Tootfinder

Field Theoretic Approach to Interacting Two Body Tunneling
Guo Ye
https://arxiv.org/abs/2510.11656 https://arxiv.org/pdf/2510.11656

Field Theoretic Approach to Interacting Two Body Tunneling
Two body tunneling problems are hard to treat analytically due to the incompatibility between tunneling and perturbation theory. The lack of classical solutions of the Euclidean Lagrangian of continuous systems further thwarts semi-classical expansions. To develop an analytic theory which provides insight on interacting two-particle tunneling, we use new results to derive the Bethe-Salpeter equation of a tunneling field theory with Yukawa coupling. We show that in the one plus one dimensional c…

Lagrangian Stability Analysis Technique for Fluid Flows
Vilas J. Shinde
https://arxiv.org/abs/2509.10316 https://arxiv.org/pdf/2509.10316

Lagrangian Stability Analysis Technique for Fluid Flows
Flow transition from a stable to unstable states and eventually to turbulence is a classical fluid mechanics phenomenon with a strong practical relevance. Conventional hydrodynamic stability deals with perturbation dynamics on a steady baseflow, typically in Eulerian reference frame. Common modal techniques, e.g., linear stability theory, involve linearization of governing flow equations and flow/geometrical simplifications, which can be tedious and restrictive. This paper presents a perturbati…

Spectroscopy and transport of nonpolarons in silicon and germanium: the influence of doping and temperature
Raveena Gupta, Joao Abreu, Matthieu J. Verstraete
https://arxiv.org/abs/2509.10192

Spectroscopy and transport of nonpolarons in silicon and germanium: the influence of doping and temperature
We perform a first-principles investigation of electron-phonon interactions in silicon and germanium, uncovering distinct non-polaronic spectral and transport fingerprints in these archetypal covalent semiconductors. Using many-body perturbation theory with the retarded cumulant expansion, we compute quasiparticle energies, lifetimes, and phonon satellites beyond the Dyson-Migdal approximation. Short-range crystal fields dominate coupling in both materials, yet their low-temperature spectral fi…

Conformal Data for the O(3) Wilson-Fisher CFT from Fuzzy Sphere Realization of Quantum Rotor Model
Arjun Dey, Loic Herviou, Christopher Mudry, Andreas Martin L\"auchli
https://arxiv.org/abs/2510.09755

Conformal Data for the O(3) Wilson-Fisher CFT from Fuzzy Sphere Realization of Quantum Rotor Model
We present a model for strongly interacting fermions with internal O(3) symmetry on the fuzzy-sphere that (i) preserves the rotational symmetry of the fuzzy sphere and (ii) undergoes a quantum phase transition in the (2+1)-dimensional O(3) Wilson-Fisher universality class. Using exact diagonalization (ED) and density matrix renormalization group (DMRG), we locate the quantum critical point via conformal perturbation theory and obtain scaling dimensions from finite-size spectra. We identify 24 p…

Control variates from Eulerian and Lagrangian perturbation theory: Application to the bispectrum
Nickolas Kokron, Shi-Fan Chen
https://arxiv.org/abs/2510.07375 https://

Control variates from Eulerian and Lagrangian perturbation theory: Application to the bispectrum
Control variates have seen recent interest as a powerful technique to reduce the variance of summary statistics measured from costly cosmological $N$-body simulations. Of particular interest are the class of control variates which are analytically calculable, such as the recently introduced 'Zeldovich control variates' for the power spectrum of matter and biased tracers. In this work we present the construction of perturbative control variates in Eulerian and Lagrangian perturbation theory, and…

Taming forward scattering singularities in partial waves
Marta Fuentes Zamoro, Benjam\'in Grinstein, Pablo Qu\'ilez
https://arxiv.org/abs/2510.08784 https://

Taming forward scattering singularities in partial waves
Perturbative partial-wave amplitudes diverge in cases with a massless exchanged particle in the $t$-channel. We argue that the divergence is an artifact of perturbation theory and give a prescription for the all-orders correction factor that renders the partial waves finite. As an example, we apply this to longitudinal $W^+W^-$ elastic scattering, for which there is a photon exchange $t$-channel contribution, and derive improved quasi-perturbative unitarity bounds on the mass of the Higgs. The …

Non-Hermitian Bethe-Salpeter Equation for Open Systems: Emergence of Exceptional Points in Excitonic Spectra from First Principles
Zhenlin Zhang, Wei Hu, Enrico Perfetto, Gianluca Stefanucci
https://arxiv.org/abs/2510.09386

Non-Hermitian Bethe-Salpeter Equation for Open Systems: Emergence of Exceptional Points in Excitonic Spectra from First Principles
In open quantum systems hosting excitons, dissipation mechanisms critically shape the excitonic dynamics, band-structure and topological properties. A microscopic understanding of excitons in such non-Hermitian settings demands a first-principles generalization of the Bethe-Salpeter equation (BSE). Building on a recently introduced nonequilibrium Green's function formalism compatible with Lindbladian dynamics, we derive a non-Hermitian BSE from diagrammatic perturbation theory on the Keldysh co…

Quasiparticle effects and strong excitonic features in exfoliable 1D semiconducting materials
Simone Grillo, Chiara Cignarella, Friedhelm Bechstedt, Paola Gori, Maurizia Palummo, Davide Campi, Nicola Marzari, Olivia Pulci
https://arxiv.org/abs/2510.09194

Quasiparticle effects and strong excitonic features in exfoliable 1D semiconducting materials
We report a comprehensive first-principles study of the electronic and optical properties of recently identified exfoliable one-dimensional semiconducting materials, focusing on chalcogenide-based atomic chains derived from van der Waals-bonded bulk crystals. Specifically, we investigate covalently bonded S3 and Te3 chains, and polar-bonded As2S3 and Bi2Te3 chains, using a fully first-principles approach that combines density-functional theory (DFT), density-functional perturbation theory (DFPT…

Noncommutative Regge-Wheeler potential: some nonperturbative results
Nikola Herceg, Tajron Juri\'c, A. Naveena Kumara, Andjelo Samsarov, Ivica Smoli\'c
https://arxiv.org/abs/2510.08125

Noncommutative Regge-Wheeler potential: some nonperturbative results
We study the gravitational perturbation theory of black holes in noncommutative spacetimes with noncommutativity of the type $[t\stackrel{\star}{,} r] = i a αA(r)$ and $[φ\stackrel{\star}{,} r] = i a βA(r)$ for arbitrary $A(r)$, which includes several Moyal-type spaces and also the $κ$-Minkowski space. The main result of this paper is an analytical expression for the effective potential of the axial perturbation modes, valid to all orders in the noncommutativity parameter. This is achieved …

Unitary perturbation theory on the light cone
St\'ephane Munier
https://arxiv.org/abs/2510.05256 https://arxiv.org/pdf/2510.05256

Unitary perturbation theory on the light cone
Light-cone perturbation theory is a powerful tool for calculating high-energy scattering amplitudes, particularly for quantum particles such as electrons, photons, or protons scattering off heavy nuclei, a process analogous to potential scattering. Central to these computations are the light-cone wave functions of incoming and outgoing particles, representing the projection of dressed initial and final states onto partonic Fock states. The dressed states are obtained by applying an evolution op…

Causal perturbation theory and scattering amplitudes
H. A. C. Grande, J. C. A Barata
https://arxiv.org/abs/2509.20573 https://arxiv.org/pdf/2509.20573

Causal perturbation theory and scattering amplitudes
Motivated by the limited interaction between the mathematical physics community and theoretical physicists - particularly in high-energy theory - we present a computation that is typically the first example in QFT courses but, to our knowledge, does not appear in the literature: the scattering amplitudes of the $λϕ^4$ model in four-dimensional space-time, derived within the framework of causal perturbation theory. Our aim is to introduce this mathematically rigorous formalism in the most acce…

Fast and Robust Non-Adiabatic Holonomic Gates for Qutrit Systems
Jie Lu, Jie-Dong Huang, Yang Qian, Ying Yan
https://arxiv.org/abs/2510.05905 https://arxiv…

Fast and Robust Non-Adiabatic Holonomic Gates for Qutrit Systems
Motivated by shortcuts to adiabaticity, we develop a framework that combines inverse engineering with time-dependent perturbation theory to implement non-adiabatic holonomic quantum computing (NHQC) in qutrit systems under realistic error sources. We derive analytical conditions that suppress second-order Rabi errors through tailored pulse parameters and eliminate detuning errors via a compensation pulse. Our analysis reveals the cancellation from the compensation pulse, which ensures robust ga…

Perturbation theory, irrep truncations, and state preparation methods for quantum simulations of SU(3) lattice gauge theory
Praveen Balaji, Cianan Conefrey-Shinozaki, Patrick Draper, Jason K. Elhaderi, Drishti Gupta, Luis Hidalgo, Andrew Lytle
https://arxiv.org/abs/2509.25865

Perturbation theory, irrep truncations, and state preparation methods for quantum simulations of SU(3) lattice gauge theory
We study methods for efficient preparation of approximate ground states of $SU(3)$ lattice gauge theory on quantum hardware. Working in a variant of the electric basis, we introduce a refinement of the irrep truncation based on the energy density of site singlets, which provides a finer gradation of simulation complexity. Using strong-coupling perturbation theory as a guide, we develop simple ansatz circuits for ground state preparation and test them via classical simulation on small lattices, …

Perturbation theory of the compressible Navier-Stokes equations and its application
Kazuyuki Tsuda
https://arxiv.org/abs/2509.13012 https://arxiv.org/pdf/2…

Perturbation theory of the compressible Navier-Stokes equations and its application
In this article, a perturbation theory of the compressible Navier-Stokes equations in $\mathbb{R}^n$ $(n \geq 3)$ is studied to investigate decay estimate of solutions around a non-constant state. As a concrete problem, stability is considered for a perturbation system from a stationary solution $u_ω$ belonging to the weak $L^n$ space. Decay rates of the perturbation including $L^\infty$ norm are obtained which coincide with those of the heat kernel. The proof is based on deriving suitable res…

Covariant cosmography in the presence of local structures: comparing exact solutions and perturbation theory
Maharshi Sarma, Christian Marinoni, Basheer Kalbouneh, Chris Clarkson, Roy Maartens
https://arxiv.org/abs/2510.03517

Covariant cosmography in the presence of local structures: comparing exact solutions and perturbation theory
Recent observational evidence of axially symmetric anisotropies in the local cosmic expansion rate motivates an investigation of whether they can be accounted for within the Lemaître-Tolman-Bondi (LTB) framework with an off-center observer. Within this setting, we compute the exact relativistic luminosity distance via the Sachs equation and compare it with the approximate expression obtained from the covariant cosmographic approach (including Hubble, deceleration, jerk and curvature parameters…

Proper Theory of Magnon Orbital Angular Momentum
Junyu Tang, Ran Cheng
https://arxiv.org/abs/2510.03322 https://arxiv.org/pdf/2510.03322

Proper Theory of Magnon Orbital Angular Momentum
The orbital motion of chargeless bosons, unlike that of electrons, does not generate a magnetic moment and thus cannot directly interact with magnetic fields. Utilizing the Aharonov-Casher effect and perturbation theory, we formulate a proper theory for the magnon orbital angular momentum (OAM) at finite temperatures, explicitly identifying both self-rotation and topological contributions, analogous to the electronic counterpart but with correct bosonic statistics. Comparing with previous studi…

Consistency of spin effects between numerical relativity and perturbation theory for inspiraling comparable-mass black hole binaries
Tousif Islam, Gaurav Khanna, Scott E. Field
https://arxiv.org/abs/2510.00531

Consistency of spin effects between numerical relativity and perturbation theory for inspiraling comparable-mass black hole binaries
Numerical relativity (NR) provides the most accurate waveforms for comparable-mass binary black holes but becomes prohibitively expensive for increasingly asymmetric mass ratios. Point-particle black hole perturbation theory (ppBHPT), which expands the Einstein equations in the small-mass-ratio limit, offers a computationally efficient alternative but is expected to break down in the comparable-mass regime because it neglects nonlinear effects. Nonetheless, several recent studies have shown tha…

General Framework for Twisted Bilayer Photonic Crystal with Interlayer Coupling and Far-Field Response
Shupeng Xu, Dun Wang, Ritesh Agarwal
https://arxiv.org/abs/2509.23952 http…

General Framework for Twisted Bilayer Photonic Crystal with Interlayer Coupling and Far-Field Response
We develop a general theory for twisted bilayer photonic crystals that takes into account both far-field response and near-field coupling. The theory is based on the framework of a generalized Rayleigh-Schrödinger perturbation theory for non-Hermitian Hamiltonians. A universal form for interlayer coupling is derived, which relates the hopping strength to the Fourier transforms of the Wannier functions in the single layer photonic crystal. For low energy states at the K point in hexagonal latti…

Understanding Polaronic Transport in Anatase TiO2 Films by Combining Precise Synthesis and First-Principles Many-Body Theory
F. Liu, Z. Yang, Y. Luo, S. Guo, C. Zhang, S. Choo, X. Xu, X. Wang, K. A. Mkhoyan, M. Bernardi, B. Jalan
https://arxiv.org/abs/2510.07097

Understanding Polaronic Transport in Anatase TiO2 Films by Combining Precise Synthesis and First-Principles Many-Body Theory
In complex oxides, charge carriers often couple strongly with lattice vibrations to form polarons-entangled electron-phonon quasiparticles whose transport properties remain difficult to characterize. Experimental access to intrinsic polaronic transport requires ultraclean samples, while theoretical descriptions demand methods beyond low-order perturbation theory. Here, we combine the growth of high-quality oxygen-vacancy-doped anatase TiO2 films by hybrid molecular beam epitaxy (MBE) with a fir…

Accelerating cosmological simulations on GPUs: a portable approach using OpenMP
M. D. Lepinzan, G. Lacopo, D. Goz, G. Taffoni, P. Monaco, P. J. Elahi, U. Varetto, M. Cytowski
https://arxiv.org/abs/2510.02873

Accelerating cosmological simulations on GPUs: a portable approach using OpenMP
In this work we present the porting to Graphics Processing Units (GPUs, using OpenMP target directives) and optimization of a key module within the cosmological {\pinocchio} code, a Lagrangian Perturbation Theory (LPT)-based framework widely used for generating dark matter (DM) halo catalogs. Our optimization focuses on a specific segment of the code responsible for calculating the collapse time of each particle involved in the simulation. Due to the embarrassingly parallel nature of this compu…

Quantum chaos and pole skipping in two-dimensional conformal perturbation theory
Curtis T. Asplund, Sebastian Fischetti, Alexandra Miller, David M. Ramirez
https://arxiv.org/abs/2509.18540

Lie-transform derivation of oscillation-center quasilinear theory
Alain J. Brizard
https://arxiv.org/abs/2509.18365 https://arxiv.org/pdf/2509.18365…

Quantum Optics and Quantum Electrodynamics of Strong Field Processes
Marcelo F. Ciappina, Misha Yu. Ivanov, Maciej Lewenstein, Javier Rivera-Dean, Philipp Stammer, Paraskevas Tzallas
https://arxiv.org/abs/2509.26602

Quantum Optics and Quantum Electrodynamics of Strong Field Processes
In its beginnings, the physics of intense laser-matter interactions was the physics of multiphoton processes. The theory was reduced then to high-order perturbation theory, while treating matter and light in a quantum manner. With the advent of chirped pulse amplification developed by D. Strickland and G. Mourou, which enabled generation of ultra-intense, ultra-short, coherent laser pulses, the need for a quantum electrodynamics description of electromagnetic (EM) fields practically ceased to e…

Slepton pair production at next-to-leading power
Lasse Lorentz Braseth, Tore Klungland, Are Raklev
https://arxiv.org/abs/2510.07397 https://arxiv.org/pdf/2…

Slepton pair production at next-to-leading power
Near threshold, cross sections for the production of heavy particles are sensitive to large logarithmic terms, which must be resummed to all orders in perturbation theory. Current state-of-the art calculations for inclusive slepton pair production at hadron colliders has focused on higher-order logarithms in the leading power of the threshold variable. Here, we evaluate the next-to-leading power contribution in the threshold variable to leading logarithmic accuracy. We find that the next-to-lea…

Obtaining the Spectral Function of Moir\'e Graphene Heavy-Fermions Using Iterative Perturbation Theory
Dumitru C\u{a}lug\u{a}ru, Haoyu Hu, Lorenzo Crippa, Gautam Rai, Nicolas Regnault, Tim O. Wehling, Roser Valent\'i, Giorgio Sangiovanni, B. Andrei Bernevig
https://arxiv.org/abs/2509.18256 …

Obtaining the Spectral Function of Moiré Graphene Heavy-Fermions Using Iterative Perturbation Theory
The spectral functions of twisted bilayer graphene (TBG) in the absence of strain have recently been investigated in both the symmetric and symmetry-broken phases using dynamical mean-field theory (DMFT). The theoretically predicted Mott-Hubbard bands and gapless semimetallic state at half-filling have since been confirmed experimentally. Here, we develop several second-order perturbation theory approaches to the topological heavy-fermion (THF) model of TBG and twisted symmetric trilayer graphe…

Magnetic-Field-Induced Geometric Response of Mean-Field Projectors: Streda Formula and Orbital Magnetization
Jihang Zhu, Chunli Huang
https://arxiv.org/abs/2510.07001 https://…

Magnetic-Field-Induced Geometric Response of Mean-Field Projectors: Streda Formula and Orbital Magnetization
We study the magnetic-field response of interacting electron systems within mean-field theory using perturbation theory. We show that the linear response of the mean-field density-matrix to a weak magnetic field is purely geometric: it depends only on wavefunction derivatives, the Berry connections linking the occupied and unoccupied subspaces, and is independent of the interaction potential and the quasiparticle dispersion. This leads to compact, gauge-invariant projector expressions for both …

Large-order perturbation theory of linear eigenvalue problems
Stephen Jonathan Chapman
https://arxiv.org/abs/2509.14763 https://arxiv.org/pdf/2509.14763

Large-order perturbation theory of linear eigenvalue problems
We consider a class of linear eigenvalue problems depending on a small parameter epsilon in which the series expansion for the eigenvalue in powers of epsilon is divergent. We develop a new technique to determine the precise nature of this divergence. We illustrate the technique through its application to four examples: the anharmonic oscillator, a simplified model of equitorially-trapped Rossby waves, and two simplified models based on quasinormal modes of Reissner-Normstrom de Sitterblack hol…

Coherence and Quantum Stability of Relativistic Superfluid States
Lasha Berezhiani, Giordano Cintia, Giacomo Contri
https://arxiv.org/abs/2509.21667 https://

Coherence and Quantum Stability of Relativistic Superfluid States
We analyze the quantum dynamics of a relativistic homogeneous superfluid in a complex scalar field theory. Unlike zero-charge condensates, which undergo quantum evaporation due to internal number-changing processes, we show that $U(1)$ superfluids preserve their internal coherence indefinitely in this theory. In particular, although not Hamiltonian eigenstates, these configurations are stable in the full quantum theory to all orders in perturbation theory. This is demonstrated by explicitly con…

The role of integrability in Fermi-Pasta-Ulam-Tsingou-like models
Matteo Gallone
https://arxiv.org/abs/2509.17753 https://arxiv.org/pdf/2509.17753

The role of integrability in Fermi-Pasta-Ulam-Tsingou-like models
In these lecture notes, we present, contextualize, and discuss the phenomenon of metastability (or prethermalization) in the Fermi-Pasta-Ulam-Tsingou lattice and similar models from the viewpoint of perturbation theory. We provide an updated state-of-the-art description of this intermediate state in terms of the underlying integrable dynamics, in particular the Korteweg-de Vries and inviscid Burgers equations.

Decoding Shake-up Satellites in XPS through Large-Scale ab initio Simulations: Spectral Signatures of Ring Fusion in Porphyrins
Jannis Kockl\"auner, Majid Shaker, Maximilian Muth, Simon Steinbach, Christoph Oleszak, Ole Lytken, Hans-Peter Steinr\"uck, Dorothea Golze
https://arxiv.org/abs/2509.26057

Decoding Shake-up Satellites in XPS through Large-Scale ab initio Simulations: Spectral Signatures of Ring Fusion in Porphyrins
In X-ray photoelectron spectroscopy (XPS), shake-up satellites arise when core ionization is accompanied by simultaneous charge-neutral valence excitations. Although these satellites can contain detailed structural information, they are rarely interpreted due to the lack of accurate and scalable theoretical methods. Here, we develop and apply a many-body perturbation theory framework within the $GW$ plus cumulant ($GW+C$) approach that enables accurate predictions of shake-up satellites in larg…

Operator dependence and robustness of spacetime-localized response in a quantum critical spin chain
Daichi Imagawa, Keiju Murata, Daisuke Yamamoto
https://arxiv.org/abs/2510.04047

Operator dependence and robustness of spacetime-localized response in a quantum critical spin chain
We investigate the phenomenon of spacetime-localized response in a quantum critical spin system, with particular attention to how it depends on the spatial profile and operator content of the applied perturbation, as well as its robustness against increase of amplitude and temporal discretization. Motivated by recent theoretical proposals linking such response patterns to the anti-de Sitter/conformal field theory correspondence, we numerically analyze the real-time dynamics of the one-dimension…

Minimal surface doublings and electrostatics for Schr\"odinger operators
Adrian Chun-Pong Chu, Daniel Stern
https://arxiv.org/abs/2509.18630 https://a…

Minimal surface doublings and electrostatics for Schrödinger operators
Twenty years ago, N. Kapouleas introduced a singular perturbation construction known as "doubling", which produces sequences of high-genus minimal surfaces converging to a given minimal surface with multiplicity two. Doubling constructions have since been implemented successfully in several settings, with deep work of Kapouleas-McGrath reducing their existence theory to the problem of finding suitable families of ansatz data on the initial minimal surface. In this paper, we introduce a variat…

First-Order Axial Perturbation of the Reissner-Nordstr\"om Metric In a Possible Chern-Simons Gravity Background
Abhishek Rout, Brett Altschul
https://arxiv.org/abs/2510.01106

First-Order Axial Perturbation of the Reissner-Nordström Metric In a Possible Chern-Simons Gravity Background
We axial perturbations of Reissner-Nordström black holes within the framework of Chern-Simons modified gravity, a theory with includes parity violation. We derive the governing equations for the perturbations, focusing on the radial function $R(r)$ and its behavior across distinct regions: near the singularity ($r \rightarrow 0$), between the inner and outer Reissner-Nordström horizons ($r_-< r< r_+$), and in the asymptotic regime ($r \rightarrow \infty$). Using a combination of analytical an…

Probing Fractional Quantum Hall states in weakly interacting Fermi gases
Viktor Bekassy, Mikael Fogelstr\"om, Johannes Hofmann
https://arxiv.org/abs/2509.22606 https://

Probing Fractional Quantum Hall states in weakly interacting Fermi gases
Quantum gases are used to simulate the physics of the lowest Landau level (LLL) with neutral atoms, which in the simplest setup is achieved by rotating the gas at the confining harmonic trap frequency, a requirement that is difficult to achieve in practice. We point out that for weakly interacting Fermi gases, this rapid-rotation limit is not needed to access the LLL: As a direct consequence of first-order perturbation theory, many-body wave functions of states in the LLL remain unchanged at an…

A simple criterion for identifying slow-fast relaxation oscillations
Lucas MacQuarrie, Pei Yu
https://arxiv.org/abs/2509.13893 https://arxiv.org/pdf/2509.1…

A simple criterion for identifying slow-fast relaxation oscillations
Simple conditions have been developed in [Zhang, Wahl and Yu, SIAM Rev. 2014; Yu and Wang, Math. Biosci. Eng. 2019], which are used to identify the existence of slow-fast relaxation oscillations that appear in differential systems, where the geometric singular perturbation theory is not applicable. In this study, we present seven models which fail to satisfy these conditions, yet still show recurrence phenomena, which motivate us to generalize these conditions to establish new simple hypothetic…

A relativistic treatment of accretion disk torques on extreme mass ratio inspirals around spinning black holes
Abhishek Hegade K. R., Charles F. Gammie, Nicol\'as Yunes
https://arxiv.org/abs/2510.03564

A relativistic treatment of accretion disk torques on extreme mass ratio inspirals around spinning black holes
We model the motion of a small compact object on a nearly circular orbit around a spinning supermassive black hole, which is also interacting with a thin equatorial accretion-disk surrounding the latter, through tools from self-force and Hamiltonian perturbation theory. We provide an analytical and relativistically-accurate formalism to calculate the rate of energy and angular momentum exchanged at Lindblad resonances. We show that strong relativistic effects can potentially cause a reversal in…

The magnon spectra of g-type altermagnet bulk CrSb
Murat Tas
https://arxiv.org/abs/2510.03759 https://arxiv.org/pdf/2510.03759

The magnon spectra of g-type altermagnet bulk CrSb
We present a calculation of the magnon spectra and chiral lifetimes of altermagnons in bulk CrSb using the many-body perturbation theory. The spin-split band structure is evident in the magnon spectra. Altermagnons attain an energy of 275 meV at the K point of the Brillouin zone. Due to large spin splitting at a specific ${\bf q}$ point along the A - M direction, lifetime differences of chiral altermagnons reach approximately 20 fs.

$C^1$ perturbations of a continuum of critical points
Rafael Ortega, Antonio J. Urena
https://arxiv.org/abs/2509.10457 https://arxiv.org/pdf/2509.10457

$C^1$ perturbations of a continuum of critical points
Given a real valued function having a nondegenerate compact manifold of critical points, some of these points survive under small $C^2$ perturbations. This is a well-known result in critical point theory. In 1986 Weinstein obtained the analogous conclusions when the perturbation is only $C^2$ and the ambient space is a finite dimensional manifold. In this work we present a complete proof for $C^1$ perturbations in infinite dimensional Hilbert spaces.

Effective delocalization in the one-dimensional Anderson model with stealthy disorder
Carlo Vanoni, Boris L. Altshuler, Paul J. Steinhardt, Salvatore Torquato
https://arxiv.org/abs/2509.13502

Effective delocalization in the one-dimensional Anderson model with stealthy disorder
We study analytically and numerically the Anderson model in one dimension with "stealthy" disorder, defined as having a power spectrum that vanishes in a continuous band of wave numbers. Motivated by recent studies on the optical transparency properties of stealthy hyperuniform layered media, we compute the localization length via the perturbation theory expansion of the self-energy. We find that, for fixed energy and small but finite disorder strength, there exists for any finite length system…

Shadow Ringing of Black Holes from Photon Sphere Quasinormal Modes
Reggie C. Pantig
https://arxiv.org/abs/2509.24479 https://arxiv.org/pdf/2509.24479

Shadow Ringing of Black Holes from Photon Sphere Quasinormal Modes
The recent convergence of gravitational-wave (GW) observations and black hole imaging provides complementary probes of strong-gravity dynamics. While the black hole shadow is typically modeled as a static feature, a dynamically perturbed spacetime in its ringdown phase must induce temporal modulations in the shadow's apparent size and shape. We develop a theoretical framework within linear perturbation theory to investigate this shadow ringing effect for a Schwarzschild black hole. By modeling …

Well-posedness of the Boltzmann and Landau Equations in Critical Spaces
Ke Chen, Quoc-Hung Nguyen, Tong Yang
https://arxiv.org/abs/2509.14845 https://arxiv…

Well-posedness of the Boltzmann and Landau Equations in Critical Spaces
This paper investigates the well-posedness of the inhomogeneous Boltzmann and Landau equations in critical function spaces, a fundamental open problem in kinetic theory. We develop a new analytical framework to establish local well-posedness near a global Maxwellian for both equations, under the assumption that the initial perturbation is small in a critical norm. A major contribution lies in the introduction of a novel anisotropic norm adapted to the intrinsic scaling invariance of the equatio…

A relativistic treatment of accretion disk torques on extreme mass-ratio inspirals around non-spinning black holes
Abhishek Hegade K. R., Charles F. Gammie, Nicol\'as Yunes
https://arxiv.org/abs/2509.20457

A relativistic treatment of accretion disk torques on extreme mass-ratio inspirals around non-spinning black holes
We develop a relativistically accurate formalism to model the interaction between stellar mass compact objects embedded in thin accretion disks around a non-spinning supermassive black hole, using tools from self-force theory and Hamiltonian perturbation theory. We then apply this formalism to analyze the evolution of a compact object on a nearly circular and equatorial orbit interacting with a thin equatorial disk. We provide analytic and relativistically-accurate expressions for the rates of …

Baryons as linked vortices in QCD matter with isospin asymmetry
Yu Hamada, Muneto Nitta, Zebin Qiu
https://arxiv.org/abs/2509.20844 https://arxiv.org/pdf/2…

Baryons as linked vortices in QCD matter with isospin asymmetry
We investigate a baryonic structure in low-energy QCD via a model-independent way using the chiral perturbation theory at the leading order, in the presence of the baryon chemical potential $μ_B$, the isospin chemical potential $μ_I$, and the electromagnetic coupling. For such a scenario in the chiral limit, it has been known that the neutral pion winds like in the chiral soliton lattice, confined within an Abrikosov-Nielsen-Olesen (ANO) vortex of the charged pions. This structure undergoes a…

Fast and accurate Gaia-unWISE quasar mock catalogs from LPT and Eulerian bias
Francesco Sinigaglia, Francisco-Shu Kitaura, Mahlet Shiferaw, Ginevra Favole, Kate Storey-Fisher, Nestor Arsenov
https://arxiv.org/abs/2509.15890

Fast and accurate Gaia-unWISE quasar mock catalogs from LPT and Eulerian bias
We present $100$ full-sky quasar spectrophotometric mock catalogs with smooth redshift evolution from $z=0$ to $z\sim 4$, tailored to analyze the Gaia-unWISE Quasar Catalog (Quaia). In particular, we apply a novel hierarchical nonlocal nonlinear bias scheme (Hicobian) to dark matter fields generated through Augmented Lagrangian Perturbation Theory on the lightcone (WebON code), calibrating the free parameters of the bias model on Abacus quasar HOD mock catalogs tuned to reproduce DESI Early Dat…

Challenges and opportunities in proximity-driven exciton-spin engineering in van der Waals heterostructures
Mushir Thodika, Dimitar Pashov, Igor Zutic, Mark van Schilfgaarde, Swagata Acharya
https://arxiv.org/abs/2509.21956

Challenges and opportunities in proximity-driven exciton-spin engineering in van der Waals heterostructures
van der Waals heterostructures consisting of transition metal dichalcogenides (TMDs) and two-dimensional (2D) magnets offer a versatile platform to study the coexistence and transformation of different excitons. By focusing on TMD WSe$_2$ and 2D magnetic CrI$_3$, as a bilayer WSe$_2$/CrI$_3$ and a trilayer CrI$_3$/WSe$_2$/CrI$_3$, we provide their description using a parameter-free, high-fidelity many-body perturbation theory. This ab initio approach allows us to elucidate the character of magn…

Post-collapse Lagrangian perturbation theory in three dimensions
Shohei Saga, St\'ephane Colombi, Atsushi Taruya, Cornelius Rampf, Abineet Parichha
https://arxiv.org/abs/2509.18971

Discovering the $D_0^\ast(2100)$ in $B$ semileptonic decays
M. -L. Du, F. -K. Guo, C. Hanhart, F. Herren, B. Kubis, R. van Tonder
https://arxiv.org/abs/2509.12133 https://

Discovering the $D_0^\ast(2100)$ in $B$ semileptonic decays
The mass and width of the lightest scalar open-charm state listed in the Review of Particle Physics, the $D_0^\ast(2300)$, are in puzzling tension with predictions from unitarized chiral perturbation theory (UChPT) and lattice QCD, which favor a lighter state at around $2100$ MeV. However, to date, no direct experimental evidence for this lighter state exists. In an effort to facilitate a direct observation, we introduce angular asymmetries of $B\rightarrow D π\ell ν$ decays that allow for a …

Twist-modulated magnetic interactions in bilayer van der Waals materials
Tomas T. Osterholt, D. O. Oriekhov, Lumen Eek, Cristiane Morais Smith, Rembert A. Duine
https://arxiv.org/abs/2509.14122

Twist-modulated magnetic interactions in bilayer van der Waals materials
The ability to control magnetic interactions at the nanoscale is crucial for the development of next-generation spintronic devices and functional magnetic materials. In this work, we investigate theoretically, by means of many-body perturbation theory, how interlayer twisting modulates magnetic interactions in bilayer van der Waals systems composed of two ferromagnetic layers. We demonstrate that the relative strengths of the interlayer Heisenberg exchange interaction, the Dzyaloshinskii-Moriya…

Valley-Selective Linear Dichroism and Excitonic Effects in Lieb-Lattice Altermagnets
Haonan Wang, Xilong Xu, Du Li, Li Yang
https://arxiv.org/abs/2509.13551 https://

Valley-Selective Linear Dichroism and Excitonic Effects in Lieb-Lattice Altermagnets
Altermagnets have recently been recognized as a distinct class of magnetic materials characterized by alternative spin-split electronic structures without net magnetization. Despite intensive studies on their single-particle spintronic and valleytronic properties, many-electron interactions and optical responses of altermagnets remain less explored. In this work, we employ many-body perturbation theory to investigate excited states and their strain tunability. Using monolayer Mn2WS4 as a repres…