Nuclear Theory
Constructing Effective Interactions via Projection-Based Inversion
Hang Yu, Serdar Elhatisari, Sebastian König et al. (+3 more)
We present a numerical prescription for extracting continuum scattering information from discrete spectra by constraining effective interactions inspired by effective field theory (EFT). Using a Multiparameter
Eigenvalue Problem (MEP) emulator, we map energies to a sum of contact potentials by recasting the inverse problem as a linear
eigenvalue equation. Because our method determines the effective interaction rather than the scattering amplitude, it can handle non-perturbative Coulomb interactions and different types of truncated
Hilbert spaces without analytic quantization conditions. It therefore allows standard bound-state codes to be used for scattering calculations without modification. We validate this prescription across multiple ab initio frameworks using
neutron-alpha scattering, alpha-alpha scattering with full Coulomb, and a prediction of
proton-$^{14}$O resonances.
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All authors Hang Yu, Serdar Elhatisari, Sebastian König, Dean Lee, Yuan-Zhuo Ma, Takayuki Miyagi
High Energy Physics (Theory)
Logarithmic Soft Photon Theorem and Waveform Tails in Higher Dimensions
Biswajit Sahoo
We derive the leading logarithmic soft-
photon theorem in $d>4$ spacetime dimensions and its classical radiative counterpart. A direct one-loop analysis in massive scalar
quantum electrodynamics (QED) yields a factorizing soft term of order $\omega^{d-4}\ln\omega$, although the charged-particle S-
matrix is infrared finite. The logarithm is generated by the scale-invariant loop-momentum region $\omega\ll|\ell|\ll\Lambda$, where $\Lambda$ denotes a characteristic hard-particle energy scale. At leading radiative order, the corresponding logarithmic contribution to the classical electromagnetic waveform arises from the long-range acceleration of the asymptotic charged particles. In even $d\geq6$, the straight-line waveform at this radiative order is distributionally supported in retarded time within an interval whose width is set by the characteristic size of the hard-scattering region, whereas the logarithmic acceleration term produces universal early- and late-time radiative tails proportional to $|u|^{-(3d-10)/2}$. In odd $d\geq5$, straight-line motion already gives a late-time tail at the same radiative order proportional to $u^{-(d-4)/2}$. The acceleration correction adds universal late- and early-time terms proportional, respectively, to $\ln u/u^{(3d-10)/2}$ and $|u|^{-(3d-10)/2}$. A comparison of Feynman and retarded boundary conditions separates the classically radiative contribution from the intrinsically
quantum part of the logarithmic soft factor.
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High Energy Physics (Phenomenology)
Two-loop QCD amplitudes for $t\bar{t}W$ production at the LHC in the leading-colour approximation
Matteo Becchetti, Dhimiter Canko, Xiang Chen et al. (+7 more)
We present a numerical computation of the two-loop QCD scattering amplitudes for the production of a top-antitop
quark pair in association with a $W$
boson ($t\bar{t}W$) at the LHC in the generalised leading-colour approximation, retaining the exact dependence on the top-
quark and $W$-
boson masses. Rather than pursuing a fully analytic calculation, we employ a hybrid framework that combines numerical evaluation with strong algebraic and analytic control, allowing ultraviolet and infrared singularities as well as large intermediate cancellations to be treated exactly. This is achieved by expressing the finite remainder in terms of a set of special functions with rational coefficients. The special functions are evaluated numerically by solving differential equations through power-series expansions, while the values of the rational coefficients are reconstructed, point by point, from finite-field evaluations. The calculation is performed in the 't Hooft-Veltman scheme and validated against an independent implementation in conventional dimensional regularisation employing a substantially different computational strategy. We finally provide the colour- and polarisation-summed hard functions evaluated on the phase-space grid used in a previous computation of the next-to-next-to-leading-order QCD corrections to the $t\bar{t}W$ cross section.
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All authors Matteo Becchetti, Dhimiter Canko, Xiang Chen, Vsevolod Chestnov, Maximilian Delto, Sara Ditsch, Tiziano Peraro, Mattia Pozzoli, Chiara Savoini, Simone Zoia
Cosmology and Nongalactic Astrophysics
Integrated cosmological memory: A dark-siren method to probe dark energy
Indranil Chakraborty, Sayantan Ghosh, Susmita Jana et al. (+2 more)
Gravitational-wave (GW) cosmology is currently bottlenecked by the scarcity of electromagnetic counterparts for bright sirens and the systematic uncertainties of
galaxy catalogs for dark sirens. We propose a purely gravitational resolution using the Integrated Cosmological
Memory (ICM)-the cumulative GW strain encoded in the spacetime geometry of an expanding Universe. While the GW transient emitted by the source provides the luminosity distance, the ICM accumulates a mathematically distinct integral of the
cosmic expansion history. We demonstrate that extracting both observables from a single binary merger completely breaks the distance-
redshift degeneracy within the gravitational sector. This establishes a novel, catalog-free dark siren framework for third-generation GW detector networks. Crucially, the resulting constraints on late-time dark energy are only weakly sensitive to the local expansion rate, providing a robust cosmological probe that can potentially mitigate the impact of the H0 tension.
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All authors Indranil Chakraborty, Sayantan Ghosh, Susmita Jana, Archana Pai, S. Shankaranarayanan
Quantum Physics
Preserving Symmetry: Spontaneous Symmetry Breaking through Decoherence
Sam Kuypers
Solids appear to have localised centres of mass, yet many-body
quantum theory describes them using translationally symmetric models that preclude localisation. Conventionally, this is resolved through spontaneous
symmetry breaking by introducing an interaction with a semiclassical environment that breaks the
symmetry. In the thermodynamic limit, the interaction can be removed while leaving the state localised. This, however, raises the question of how localisation arises outside the thermodynamic limit, i.e., in finite
quantum systems (Wallace, 2018). Here, we show that, by quantising the environment, the localisation of finite systems occurs within decoherent branches, while the state vector of the composite system remains translationally symmetric. Our approach is analogous to the Page-Wootters construction (Page & Wootters, 1983) and
quantum reference frames; moreover, we recover the semiclassical description as a limiting case while predicting experimentally distinguishable corrections away from this limit.
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High Energy Astrophysical Phenomena
Thermal evolution of neo-neutron stars. II. Temperature-dependent crusts
Sagnik Chatterjee, Mikhail V. Beznogov, Dany Page et al. (+1 more)
The neo-
neutron star phase is an intermediate stage in the
evolution from a hot,
lepton-rich compact object, which is formed in the aftermath of a core-collapse
supernova or an
accretion-induced collapse of a white
dwarf, to a cold deleptonized
neutron star (NS). Alternatively, this phase can occur after a binary NS merger if the final compact object does not collapse immediately into a black hole. Radial temperature profiles provided by numerical simulations of proto-NS
evolution suggest that the composition and mechanical structure of the
star's core at the beginning of the neo-NS phase are approximately identical to those of a cold NS. In contrast, the composition and mechanical structure of the outer layers (i.e., the crust) are expected to change as the
star cools. The thermal
evolution of neo-NSs with temperature-dependent (inner) envelopes was considered by Beznogov et al. (2020). Here, we investigated what happens if the equation of state (EoS) of the entire crust, including its composition, depends on temperature. We analyzed the thermal, mechanical, and chemical
evolution of neo-NSs by further developing and employing neo-NSCool, our NS thermal
evolution code. First, we show that thermally dripped
neutrons slightly slow down the cooling during the early thermal relaxation stage. Then, we demonstrate that the EoSs featuring exotic light species in the deepest layers of the crust result in significantly slower cooling in the
photon-cooling era compared to the EoSs that favor massive
nuclei. The crust's composition also impacts the crystallization process as well as the contraction of the crust during cooling. The EoSs with light
nuclei cause the innermost layers to remain
liquid for a longer time than the EoSs with heavy
nuclei.
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All authors Sagnik Chatterjee, Mikhail V. Beznogov, Dany Page, Adriana R. Raduta
Disordered Systems and Neural Networks
A Spectral Route to Directed-Polymer Glasses
Sen Mu, Abbas Ali Saberi and Mehran Kardar
A finite density of mutually avoiding directed
polymers in a quenched random medium is a minimal model of glassy line matter. The dilute theory, solved by replica Bethe ansatz, predicts an interaction free energy proportional to $\rho^2$ and disorder cumulants with distinct power-law dependences on the density $\rho$, but direct numerical tests have been hindered by the combinatorially large many-
polymer transfer
matrix. We recast the problem as filling logarithmic
eigenvalues of a single-
polymer transfer-
matrix product, obtaining the quenched free energy, its cumulants, and a disorder-induced linear spectral edge consistent with the replica prediction.
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Solar and Stellar Astrophysics
Statistical Study of Solar Prominence Plumes Based on NVST H$\alpha$ Observations
Yangrui Chen, Yijun Hou, Jincheng Wang et al. (+9 more)
Plumes are one of the most representative dynamic features observed in prominences and play a key role in mass and
magnetic transport within them. However, their physical nature and triggering processes remain actively debated. Based on limb H$\alpha$ observations from the New
Vacuum Solar Telescope (NVST) during 2013–2025, we statistically investigated 34 plumes with clear and complete evolutions by developing an automated image-processing pipeline. It is revealed that plume lifetimes mainly range from 300 s to 700 s, with vertical displacements between 3–7 Mm. The mean widths and velocities are concentrated in the range of 0.5–1.5 Mm and 10–20 km s$^{-1}$, respectively. Besides wide distribution ranges, plume parameters exhibit irregular
evolution fluctuations, indicating that the formation and
evolution of various plumes may exhibit different physical patterns. Correlation analysis among the parameters further reveals that: (1) Positive correlations were found among lifetime, vertical displacement, and mean width, indicating an intrinsic coupling between the temporal and spatial scales of plumes. (2) Trajectory
curvature is negatively correlated with lifetime, vertical displacement, and velocity. Accelerating and width-contracting plumes typically have lower
curvature, suggesting that
curvature may reflect environmental influences and the stability of plumes. (3) Plumes with higher initial velocities were more likely to be accompanied by precursor brightening, suggesting that these plumes may be triggered by
magnetic reconnection. Furthermore, we infer that some plumes in non-bubble regions may be inherently driven by mini-filament eruptions. These results establish a statistical framework for prominence plumes and reveal diversity in their dynamical
evolution and triggering mechanisms.
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All authors Yangrui Chen, Yijun Hou, Jincheng Wang, Ting Li, Shuo Yang, Yilin Guo, Junyi Zhang, Haitang Li, Feiyang Sha, Qing Zhou, Yu Liu, Xiaoli Yan
Cosmology and Nongalactic Astrophysics
How Dilatation Invariance Suppresses Loop Corrections to Curvature Perturbations on CMB Scales
Danilo Artigas, Shi Pi, Takahiro Tanaka et al. (+1 more)
Departures from standard slow-roll (SR) inflation have attracted increasing interest in recent years. In particular, scenarios that strongly enhance the power spectrum of the
curvature perturbation are often proposed as a mechanism for producing
primordial black holes, which could account for part or the totality of dark matter. An ongoing debate in these models is whether non-linear interactions of cosmological perturbations on small scales, namely loop corrections, can become sufficiently large to backreact on CMB scales. In this work, we adopt a non-linear framework, dropping spatial-gradient terms, to study loop corrections at super-Hubble scales. Our focus is to clarify the role of spatial-diffeomorphism invariance, especially dilatation invariance, which is the
symmetry under overall rescaling of spatial coordinates, in demonstrating the suppression of loop corrections to the CMB power spectrum. This analysis is valid for any inflaton potential, both with smooth and sharp transitions, and at any loop order, as long as the CMB scales cross the horizon during an SR phase. We compare this result with the different explanations proposed in the literature using various gauge choices, and show our analysis is consistent both in the comoving and in the spatially-flat gauges. In particular, we show that in the spatially-flat gauge, the cubic interaction contains a term that diverges in the sharp transition limit. However, this contribution is exactly cancelled by the quartic interaction.
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All authors Danilo Artigas, Shi Pi, Takahiro Tanaka, Yuko Urakawa
Soft Condensed Matter
Synthetic paracrine signaling of colloids drives self-assembly limit cycles
Tim E. Veenstra, René van Roij, Pepijn G. Moerman et al. (+1 more)
Developing synthetic materials that exhibit life-like behavior, such as internally driven cycles, remains a central challenge in active matter. Here, we introduce a minimal colloidal model of chemical signaling in which particles produce diffusing signaling molecules that selectively promote or inhibit attractive interactions among neighboring particles. This bio-inspired, paracrine-like signaling mechanism generates context- and history-dependent many-body interactions that break time-reversal
symmetry and drive the system far from
equilibrium, leading to the spontaneous emergence of autonomous, internally sustained limit cycles in the composition of particle clusters. Using computer simulations, we map the resulting nonequilibrium phase behavior and identify distinct dynamical regimes controlled by the rates of signal production and degradation, together with the
diffusion range of the signaling molecules. Among these, we find a robust oscillatory state in which particle clusters autonomously assemble in a cyclic fashion, driven entirely by internal feedback loops. Our results establish paracrine-signaling colloids as a minimal, physically realizable platform for programmable nonequilibrium materials with life-like functionality and provide a general route toward synthetic active matter with self-regulated collective dynamics.
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All authors Tim E. Veenstra, René van Roij, Pepijn G. Moerman, Marjolein Dijkstra
High Energy Physics (Theory)
Cluster Algebras, Cube Roots, and Energy Correlators in $\mathcal{N}=4$ SYM
Dani Kaufman, Marcus Spradlin, Anastasia Volovich et al. (+1 more)
We provide a cluster algebraic construction of the cube root symbol letters that appear at leading order in the near-collinear expansion of the four-point energy correlator in $\mathcal{N}=4$ SYM theory.
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All authors Dani Kaufman, Marcus Spradlin, Anastasia Volovich, Kai Yan
Strongly Correlated Electrons
Cavity control of quantum phase transitions in a two-dimensional Kondo lattice
Jun Mochida, Atac Imamoglu and Yuto Ashida
Cavity
quantum electrodynamics offers a route to control
quantum phases by using
vacuum fluctuations of confined electromagnetic fields. In particular, planar cavities based on polar van der Waals materials can generate strongly confined modes and are promising for controlling two-dimensional correlated materials. Recently, moiré materials have become central platforms for studying two-dimensional heavy-
fermion systems and their
quantum phase transitions. Kondo
lattices provide a prototypical model for studying
quantum phase boundaries, driven by competition between Kondo screening and the ordering of local
magnetic moments. We show that a cavity-induced interaction can shift the
quantum phase transitions between a heavy-
fermion phase and an
antiferromagnetic phase in a two-dimensional Kondo
lattice through a momentum-dependent self-energy of the conduction bands. For the longitudinal projected field motivated by h-BN
hyperbolic phonon polaritons, the self-energy favors Kondo hybridization and expands the heavy-
fermion region. Transverse and circular in-plane model structures give distinct effects, with the transverse case relatively favoring the magnetically ordered phase and the circular case lying between the longitudinal and transverse cases. These results indicate that electromagnetic
vacuum fluctuations can effectively modify the control parameters of strongly correlated two-dimensional Kondo materials.
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Quantum Physics
Entanglement Distillation of some Rank-Five Symmetric NPT States in Two-Qutrit Systems
Yuwei Lei, Zihua Song, Lin Chen et al. (+1 more)
Entanglement distillation is a fundamental task in
quantum information processing. In this work, we investigate the distillability properties of a class of two-qutrit symmetric NPT states of rank five. We resolve the 1-distillability problem for this class by proving that the previously open interval of the
eigenvalue parameter is 1-undistillable. For the 2-distillability, we uncover a structural obstruction showing that no Schmidt-rank-two vector has a negative expectation in the relevant subspace. We also perform numerical investigations to explore the 2-distillability beyond this obstruction.
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All authors Yuwei Lei, Zihua Song, Lin Chen, Mingju Liu
High Energy Physics (Theory)
Gabriel Cuomo, Simone Giombi and Luigi Tizzano
The lightlike Wilson line cusp underlies the Sudakov double logarithm and is a central ingredient in gauge-theory factorization. We ask what replaces this behavior for general conformal line defects in Lorentzian signature. We argue that, when the defects admit local endpoint operators, the cusp anomalous dimension has a finite large-boost limit fixed by the scaling dimensions of the corresponding defect-creation operators. We further analyze the distinct analytic continuations of the cusp, elucidate their physical interpretations, and derive a positivity condition on the Lorentzian cusp anomalous dimension. We test these predictions in several perturbative examples, including pinning-field defects and
spin impurities, and discuss their possible implications for gauge theories.
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Quantum Physics
Inverse Design of Quantum Control Sequences with Fourier Neural Operators
Anastasia Pipi, Valentin Duruisseaux, Emily Been et al. (+4 more)
Quantum optimal control is a key tool for steering
quantum dynamics, but its computational cost grows rapidly with the
Hilbert space dimension. Here, we introduce a
Fourier Neural Operator (FNO)-based framework for learning high dimensional molecular
quantum dynamics and accelerating the inverse design of control protocols. Given an initial molecular population distribution,
laser frequency, and polarization, the FNO predicts molecular-motional population dynamics up to $10^7$ times faster than GPU-accelerated numerical propagation with CUDA-Q Dynamics. Using this fast and differentiable surrogate, we develop the FNO
stochastic pulse-measurement planner (FNO-SPMP), which constructs pulse sequences to purify an initially mixed Boltzmann distribution. We demonstrate the protocol in an 888-dimensional subspace of the hydronium molecule at 20 K, achieving a target-state population of 0.98 with a sequence success rate of up to 86.2%. In a shared discrete control space, FNO-SPMP achieves nearly twice the success rate of a reinforcement-learning baseline while using roughly half as many
quantum control pulses and reducing pulse-sequence generation time from approximately 10 hours to 10-20 minutes. These results show that operator-learning surrogates can enable inverse design in
quantum systems whose
Hilbert spaces are too large for conventional direct optimization.
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All authors Anastasia Pipi, Valentin Duruisseaux, Emily Been, Xuecheng Tao, Taylor L. Patti, Anima Anandkumar, Prineha Narang
Quantum Physics
Fidelity-Based Robustness Margins for Finite-Time Quantum Control
S. P. O'Neil, F. C. Langbein, C. A. Weidner et al. (+2 more)
We develop a structure-specific fidelity-threshold robustness margin for finite-dimensional closed
quantum systems under piecewise-constant coherent control. A scalar physical parameter may perturb the drift, a control
Hamiltonian, or another declared
Hamiltonian component across the control horizon. A differential sensitivity bound for trace-amplitude gate fidelity yields a threshold-dependent Lipschitz constant on the connected safe parameter component and hence a certified finite perturbation radius. Recentering this certificate produces an iterative one-dimensional method that takes certified safe steps toward the first fidelity-threshold boundary in either parameter direction. A three-
qubit gate-control example shows that these finite margins vary by up to a factor of three across controllers of comparable nominal fidelity and contain structure-dependent information not captured by nominal differential sensitivity alone.
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All authors S. P. O'Neil, F. C. Langbein, C. A. Weidner, E. A. Jonckheere, S. Schirmer
General Relativity and Quantum Cosmology
Gravitational Enstrophy: Local Geometric Origin and Energy-Cascade Constraints
Luis Lehner
Two-dimensional incompressible fluids conserve energy and enstrophy in the inviscid limit. Fjørtoft's argument uses this pair to constrain nonlinear energy transfer. We examine the corresponding question in General Relativity using the
magnetic Weyl functional $\mathcal Z=\int B_{ab}B^{ab}\sqrt{\gamma}\,d^3x$. Its transverse radiativ e part carries an additional frequency-squared weight relative to gravitational-wave energy: $\delta\mathcal Z_k\simeq\omega_k^2W_k$ in the radiation zone, with $W=8\pi G E_{\rm GW}$. We derive its balance law from the Bianchi identities, obtaining the algebraic cancellations, bulk sources and boundary fluxes. Conservation of positive e nergy and
curvature norm through nonlinear transfer gives a Fjørtoft constraint when their weights are ordered. Resonant weak-wave interactions generally change the c urvature norm; $2\leftrightarrow2$ dynamics instead conserves energy and wave action. We examine the competition between transfer and linear losses in Kerr and AdS backg rounds, where long-lived or confined modes provide time for nonlinear
evolution. In the hydrodynamic regime of AdS$_4$, a fluid-weighted
magnetic Weyl functional inherit s fluid enstrophy conservation in the inviscid limit. We compute its proportionality coefficient to boundary enstrophy in closed form at leading gradient order, giving a bulk diagnostic for
holographic turbulence.
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Astrophysics of Galaxies
Circumgalactic medium depletion drives satellite quenching in IllustrisTNG
Natan de Isídio, Paola Popesso, Sandro Tacchella et al. (+5 more)
Satellite
galaxies dominate the quenched population at low
stellar masses ($M_\star \lesssim 10^{10}~\rm M_\odot$), yet identifying which processes shut down their
star formation, their relative importance, and on what timescales, remains a central problem in
galaxy evolution. We use MaNGA-like mock
galaxies from IllustrisTNG to dissect different satellite quenching pathways, paying special
attention to the role of the circumgalactic medium (CGM) during quenching phase. We reconstruct the baryonic, dark matter, structural, and chemical histories of $\sim$7 300
galaxies (2 800 satellites), using time since infall as the physical axis along which quenching unfolds. Satellites retain rotation-supported
stellar kinematics throughout quenching, with disturbed velocity fields confined to systems with $M_\star \lesssim 10^{10.5}~\rm M_\odot$. For the first time, we present the coupled time
evolution of the depletion of both the hot and cool gas reservoirs after infall: satellites lose $\sim$90% of their hot CGM within $\sim$$4.2^{+0.6}_{-0.6}$ Gyr, increasing with residence time and independent of
stellar mass. The hot gas mass correlates strongly with SFR, establishing the CGM as the long-term fuel reservoir, unlike quenched centrals, which retain massive hot
halos likely maintained by AGN feedback. Present-day quenched satellites were accreted earlier than
star-forming ones (6.5$^{+0.3}_{-0.3}$ vs. 4.3$^{+0.3}_{-0.3}$ Gyr ago), forming
stars for at least $\sim$3 Gyr after infall before declining sharply, consistent with a delayed-then-rapid quenching scenario. Losing little
stellar mass, yet with their gas depleted and their dark matter and metal-poor
stellar outskirts tidally stripped, satellites emerge more compact and metal-rich than centrals at fixed mass. Our results suggest the gradual erosion of the hot CGM as the key link connecting infall to the slow shutdown of
star formation.
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All authors Natan de Isídio, Paola Popesso, Sandro Tacchella, Anna Pasquali, Ilaria Marini, Daudi Mazengo, Victoria Toptun, Sean McGee
Materials Science
Machine Learning-Guided Screening of Advantageous Solvents for Solid Polymer Electrolytes in Lithium Metal Batteries
Jiadong Shen, Junjie Chen, Xiaosa Xu et al. (+8 more)
Trace residual solvents in solid
polymer electrolytes (SPEs) significantly affect electrolyte and interface properties, where optimal selection enhances ionic conductivity and transference numbers. However, solvent complexity hinders general screening methods. We establish a universal criterion linking electronic (HOMO, LUMO) and macroscopic properties (dielectric constant, dipole moment, polarizability) via machine learning on an approximately 10,000-solvent
dataset from high-throughput DFT. Two solvents, N-methoxy-N-methyl-2,2,2-trifluoroacetamide and 2,2,2-trifluoro-N,N-dimethylacetamide, were identified. Experimental incorporation of trace N-methoxy-N-methyl-2,2,2-trifluoroacetamide into a poly(vinylidene fluoride-co-hexafluoropropylene)
matrix achieves a 4.5 V window, 5.5x10^-4 S cm^-1 conductivity (30 C), and 0.78 Li+ transference number. The
cell retains 86.7% capacity over 500 cycles (LiFePO4) and 98.7% after 200 cycles at 2C (LiNi0.9Co0.05Mn0.05O2), outperforming 2,2,2-trifluoro-N,N-dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone, and dimethyl sulfoxide. This synergy enables balanced ion transport, wide stability, and cycling durability, advancing safer, high-energy lithium metal batteries. Our integrated approach establishes a solvent screening paradigm for rational SPE design, accelerating next-generation battery development.
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All authors Jiadong Shen, Junjie Chen, Xiaosa Xu, Jin Li, Zhenyu Wang, Pengzhu Lin, Zixiao Guo, Yu Wang, Jing Sun, Baoling Huang, Tianshou Zhao
Mathematical Physics
On the dependence of the zero-free region of a partition function on the external field
Alexander Barvinok
Let $\{0, 1\}^n$ be the Boolean cube, endowed with the probability product measure, where ${\Bbb P}(1)=p$ and ${\Bbb P}(0)=q$ with $0 < p \leq q$ and $p+q=1$. For $i=1, \ldots, m$, let $\phi_i: \{0, 1\}^n \longrightarrow {\Bbb C}$ be $L_i$-Lipschitz functions in the Hamming metric, such that each $\phi_i$ depends on at most $r$ coordinates of $x \in \{0, 1\}^n$, where $rp \geq 12$. For $j=1, \ldots, n$, let $I_j $ be the set of indices $i$ such that $\phi_i$ depends on the $j$-th coordinate. We prove that $E \exp\left\{ \sum_{i=1}^m \phi_i \right\} \ne 0$ provided $\sum_{i \in I_j} L_i \leq {1 \over 10 \sqrt{rp}}$ for all $j$. This translates into a regime for $\pm 1$
spin systems, where a linear increase in the energy of multi-
spin interactions requires only a logarithmic increase of the external field to keep the partition function zero-free and the system away from the phase transition. As a corollary, we obtain efficient deterministic
algorithms to approximate the partition function in the zero-free region.
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Nuclear Theory
Finite-spectrum Lorentz integral transform calculation of the $^{4}$He photoabsorption cross section in the no-core shell model
P. Yin, H. T. Zhao, C. Y. Zhai et al. (+11 more)
We develop and validate a finite-spectrum implementation of the Lorentz integral transform (LIT) within the ab initio no-core shell model (NCSM) for calculating the photoabsorption cross section of $^4$He. A large set of $1^-$ eigenstates is explicitly calculated in the NCSM, and the LIT is constructed from their excitation energies and the corresponding $E1$ transition strengths. This finite-spectrum approach is complementary to conventional inhomogeneous-equation and Lanczos-based implementations of the LIT method for photoabsorption cross sections. Using the Daejeon16 interaction, we extract the photoabsorption cross section and examine its stability with respect to the model-space truncation, excitation-energy cutoff, and LIT parameters. The reliability of the finite-spectrum extraction is assessed by comparing the $E1$ polarizability and bremsstrahlung sum rule obtained from the discrete NCSM spectrum with the same quantities obtained by integrating the extracted cross section. The extracted cross section captures the principal features of the available $^4$He photonuclear data in the
giant-dipole-resonance region and is consistent, in the low-energy rise and main-peak region, with earlier
chiral-interaction NCSM-LIT results obtained from Lanczos-based evaluations, while the present calculation with the Daejeon16 interaction exhibits a more pronounced high-energy shoulder. The present work provides a controlled finite-spectrum NCSM-LIT route from explicitly calculated many-body eigenstates and transition strengths to photoabsorption cross sections.
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All authors P. Yin, H. T. Zhao, C. Y. Zhai, J. P. Vary, H. Li, J. M. Dong, H. J. Ong, X. Zhao, P. J. Fasano, A. M. Shirokov, J. Chen, D. Y. Tao, B. Zhou, C. Ji
Mathematical Physics · Cross-listed from math.DS
Pattern formation: reactivity is not necessary for chemotaxis–driven instabilities
Angela Monti
A classical result by Neubert, Caswell and Murray states that reactivity of a spatially homogeneous
equilibrium is a necessary condition for
diffusion-driven (Turing) instability. In this work, we investigate whether the same conclusion remains valid in the presence of chemotaxis. We consider a general reaction–
diffusion system coupled with a chemotactic flux and establish necessary conditions for asymptotic instability. We show that the classical requirement of reactivity can be relaxed when the chemotactic contribution is sufficiently strong. In particular, while reactivity remains necessary for Turing instability, it is not a necessary condition for chemotaxis-driven instability. From a computational viewpoint, we extend the
matrix-oriented formulation developed for reaction–
diffusion systems to the more general class of reaction–
diffusion–chemotaxis models. The chemotactic transport term is discretized in a form compatible with the
matrix-oriented approximation of the
diffusion operator, yielding an efficient numerical framework for the simulation of chemotaxis-driven pattern formation. A
geometric interpretation of the instability region is presented, highlighting the distinct roles played by
diffusion and chemotaxis. The theoretical and numerical developments are illustrated through two representative examples: a chemotaxis-extended Schnakenberg model, showing how chemotaxis modifies classical Turing patterns, and a predator–prey model, demonstrating that chemotaxis alone can induce pattern formation in the absence of both reactivity and
diffusion-driven instability. These results reveal a fundamental difference between
diffusion-driven and chemotaxis-driven mechanisms of spatial self-organization and provide new theoretical and computational insights into the role of non-symmetric transport processes in biological pattern formation.
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High Energy Astrophysical Phenomena
Revisiting the XMM-Newton Observations of the Galactic Microquasar SS 433: Implications for the Origin of the Ultrahigh-Energy Emission Detected by LHAASO
Chao-Nan Tong, Hong-Bin Tan and Ruo-Yu Liu
Recently, the Large High Altitude Air Shower Observatory (LHAASO) detected ultrahigh-energy (UHE;
photon energy E>100TeV) $\gamma$-ray emission toward SS 433, the microquasar embedded in the W50 nebula, making it a promising
Galactic PeVatron candidate. We reanalyze the archival XMM-Newton observations covering the bipolar jets and the thermal X-ray shell north of SS 433, and derive spatially resolved profiles of the nonthermal X-ray intensity and
photon index along both jets. The jet emission softens with distance from the source, implying a correspondingly evolving electron population. In particular, a hard electron component appears close to the jet bases, which can account for the UHE emission from SS 433 via inverse Compton radiation if the
magnetic field remains approximately uniform along the jets. The result, however, is highly sensitive to the
magnetic field profile. For flux-conserving configurations in which the field decreases as the jet expands, the stronger field required in the inner regions may reduce the number of X-ray-emitting electrons and suppress their inverse Compton emission. Furthermore, electron transport calculations show that injection only at the jet bases cannot reproduce the observed intensity and spectral
evolution, particularly the downstream re-brightening features, indicating additional particle injection and/or re-acceleration within the jets.
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Mesoscale and Nanoscale Physics
Machine Learning Bandgap Prediction of Nanoporous Graphenes with Water
Sneha Mittal, Alan E. Anaya Morales, Victor Rosendal et al. (+1 more)
The structure and dynamical behavior of water confined at or within nanostructures is a topic central to many fields, from biology to emerging electronics such as carbon nanostructures. Nanoporous
graphene (NPG) containing periodic nanoscale pores with specific
topologies has emerged as a promising material in carbon-based nanoelectronics; however, its interaction with ambient water remains poorly understood. Here, we combine density functional theory (DFT), ab initio molecular dynamics (AIMD), and interpretable machine learning (ML) to reveal how water controls
quantum transport in NPGs. Depending on the local hydration structure, the bandgap varies by more than a factor of two across NPG and nitrogen-doped hybrid (h-NPG) systems. To uncover the underlying mechanism, we develop Smooth Overlap of Atomic Positions (SOAP)-based black-box and physics-informed grey-box ML models. The Gaussian process regression model achieves near-DFT accuracy while enabling physical interpretation. Analysis identifies water dipole orientation, water-substrate distance, water center-of-geometry, and ribbon-resolved dipole moments as the dominant factors controlling bandgap modulation across NPG and h-NPG systems.
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All authors Sneha Mittal, Alan E. Anaya Morales, Victor Rosendal, Mads Brandbyge
High Energy Physics (Phenomenology)
Hierarchical Axiverse
Hai-Jun Li
String compactifications generically produce ${\cal O}(100)$ light
axion-like particles, yet low-energy mixing has not previously been exploited as a structuring constraint on their spectrum. We show that the requirement of well-defined QCD-induced mass mixing forces the
axion masses into a hierarchically spaced ordering, while
stochastic mixing organizes the decay constants into a hierarchically split distribution – two populations separated by an essentially empty window. Both patterns are insensitive to ultraviolet input and satisfy the relevant Swampland constraints within standard large-volume compactifications. We term this emergent pattern the hierarchical axiverse.
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Strongly Correlated Electrons
Microscopic Origin of Random Singlet Behavior in B-site Disordered Spin-1/2 Perovskite BaCu_1/3Nb_2/3O_3 Revealed by EXAFS and Thermodynamics
Sagar Mahapatra, Francesco De Angelis, Martin Etter et al. (+5 more)
We report a combined structural and thermodynamic study of the ABO$_3$-type disordered perovskite BaCu$_{1/3}$Nb$_{2/3}$O$_3$ (BCNO), whose B site is jointly occupied by Cu and Nb in the $1:2$ ratio. Using synchrotron powder x-ray diffraction (XRD) and x-ray absorption fine structure (XAFS) spectroscopy, we investigate the microscopic nature of Cu$^{2+}$/Nb$^{5+}$ disorder on the pseudo-cubic B-sublattice and its relation to the emergent random-singlet (RS) behavior evidenced at low temperatures. While XRD reveals no long-range Cu/Nb ordering and average site occupancy consistent with stoichiometry, XAFS reveals a peculiar local chemical order characterized by preferential heteroatomic Cu$:$Nb correlations. This local arrangement strongly suppresses direct Cu$:$Cu linkages, despite the Cu concentration being close to the percolation threshold of a cubic
lattice. The resulting exchange network explains the absence of
spin-glass freezing or long-range
magnetic order in the presence of substantial
antiferromagnetic interactions, as indicated by a Curie-Weiss temperature $\Theta_{CW}\approx -50$ K. Instead, the
magnetic susceptibility $\chi(T)$ and specific heat $c_p(T)$ exhibit power-law behavior and characteristic single-parameter $T/H$ scaling over broad temperature and
magnetic-field ranges, consistent with random-singlet phenomenology. Notably, at very low temperatures, the specific heat behavior transitions from $T^{1-\gamma}$ ($\gamma \approx 0.6$ from the $T/H$ scaling) in zero-field to a T-linear dependence under high field, indicating a crossover to a distinct low-energy regime whose microscopic origin remains to be established.
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All authors Sagar Mahapatra, Francesco De Angelis, Martin Etter, Edmund Welter, M. P. Saravanan, Rajeev Rawat, Carlo Meneghini, Surjeet Singh
Quantum Physics
DAMPyF: a Python implementation of the DAMPF method for the simulation of open-system dynamics
Nicola Lorenzoni, Susana F. Huelga and Martin B. Plenio
DAMPyF is an open-source Python implementation of the dissipation-assisted
matrix product factorization (DAMPF) method, a tensor-network-based approach for the numerically exact simulation of finite-dimensional
quantum systems coupled to bosonic environments. The method relies on a pseudomode representation of structured reservoirs and a
matrix-product-state representation of the density
matrix of the extended system, comprising the system and the pseudomodes. DAMPyF currently provides two workflows. First, it supports excitation energy-transfer dynamics within the single-system-excitation
manifold, in which a system excitation is propagated in time. Second, it provides a high-level workflow tailored to molecular spectroscopy, in which the system levels represent electronic states and optical coherences are propagated for the subsequent computation of linear spectra, including absorption and circular dichroism. This paper describes the physical model, the DAMPF
algorithm, the user-facing code structure, installation and execution, input and output formats, and minimal examples.
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Optics
Fully Distributed Fiber-Optic Sensing Enabled by Kalman Filtering
Juan M. Marin, Roman Ermakov, Florian Azendorf et al. (+3 more)
Signal fading creates points along the fiber where phase cannot be extracted, so they are conventionally discarded. Instead, we propose a Kalman-based solution for {\phi}-OTDR full-fiber monitoring. Experiments demonstrate phase and temperature estimation with approximately 15 times better spatial density than if removing these points.
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All authors Juan M. Marin, Roman Ermakov, Florian Azendorf, André Sandmann, Francesco Da Ros, Darko Zibar
Quantum Gases
Quantum Impurities as Probes of Finite-Temperature Fluctuations in Two-Dimensional Bose Gases
Victor Velasco, Gabriele Spada, Giovanni Midei et al. (+2 more)
Two-dimensional
quantum gases provide a distinctive setting in which enhanced thermal fluctuations, finite-size effects, and two-body bound-state formation are intrinsically intertwined. In this work, we study a single attractive
impurity immersed in a finite, weakly interacting two-dimensional Bose gas, where finite size stabilizes a nonzero condensate fraction by introducing an infrared momentum scale, thereby enabling a Bogoliubov description of the bath. Using a hybrid approach that combines finite-temperature many-body scattering theory with input from path-integral Monte Carlo, we analyze the
impurity quasiparticle energy across the condensate and normal regimes. The infrared scale generates a
phonon-activation temperature below which the
impurity energy remains nearly temperature independent. Once the resolved
phonon modes become thermally populated, their contribution competes with condensate depletion, producing a nonmonotonic temperature dependence of the polaron energy. These results suggest that attractive Bose polarons may serve as sensitive probes of finite-size thermal fluctuations,
phonon dressing, and bound-state physics in low-dimensional Bose gases.
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All authors Victor Velasco, Gabriele Spada, Giovanni Midei, Andrea Perali, Luis A. Peña Ardila
Nuclear Theory
Microscopic Statistical Calculation of Nuclear Level Density Based on Relativistic Density Functional Theory
Zi-Cheng Wang, Peng-Xiang Du, Jian Li et al. (+2 more)
A microscopic statistical model based on the relativistic density functional theory (RDFT) is developed to calculate the
nuclear level density (NLD). The approach employs self-consistent single-particle levels obtained from RDFT as input, incorporates pairing correlations within a finite-temperature Bardeen-Cooper-Schrieffer (BCS) theory, and accounts for rotational and vibrational collective enhancement effects. The
spin cut-off parameter is calculated from the single-particle levels, thereby naturally retaining the shell effects and the structural characteristics of different
nuclei. Using the shape-coexisting
nucleus 98Sr as a representative example, the microscopic origin of the deformation effect on the NLD is investigated. In addition, the calculated NLDs are systematically compared with those from various phenomenological and microscopic models, as well as with available experimental data. The results indicate that although certain discrepancies exist among different models, they exhibit consistent overall evolutionary trends. Meanwhile, the RDFT-based microscopic statistical approach is capable of providing a reasonable description of the experimental NLDs as well as the s- and p-wave
neutron resonance spacings.
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All authors Zi-Cheng Wang, Peng-Xiang Du, Jian Li, T. M. Shneidman, Shan-Gui Zhou