery of 2-D Stochastic Generators
Sai Sathvik Gullipalli and Eshwar R A
Recovering two-dimensional Ito generators from trajectory data is difficult because drift increments have low signal-to-noise, bivariate weak designs can be ill-conditioned, and unconstrained tensor estimates need not be positive semidefinite. We study WG-SINDy
estimator combining covariance-shaped spatial kernels, a ridge-stabilized local-
polynomial projection, adaptive-LASSO/STLSQ selection, one in-sample per-component feasible diagonal GLS pass, and a PSD projection–Cholesky read-out with mild isotropic shrinkage. The released
estimator uses a data-dependent full-cloud smoother and one in-sample per-component feasible diagonal GLS pass; accordingly, we do not claim exact finite-sample martingale cancellation or a feasible-GLS efficiency
theorem for the reported implementation. We evaluate the
estimator on 29 synthetic two-dimensional systems: 19 meet their declared per-system recovery contracts, eight are retained as named limits, and two remain scoped reviews. Across the 19 PASS rows, the median central-grid drift metric is 0.204 and the median tensor error is 0.0397. Among the six systems with a finite, non-degenerate off-diagonal target, the median $a_{12}$ cosine is 0.997. Positive-semidefinite validity is imposed by construction. These results are synthetic, in-sample sampled-region diagnostics and do not establish universal or real-data recovery.
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Materials Science
Many-body interactions in the dielectric theory of stopping power of solids for classical and quantum projectiles
Vladimir U. Nazarov and Vyacheslav M. Silkin
We take account of the many-body dynamic interactions by including the wave-vector and frequency-dependent exchange and correlations (xc) kernel $f_{xc}(\qv,\omega)$ in the framework of the dielectric theory of the stopping power of
crystals for moving charges. The cases of classical and
quantum projectiles are considered. We find that (I) the role of the xc effects in slowing of charges in crystalline solids is more pronounced than it is within the jellium model and (II) For velocities below the stopping maximum, inclusion of xc leads to the improvement of the comparison of the theory with experiment over a range of solid targets. On the other hand, in the high-velocity regime, the role of the dynamic xc proves negligible, which does not contradict experiment, and which we substantiate analytically within the jellium model of the target. The input to our theory is the microscopic dielectric
matrix $\epsilon_{\Gv \Gv'}(\qv,\omega)$ within the random phase approximation (i.e., with neglect of $f_{xc}$), the calculation of which
matrix is implemented in the existing solid-state codes.
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Instrumentation and Methods for Astrophysics
Estimation of the laser guide star uplink tip-tilt using aperture size diversity
Pierre Jouve, Thierry Fusco, Carlos M. Correia et al. (+3 more)
Laser guide
star (LGS) adaptive optics cannot directly measure tip-tilt (TT), forcing reliance on natural guide
stars and limiting sky coverage. We propose estimating the uplink TT from telemetry acquired at the
laser launch
telescope alone, operated in a monostatic configuration as both emitter and receiver. Extracting TT over concentric disks of different diameters within the receiving pupil yields signals mixing uplink and downlink contributions in different proportions; this aperture size diversity, combined with an LMMSE
estimator, disentangles the uplink component. Simulations show a residual error of 24 mas for a single turbulent layer and 34 mas with two layers.
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All authors Pierre Jouve, Thierry Fusco, Carlos M. Correia, Cédric Taissir Heritier, Jean-François Sauvage, Benoit Neichel
Earth and Planetary Astrophysics
Discrimination of Tectonic, Swarm and Impact-related Marsquakes using Spectral Characteristics
Simon C. Stähler, Savas Ceylan, Nikolaj Dahmen et al. (+2 more)
The NASA InSight mission observed over 2000 marsquakes in the course of its three year mission. These quakes varied in magnitude between 1.5 and 4.5, as well as in spectral content. We present a simple framework to describe the spectral characteristics of all observed marsquakes, based on source process; propagation through the mantle or crust; and local, receiver-side amplification. We assign to each quake an objective measure of its amplitude, as well as the spectral decay created by the duration of the rupture and the dampening of high frequencies due to visco-elastic attenuation. Together, this allows us to obtain characteristic patterns of the whole marsquake
dataset, e.g. in terms of event magnitudes, source size, and - for quakes caused by meteoritic impacts - crater size. We show that a significant fraction of all marsquakes - the high-frequency quakes - form a swarm that is likely not caused by tectonic processes in rocks. Our analysis allows separation of the whole marsquake catalogue into three event classes, of tectonic quakes, meteoritic impacts, and swarm events. We finally conclude that the largest marsquake, S1222a, most likely belongs to the group of meteoritic impacts.
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All authors Simon C. Stähler, Savas Ceylan, Nikolaj Dahmen, John Clinton, Domenico Giardini
Instrumentation and Methods for Astrophysics
Scaling laws for multi-object spectrographs: empirical relationships and the photonic advantage of CAWSMOS
Kalaga V. Madhav and Martin M. Roth
Conventional multi-object spectrographs (MOS) incur masses and costs that scale unfavourably with channel count~$N_\mathrm{ch}$ and resolving power~$\mathcal{R}$. A
dataset of eight fibre-fed MOS-VIS instruments (1995–2024) is compiled and analysed. Ordinary least-squares fitting yields a mass function $M \propto N_\mathrm{ch}^{0.78\pm0.28}$; the resolving-power exponent is empirically consistent with zero ($\gamma = 0.20\pm0.37$) but is predicted analytically to lie in $\mathcal{R}^{0.8\text{--}2.0}$. Leave-one-out cross-validation confirms sub-linear channel-count scaling ($\beta\in[0.59,1.13]$, mean 0.79), with HERMES and AAOmega – sharing the same
telescope and $N_\mathrm{ch}=392$ across a factor of~7 in $\mathcal{R}$ at essentially equal estimated mass – providing a direct empirical confirmation that $\gamma\approx 0$. Cost per channel decreases as $N_\mathrm{ch}^{-0.22\text{ to }-0.53}$ for all assumed cost–mass exponents $k\in[0.6,1.0]$, demonstrating a genuine economy of scale. The photonic integrated-
circuit (PIC) approach
embodied by the arrayed waveguide grating (AWG)-based PAWS demonstrator and the proposed CAWSMOS instrument decouples dispersive element size from $N_\mathrm{ch}$ and $\mathcal{R}$, with chip-area scaling as $\mathcal{R}^{1\text{--}1.5}$ instead of $\mathcal{R}^{3}$. Applied to the Wide-field Spectroscopic
Telescope (WST), the model predicts $\sim$140 tonnes for a conventional NIR spectrograph system against $\sim$200 kg for a CAWSMOS equivalent, with projected costs of EUR 300–700M conventional versus EUR 40–120M photonic ($6$–$15\times$ reduction). AWG-based photonics are identified as a strategially important enabling technology for WST.
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Quantum Physics
Benchmarking loss functions for trainable quantum feature maps
Nguyen Dinh Quyen, Vu Tuan Hai, Quoc Chuong Nguyen et al. (+2 more)
Many
quantum machine learning models employ
quantum feature maps to encode classical data into
quantum states. While fixed feature maps often lack sufficient expressivity for complex nonlinear classification tasks, trainable
quantum feature maps (TQFMs) enable adaptive
quantum kernels with enhanced learning capability. Different loss functions can induce distinct optimization dynamics, yet their effects remain poorly understood. In this work, we apply the Log-Likelihood Loss function for TQFMs and provide a systematic comparison with Distance Loss and Measurement Loss. Through extensive numerical experiments, we compare their optimization dynamics, computational costs, and classification performance. Our results show that Log-Likelihood Loss consistently achieves more stable optimization than Measurement Loss while retaining linear computational complexity. The resulting
benchmark offers practical guidance for balancing trainability, computational efficiency, and predictive performance in
quantum kernel optimization.
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All authors Nguyen Dinh Quyen, Vu Tuan Hai, Quoc Chuong Nguyen, Le Bin Ho, Lan Nguyen Tran
General Relativity and Quantum Cosmology
Magnetically charged spinning particles around a regular black hole: constraints on the monopole charge from quasi-periodic oscillations
Shokhzod Jumaniyozov, Javlon Rayimbaev, Chengxun Yuan et al. (+3 more)
We investigate the dynamics of magnetically charged spinning test particles in the spacetime of the Bardeen regular black hole, sourced by nonlinear electrodynamics and featuring a
magnetic monopole charge parameter g. Using the Mathisson-Papapetrou-Dixon equations with the Tulczyjew
spin condition, extended by the Coulomb-like force between the particle's
magnetic charge and the monopole, we derive the effective potential for equatorial motion and analyze circular orbits, the innermost stable circular orbit (ISCO), superluminality constraints and high-energy collisions. Solving the ISCO conditions perturbatively around Schwarzschild, we obtain exact coefficients, r_ISCO, and show that the
magnetic coupling \lambda g shifts r_ISCO only at higher order while it changes the ISCO energy and angular momentum at first order. We compute radiative efficiencies (up to \simeq 8% in the explored range, against 5.72% for Schwarzschild) and the orbital and radial epicyclic frequencies, including the ISCO and the 3:2 resonance, whose frequency at fixed mass is shifted by 5–11% for g/M=0.5–0.7.
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All authors Shokhzod Jumaniyozov, Javlon Rayimbaev, Chengxun Yuan, Ahmadjon Abdujabbarov, Faisal Javed, Satimbay Palvanov
High Energy Physics (Phenomenology)
Neutrino superradiance constraint on asteroid-mass PBH Dark Matter and beyond
Yi-Xuan Lin, Priyanka Sarmah and Martin Spinrath
Primordial Black Holes (PBHs) are an attractive candidate for Dark Matter (DM) and there has been extensive experimental efforts to look for them. The asteroid-mass window, $M_{\text{PBH}} \sim 10^{17} - 10^{23}$ g, is particularly interesting, since PBHs in this range may still constitute all of DM. In this work, we study a scenario in which rotating PBHs are surrounded by superradiantly produced
boson clouds that emit an approximately steady and nearly monochromatic flux of
neutrinos in the few MeV range. We compute both the
Galactic and extragalactic
neutrino fluxes from such PBH populations and compare them with existing low-energy antineutrino limits from Borexino, KamLAND, and Super-Kamiokande. For scalar
bosons, we find that these
neutrino searches can strongly constrain a significant part of the asteroid-mass window and extend to somewhat larger masses. For instance, for rapidly rotating PBHs with
spin ã = 0.9 and gravitational fine-structure coupling $\alpha_g=0.25$, the strongest bound on dark matter fraction reaches approximately $f_{\text{PBH}} \sim 10^{-7}$ around $M_{\text{PBH}} \sim 2 \times 10^{22}$ g for a Yukawa coupling $g_{\nu \phi} = 10^{-4}$. These constraints can be significantly stronger than existing microlensing limits in the same mass range. Our results provide a complementary
neutrino probe of PBH DM, distinct from previous
neutrino constraints based mainly on Hawking evaporation from lighter PBHs.
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Quantum Gases
Solitary waves of attracting SU(N) fermions
Aysha Alsubaihi, Wayne J. Chetcuti, Frederic Chevy et al. (+2 more)
We study the formation, dynamics, and disorder robustness of bound states in attractively interacting SU(N)
fermions on a one-dimensional ring
lattice. Using exact diagonalization in fixed-momentum sectors and Bethe ansatz exact results as a guide, we resolve the many-body spectrum into bands related to the possible partitions of the particles into bound composites, and characterize their internal structure also through density-density and N-body correlations. A pinning quench protocol reveals a transition from dispersive spreading to dynamical localization as the attractive interaction increases relative to the single-particle hopping. We find that the bound state dynamics for one-particle per component occurs as a many-body
quantum walk similar to that of a single particle with a re-normalized effective mass. Such a property, that is the
quantum version of the shape-preserving motion of classical
solitons, can provide the dynamical signature of the fermionic solitary waves. We probe the robustness of the fermionic bound-state dynamics under on-site disorder.
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All authors Aysha Alsubaihi, Wayne J. Chetcuti, Frederic Chevy, Juan Polo, Luigi Amico
Earth and Planetary Astrophysics
A Fast Concentric-disk Contour Integration Method For Microlensing Limb-darkening Effect
Suwei Wang
Incorporating limb darkening is a computationally demanding step in contour-integration-based microlensing modeling. Conventional concentric-ring integration is incompatible with high-order quadrature schemes, limiting efficiency. We develop a new concentric-disk method, which reformulates the limb-darkening integral and enables the application of high-order adaptive quadrature, significantly accelerating the computation. While mainly demonstrated using a linear limb-darkening profile, the method readily extends to more general limb-darkening profiles. As a source effect, it applies to lens systems of any complexity. The method achieves a convergence rate scaling faster than $N_{\rm{uni}}^{-4}$ with the number of uniform-source magnification evaluations $N_{\rm{uni}}$, a significant improvement over the concentric-ring $N_{\rm{uni}}^{-2}$ scaling. For a relative accuracy of $10^{-6}$, the concentric-disk approach typically requires only $30\%$ or less of the computational cost of traditional
algorithms. This method has been implemented in the binary-lens contour integration code Twinkle, providing an efficient and precise tool for analyzing current and future high-precision microlensing observations.
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General Relativity and Quantum Cosmology
Particle decay and energy conservation in the Kerr-Newman black hole
Bing-Bing Chen, Guo-Ping Li, Ke Wang et al. (+1 more)
In this paper, we study the decay of a particle in Kerr–Newman spacetime. Both theoretical analysis and numerical simulations show that when a particle splits in Kerr–Newman spacetime, its mass is inevitably reduced, and this mass deficit is transformed into kinetic energy in the center-of-mass frame. We denote the parent particle as $O$ and the daughter particles as $A$ and $B$. We also find that as the charge parameter $Q$ increases, the specific angular momenta of the parent particle $O$ and the daughter particle $B$ become smaller, the masses of the two daughter particles become larger, the absolute values of their specific energies become smaller, the relative Lorentz factors among the three particles become smaller, and their four-velocities also become smaller. These trends are opposite to those observed when increasing the cosmological constant in Kerr–de Sitter spacetime.
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All authors Bing-Bing Chen, Guo-Ping Li, Ke Wang, Xiao-Xiong Zeng
Fluid Dynamics
Variable-Lattice-Density Optimization of Pin-Fin Heat Sinks under High-Reynolds-Number Flow Conditions
Yoshikatsu Furusawa, Kunitaka Shintani, Shunsuke Hirotani et al. (+1 more)
This study extends variable-
lattice-density optimization to high-Reynolds-number flows for the design of periodically arranged pin-fin heat sinks. Effective permeability and drag coefficient are identified from unit-
cell Reynolds-averaged Navier–Stokes analyses of cylindrical pin-fin arrays and incorporated into a reduced model based on the Darcy–Forchheimer law for macroscopic design exploration. To enable stable optimization under high-Reynolds-number conditions, a dual-mesh framework is introduced, in which the flow field and sensitivities are evaluated on a fine mesh, whereas the design variables are updated on a coarse mesh corresponding to the unit-
cell arrangement. For the base condition, the $L_2$ norm of the temperature deviation from the area-averaged temperature is decreased from 4.38 K to 1.00 K in the reduced model, and geometry-resolved analysis of the reconstructed design confirms a reduction from 5.98 K to 1.17 K. Additional calculations with higher inlet velocities and modified outlet locations show that the proposed method captures the dominant flow-redistribution trends under different operating and
geometric conditions, although the thermal objective became less accurate when local solid-temperature variations became pronounced. These results indicate that the proposed approach is useful as practical design-exploration for identifying candidate pin-fin heat sink configurations under high-Reynolds-number conditions.
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All authors Yoshikatsu Furusawa, Kunitaka Shintani, Shunsuke Hirotani, Kentaro Yaji
Quantum Physics
Sparse anisotropic positive maps for qutrit entanglement: exact indecomposability and PPT geometry
Massimiliano F. Sacchi
Positive but not completely positive maps provide one of the most direct ways to detect
entanglement beyond the positive-partial-transpose (PPT) criterion. We introduce and analyze an exactly solvable two-parameter family of sparse bistochastic positive maps on qutrits, in which two coherence channels are independently tuned by parameters $w$ and $z$. The sparse structure makes the full phase diagram analytic: positivity holds exactly on the square $0\le w,z\le2/3$, complete positivity on the smaller square $0\le w,z\le1/3$, and decomposability is lost precisely outside a quarter circle in the corner $w,z\ge1/3$. The indecomposable region is certified by explicit PPT entangled state adapted to the same witness geometry. At the endpoint $W_*=W(2/3,2/3)$ we construct a four-parameter family of PPT edge states of rank type $(5,5)$, derive their analytic detection region, and show that the corresponding rays are exposed faces of the PPT cone. Finally, although $W_*$ is not optimal, we give an explicit optimal refinement whose detection region on this family is strictly larger. The result is an analytically tractable qutrit setting in which positivity, indecomposability, PPT
entanglement, optimality, and exposed convex geometry can be studied in a single framework.
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Astrophysics of Galaxies
Accretion-disk formation around orbiting stellar black holes in gaseous star clusters
Zacharias Roupas
We consider low-mass black holes (BHs) moving in regular orbits in the cores of non-rotating gaseous
star clusters, representative of proto-
stellar clusters or the centers of protogalaxies. We argue that as the BH's sphere of influence – the Bondi sphere – is advected along the BH trajectory, the transverse velocity shear between the inner and outer hemispheres injects angular momentum, driving the formation of an
accretion disk. Coriolis forces oppose angular momentum injection, delaying disk formation but not preventing it. The disk lies in the BH orbital plane and is counter-rotating with respect to the orbital BH motion. We verify this picture with 2D and 3D hydrodynamic simulations in the non-inertial frame of the orbiting BH. We find that the disk-formation timescale following a disruption event is of order the Bondi crossing timescale, $\tau_{\rm d} \sim R_{\rm B}/V_{\bullet}$, and that the disk radius is of order $R_{\rm d} \sim \omega_{\bullet}^2 R_{\rm B}^4/ G m_{\bullet} $, set by the circularization radius of gas captured in the Bondi sphere. For the case of a BH with $m_{\bullet} = 50\,{\rm M}_\odot$, inside the core of a typical compact proto-
stellar cluster, these values read $\tau_{\rm d} \sim 0.1 P_{\rm orbit}$ and $R_{\rm d} \sim 10^{-3} R_{\rm B}$.
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Disordered Systems and Neural Networks · Cross-listed from math.PR
Renormalisation of Inhomogeneous Random Graphs
Luca Avena, Diego Garlaschelli, Rajat Subhra Hazra et al. (+1 more)
We consider inhomogeneous random graphs in which vertices are assigned i.i.d.\ random weights, pairs of distinct vertices are connected by an edge independently with a probability that is a bi-variate function of the weights of the vertices, and single vertices are connected to themselves by a self-loop independently with a probability that is a uni-variate function of the weight of the vertex. We apply a renormalisation transformation in which vertices are aggregated into groups of equal size according to a greedy
algorithm, namely, distinct groups of aggregated vertices are connected by an aggregated edge if and only if there is at least one edge connecting two constituent vertices across the groups, while a group of aggregated vertices is connected to itself by an aggregated self-loop if and only if there is at least one self-loop at an internal vertex or one edge connecting a pair of distinct internal vertices. We analyse what happens when the renormalisation transformation is iterated. In particular, we show that, starting from appropriately scaled connection functions, the iterated renormalised graphs converge to a two-parameter family of random graphs, acting as an attractor in a universality class. We consider a light-tailed regime, for which the scaling limit is a homogeneous Erdős–Rényi random graph, and a heavy-tailed regime, for which the scaling limit is an inhomogeneous random graph with stable infinite-mean random weights and an exponential disconnection function. Different scalings are needed for the two regimes. Which of the two regimes prevails depends on the choice of the connection functions and the choice of the law of the random weights.
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All authors Luca Avena, Diego Garlaschelli, Rajat Subhra Hazra, Frank den Hollander
Quantum Physics
Strain-Induced Detuning of a Dressed Nitrogen-Vacancy Qubit: Effective Two-Level Theory and Its Validity
Jihyeon Jeon, Donghun Lee, Seok-Kyun Son et al. (+1 more)
The nitrogen-vacancy (NV) center in diamond can be operated as a microwave-dressed
qubit. In the ideal two-level limit, its transition frequency is first-order insensitive to static
magnetic fields, providing robustness against
magnetic detuning noise. In practical diamond devices, however, residual transverse
crystal strain mixes the $\ket{m_{s}=\pm1}$
spin sublevels and modifies the dressed
qubit. In this study, we derive an analytical effective two-level model of a strained dressed NV
qubit by perturbatively eliminating the far-detuned spectator state from the full three-level dressed
Hamiltonian. We obtain closed-form expressions for the dressed-state splitting, the
spin-locking mixing angle, and the longitudinal
magnetic-field coupling. We show that transverse strain shifts the dressed-state resonance and tilts the
spin-locking axis. These two effects restore a finite DC-field response and thereby quantify the loss of
magnetic robustness. We demonstrate these features in simulated pulsed electron
spin resonance spectra that incorporate rate-equation-based optical readout. We further derive exact validity criteria from the
eigenvalues and spectator weights of the full three-level
Hamiltonian. For practical use, we reduce these criteria to two controlled guidelines: the spectator-like branch must remain above the nominal upper dressed state, and its branch-specific admixture must remain small. A validity diagram over the axial-field–transverse-strain plane summarizes these approximate conditions and provides practical guidelines for designing dressed-NV sensing experiments.
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All authors Jihyeon Jeon, Donghun Lee, Seok-Kyun Son, Nojoon Myoung
Plasma Physics
Impact of Residual Angular Chirp in a Petawatt-class Laser System on Laser-driven Proton Acceleration
Qingfan Wu, Minjian Wu, Jiarui Zhao et al. (+25 more)
Laser-driven
proton acceleration has attracted considerable interest owing to its appealing potential in versatile applications including cancer therapy.
Proton energies depend critically on the on-target intensities, yet the detrimental impact of focal spot degradation induced by spatiotemporal couplings on the acceleration remains insufficiently elucidated. In this study, we demonstrate that residual angular chirp (AC), stemming from minor misalignments of the grating compressor in a Petawatt-class
laser system, acts as a critical bottleneck for
proton acceleration. Experimental results reveal that even around 100 microradians of grating misalignment induces substantial focal-spot elongation and a pronounced reduction in peak intensity. By implementing an in situ spectral-blocking diagnostic, we effectively eliminated the residual AC and restored a near-diffraction-limited focus. This optimization led to a significant recovery of the on-target intensity, resulting in a twofold increase in the
proton cutoff energy. Our work presents a successful demonstration of diagnosing and eliminating residual AC. This provides a practical reference for generating high-energy
proton beams and supporting their diverse applications in a PW-class
laser.
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All authors Qingfan Wu, Minjian Wu, Jiarui Zhao, Ying Gao, Haoran Chen, Tan Song, Zhongshuai Zhang, Zhangyi Wu, Tianhao Liang, Shirui Xu, Ziyang Peng, Hui Zhang, Tianqi Xu, Qihang Han, Chenghao Hua, Ke Chen, Pengcheng Fan, Yuntian Xie, Xianduo Li, Peiqiang Liu, Xiangyu Nong, Shengxuan Xu, Liyong Ma, Yixing Geng, Chen Lin, Yanying Zhao, Xueqing Yan, Wenjun Ma