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Physics

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Tuesday 4 August

General Relativity and Quantum Cosmology

New gravitational instanton: shadow of an extra dimension

Reinoud Jan Slagter

We present an exact gravitational instanton solution on a five-dimensional, conformally invariant, Kerr-like warped Riemannian brane-world manifold. The geometry can be described as the Kähler manifold $\mathbb{C}^1\times\mathbb{C}^1\times \mathbb{R}$. By applying a double cover of $S^3$ through stereographic projection onto $\mathbb{C}P^1\times \mathbb{C}P^1$ of the effective four-dimensional manifold, together with the Klein surface construction, we exploit the underlying $\mathbb{Z}_2$ symmetry. The instanton is then obtained by fibering over the antipodal $S^2$. The metric is determined by a first-order differential equation containing an integer parameter, while the equation governing the angular momentum component decouples from the remaining field equations. Finally, we show that our solution admits an analytic complex transformation to a locally conformally related Kähler manifold possessing a Kähler potential, thereby making the self-dual structure manifest.
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Cosmology and Nongalactic Astrophysics

Cosmic Velocity Flows: from Theory to Observations

Saee Dhawalikar

The Large-Scale Structure (LSS) of the Universe forms a complex network of nodes, filaments, sheets, and voids known as the Cosmic Web. As current and upcoming galaxy surveys increasingly probe the quasi-linear and non-linear regimes of structure formation, understanding its geometry and dynamics is essential for precision cosmology. In particular, cosmic filaments, which channel matter across the web, are central to these dynamical processes. This thesis develops numerical tools to study the non-linear cosmic web. First, the Sahyadri suite of high-resolution cosmological $N$-body simulations is introduced, providing a framework for precision studies of LSS and its cosmological dependence. A calibration framework for filament reconstruction is then developed using controlled filament realizations, enabling systematic investigation of reconstruction biases. The effects of filament curvature and reconstruction noise on inferred filament properties are quantified, and a novel Fourier-space smoothing approach is introduced to improve profile recovery. The thesis further presents Skeletor, a Voronoi-based filament finder that identifies filamentary structures directly from discrete tracers while explicitly incorporating the hierarchical nature of the cosmic web. A novel framework for classifying sub-filamentary structure is developed. Applying these tools to cosmological simulations reveals distinct properties of filament substructure and provides a detailed view of filament phase space, including coherent inflows, multistreaming, and caustic-like features. Together, these developments provide a framework for studying the geometry, hierarchy, and dynamics of the non-linear cosmic web. More broadly, they contribute to the ongoing effort to build a physically motivated understanding of the non-linear cosmic web beyond traditional measures of clustering.
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Materials Science

The New High-entropy Compound RhMnFeCoGe4 with Cubic Non-centrosymmetric B20 Structure

V. A. Sidorov, V. N. Krasnorussky, A. V. Bokov et al. (+8 more)

A novel high-entropy compound, RhMnFeCoGe$_4$, with a cubic non-centrosymmetric B20 struc- ture, has been synthesized under conditions of high pressure and temperature. The electrical transport and magnetic properties of the obtained compound at both ambient and elevated pres- sures have been investigated. In addition, nuclear magnetic resonance (NMR) spectra were obtained at 4.2 K and ab initio calculations were performed. The new material exhibits ferromag- netic behavior with a critical temperature of $T_C$ = 146 K and a spontaneous moment of 2.5 $\mu_B$ per formula unit. The magnetization data obtained at the critical region yielded the critical temperature and exponents, which were found to be $T_C$ = 146(1) K, $\beta$ = 0.337(1), $\gamma$ = 1.121(1), and $\delta$ = 4.326(1). The magnetic moments of Mn and Co were determined from NMR spectra to be 2.2 $\mu_B$ and 0.5 $\mu_B$, respectively. Ab initio calculations yielded reasonable values for the lattice parameter and the magnetic moments of all constituents. The density of states and band structure are determined for both paramagnetic and ferromagnetic states. Lattice compression results in the increase in the $T_C$.
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All authors V. A. Sidorov, V. N. Krasnorussky, A. V. Bokov, Z. N. Volkova, A. P. Gerashchenko, N. M. Chtchelkatchev, M. V. Magnitskaya, D. A. Salamatin, A. V. Semeno, V. V. Brazhkin, A. V. Tsvyashchenko

Lattice Field Theory

A first look at Structured-Multiscale Algebraic Multigrid for Lattice Field Theory

Pauline Schauerte, Jaime Fabián Nieto Castellanos, Arnold Krechel et al. (+2 more)

State-of-the-art solvers for the Dirac equation in Lattice QCD are based on adaptive multigrid methods. These require fine-tuning of many algorithmic parameters to achieve optimal performance. We apply a new multigrid approach to Lattice Field Theory adapted from oil-reservoir simulations: Structured-Multiscale Algebraic Multigrid (SM-AMG). This method builds compact aggregates with overlapping borders to coarsen the grid and yields accurate interpolation. A key advantage is that aggregate size is the primary tunable parameter. For our results, we used SM-AMG in an algebraic approach, called Aggregative-Multiscale AMG (AM-AMG). We benchmark the efficiency of AM-AMG against that of DD$\alpha$AMG, a successful adaptive multigrid solver which alleviates critical slowing down. The two solvers are compared within the framework of the two-flavor Schwinger model using the Wilson discretization. On fine lattices, the operation count of both methods is similar near the critical point and for large volumes, reflecting a comparable computational cost. However, the number of fine-grid iterations is larger for AM-AMG. On coarse lattices, AM-AMG encounters difficulties to remove the low modes close to the critical mass.
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All authors Pauline Schauerte, Jaime Fabián Nieto Castellanos, Arnold Krechel, Marc Alexander Schweitzer, Stefan Krieg

Mesoscale and Nanoscale Physics

Vector-field control and emergent basal-plane anisotropy of magnetic textures in noncentrosymmetric (Fe$_{0.63}$Ni$_{0.3}$Pd$_{0.07}$)$_3$P

Victor Ukleev, Oleg I. Utesov, Lorenzo Ubilla et al. (+17 more)

(Fe$_{0.63}$Ni$_{0.3}$Pd$_{0.07}$)$_3$P is a room-temperature magnet with $S_4$ symmetry that hosts a rich variety of topological spin textures. Here, we report a combined resonant small-angle x-ray scattering and ptychography study of (Fe$_{0.63}$Ni$_{0.3}$Pd$_{0.07}$)$_3$P in vector magnetic fields over a broad temperature range. We demonstrate deterministic vector-field control of magnetic stripe domains, where in-plane fields continuously rotate their orientation via a transition from a chiral stripe to an achiral fan configuration. Furthermore, at 50 K and below, the stripe orientation becomes metastably pinned and retains its field-trained direction. While the magnitude of the wavevector is nearly isotropic within the basal plane at room temperature, a pronounced temperature evolution of anisotropic interactions emerges upon cooling. In particular, non-trivial anisotropy axes develop at 20-50 K reflecting the combined effects of magnetocrystalline anisotropy, anisotropic exchange, and Dzyaloshinskii-Moriya interaction (DMI), whose effective orientation is found to rotate with temperature. These results establish (Fe$_{0.63}$Ni$_{0.3}$Pd$_{0.07}$)$_3$P as a model system for vector-field control of chiral spin textures and reveal a previously unrecognized temperature-driven evolution of the effective DMI landscape in a noncentrosymmetric magnet.
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All authors Victor Ukleev, Oleg I. Utesov, Lorenzo Ubilla, Chen Luo, Radu-Marius Abrudan, Peter Wild, Holger Kropf, Moritz Winter, Sebastian Schneider, Alexander Tahn, Bernd Rellinghaus, Tim A. Butcher, Simone Finizio, Sebastian Wintz, Markus Weigand, Max T. Birch, Yoshinori Tokura, Yasujiro Taguchi, Kosuke Karube, Florin Radu

High Energy Physics (Phenomenology)

Probing Heavy-Quark Spin Symmetry in Double $J/\psi$ Hadroproduction

Zhi-Guo He, Xiao-Bo Jin and Bernd A. Kniehl

We perform the first complete $\mathcal{O}(\alpha_s^5)$ analysis of the prompt hadroproduction of $J/\psi$ pairs with large transverse momenta $p_T^{\psi\psi}$ in the nonrelativistic-QCD factorization framework, including all possible Fock state combinations $c\bar{c}(m)+c\bar{c}(n)$, with $m,n={}^3S_1^{[1,8]},{}^1S_0^{[8]},{}^3P_J^{[1,8]}$. We observe that CMS and ATLAS data constrain a specific linear combination of the long-distance matrix elements (LDMEs) $\langle\mathcal{O}^{J/\psi}({}^1S_0^{[8]})\rangle$ and $\langle\mathcal{O}^{J/\psi}({}^3P_0^{[8]})\rangle$. In conjunction with two other combinations fixed by single prompt $J/\psi$ hadroproduction, we gain a new LDME set, which turns out to be largely compatible with the world data of prompt $J/\psi$ yield and polarization and to probe heavy-quark spin symmetry, by which agreement is established with LHCb data of prompt $\eta_c$ yield. Our $\mathcal{O}(\alpha_s^5)$ predictions also nicely agree with CMS and ATLAS data in the lowest bins of $J/\psi$ pair invariant mass $m^{\psi\psi}$, beyond leading-order kinematics.
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Solar and Stellar Astrophysics

Hot water emission during an outburst in a classical T Tauri star

Zhen Guo, Javier Osses, Vitor Fermiano et al. (+34 more)

In this paper, we present observations of an eruptive young star in the Rosette Nebula, identified by the Gaia Science Alerts system using Gaia time series data. We aim to investigate the evolution of the brightness and mass accretion rate of V557 Mon throughout its outburst and subsequent decline. In addition, we trace the evolution of the inner accretion disk during the outburst by monitoring molecular emission features. We compiled multi-band photometric time series from Gaia, ZTF, and several 1 m-class ground-based telescopes and obtained optical and near-infrared spectra at multiple epochs covering the outburst and fading phases. Stellar parameters were derived from quiescent colour/spectra and spectral energy distribution (SED) fitting. We also measured the mass accretion rate and fit models to molecular emission bands. Since late 2024, V557 Mon has undergone a year-long outburst consistent with EXor variability. Based on quiescent photometry, V557 Mon has a spectral type of M1 with an extinction of AV = 1.8+_0.3 mag, consistent with a 0.4-0.5 M_sol star at an age of 2 Myr. Our multi-epoch spectra and u-band photometry indicate a peak accretion rate of 6.3x10^(-7)M_sol/yr during the outburst, roughly 70 times higher than in quiescence. We report the detection of hot water vapour emission bands, together with TiO, VO, and CO emission features. Using ExoMol models, we measured the inner-disk temperature changed from 3000 K to 2000 K during the fading phase of the outburst. We report a recent EXor outburst in a low-mass Class II YSO. Our observations reveal the transient formation of a hot molecular inner disk, traced by variable water vapour emission during the EXor event. A positive correlation is found between the molecular excitation temperature and the overall stellar brightness.
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All authors Zhen Guo, Javier Osses, Vitor Fermiano, Yuting Zhou, Min Fang, Gregory Herczeg, Adolfo Carvalho, Vardan Elbakyan, Lynne Hillenbrand, Mutian Wang, Hanpu Liu, Yao Liu, Cesar Briceno, Koshvendra Singh, Valentin D. Ivanov, Joe Ninan, Teresa Giannini, Aldo Aliaga, Calum Morris, Matias Montesinos, He Zhao, Carlos Contreras Pena, Jessy Jose, Tarak Chand, Wen-Ping Chen, Wei-Hao Wang, Yang Huang, Camila Lopez, Pablo Fernandez-Schlosser, Diego Correa-Herrera, Radostin Kurtev, Vania Rodriguez, Carolina Lizana-Vidal, Jura Borissova, Michael Kuhn, Roberto K. Saito, Ram K. Yadav

Applied Physics

Thermodynamically consistent initialization of the Maxwell–Cattaneo—Vernotte heat conduction model: Analytical solutions and engineering applications

Zalán Sándor and Róbert Kovács

This paper investigates the numerical initialization of the one-dimensional Maxwell–Cattaneo–Vernotte (MCV) heat conduction model, addressing the critical mathematical challenge of defining the initial time derivative for non-equilibrium states. In modern high-frequency thermal engineering applications, traditional time-integration schemes and commercial finite-element solvers frequently introduce severe numerical artifacts when handling non-Fourier models. This study systematically evaluates three initialization strategies: a zero derivative, a spatially uniform non-zero derivative, and an exact space-dependent derivative. Using an explicit staggered finite-difference scheme, the transient responses to an exponentially distributed initial temperature field under adiabatic boundary conditions are compared against an analytical solution using the Galerkin method. The results demonstrate that assuming a zero or spatially uniform initial derivative introduces significant unphysical oscillatory deviations, leading to heat-flux prediction errors as the relaxation time increases. Conversely, mapping the exact space-dependent derivative onto the staggered grid preserves the local thermodynamic structure of the initial state, yielding robust transient responses that match the analytical benchmark without meaningful computational overhead. These findings establish a thermodynamically consistent initialization technique that can be extended to non-local models as well.
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Materials Science

Spin-Chirality-Driven Bulk Photovoltaic Effect in van der Waals Magnet CrSBr

Dezhao Wu, Yong Xu, Meng Ye et al. (+1 more)

The bulk photovoltaic effect (BPVE) manifests with remarkable diversity in magnetic materials. Here, we establish vector spin chirality as a tunable knob for generating an unconventional time-reversal-even magnetic BPVE, comprising the chiral shift current (CSC) and chiral injection current (CIC). Using bilayer antiferromagnetic (AFM) CrSBr as a prototype, we theoretically demonstrate the emergence of CSC and CIC. Compared with conventional photovoltaic currents arising from noncentrosymmetric crystal structures or collinear magnetic orderings, CSC and CIC not only possess comparable magnitudes but also exhibit exceptional tunability. Specifically, they can be switched on and off by magnetic-field-induced spin canting, reversed in direction upon canting-direction reversal, and continuously modulated in intensity via canting-angle variation. Furthermore, we reveal an unusual optical transition channel governing both currents in CrSBr. Our work establishes an unconventional magnetic BPVE with remarkable controllability, offering opportunities for optoelectronic and magnetic-sensing applications in noncollinear magnets.
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All authors Dezhao Wu, Yong Xu, Meng Ye, Wenhui Duan

Data Analysis and Statistics · Cross-listed from cs.DL

A repository for discovery and reuse of higher-order network datasets

Florian Frantzen and Michael T. Schaub

Higher-order network datasets are dispersed across publications, institutional archives, and software-specific collections, making them difficult to discover, compare, and reuse. We introduce the Aachen Higher-Order Repository of Networks (AHORN), a curated repository of standardized higher-order network datasets derived from publicly released sources. Each dataset entry links a converted dataset to its source, metadata, citation guidance, conversion code, and version history. The repository supports browsable and machine-readable discovery, revision-specific downloads, format validation, and exports for interoperable reuse. We describe the repository architecture, curation workflow, access tools, and the coverage and limitations of the catalog snapshot analyzed in this article.
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Solar and Stellar Astrophysics

Wave excitation by a collapsing granule: insights from IFU observations and high-resolution RMHD simulations

J. Buttler, G. Vigeesh, I. Milić et al. (+5 more)

Context. Granular collapse is an ubiquitous process of granular evolution on the solar surface, but it is hard to analyze in sufficient spatial, temporal, and spectral detail. Aims. We analyze the change in physical conditions in the photosphere during a specific granular collapse event and the subsequent atmospheric response. Methods. We contrast a high-resolution radiative magneto-hydrodynamic simulation of a granular collapse performed using the CO5BOLD code with the recent integral field unit observations carried out using the MiHI instrument at the Swedish 1-m Solar Telescope. Results. Our analysis shows that the observed and simulated granular collapse show remarkable similarity. Specifically, they both exhibit the signature of a wave pulse excited in the deep photosphere and visible up to the temperature minimum. This wave is detectable through a blue-wing emission in the observed and synthetic Na i D1 line. We also estimate the acoustic energy flux carried by the wave and analyze its initiation. Conclusions. Combining high-resolution IFU spectropolarimetry and state-of-the-art simulations of the solar lower atmosphere, this study showcases our current capabilities in identifying specific physical processes taking place during the granular collapse and their impact on the atmosphere above.
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All authors J. Buttler, G. Vigeesh, I. Milić, M. van Noort, S. M. Díaz Castillo, C. J. Díaz Baso, F. Riva, O. Steiner

Materials Science

Anisotropic Phonon Heat Flow and Thermoelectric Response in Tetragonal GeS$_2$ and GeSe$_2$

Neeraj Kulhari, Krishna Swaroop Sharma and K. C. Bhamu

The electronic structure, lattice dynamics, bonding, elastic response, and anisotropic thermoelectric transport properties of tetragonal GeS$_2$ and GeSe$_2$ were investigated using density functional theory, density functional perturbation theory, Wannier interpolation, and scattering-aware Boltzmann transport. The relaxed structures are mechanically and dynamically stable within the calculated harmonic description. The HSE03/Wannier band gaps are 2.48 eV for GeS$_2$ and 1.23 eV for GeSe$_2$, while substitution of S by Se lowers the upper phonon frequency from approximately 13.6 to 10.3 THz. The phonon Boltzmann transport calculations reveal pronounced lattice-transport anisotropy. Within the relaxation-time approximation, the 300 K in-plane and cross-plane lattice thermal conductivities are 26.86 and 1.19 W m$^{-1}$ K$^{-1}$ for GeS$_2$, and 18.74 and 1.52 W m$^{-1}$ K$^{-1}$ for GeSe$_2$, respectively. At 800 K, these values decrease to 10.22 and 0.46 W m$^{-1}$ K$^{-1}$ for GeS$_2$, and 7.25 and 0.58 W m$^{-1}$ K$^{-1}$ for GeSe$_2$. Frequency-resolved analysis shows that low-frequency phonons carry most of the heat, whereas the small cross-plane values reflect restricted out-of-plane phonon transport. Combining the ShengBTE RTA lattice tensors with AMSET electronic coefficients gives $zT=0.257$ for n-type cross-plane GeS$_2$ at 800 K and $10^{19}$ cm$^{-3}$. The corresponding PBE-AMSET estimate for GeSe$_2$ is $zT=0.066$ for p-type cross-plane transport at 800 K and $3\times10^{20}$ cm$^{-3}$. LOBSTER analysis identifies mixed covalent–ionic Ge–X bonding, with Ge–S bonds having a larger stabilizing ICOHP magnitude than Ge–Se bonds ($-5.27$ versus $-4.74$ eV per bond). These results identify tetragonal GeX$_2$ compounds as strongly anisotropic thermoelectrics with moderate calculated $zT$ values whose cross-plane response benefits from suppressed lattice heat transport.
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General Relativity and Quantum Cosmology

Global hyperbolicity meets order completeness

E. Minguzzi

Recently, an order completeness property has attracted attention in some low regularity spacetime geometry literature, where it was named `chronocompleteness'. In this work we prove that, in the framework of standard Lorentzian geometry, this property is equivalent to global hyperbolicity. The equivalence of global hyperbolicity with other more traditional forms of order completeness is also established.
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Quantum Physics

Matrix Product Evolution: A Method for Simulating Quantum Circuits Using Tensor Networks

Haruyuki Kawabe, Minoru Nagai, Tsuyoshi Okubo et al. (+1 more)

Classical simulation of quantum circuits is an essential tool in quantum information science, but its applicability is constrained by the exponential growth of the Hilbert space and the entanglement structure of quantum states. In this work, we introduce Matrix Product Evolution (MPE), a tensor-train representation of quantum circuits constructed along the circuit depth rather than along the qubit index. Within this formulation, the simulation of a quantum circuit is modeled as the contraction of multiple MPE tensors. We develop an efficient contraction strategy based on a zip-up procedure to carry out this contraction in practice. We investigate the numerical behavior of this MPE-based contraction framework through simulations of random quantum circuits and the time evolution of a quantum many-body state. Our results characterize the growth of temporal bond dimensions, clarify how post-selection modifies the contraction cost and approximation accuracy, and identify regimes in which depth-oriented tensor-network contractions provide a useful complement to standard MPS-based simulation approaches.
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All authors Haruyuki Kawabe, Minoru Nagai, Tsuyoshi Okubo, Synge Todo

Cosmology and Nongalactic Astrophysics

Modified Cosmological Expansion and the JWST CMB Optical Depth Tension in Self Interaction Gravity

Subhadeep Mukherjee, Shashank Shekhar Pandey and A. S. Majumdar

Recent James Webb Space Telescope (JWST) observations favor an earlier and more efficient reionization history, leading to Thomson-scattering optical depths larger than those inferred from the cosmic microwave background (CMB). We investigate whether this tension can be alleviated within the framework of self-interaction (SI) gravity by modifying the cosmological expansion history while retaining the standard astrophysical description of reionization. The SI gravity parameters are constrained through a Bayesian MCMC analysis of the Union3 Type Ia supernova and DESI DR2 Baryon Acoustic Oscillations (BAO) data. The resulting expansion history is then used to predict the ionization history and Thomson optical depth. We find that the predicted optical depth decreases from $\tau_{\rm{CMB}}\simeq0.076$ in $\Lambda$CDM to $\tau_{\rm{CMB}}\simeq0.061$, consistent with the Planck PR4 measurement within $1\sigma$, thereby substantially reducing the optical-depth tension.
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High Energy Physics (Theory)

Genus-One Rigidity of Bounded Virasoro Pairings for 3D Gravity

Xingyang Yu

We study whether varying the topological boundary of the doubled Virasoro TQFT can produce distinct torus pairings for an ensemble interpretation of 3D gravity. In the ordinary nondegenerate sector, every bounded pairing that commutes with the modular transformations is scalar, and vacuum normalization selects the diagonal pairing. The proof identifies the modular transformations with the even Weil representation and applies the Cowling–Steger lattice-restriction theorem. Under the ordinary block-diagonal vacuum–continuum ansatz, positivity and the two vacuum marginals also make a Borel-measure pairing bounded, without assuming absolute continuity; modular invariance then forces the same diagonal pairing. These two classes therefore contain no distinct torus pairings to average. A nontrivial Virasoro boundary ensemble must involve genus-one data outside these classes, additional sectors or vacuum–continuum couplings, or information invisible in the torus pairing. Elementary proofs in explicit regular sectors explain the rigidity mechanisms, and numerical calculations provide independent checks.
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Statistical Mechanics

Fibonacci number systems and the localization criterion in the many-body Aubry-André model

Balázs Hetényi

We introduce an extension of the Fibonacci number system, we call the fractional Fibonacci number system, which interpolates between the Fibonacci number system (used for natural numbers) and the irrational base-$\phi$ number system, which can be used to represent real numbers. The number system finds its use in interpreting the localization phase diagram of the many-body non-interacting Aubry-André model. For finite system sizes a localization criterion can be obtained if the particle density is written in the fractional Fibonacci number system. In the thermodynamic limit, the criterion remains, but in this case the particle density is expressed in base-$\phi$. The nature of the thermodynamic limit is also discussed.
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Exactly Solvable and Integrable Systems

Painlevé Integrability, Auto-Bäcklund Transformation and the exact solutions of (1+2) Kudryashov-Sinelshchikov (KS) equation

Apeksha Patil, Amlan Kanti Halder and Rajeswari Seshadri

In this research work, we consider a nonlinear fourth-order (1+2)-dimensional Kudryashov-Sinelshchikov (KS) equation which represents the wave propagation of pressures in liquids that contain gas bubbles. A direct Integrability of the KS equation is analysed using Painleve Analysis with Singular Manifold Method (SMM). With the help of WTC algorithm, we show that the (1+2) KS equation is Painleve integrable. Then by truncating the Painleve expansion we obtain the Auto-Backlund Transformation (ABT). By taking suitable forms of Manifold, various exact solutions based on the obtained Auto-Backlund transformation are derived. The consistancy check for these solutions are also performed. Representative solutions are presented in the from of 2D and 3D plots to understand the geometric perspective of the solutions.
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Adaptation and Self-Organizing Systems

Analysis of inverse stochastic resonance: Effects of neural excitability and timescale separation

Marius E. Yamakou, Torben Krüger and Hermann Schulz-Baldes

We analyze inverse stochastic resonance (ISR) in a bistable FitzHugh–Nagumo neuron driven by additive noise in the voltage variable, focusing on how neural excitability and timescale separation regulate the noise-induced modulation of spiking activity. A codimension-two bifurcation analysis identifies a narrow bistable region in which a stable fixed point and a stable limit cycle coexist, separated by an unstable periodic orbit. Finite-time Monte Carlo simulations show that the occupation of the limit-cycle basin may appear to depend on the initial basin when rare transitions are not fully resolved. We prove that this dependence is not asymptotic: the stochastic system admits a unique invariant probability measure, so long-time firing statistics are independent of the initial basin of attraction. The parameter dependence of ISR is characterized by quasi-potential barriers computed with a geometric minimum action method for the degenerate noise. The difference between the limit-cycle and fixed-point quasi-potentials partitions the bistable wedge into two escape-dominated regimes. A reduced metastable two-state Markov approximation yields a weak-noise formula for the limit-cycle basin occupation probability, a sign criterion for genuine ISR, and a semiquantitative prediction of the ISR-minimizing noise amplitude. In the fitted regime with a negative effective exponent, a genuine ISR minimum occurs only when the limit-cycle quasi-potential exceeds that of the fixed point. These results provide an escape-balance mechanism linking intrinsic neuronal parameters to asymptotic noise-induced spike suppression.
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High Energy Physics (Experiment)

New measurements of $B^+_c$ decays into single charm final states

LHCb collaboration: R. Aaij, A.S.W. Abdelmotteleb, C. Abellan Beteta et al. (+1147 more)

Using proton-proton collision data corresponding to an integrated luminosity of $9 \,\textrm{fb}^{-1}$ collected by the LHCb experiment, searches are performed for $B^+_c$ mesons decaying to a charm and a charmless meson pair. Five products of branching fraction, ${\cal B}(B^+_c\!\to DX)$, and fragmentation ratio $f_c\big/f_u$ are reported, \begin{align*} R_{D^+ K^{*0}} &= ( 1.42 \pm 0.23 \pm 0.07 \pm 0.11 ) \times 10^{-6}, \\ R_{D^{*0} K^+} &= (1.46 \pm 0.30 \pm 0.11 \pm 0.05 ) \times 10^{-6}, \\ R_{D^+_s \phi}\ \ \ &= ( 4.0\pm 1.3 \pm 0.2 \pm 0.5) \times 10^{-7 }, \\ R_{D^0 K^+}\ &= ( 9.7 \pm 1.0 \pm 0.4 \pm 0.3 ) \times 10^{-7}, \\ R_{D^0 \pi^+}\ &<\ 1.4 \times 10^{-7}\ \text{at 95% CL}. \end{align*} In each case, the first uncertainty is statistical, the second is systematic and the third includes external uncertainties. The first result is a first observation, the second and third exhibit clear evidence and the fourth improves the precision of previous measurements by a factor two. Additionally, the $CP$ asymmetry in $B^+_c\!\to D^0 K^+$ decays is measured and found to be compatible with zero.
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All authors LHCb collaboration: R. Aaij, A.S.W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A.A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, C. Agapopoulou, C.A. Aidala, Z. Ajaltouni, S. Akar, K. Akiba, P. Albicocco, J. Albrecht, F. Alessio, Z. Aliouche, P. Alvarez Cartelle, R. Amalric, S. Amato, J.L. Amey, Y. Amhis, L. An, L. Anderlini, M. Andersson, A. Andreianov, P. Andreola, M. Andreotti, D. Andreou, A. Anelli, D. Ao, F. Archilli, M. Argenton, S. Arguedas Cuendis, A. Artamonov, M. Artuso, E. Aslanides, R. Ataíde Da Silva, M. Atzeni, B. Audurier, D. Bacher, I. Bachiller Perea, S. Bachmann, M. Bachmayer, J.J. Back, P. Baladron Rodriguez, V. Balagura, A. Balboni, W. Baldini, L. Balzani, H. Bao, J. Baptista de Souza Leite, C. Barbero Pretel, M. Barbetti, I.R. Barbosa, R.J. Barlow, M. Barnyakov, S. Barsuk, W. Barter, M. Bartolini, J. Bartz, J.M. Basels, S. Bashir, G. Bassi, B. Batsukh, P.B. Battista, A. Bay, A. Beck, M. Becker, F. Bedeschi, I.B. Bediaga, N.A. Behling, S. Belin, K. Belous, I. Belov, I. Belyaev, G. Benane, G. Bencivenni, E. Ben-Haim, A. Berezhnoy, R. Bernet, S. Bernet Andres, A. Bertolin, C. Betancourt, F. Betti, J. Bex, Ia. Bezshyiko, J. Bhom, M.S. Bieker, N.V. Biesuz, P. Billoir, A. Biolchini, M. Birch, F.C.R. Bishop, A. Bitadze, A. Bizzeti, T. Blake, F. Blanc, J.E. Blank, S. Blusk, V. Bocharnikov, J.A. Boelhauve, O. Boente Garcia, T. Boettcher, A. Bohare, A. Boldyrev, C. Bolognani, R. Bolzonella, R.B. Bonacci, N. Bondar, A. Bordelius, F. Borgato, S. Borghi, M. Borsato, J.T. Borsuk, S.A. Bouchiba, M. Bovill, T.J.V. Bowcock, A. Boyer, C. Bozzi, A. Brea Rodriguez, N. Breer, J. Brodzicka, A. Brossa Gonzalo, J. Brown, D. Brundu, E. Buchanan, A. Buonaura, L. Buonincontri, A.T. Burke, C. Burr, J.S. Butter, J. Buytaert, W. Byczynski, S. Cadeddu, H. Cai, A. Caillet, R. Calabrese, S. Calderon Ramirez, L. Calefice, S. Cali, M. Calvi, M. Calvo Gomez, P. Camargo Magalhaes, J.I. Cambon Bouzas, P. Campana, D.H. Campora Perez, A.F. Campoverde Quezada, S. Capelli, L. Capriotti, R. Caravaca-Mora, A. Carbone, L. Carcedo Salgado, R. Cardinale, A. Cardini, P. Carniti, L. Carus, A. Casais Vidal, R. Caspary, G. Casse, M. Cattaneo, G. Cavallero, V. Cavallini, S. Celani, D. Cervenkov, S. Cesare, A.J. Chadwick, I. Chahrour, M. Charles, Ph. Charpentier, E. Chatzianagnostou, M. Chefdeville, C. Chen, S. Chen, Z. Chen, A. Chernov, S. Chernyshenko, X. Chiotopoulos, V. Chobanova, S. Cholak, M. Chrzaszcz, A. Chubykin, V. Chulikov, P. Ciambrone, X. Cid Vidal, G. Ciezarek, P. Cifra, P.E.L. Clarke, M. Clemencic, H.V. Cliff, J. Closier, C. Cocha Toapaxi, V. Coco, J. Cogan, E. Cogneras, L. Cojocariu, S. Collaviti, P. Collins, T. Colombo, M. Colonna, A. Comerma-Montells, L. Congedo, A. Contu, N. Cooke, I. Corredoira, A. Correia, G. Corti, J. Cottee Meldrum, B. Couturier, D.C. Craik, M. Cruz Torres, E. Curras Rivera, R. Currie, C.L. Da Silva, S. Dadabaev, L. Dai, X. Dai, E. Dall'Occo, J. Dalseno, C. D'Ambrosio, J. Daniel, A. Danilina, P. d'Argent, G. Darze, A. Davidson, J.E. Davies, A. Davis, O. De Aguiar Francisco, C. De Angelis, F. De Benedetti, J. de Boer, K. De Bruyn, S. De Capua, M. De Cian, U. De Freitas Carneiro Da Graca, E. De Lucia, J.M. De Miranda, L. De Paula, M. De Serio, P. De Simone, F. De Vellis, J.A. de Vries, F. Debernardis, D. Decamp, V. Dedu, S. Dekkers, L. Del Buono, B. Delaney, H.-P. Dembinski, J. Deng, V. Denysenko, O. Deschamps, F. Dettori, B. Dey, P. Di Nezza, I. Diachkov, S. Didenko, S. Ding, L. Dittmann, V. Dobishuk, A.D. Docheva, C. Dong, A.M. Donohoe, F. Dordei, A.C. dos Reis, A.D. Dowling, W. Duan, P. Duda, M.W. Dudek, L. Dufour, V. Duk, P. Durante, M.M. Duras, J.M. Durham, O.D. Durmus, A. Dziurda, A. Dzyuba, S. Easo, E. Eckstein, U. Egede, A. Egorychev, V. Egorychev, S. Eisenhardt, E. Ejopu, L. Eklund, M. Elashri, J. Ellbracht, S. Ely, A. Ene, J. Eschle, S. Esen, T. Evans, F. Fabiano, L.N. Falcao, Y. Fan, B. Fang, L. Fantini, M. Faria, K. Farmer, D. Fazzini, L. Felkowski, M. Feng, M. Feo, A. Fernandez Casani, M. Fernandez Gomez, A.D. Fernez, F. Ferrari, F. Ferreira Rodrigues, M. Ferrillo, M. Ferro-Luzzi, S. Filippov, R.A. Fini, M. Fiorini, M. Firlej, K.L. Fischer, D.S. Fitzgerald, C. Fitzpatrick, T. Fiutowski, F. Fleuret, M. Fontana, L.A. Foreman, R. Forty, D. Foulds-Holt, V. Franco Lima, M. Franco Sevilla, M. Frank, E. Franzoso, G. Frau, C. Frei, D.A. Friday, J. Fu, Q. Führing, Y. Fujii, T. Fulghesu, E. Gabriel, G. Galati, M.D. Galati, A. Gallas Torreira, D. Galli, S. Gambetta, M. Gandelman, P. Gandini, B. Ganie, H. Gao, R. Gao, T.Q. Gao, Y. Gao, Y. Gao, Y. Gao, L.M. Garcia Martin, P. Garcia Moreno, J. García Pardiñas, P. Gardner, K.G. Garg, L. Garrido, C. Gaspar, R.E. Geertsema, L.L. Gerken, E. Gersabeck, M. Gersabeck, T. Gershon, S. Ghizzo, Z. Ghorbanimoghaddam, L. Giambastiani, F.I. Giasemis, V. Gibson, H.K. Giemza, A.L. Gilman, M. Giovannetti, A. Gioventù, L. Girardey, P. Gironella Gironell, C. Giugliano, M.A. Giza, E.L. Gkougkousis, F.C. Glaser, V.V. Gligorov, C. Göbel, E. Golobardes, D. Golubkov, A. Golutvin, S. Gomez Fernandez, W. Gomulka, F. Goncalves Abrantes, M. Goncerz, G. Gong, J.A. Gooding, I.V. Gorelov, C. Gotti, J.P. Grabowski, L.A. Granado Cardoso, E. Graugés, E. Graverini, L. Grazette, G. Graziani, A.T. Grecu, L.M. Greeven, N.A. Grieser, L. Grillo, S. Gromov, C. Gu, M. Guarise, L. Guerry, M. Guittiere, V. Guliaeva, P.A. Günther, A.-K. Guseinov, E. Gushchin, Y. Guz, T. Gys, K. Habermann, T. Hadavizadeh, C. Hadjivasiliou, G. Haefeli, C. Haen, M. Hajheidari, G. Hallett, M.M. Halvorsen, P.M. Hamilton, J. Hammerich, Q. Han, X. Han, S. Hansmann-Menzemer, L. Hao, N. Harnew, T.J. Harris, M. Hartmann, S. Hashmi, J. He, F. Hemmer, C. Henderson, R.D.L. Henderson, A.M. Hennequin, K. Hennessy, L. Henry, J. Herd, P. Herrero Gascon, J. Heuel, A. Hicheur, G. Hijano Mendizabal, J. Horswill, R. Hou, Y. Hou, N. Howarth, J. Hu, W. Hu, X. Hu, W. Huang, W. Hulsbergen, R.J. Hunter, M. Hushchyn, D. Hutchcroft, M. Idzik, D. Ilin, P. Ilten, A. Inglessi, A. Iniukhin, A. Ishteev, K. Ivshin, R. Jacobsson, H. Jage, S.J. Jaimes Elles, S. Jakobsen, E. Jans, B.K. Jashal, A. Jawahery, V. Jevtic, E. Jiang, X. Jiang, Y. Jiang, Y.J. Jiang, M. John, A. John Rubesh Rajan, D. Johnson, C.R. Jones, T.P. Jones, S. Joshi, B. Jost, J. Juan Castella, N. Jurik, I. Juszczak, D. Kaminaris, S. Kandybei, M. Kane, Y. Kang, C. Kar, M. Karacson, D. Karpenkov, A. Kauniskangas, J.W. Kautz, M.K. Kazanecki, F. Keizer, M. Kenzie, T. Ketel, B. Khanji, A. Kharisova, S. Kholodenko, G. Khreich, T. Kirn, V.S. Kirsebom, O. Kitouni, S. Klaver, N. Kleijne, K. Klimaszewski, M.R. Kmiec, S. Koliiev, L. Kolk, A. Konoplyannikov, P. Kopciewicz, P. Koppenburg, M. Korolev, I. Kostiuk, O. Kot, S. Kotriakhova, A. Kozachuk, P. Kravchenko, L. Kravchuk, M. Kreps, P. Krokovny, W. Krupa, W. Krzemien, O. Kshyvanskyi, S. Kubis, M. Kucharczyk, V. Kudryavtsev, E. Kulikova, A. Kupsc, B. Kutsenko, D. Lacarrere, P. Laguarta Gonzalez, A. Lai, A. Lampis, D. Lancierini, C. Landesa Gomez, J.J. Lane, R. Lane, G. Lanfranchi, C. Langenbruch, J. Langer, O. Lantwin, T. Latham, F. Lazzari, C. Lazzeroni, R. Le Gac, H. Lee, R. Lefèvre, A. Leflat, S. Legotin, M. Lehuraux, E. Lemos Cid, O. Leroy, T. Lesiak, E.D. Lesser, B. Leverington, A. Li, C. Li, H. Li, K. Li, L. Li, M. Li, P. Li, P.-R. Li, Q. Li, S. Li, T. Li, T. Li, Y. Li, Y. Li, Z. Lian, X. Liang, S. Libralon, C. Lin, T. Lin, R. Lindner, H. Linton, V. Lisovskyi, R. Litvinov, F.L. Liu, G. Liu, K. Liu, S. Liu, W. Liu, Y. Liu, Y. Liu, Y.L. Liu, A. Lobo Salvia, A. Loi, T. Long, J.H. Lopes, A. Lopez Huertas, S. López Soliño, Q. Lu, C. Lucarelli, D. Lucchesi, M. Lucio Martinez, V. Lukashenko, Y. Luo, A. Lupato, E. Luppi, K. Lynch, X.-R. Lyu, G.M. Ma, S. Maccolini, F. Machefert, F. Maciuc, B. Mack, I. Mackay, L.M. Mackey, L.R. Madhan Mohan, M.J. Madurai, A. Maevskiy, D. Magdalinski, D. Maisuzenko, M.W. Majewski, J.J. Malczewski, S. Malde, L. Malentacca, A. Malinin, T. Maltsev, G. Manca, G. Mancinelli, C. Mancuso, R. Manera Escalero, F.M. Manganella, D. Manuzzi, D. Marangotto, J.F. Marchand, R. Marchevski, U. Marconi, E. Mariani, S. Mariani, C. Marin Benito, J. Marks, A.M. Marshall, L. Martel, G. Martelli, G. Martellotti, L. Martinazzoli, M. Martinelli, D. Martinez Gomez, D. Martinez Santos, F. Martinez Vidal, A. Martorell i Granollers, A. Massafferri, R. Matev, A. Mathad, V. Matiunin, C. Matteuzzi, K.R. Mattioli, A. Mauri, E. Maurice, J. Mauricio, P. Mayencourt, J. Mazorra de Cos, M. Mazurek, M. McCann, L. Mcconnell, T.H. McGrath, N.T. McHugh, A. McNab, R. McNulty, B. Meadows, G. Meier, D. Melnychuk, F.M. Meng, M. Merk, A. Merli, L. Meyer Garcia, D. Miao, H. Miao, M. Mikhasenko, D.A. Milanes, A. Minotti, E. Minucci, T. Miralles, B. Mitreska, D.S. Mitzel, A. Modak, R.A. Mohammed, R.D. Moise, S. Mokhnenko, E.F. Molina Cardenas, T. Mombächer, M. Monk, S. Monteil, A. Morcillo Gomez, G. Morello, M.J. Morello, M.P. Morgenthaler, J. Moron, W. Morren, A.B. Morris, A.G. Morris, R. Mountain, H. Mu, Z. Mu, E. Muhammad, F. Muheim, M. Mulder, K. Müller, F. Muñoz-Rojas, R. Murta, P. Naik, T. Nakada, R. Nandakumar, T. Nanut, I. Nasteva, M. Needham, N. Neri, S. Neubert, N. Neufeld, P. Neustroev, J. Nicolini, D. Nicotra, E.M. Niel, N. Nikitin, Q. Niu, P. Nogarolli, P. Nogga, C. Normand, J. Novoa Fernandez, G. Nowak, C. Nunez, H.N. Nur, A. Oblakowska-Mucha, V. Obraztsov, T. Oeser, S. Okamura, A. Okhotnikov, O. Okhrimenko, R. Oldeman, F. Oliva, M. Olocco, C.J.G. Onderwater, R.H. O'Neil, D. Osthues, J.M. Otalora Goicochea, P. Owen, A. Oyanguren, O. Ozcelik, F. Paciolla, A. Padee, K.O. Padeken, B. Pagare, P.R. Pais, T. Pajero, A. Palano, M. Palutan, X. Pan, G. Panshin, L. Paolucci, A. Papanestis, M. Pappagallo, L.L. Pappalardo, C. Pappenheimer, C. Parkes, D. Parmar, B. Passalacqua, G. Passaleva, D. Passaro, A. Pastore, M. Patel, J. Patoc, C. Patrignani, A. Paul, C.J. Pawley, A. Pellegrino, J. Peng, M. Pepe Altarelli, S. Perazzini, D. Pereima, H. Pereira Da Costa, A. Pereiro Castro, P. Perret, A. Perrevoort, A. Perro, M.J. Peters, K. Petridis, A. Petrolini, J.P. Pfaller, H. Pham, L. Pica, M. Piccini, L. Piccolo, B. Pietrzyk, G. Pietrzyk, D. Pinci, F. Pisani, M. Pizzichemi, V.M. Placinta, M. Plo Casasus, T. Poeschl, F. Polci, M. Poli Lener, A. Poluektov, N. Polukhina, I. Polyakov, E. Polycarpo, S. Ponce, D. Popov, S. Poslavskii, K. Prasanth, C. Prouve, D. Provenzano, V. Pugatch, G. Punzi, S. Qasim, Q. Qian, W. Qian, N. Qin, S. Qu, R. Quagliani, R.I. Rabadan Trejo, J.H. Rademacker, M. Rama, M. Ramírez García, V. Ramos De Oliveira, M. Ramos Pernas, M.S. Rangel, F. Ratnikov, G. Raven, M. Rebollo De Miguel, F. Redi, J. Reich, F. Reiss, Z. Ren, P.K. Resmi, R. Ribatti, G. Ricart, D. Riccardi, S. Ricciardi, K. Richardson, M. Richardson-Slipper, K. Rinnert, P. Robbe, G. Robertson, E. Rodrigues, A. Rodriguez Alvarez, E. Rodriguez Fernandez, J.A. Rodriguez Lopez, E. Rodriguez Rodriguez, J. Roensch, A. Rogachev, A. Rogovskiy, D.L. Rolf, P. Roloff, V. Romanovskiy, A. Romero Vidal, G. Romolini, F. Ronchetti, T. Rong, M. Rotondo, S.R. Roy, M.S. Rudolph, M. Ruiz Diaz, R.A. Ruiz Fernandez, J. Ruiz Vidal, A. Ryzhikov, J. Ryzka, J.J. Saavedra-Arias, J.J. Saborido Silva, R. Sadek, N. Sagidova, D. Sahoo, N. Sahoo, B. Saitta, M. Salomoni, I. Sanderswood, R. Santacesaria, C. Santamarina Rios, M. Santimaria, L. Santoro, E. Santovetti, A. Saputi, D. Saranin, A. Sarnatskiy, G. Sarpis, M. Sarpis, C. Satriano, A. Satta, M. Saur, D. Savrina, H. Sazak, F. Sborzacchi, L.G. Scantlebury Smead, A. Scarabotto, S. Schael, S. Scherl, M. Schiller, H. Schindler, M. Schmelling, B. Schmidt, S. Schmitt, H. Schmitz, O. Schneider, A. Schopper, N. Schulte, S. Schulte, M.H. Schune, R. Schwemmer, G. Schwering, B. Sciascia, A. Sciuccati, I. Segal, S. Sellam, A. Semennikov, T. Senger, M. Senghi Soares, A. Sergi, N. Serra, L. Sestini, A. Seuthe, Y. Shang, D.M. Shangase, M. Shapkin, R.S. Sharma, I. Shchemerov, L. Shchutska, T. Shears, L. Shekhtman, Z. Shen, S. Sheng, V. Shevchenko, B. Shi, Q. Shi, Y. Shimizu, E. Shmanin, R. Shorkin, J.D. Shupperd, R. Silva Coutinho, G. Simi, S. Simone, N. Skidmore, T. Skwarnicki, M.W. Slater, J.C. Smallwood, E. Smith, K. Smith, M. Smith, A. Snoch, L. Soares Lavra, M.D. Sokoloff, F.J.P. Soler, A. Solomin, A. Solovev, I. Solovyev, N.S. Sommerfeld, R. Song, Y. Song, Y. Song, Y.S. Song, F.L. Souza De Almeida, B. Souza De Paula, E. Spadaro Norella, E. Spedicato, J.G. Speer, E. Spiridenkov, P. Spradlin, V. Sriskaran, F. Stagni, M. Stahl, S. Stahl, S. Stanislaus, E.N. Stein, O. Steinkamp, O. Stenyakin, H. Stevens, D. Strekalina, Y. Su, F. Suljik, J. Sun, L. Sun, D. Sundfeld, W. Sutcliffe, P.N. Swallow, K. Swientek, F. Swystun, A. Szabelski, T. Szumlak, Y. Tan, Y. Tang, M.D. Tat, A. Terentev, F. Terzuoli, F. Teubert, E. Thomas, D.J.D. Thompson, H. Tilquin, V. Tisserand, S. T'Jampens, M. Tobin, L. Tomassetti, G. Tonani, X. Tong, D. Torres Machado, L. Toscano, D.Y. Tou, C. Trippl, G. Tuci, N. Tuning, L.H. Uecker, A. Ukleja, D.J. Unverzagt, B. Urbach, E. Ursov, A. Usachov, A. Ustyuzhanin, U. Uwer, V. Vagnoni, V. Valcarce Cadenas, G. Valenti, N. Valls Canudas, H. Van Hecke, E. van Herwijnen, C.B. Van Hulse, R. Van Laak, M. van Veghel, G. Vasquez, R. Vazquez Gomez, P. Vazquez Regueiro, C. Vázquez Sierra, S. Vecchi, J.J. Velthuis, M. Veltri, A. Venkateswaran, M. Verdoglia, M. Vesterinen, D. Vico Benet, P. Vidrier Villalba, M. Vieites Diaz, X. Vilasis-Cardona, E. Vilella Figueras, A. Villa, P. Vincent, F.C. Volle, D. vom Bruch, N. Voropaev, K. Vos, C. Vrahas, J. Wagner, J. Walsh, E.J. Walton, G. Wan, C. Wang, G. Wang, H. Wang, J. Wang, J. Wang, J. Wang, J. Wang, M. Wang, N.W. Wang, R. Wang, X. Wang, X. Wang, X.W. Wang, Y. Wang, Y.H. Wang, Z. Wang, Z. Wang, Z. Wang, J.A. Ward, M. Waterlaat, N.K. Watson, D. Websdale, Y. Wei, J. Wendel, B.D.C. Westhenry, C. White, M. Whitehead, E. Whiter, A.R. Wiederhold, D. Wiedner, G. Wilkinson, M.K. Wilkinson, M. Williams, M.J. Williams, M.R.J. Williams, R. Williams, Z. Williams, F.F. Wilson, M. Winn, W. Wislicki, M. Witek, L. Witola, G. Wormser, S.A. Wotton, H. Wu, J. Wu, X. Wu, Y. Wu, Z. Wu, K. Wyllie, S. Xian, Z. Xiang, Y. Xie, A. Xu, J. Xu, L. Xu, L. Xu, M. Xu, Z. Xu, Z. Xu, Z. Xu, K. Yang, S. Yang, X. Yang, Y. Yang, Z. Yang, V. Yeroshenko, H. Yeung, H. Yin, X. Yin, C.Y. Yu, J. Yu, X. Yuan, Y Yuan, E. Zaffaroni, M. Zavertyaev, M. Zdybal, F. Zenesini, C. Zeng, M. Zeng, C. Zhang, D. Zhang, J. Zhang, L. Zhang, S. Zhang, S.L. Zhang, Y. Zhang, Y.Z. Zhang, Y. Zhao, A. Zharkova, A. Zhelezov, S.Z. Zheng, X.Z. Zheng, Y. Zheng, T. Zhou, X. Zhou, Y. Zhou, V. Zhovkovska, L.Z. Zhu, X. Zhu, X. Zhu, V. Zhukov, J. Zhuo, Q. Zou, D. Zuliani, G. Zunica

Instrumentation and Detectors

Real-Time Smart Self-Mixing Interferometry Sensor With Embedded Neural Network

Pierre-Emmanuel Novac, Laurent Rodriguez and Stéphane Barland

Self-mixing interferometry is a measurement ap- proach in which a laser beam is re-injected into the emitting laser itself after reflection on a target. Information about the position of the target can be obtained from monitoring the voltage across the laser. However, analyzing this signal is difficult. In previous works, neural networks have been used with great success to process this data. In this article, we present an updated prototype of an integrated sensor based on self-mixing interferometry with embedded neural networks. It consists of a semiconductor laser (acting both as light emitter and detector) equipped with an embedded platform for data processing. The platform includes an ADC (Analog-to-Digital Converter) and an STM32U575ZI microcontroller. The microcontroller runs a residual neural network in charge of reconstructing the displacement of a target from the interferometric signal entering the ADC. We assess the robustness of the neural network to unwanted signal amplitude variations, the impact of different network weights quantization choices required to run the network on the microcontroller, and the energy consumption of the system. Finally, we provide a demonstration of target displacement reconstruction fully running on the embedded platform in real-time. Our results pave the way towards robust, low power and versatile sensors based on self-mixing interferometry and embedded neural networks.
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Exactly Solvable and Integrable Systems

Lie symmetry, Painlevé analysis and Conservation laws for (1+2)-Dimensional Kudryashov-Sinelshchikov (KS) equation

Apeksha Patil, Amlan Kanti Halder and Rajeswari Seshadri

The wave propagation of pressures in liquids that contain gas bubbles are an important concern in fluid dynamics and mathematical physics. The Kudryashov Sinelshchikov equation offers a useful mathematical framework in the study of nonlinear wave motion in bubbly liquids with reference to the effects of viscosity and heat exchange between liquid and gaseous phases. This paper examines the dimensional reduced (1 + 2)-dimensional Kudryashov Sinelshchikov equation, a fourth-order nonlinear partial differential equation. Analyzing the Lie symmetry, an infinite dimension Lie algebra is obtained because of the presence of arbitrary functions. By applying the commutative relation between these vector fields and choosing the specific forms for the arbitrary functions, helps the governing PDE to reduce to fourth order ODEs. The reduced equations are then investigated using the Painleve analysis to give solutions in the form of Laurent series. In addition, multiplier approach is used to obtain the conserved vectors and to analyzed conservations properties of the equation. We obtain four cases and the Conservation laws were verified for all the cases.
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Cosmology and Nongalactic Astrophysics

SCRIPT in the Cosmic Dawn: Distinguishing Redshift-Evolving Galaxy Populations with 21-cm Fluctuations

Janakee Raste and Tirthankar Roy Choudhury

Recent James Webb Space Telescope (JWST) observations suggest an unexpectedly high abundance of luminous galaxies at $z \gtrsim 10$, challenging traditional models of star formation. The 21-cm signal of neutral hydrogen offers a complementary, volume-averaged probe of these early epochs. In this work, we present a major extension to the explicitly photon-conserving semi-numerical framework SCRIPT, enabling the self-consistent calculation of spin temperature fluctuations driven by inhomogeneous Lyman-$\alpha$ coupling and X-ray heating during the Cosmic Dawn. Using this framework, we compare a JWST-informed fiducial galaxy model, featuring a redshift-evolving star-formation efficiency, against a static baseline model. We demonstrate that the global 21-cm signal is highly degenerate: a static galaxy population can replicate the absorption trough of an evolving population if a steep, mass-dependent X-ray efficiency is invoked to shift intergalactic medium heating toward highly abundant, low-mass halos. However, this degeneracy is definitively broken by the 21-cm power spectrum. Because spatial fluctuations retain a structural memory of the clustering bias of the source halos, the tuned static model predicts a substantially lower power spectrum amplitude across all characteristic peaks. We conclude that combining global and fluctuation measurements is essential to robustly constrain the redshift evolution of high-redshift galaxies.
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Quantum Physics

Suppressing Cavity Frequency Noise Using a Kerr Nonlinearity

J.P. van Soest, S. Meilof, G.L. Bhai et al. (+3 more)

Resonance-frequency fluctuations can limit the sensitivity and stability of superconducting microwave cavities used for qubit readout, optomechanical displacement sensing, and magnetic flux detection. Here, we demonstrate the suppression of resonance-frequency fluctuations by locking a noisy nonlinear superconducting microwave cavity to a strong pump tone. The Kerr nonlinearity of this system, whereby the resonance frequency depends on the intracavity field amplitude, gives rise to an intrinsic feedback mechanism that enables passive stabilization without active external feedback. Using two-tone spectroscopy, we experimentally characterize the intrinsic nonlinear feedback mechanism and investigate its temporal stability through Allan deviation analysis. The frequency fluctuations of the locked cavity mode are reduced by nearly two orders of magnitude, reaching the $1/f$ noise floor, without continuous frequency tracking or active control. Kerr locking provides a general approach for self-stabilizing nonlinear microwave resonators by suppressing low-frequency cavity noise while preserving sensitivity to signals outside the locking bandwidth. This approach may benefit a broad range of systems, including SQUID-based resonators, optomechanical devices, and parametric amplifiers.
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All authors J.P. van Soest, S. Meilof, G.L. Bhai, M. Villiers, C.A. Potts, G.A. Steele

Fluid Dynamics

Modelisation of chaotic systems with a latent Stochastic Differential Equation

Ismaël Zighed, Nicolas Thome, Patrick Gallinari et al. (+1 more)

Stochastic Differential Equations (SDEs) have become a cornerstone of scientific machine learning, though they are predominantly utilized as algorithmic tools for uncertainty quantification or distribution matching. In contrast, leveraging SDEs fundamentally to model macroscopic, nonlinear physics as stochastic processes remains largely unexplored. This work introduces a probabilistic, non-intrusive reduced-order model (ROM) for chaotic dynamical systems. We argue that projecting high-dimensional nonlinear dynamics onto a low-dimensional manifold introduces irreducible uncertainty, compounded by the chaotic attractors and multi-admissible futures inherent to turbulent flows. Consequently, a chaotic system governed by a partial differential equation can be effectively modeled by an SDE in a suitable latent space. To this end, a nonlinear autoencoder is employed to map the flow field into a low-dimensional representation, within which the temporal evolution is explicitly governed by an SDE. The predictable component of the dynamics is captured by a learned drift term, while state-dependent stochasticity is absorbed by a diffusion term. We demonstrate that this probabilistic framework successfully propagates highly nonlinear states, offering a robust alternative to traditional deterministic methodologies for chaotic regimes. Ultimately, our model generates new chaotic flow trajectories that remain locally and globally consistent with the true transition kernel learned from Direct Numerical Simulation (DNS) data. Even though these generated trajectories are unique and distinct from the training set, they preserve the underlying statistics and manifolds, validating the strong generative performance and robustness of our methodology.
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All authors Ismaël Zighed, Nicolas Thome, Patrick Gallinari, Taraneh Sayadi

Earth and Planetary Astrophysics

A study on the contribution of the interplanetary medium in radio occultation experiments

Keshav Aggarwal, R. K. Choudhary, Abhirup Datta et al. (+4 more)

Irregularities in electron density within the interplanetary medium (IPM) can cause fluctuations in the Doppler frequency of spacecraft radio signals. The amplitude of these fluctuations depends on factors such as the carrier frequency, propagation geometry, and link configuration. However, quantitative characterization of these effects across different frequencies in various occultation experiments is currently limited. We analyze five complementary datasets: two-way S-band observations from Chandrayaan-3 outside the lunar ionosphere, two-way S-band data from Chandrayaan-2 during lunar occultation, one-way S/X band measurements from the Venus Express Radio Science (VeRa)/Akatsuki Radio Science (Akatsuki) under IPM-only conditions, and one-way X-band Akatsuki data during solar occultation. The Chandrayaan-3 and Akatsuki IPM observations isolate IPM effects by excluding contributions from planetary atmospheres, the lunar ionosphere, and, except during solar occultation, the solar corona. Chandrayaan-3 data sample dynamically evolving Earth-Moon geometries and exhibit weak, mHz-level Doppler fluctuations, while Chandrayaan-2 observations provide near-lunar plasma benchmarks with higher amplitudes, during quiet time solar and geomagnetic conditions. Akatsuki and VeRa's IPM-only measurements capture long-path interplanetary effects, whereas Akatsuki solar occultation data reveal strong coronal signatures. Power spectral density analysis indicates Kolmogorov-like turbulence for lunar occultation and solar occultation cases, while IPM-only spectra show low-amplitude fluctuations. These results quantify the IPM contribution to Doppler noise, demonstrate the enhanced plasma sensitivity of two-way coherent links, and provide constraints relevant to turbulence modelling, precision spacecraft tracking, and the interpretation of radio occultation experiments.
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All authors Keshav Aggarwal, R. K. Choudhary, Abhirup Datta, Soumyaneal Banerjee, R. Manikantan, Anshuman Sharma, Takeshi Imamura

Quantum Physics

Mesoscopic Quantum Communication via Photon-Number Moments

Gabriele Cenedese, Alex Pozzoli, Luca Razzoli et al. (+1 more)

Mesoscopic optical states are a promising resource for quantum communication, combining robustness against losses with the preservation of genuine quantum features. Here, we propose a quantum communication protocol in which information is encoded in the first and second moments of the photon-number distributions of classical optical states, and then decoded by photon-number-resolving detectors. Security relies on the nonclassical photon-number correlations of a twin-beam state transmitted alongside the signal in the quantum channel, providing an experimentally accessible security witness against both intercept-resend and beam-splitter attacks investigated in this work. Numerical simulations performed in experimentally accessible parameter regimes support the feasibility and security of the proposed communication protocol, yielding nonzero key generation rates under the considered eavesdropping attacks, and motivating its future experimental implementation.
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All authors Gabriele Cenedese, Alex Pozzoli, Luca Razzoli, Alessia Allevi

High Energy Physics (Experiment)

Evidence of the $e^+ e^-\to f_1(1285)$ reaction with the CMD-3 detector at VEPP-2000

E.P. Solodov, R.R. Akhmetshin, A.N. Amirkhanov et al. (+53 more)

A search for the $e^+ e^-\to f_1(1285)$ reaction is performed with the CMD-3 detector at the VEPP-2000 collider. Data from a scan in the center-of-mass energy range Ec.m.=1.20–1.36 GeV with 109.1 pb$^{-1}$ of the integrated luminosity is used. A dedicated 51.7 pb$^{-1}$ have been collected at the $f_1(1285)$ resonance peak energy Ec.m.=1282 MeV, where $26.5 \pm 7.4$ events have been found in the $e^+ e^-\to\eta\pi^0\pi^0$ reaction. No indication of the signal is observed in the scan data. We interpret the result as a statistical 4.5$\sigma$ evidence of the C-even resonance production in the $e^+ e^-\to f_1(1285)\to\eta\pi^0\pi^0$ reaction via the two-photon interaction. The production cross section is found to be $\sigma(e^+ e^-\to f_1) = 0.074 \pm 0.021 \pm 0.010$ nb, and the corresponding branching fraction to the $e^+ e^-$ pair is $B(f_1(1285)\to e^+e^-) = (8.3 \pm 2.3 \pm 1.1)\times 10^{-9}$.
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All authors E.P. Solodov, R.R. Akhmetshin, A.N. Amirkhanov, A.V. Anisenkov, V.M. Aulchenko, N.S. Bashtovoy, E.V. Bedarev, D.E. Berkaev, A.E. Bondar, A.V. Bragin, D.E. Chistyakov, V.S. Denisov, E.A. Eminov, D.A. Epifanov, L.B. Epshteyn, A.L. Erofeev, G.V. Fedotovich, L.B. Fomin, A.O. Gorkovenko, A.A. Grebenuk, S.S. Gribanov, D.N. Grigoriev, F.V. Ignatov, V.L. Ivanov, A.S. Kasaev, S.V. Karpov, V.F. Kazanin, I.A. Koop, A.A. Korobov, A.N. Kozyrev, P.P. Krokovny, A.S. Kuzmin, T.A. Kuznetsov, I.B. Logashenko, P.A. Lukin, K.Yu. Mikhailov, I.V. Obraztsov, V.G. Petrochenko, N.A. Petrov, A.S. Popov, S.A. Rastigeev, Yu.A. Rogovsky, A.A. Ruban, A.E. Ryzhenenkov, A.V. Semenov, V.E. Shebalin, D.N. Shemyakin, B.A. Shwartz, D.B. Shwartz, M.V. Timoshenko, V.M. Titov, A.A. Talyshev, S.S. Tolmachev, A.I. Vorobiov, D.S. Zhadan, Yu.V. Yudin

Cosmology and Nongalactic Astrophysics

Tomographer: End-to-end Redshift Distribution Estimation for Source Catalogs and Intensity Maps

Yi-Kuan Chiang, Yu Voon Ng, Yu-Ren Lin et al. (+2 more)

Redshift information is central to nearly every extragalactic and cosmological application of sky surveys, yet only a small fraction of cataloged sources, and none of the photons forming diffuse backgrounds, have spectroscopic redshifts. Clustering-based redshift inference estimates the redshift distribution of an arbitrary dataset through spatial cross-correlation with a reference sample of known redshifts. It relies only on positional information, making it applicable to any tracer of large-scale structure, including source populations and diffuse intensity maps. Its broader adoption, however, has been limited by technical barriers: assembling and characterizing spectroscopic references, expensive pair-counting computations, theoretical corrections, and systematic control. To remove these barriers, we introduce Tomographer, an end-to-end clustering-redshift framework. The key design feature is a set of precomputed "activation maps" encoding the spatial pair information of 3 million SDSS spectroscopic galaxies and quasars up to $z\sim4$ over $10{,}000\,{\rm deg}^2$. This eliminates user-end pair counting, reducing computational scaling from $O(N\log N)$ to $O(1)$ map multiplications. Given a source catalog or intensity map, Tomographer returns the bias-weighted redshift distribution, $b(z)\,{\rm d}N/{\rm d}z(z)$ or $b(z)\,{\rm d}I/{\rm d}z(z)$. We validate the framework against samples with known redshifts, demonstrate accurate uncertainty estimates, and show robustness to survey footprint, spatially varying selection functions, beam smoothing, and foreground contamination. We showcase applications to source catalogs selected by flux, color, photometric redshift, morphology, or variability, and to intensity maps from radio to X-rays. Future Tomographer releases will incorporate additional wide-field spectroscopic reference samples as they become available.
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All authors Yi-Kuan Chiang, Yu Voon Ng, Yu-Ren Lin, Manuchehr Taghizadeh-Popp, Brice Ménard

Strongly Correlated Electrons

Magnetoresistance in Magnetic Weyl semimetal Mn$_{3}$ZnC

Sunil Gangwar and C. S. Yadav

The magnetoresistance (MR) in magnetic materials reveal an intriguing spin-dependent electron scattering, highlighting the role of spin polarization on the electronic transport properties. This becomes even more interesting for the topological magnetic materials where a finite Berry curvature leads to an intrinsic scattering channel also. In this report, we investigate MR of Mn$_{3}$ZnC, an antiperovskite magnetic nodal line semimetal. Mn$_{3}$ZnC shows a ferromagnetic (FM) transition at $\sim$ 420 K, followed by an ferrimagnetic (FIM) transition at $\sim$ 195 K. We focus on the interpretation of MR data and highlight the relation between MR and its magnetization. The signature of magnetization induced MR shows correlation at low magnetic fields and displays distinct behaviors in the FIM and FM states. Similar to the isothermal magnetization M(H) curve of FM and FIM state, the MR curves exhibit a sharp increase, followed by a linear behavior at higher fields. As the magnetic field varies, the cusp-like anomaly becomes more pronounced, and vanishes at the magnetic phase transition, which then reappears as the temperature increases. The sign change in the MR curves in the FIM state is attributed to a drastic change in the carrier mobility. Interestingly, this system shows a positive MR in FM state at very low field, which is quite unusual.
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