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Physics

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Friday 9 October

General Relativity and Quantum Cosmology

An exact rotating black hole solution in Palatini Kalb-Ramond gravity

A. A. Araújo Filho

We construct an exact stationary axisymmetric vacuum configuration in metric affine Kalb-Ramond gravity with zero cosmological constant. Independent variation of the metric, connection, and antisymmetric field yields the complete field equations and the algebraic relation between the physical and auxiliary geometries. A Kerr auxiliary metric and a closed corotating vacuum two form of fixed positive norm determine the physical metric. The tensor kernel contains the horizon generator, and the metrics, independent connection, and vacuum field share a smooth extension across the nonextremal physical Killing horizon and the rotation axes at finite radius for unequal deformation factors. We obtain an explicit sufficient domain for a causal exterior and an asymptotically locally flat end at fixed nonpolar angles. The physical Hamiltonian yields the timelike and null equations, equatorial effective potentials, circular orbit properties, radial stability, and perihelion advance. Numerical photon evolution determines the critical curve on an orthonormal observer screen. Its size, shape, and centroid depend on $\epsilon=\xi_2b^2/[2(1+\xi_1b^2)]$ at fixed normalized mass scale and spin, with Kerr recovered at $\epsilon=0$. Geometric observations probe this combination and retain an exact degeneracy between the curvature couplings. A static equatorial comparison with Mercury gives a conditional sensitivity of $2.30\times10^{-11}$ for $|2\epsilon|$ under the stated angular convention and mass setting.
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Mathematical Physics · Cross-listed from math.AP

Existence and uniqueness of bound states with prescribed number of nodes for nonlinear dispersive equations on spherically symmetric manifolds

Valentino Badalucco

Standing waves $e^{i\omega t}u(x)$ of nonlinear dispersive equations, such as the nonlinear Schrödinger and Klein–Gordon equations, have a profile $u$ that solves a nonlinear elliptic ODE of the form $\Delta u+f(u)=0$. We prove the existence of radial bound states with a prescribed number of nodal surfaces for this equation, on a large class of spherically symmetric manifolds and nonlinearities $f$. Under mild assumptions, we prove uniqueness of such bound states for the model nonlinearity $f(u)=|u|^{p-1}u-u$. Both existence and uniqueness results apply to some manifolds with a singularity at the origin.
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Quantum Physics · Cross-listed from cs.LG

QTestBench: A Test Framework for Evaluating LLM-Generated Quantum Code

Meriem Terki, Nouhaila Innan, Minghao Shao et al. (+3 more)

Large language models (LLMs) have shown strong results in classical code generation and are increasingly used to write the unit tests that safeguard that code. Whether they can do the same for quantum software is less clear, because quantum programs are probabilistic, depend on numerical tolerances, and are judged by domain-specific checkers, so a well-formed test can still disagree with the benchmark's verdict. Existing quantum benchmarks measure whether a model produces a correct solution, but not whether its tests can distinguish correct implementations from faulty ones. We introduce QTestBench, a framework that evaluates LLM-generated quantum test suites against independent benchmark checkers, never treating the tests themselves as ground truth. For each task, QTestBench prompts models to produce syntactic, semantic, and behavioral tests, injects candidate solutions at runtime, and compares each test verdict with the checker's label under three validation cohorts, each answering a distinct diagnostic question. We benchmark five LLMs on eight PennyLane QHack challenges and ten Qiskit HumanEval tasks. Generated suites almost always execute, but discrimination lags behind: the best generator reaches a test quality of 0.71 on QHack and 0.34 on Qiskit HumanEval, so executability alone overstates test quality. Oracle-verified synthetic mutants stabilize bug-detection estimates when natural faulty solutions are scarce, as on three of ten Qiskit tasks that yield none. QTestBench offers a reproducible, cross-framework benchmark for the trustworthiness of LLM-generated quantum tests.
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All authors Meriem Terki, Nouhaila Innan, Minghao Shao, Muhammad Kashif, Alberto Marchisio, Muhammad Shafique

Quantum Physics

Diversity-Aware Ensemble of Quantum-Classical Models via Combinatorial Fusion

Jingyan Xu, Yuanhong Wu, Samuel Yen-Chi Chen et al. (+3 more)

Variational quantum circuits (VQCs) are highly sensitive to circuit architecture, yet most quantum machine learning pipelines select a single best design and discard the remaining candidates. This paper addresses whether the structural diversity across quantum circuit search spaces can be used to produce stronger predictions through model fusion. We apply Combinatorial Fusion Analysis (CFA), a model fusion framework that selects and combines multiple scoring systems using rank-score function (RSF) and cognitive diversity (CD), to a pool of 29 architecturally diverse classical models and quantum circuits. Using a diversity-aware model selection method, we identify subsets of maximally diverse models and combine them with both score and rank combination. Experiments on four binary classification benchmarks covering different domains demonstrate that CFA-based hybrid classical-quantum fusion consistently outperform the best individual model on every dataset considered with improvements up to 6.03% in accuracy. When comparing with relevant literatures, the CFA framework further achieves superior performance across all four datasets.
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All authors Jingyan Xu, Yuanhong Wu, Samuel Yen-Chi Chen, Sean Patten, Christina Schweikert, D. Frank Hsu

Medical Physics · Cross-listed from math.OC

Warm-IP: A Path-Following ADMM Warm Start for Interior-Point Quadratic Programming

Babak Aslani, Mojtaba Tefagh, Gourav Jhanwar et al. (+1 more)

Interior-point (IP) methods are powerful second-order optimization algorithms but can make slow progress during early iterations. We propose Warm-IP, a hybrid framework that combines a path-following variant of the alternating direction method of multipliers (ADMM) with a primal–dual IP method. The ADMM phase generates a warm start that remains close to the central path, enabling the subsequent IP phase to rapidly refine the solution to high accuracy. We evaluate Warm-IP on a diverse collection of real-world and synthetic quadratic programming (QP) instances and compare it with leading commercial solvers (MOSEK and Gurobi) and open-source solvers (Clarabel, PIQP, and OSQP). We also curate and release a new benchmark of large-scale QPs from cancer radiotherapy treatment planning, built from real patient data and provided in canonical QP form, with instances containing hundreds of thousands of constraints. Warm-IP substantially outperforms existing solvers on large-scale problems. On the large-scale radiotherapy benchmark comprising 60 lung cancer cases, for example, Warm-IP solves an instance in 47 seconds on average with no failures, while the strongest competitors, MOSEK and Gurobi, average 55 seconds with failures on 23% of the cases and roughly 240 seconds with no failures, respectively. To support reproducibility and future benchmarking, we publicly release the implementation and benchmark data through a \href{https://github.com/Radiotherapy-Optimization/Warm-IP}{GitHub repository}. These results demonstrate that appropriately warm-started IP methods can combine the rapid initial progress of first-order methods with the high-accuracy convergence of second-order methods.
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All authors Babak Aslani, Mojtaba Tefagh, Gourav Jhanwar, Masoud Zarepisheh

Statistical Mechanics

Replica Transition at Measurement-Altered Ising Criticality

Kabir Khanna, Sara Murciano and Romain Vasseur

Performing measurements on gapless quantum ground states can give rise to new universal phenomena, whose origins remain poorly understood even for the paradigmatic Ising critical point. Replica methods offer a natural framework to study such post-measurement ensembles, with the replica limit $Q\to 1$ describing physical Born-averaged observables. Here we show that, for the monitored critical Ising chain, the replicated post-measurement ensemble of states itself undergoes a phase transition precisely at the physically relevant replica limit $Q \to 1$, preventing standard replica treatments. We use boundary conformal field theory (BCFT) methods to explain the underlying mechanism of this transition. Our methods yield a perturbative analytic calculation of the universal $O(1)$ constant in the Shannon entropy of the measurement record, previously known only numerically. We also apply our tools to study measurement-averaged spin correlators, providing a unified description of the universal properties of measurement outcomes and post-measurement states in the critical Ising chain.
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Fluid Dynamics

Particle dynamics in a microfluidic T-junction vortex flow: the role of history force

Matteo Chiatto, Luigi de Luca, Howard A. Stone et al. (+1 more)

The motion of inertial particles suspended in a carrier fluid, together with the dynamics of the underlying vortical structures, is investigated in a square microfluidic T-junction. The coherent structures forming near the branching strongly affect the particle distribution and may promote particle trapping around the T-region. Single-phase numerical simulations of the unperturbed base flow are combined with integration of the particle force balance equation, which, unlike most previous studies, includes the Basset-Boussinesq (BB) history force. The flow topology is analysed for $Re=500$ and $570$, while particle properties are varied through the Stokes number $St$ and the particle-to-fluid density ratio $\rho$. At $Re=500$ the base flow exhibits a steady vortex pair, whereas at $Re=570$ a Hopf bifurcation gives rise to a helical oscillation of the primary vortex pair characterized by periodic breathing. The BB history force has a non-negligible impact over the whole range of $(\rho, St)$ pairs investigated. It acts as an additional viscous force which, together with the drag of the relative motion, opposes the pressure-gradient force, widening particle spiral trajectories radially and elongating them axially. Its inclusion reduces the basin of attraction, indicating that memory effects promote particle displacement away from the vortex core and weaken trapping. At $Re=570$, spectral proper orthogonal decomposition characterizes the breathing of the primary vortex pair. Particles injected at a given location interact with the vortical structure at different phases of the cycle depending on the injection time, producing substantially different trajectories. This phase dependence is reflected in the shape and extent of the basin of attraction, quantified through the trapping probability over the inlet section and the probability density functions of the force components.
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All authors Matteo Chiatto, Luigi de Luca, Howard A. Stone, Francesco Grasso

Materials Science

Improved screening of doped ZrO$_2$ catalysts for CO$_2$ hydrogenation from graph-based machine learning

Karsten Walz Jensen, Mie Andersen and Raffaele Cheula

Dopants can tune the activity of zirconia-based CO$_2$ hydrogenation catalysts through changes in adsorbate and transition-state (TS) energetics. Computing these quantities with density functional theory (DFT) becomes expensive when several dopants, reaction intermediates, and TSs must be screened. Here, we further develop the graph-based machine learning method Wasserstein Weisfeiler-Lehman Gaussian Process Regression (WWL-GPR): we introduce additional electronic-structure and local-environment features relevant for oxide surfaces and use the resulting model to predict adsorption and TS energies on ZrO$_2$(101) surfaces doped with Al$^{3+}$, Cd$^{2+}$, Ga$^{3+}$, In$^{3+}$, and Zn$^{2+}$. Adsorbate-surface structures are represented as attributed graphs that combine bonds connectivity and features. We benchmark WWL-GPR against thermodynamic scaling relations (TSR) for reaction intermediates and Bronsted-Evans-Polanyi relations (BEP) for TSs, and then propagate the predicted energies to microkinetic CH$_3$OH-yield estimates. WWL-GPR consistently improves the prediction of reaction intermediate energetics relative to linear scaling approaches and provides TS estimates that are competitive with BEP-based models. These improvements become especially relevant when the predicted energetics are propagated through the reaction network. Microkinetic calculations show that WWL-GPR-derived energies give CH$_3$OH yields closer to DFT-derived yields than the linear-relation workflow. Degree-of-rate-control analysis links the activity errors to dopant-dependent rate-controlling steps, including HCOO* formation, H$_2$COOH* dissociation, and H$_3$CO* formation. These results support WWL-GPR as a data-efficient surrogate for connecting atomistic energetics with catalyst-screening observables on doped oxide surfaces.
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Lattice Field Theory

Evidence of Taste-Symmetry restoration for Kähler-Dirac fermions on Euclidean Dynamical Triangulations

Mingwei Dai, Walter Freeman, Mason Grieb et al. (+3 more)

We study the spectrum of two-particle bound states of Kähler-Dirac fermions coupled via gravity in Euclidean Dynamical Triangulations (EDT). We work in the quenched approximation, where the geometry is allowed to fluctuate, but there is no back-reaction from the matter on the geometry. The Kähler-Dirac action respects an exact $U(1)$ symmetry that is related to continuum chiral symmetry, and this $U(1)$ symmetry ensures that some of the bound-state masses vanish in the chiral limit of vanishing fermion bare mass. The bound-state masses that are not protected by the $U(1)$ symmetry do not vanish in the chiral limit, but the scale associated with the symmetry breaking does not appear to be a physical scale like the Planck mass or the curvature scale of the emergent de Sitter background. Rather, the mass scale associated with this non-degeneracy appears to be a positive power of the lattice spacing, decreasing as the continuum limit is approached. This suggests that Kähler-Dirac fermions in EDT can be interpreted as the gravity analog of staggered fermions in flat-space lattice field theories, with similar behavior.
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All authors Mingwei Dai, Walter Freeman, Mason Grieb, Jack Laiho, Marc Schiffer, Judah Unmuth-Yockey

Quantum Physics

Locality-Preparation Time Tradeoffs in Dissipative Quantum Systems

Philipp Westhoff, Sara Murciano and Mattia Moroder

Dissipative state preparation engineers quantum many-body states as steady states of an open-system dynamics. The spatial range of the required dissipation sets both the feasibility of analog implementations and the connectivity and control complexity of digital ones. Yet how this locality quantitatively constrains preparation times remains largely unknown. Here, we establish an exact locality-preparation time relation for quadratic fermionic systems and develop a construction that optimizes the locality of the dissipative dynamics while preserving the target state. Applied to the Kitaev chain, our framework reveals sharply different locality-preparation time tradeoffs in critical and gapped regimes. At criticality, suppressing the algebraic tails of the jump operators necessarily forces the preparation time to grow algebraically with system size. By contrast, both trivial and topological gapped phases admit exponentially localized dissipation with a finite preparation time in the thermodynamic limit. Our results identify when fast dissipative preparation is compatible with local control and when criticality imposes an unavoidable dynamical cost.
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Statistical Mechanics

Scalene Yang-Baxter triples realize all nearest-neighbour Hamiltonians with global additive symmetries

Pramod Padmanabhan, Somnath Maity, Akash Sinha et al. (+1 more)

We establish that bond Hamiltonian densities, up to local difference terms whose sum vanishes under periodic boundary conditions, lying in the commutant of bond operators, $w_j\pm w_{j+1}$, is a necessary and sufficient condition for a one-dimensional nearest-neighbour Hamiltonian to conserve a uniform or staggered sum of the one-site operators $w_j$. Starting from these local commutants, we show that every such Hamiltonian and its conserved charge can be obtained from monodromy matrices constructed using regular and non-regular members of scalene Yang-Baxter triples. The results hold on periodic chains of length $L\geq3$, with even length required in the staggered case. The results do not require translation invariance, and hence the interaction on each bond can be chosen independently from the full corresponding commutant. Our representation-independent construction applies in arbitrary finite local dimension and exhausts the Hamiltonians with either prescribed additive symmetry, without requiring ordinary Yang-Baxter integrability. We illustrate the construction with spin-$\tfrac12$ and spin-1 systems and discuss its relation to the double-commutant theorem. Classifying the one-site generators $w$ and their associated bond commutants provides a route to classifying such Hamiltonians with additive conserved charges.
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All authors Pramod Padmanabhan, Somnath Maity, Akash Sinha, Vladimir Korepin

Optics

PhySeqNet: physics-informed fluorescent foci detection for BARseq spatial transcriptomics

Neha Goswami, John Hover, Renae Galluccio et al. (+4 more)

BARseq enables spatially resolved gene-expression profiling across intact tissue, but its sensitivity depends on accurate detection and decoding of dense fluorescent rolonies. Existing spot-calling approaches can be conservative where signals overlap, while supervised deep learning is limited by the lack of reliable manual ground truth in real tissue images. Here we present PhySeqNet, a physics-informed deep learning framework for annotation-free fluorescent foci detection in BARseq. PhySeqNet trains U-Net detectors entirely on semi-synthetic images generated from an instrument-matched optical model combined with real sample-free experimental noise, and is integrated into pyBARseq, a modular Python pipeline for BARseq analysis. PhySeqNet achieved high detection performance on held-out simulated data across wavelength bands. On real tissue images, where ground truth is unavailable, we evaluated detections by forward-model reconstruction: PhySeqNet with conservative barcode-aware non-maxima suppression (NMSB) achieved higher reconstruction fidelity (NCC and MS-SSIM) than the BarDensr single-shot estimator, tuned classical spot detectors, and a pretrained deep-learning detector. In the analyzed brain section, PhySeqNet with NMSB yielded a median of 51 counts per cell versus 47 for BarDensr, with a similar number of genes detected per cell. The recovered transcripts produced spatial expression patterns qualitatively consistent with Allen MERFISH reference data and preserved cell-type composition after scANVI label transfer. These results show that physics-informed simulation can train practical, annotation-free detectors that improve BARseq sensitivity without disrupting downstream biological interpretation.
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All authors Neha Goswami, John Hover, Renae Galluccio, Yichen Wu, Huiqing Zhan, Xiaoyin Chen, Anthony M. Zador

General Relativity and Quantum Cosmology

Internal translation gauging and local gravitational energy in Weyl gauge theory

Michael Hobson, Will Barker and Anthony Lasenby

We investigate the local gravitational source and charges obtained by introducing translations as an internal Stückelberg redundancy in Weyl gauge theory. The internal-$T(4)$-invariant dressed coframe identifies the source of the translational potential with the existing coframe variational derivative, without introducing new dynamics. We derive an excitation/source equation and balance law whose structure is independent of the constitutive parameters of the parity-even quadratic torsion family. The gravitational self-current, defined relative to a specified gravitational/matter split and boundary representative, gives a density invariant under the internal gauge factors once its frame index is contracted with the coframe; this invariance neither establishes ordinary conservation nor identifies the density with the external translation Noether current. A surface charge follows by contraction with a covariantly constant internal direction, and we separately derive the three-sector Noether superpotential of generalized reducibility, with the asymptotic conditions for conservation of its flux. At the teleparallel equivalent of general relativity (TEGR) the excitation reduces to the teleparallel superpotential and the covariant coframe–connection pair gives the Schwarzschild ADM energy; flat cosmology and transverse-traceless waves give further checks. Away from TEGR, an exact solution of New General Relativity gives a charge whose fractional difference from the Kepler mass is half the deviation of the post-Newtonian spatial-curvature parameter from unity, at the adopted normalisation; independent Hamiltonian charge matching remains open. Finally, the integrable Hamiltonian charge is invariant under covariant Lagrangian boundary terms at fixed reference normalisation and presymplectic representative.
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Astrophysics of Galaxies

Insights from the stability of methanol maser flare properties I: G9.62+0.20E

S.P. van den Heever and D.J. van der Walt

The brightest 6.7 GHz methanol maser in the Galaxy is associated with the high-mass star-forming region (HMSFR) G009.62+0.20E. Additionally, this methanol maser shows periodic flaring observed at 6.7 and 12.2 GHz. Several models have been hypothesized to explain the periodicity, including periodic accretion, spiral shocks in the gaps of circumbinary disks, pulsating stars, dicke's superradiance, and a colliding wind binary (CWB) system. We analyzed the time series of the 1.22 km s-1 feature of the 6.7 GHz methanol maser spectrum and the 1.25 km s-1 feature of the 12.2 GHz methanol maser spectrum over the monitoring duration of roughly 20 years, to determine an updated period, analyze the stability and repeatability of the flares, the temporal behavior of the flare profile, and the duty cycle of the flare profile based on the updated period. From these results, it is argued for or against any of the mechanisms that have been proposed to explain the periodicity. Lomb-Scargle (LS) and phase dispersion minimization (PDM) methods were used to determine the methanol maser period at 6.7 and 12.2 GHz. Once the period has been determined, phase-folding or period-folding was used to analyze the flare shape, flare stability, and duty cycle of the flares. The periods of the 6.7 and 12.2 GHz methanol masers were determined to be ~ 243.0 +- 0.3 days. The flares are highly repeatable, stable, and show almost identical shapes, as well as their duty cycles. A replicated kernel density estimator (KDE) of the flare shape reproduces the time series very well over a time span of ~ 8000 days. After careful consideration of the proposed mechanisms for periodic methanol masers, we conclude that all but one, the CWB model, have been ruled out as a possible driver of this flare profile. It has also been established that the CWB model can qualitatively explain the flare profile of the periodic methanol masers.
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High Energy Astrophysical Phenomena

TeV Gamma-Ray Emission in the DA 495 Region from HAWC Observations of J1952+2924, J1954+2837, and J1958+2848

R. Alfaro, C. Alvarez, E. Anita-Rangel et al. (+82 more)

Previous observations of the DA 495 region, which contains the pulsar wind nebula (PWN) DA 495 and other very-high-energy (VHE; $>100~\textrm{GeV}$) gamma-ray emitters, showed inconsistent results across different VHE experiments, including differences in the measured flux of DA 495 and in the number of reported sources. Our new dedicated analysis using 3071 days of HAWC data resolves these discrepancies. We identify three extended sources, HAWC J1952+2924 (DA 495), HAWC J1954+2837, and HAWC J1958+2848, all with curved spectra, and find a hint of a fourth source. For DA 495, a multi-wavelength analysis, including our results, radio, X-ray, and other gamma-ray data, reveals that its extended emission is best described by leptonic interactions with an inferred magnetic field of $B\sim10~\mu\textrm{G}$ and that hadronic components are not required. On the other hand, we interpret the other two sources, which have no confirmed counterparts, as TeV halos associated with nearby pulsars, PSR J1954+2836 and PSR J1958+2846, respectively. These results reinforce the interpretation of DA 495 as a leptonic-dominated PWN and add two candidates to the growing population of TeV halos.
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All authors R. Alfaro, C. Alvarez, E. Anita-Rangel, M. Araya, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, P. Bangale, A. Bernal, T. Capistrán, A. Carramiñana, S. Casanova, U. Cotti, J. Cotzomi, S. Coutiño de León, E. De la Fuente, N. Di Lalla, R. Diaz Hernandez, M. A. DuVernois, J. C. Díaz-Vélez, C. Espinoza, N. Fraija, S. Fraija, A. Galván-Gámez, J. A. García-González, F. Garfias, N. Ghosh, A. Gonzalez Muñoz, M. M. González, J. A. González, J. A. Goodman, J. Gyeong, J. P. Harding, I. Herzog, D. Huang, F. Hueyotl-Zahuantitla, P. Hüntemeyer, A. Iriarte, S. Kaufmann, D. Kieda, K. Leavitt, W. H. Lee, H. León Vargas, A. L. Longinotti, G. Luis-Raya, K. Malone, O. Martinez, J. Martínez-Castro, J. A. Matthews, P. Miranda-Romagnoli, P. E. Mirón-Enriquez, J. A. Morales-Soto, E. Moreno, M. Mostafá, M. Najafi, L. Nellen, M. U. Nisa, R. Noriega-Papaqui, M. Osorio-Archila, E. Ponce, Y. Pérez Araujo, E. G. Pérez-Pérez, C. D. Rho, D. Rosa-González, M. Roth, A. Sandoval, J. Serna-Franco, M. Shin, A. J. Smith, Y. Son, R. W. Springer, O. Tibolla, I. Torres, R. Torres-Escobedo, L. Villaseñor, X. Wang, Z. Wang, I. J. Watson, H. Wu, S. Yu, S. Yun-Cárcamo, X. Zhang, H. Zhou, C. de León

Accelerator Physics

Physics of stabilization and dynamic control of CW magnetrons for superconducting accelerators

G. Kazakevich, R.P. Johnson, I. Gonin et al. (+2 more)

Powerful CW magnetrons were suggested for feeding RF cavities of superconducting accelerators because they provide higher efficiency and lower RF power cost than the traditionally used klystrons, IOTs, or solid-state amplifiers. RF amplifiers driven by a master oscillator serve as coherent RF sources. CW magnetrons are regenerative RF self-oscillators with a huge regenerative gain. This causes regenerative instability with notable noise when a magnetron operates as a self-oscillator, i.e., with the anode voltage above the threshold of self-excitation. An injection locking by a small signal was proposed for phase stabilization of magnetrons. In this case, CW magnetrons with injection-locked (coherent) oscillations generate a notable level of noise. This may preclude the use of CW magnetrons in this mode in superconducting RF (SRF) accelerators. This work discusses our analytical results, PIC simulations, and previously obtained analytical and experimental data regarding the operation and control of CW magnetrons. These results led to the development of methods which are most suitable for SRF accelerators.
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All authors G. Kazakevich, R.P. Johnson, I. Gonin, V. Yakovlev, Ya. Derbenev

Earth and Planetary Astrophysics

The origin of the large heavy element contents of warm Jupiters

Bertram Bitsch

Planet interior models have revealed that warm Jupiters should harbor large heavy element masses (up to 30-40% of the planetary mass). Within the pebble drift and evaporation scenario, inward drifting pebbles can evaporate and enrich the inner disc with vapor to super-stellar values, accreteable by giant planets. As H$_2$O ice evaporates in the inner disc, while CO$_2$, CH$_4$ and CO evaporate in the outer disc, the enrichment of the disc with vapor decreases with increasing orbital distance. We use the chemcomp code to model the migration and growth of planets via pebble and gas accretion in discs around stars with different masses and discs with different sizes. We show (i) that pebble drift and evaporation can explain the wide range of derived heavy element contents of giant planets. (ii) Giant planets forming around stars with larger disc sizes can accrete larger quantities of heavy elements, because these discs can maintain a high pebble flux for a longer time. (iii) Planets forming or migrating interior to the water ice line can accrete larger amounts of heavy elements via the accretion of vapor enriched gas compared to planets forming in the outer disc regions. (iv) Metal rich stars can allow the formation of planets that are more enriched in heavy elements, if they form in the inner disc regions. Planets forming in the outer disc regions will be - independently of the disc metallicity - much less enriched compared. (v) Planets forming in discs with the same size and total mass, but around stars with higher mass, are only marginally more enriched compared to their counterparts forming around lower mass star. Our study suggests that the trend of increasing total heavy element mass with increasing planetary mass is caused by the accretion of vapor enriched gas in discs with different sizes in the combination with different origins of warm giant planets from the inner and outer disc.
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Astrophysics of Galaxies

A dust-reddened quasar in a [C II]-luminous host at z=6.55

Daming Yang, Joseph F. Hennawi, Rychard Bouwens et al. (+18 more)

Most known quasars at $z>6$ were selected through their rest-frame UV emission. Only a small number of reddened quasars have been identified at these redshifts, leaving their nuclear and host-galaxy properties poorly constrained. We present JWST/NIRSpec spectroscopy and ALMA band 6 observations of the quasar J1440+0019 at $z=6.5488$, revealing its dust-reddened nature and jointly characterizing its nucleus and host galaxy. The continuum is best described by an SMC-like extinction law with $E(B-V)=0.20\pm0.03$. Three absorption systems detected in N V, Si IV, and C IV are blueshifted by approximately $900$–$3600$ km s$^{-1}$ and likely trace an ionized nuclear outflow. The broad Mg II line and extinction-corrected continuum yield a black-hole mass of $\log(M_{\rm BH}/M_\odot)=9.04\pm0.42$, a bolometric luminosity of $L_{\rm bol}\simeq1.1\times10^{47}$ erg s$^{-1}$, and an Eddington ratio of $\lambda_{\rm Edd}\simeq0.8$. ALMA observations further reveal its host galaxy to be among the most [C II]-luminous known at $z>6$, with $L_{\mathrm{[C II]}}=(7.21\pm0.25)\times10^9 L_\odot$. For a fiducial dust temperature of 47 K and emissivity index $\beta=1.6$, the dust continuum implies $L_{\rm TIR}=8.9\times10^{12} L_\odot$ and $M_{\rm dust}=4.0\times10^8 M_\odot$. The inferred dynamical mass places J1440+0019 in the region of the $M_{\rm BH}$–$M_{\rm dyn}$ plane occupied by high-redshift blue quasars. These observations reveal a moderately reddened, rapidly accreting quasar in a luminous, dust-rich host during reionization. Its measured nuclear and host-galaxy properties provide an observational reference for identifying and characterizing similar systems in future systematic searches with wide-area infrared surveys.
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All authors Daming Yang, Joseph F. Hennawi, Rychard Bouwens, Timo Kist, Eduardo Bañados, Hiddo S. B. Algera, Aaron J. Barth, Sarah E. I. Bosman, Frederick B. Davies, Anna-Christina Eilers, Xiaohui Fan, Victoria A. Fawcett, Yuming Fu, Anniek J. Gloudemans, Francesco Guarneri, Bin Jia, Elia Pizzati, Huub Röttgering, Jan-Torge Schindler, Feige Wang, Jinyi Yang

High Energy Physics (Phenomenology)

Utilizing Neural Networks for Solving Functional Renormalization Group Flow Equations

J. Gurzó and G. Fejős

A novel physics-informed neural networks (PINNs) based approach for solving functional renormalization group flow equations is presented. We investigate the finite temperature phase transition in $O(N)$ models without relying on the large-$N$ approximation, which was used in earlier attempts with similar methods. We argue that these previous solutions cannot easily be generalized for more complex symmetries, and hence our approach can provide new insight. Our technique relies on a series of ansätze that combines the small- and large-field approximation schemes with a neural network, leading to a highly accurate approximation over the entire field range. We compare the PINNs approach with traditional grid-based Runge-Kutta results and show that the network can successfully learn the temperature, field, and scale dependencies of the effective potential in the local potential approximation.
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Soft Condensed Matter

Arrested phase separation and amorphous patterns in charged binary fluids

Logan H. Grant, Ana Bensabat, Eva Pospivsilova et al. (+6 more)

Frustration generated by competing interactions can stabilise patterns with tunable lengthscales which evade indefinite coarsening and macroscopic phase separation. Here we investigate a charged binary fluid in which the tendency toward phase separation is opposed by screened electrostatic repulsion. Combining analytics and numerical simulations, we identify a regime of arrested phase separation characterised by finite-wavelength instability. The resulting states include droplet and labyrinthine phases in two dimensions, and droplets, concentric shells and tubular structures in three dimensions. Surprisingly, some of these structures are amorphous morphologies that emerge reproducibly from different initial conditions. Free-energy estimates suggest that these disordered structures may be thermodynamically stabilised by frustration, rather than being kinetically trapped. Our results identify a simple mechanism through which the competition between phase separation and screened electrostatics can generate equilibrium amorphous microphases with glassy features.
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All authors Logan H. Grant, Ana Bensabat, Eva Pospivsilova, Joost de Graaf, Alexander Morozov, Giuseppe Negro, Ciprian G. Pruteanu, Tyler N. Shendruk, Davide Marenduzzo

Mathematical Physics

Perturbed isotropic oscillators with inversion symmetry

Antonella Marchesiello, Rita Mastroianni and Giuseppe Pucacco

We consider the normal form of a 1:1 detuned resonance that can be related, via a double averaging process, to the three body problem of celestial mechanics. In view of the symmetry in the gravitational coupling between the planets, the obtained normal form exhibits inversion symmetry. We provide an analytical prediction of the possible bifurcations in terms of the detunings and the other physical parameters of the system. We show that the bifurcation scenario is rich. It includes bifurcation sequences where the unstable orbit appearing after a saddle-node bifurcation can have a reversed pitchfork bifurcation, where it turns into stability with the birth of two unstable orbits, which eventually reconnect with one of the two quasi-normal modes. Furthermore, another scenario shows a standard pitchfork in which one of the quasi-normal modes becomes unstable, giving rise to a pair of stable periodic orbits. By introducing coupling and asymmetry parameters, we provide an effective way to discern all the possible sequences of bifurcations.
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Astrophysics of Galaxies

A strategy for astrometric quasar selection with Gaia DR3 and its application to discover new luminous $z>2$ quasars

J. Li and J. P. U. Fynbo

We aim to provide a cookbook for purely astrometric selection of quasars with Gaia DR3 and to provide an example of its use for the identification of very luminous $z>2$ quasars. We analyse the Gaia DR3 astrometry of confirmed quasars and stationary sources. We show that the proper motion signal to noise $\mu/\sigma_{\mu}$ follows a Rayleigh-like distribution. We also show the importance of properly taking into account the correlation between proper motions in right ascension and declination, as well as the non-linear error propagation. We adopt the Mahalanobis distance to the null proper-motion hypothesis. A scaled $\chi^2$ distribution with $k=2$ and scale $s=1.1485$ is fitted to Gaia-CRF3; the corresponding $\pm2\sigma$ Gaussian-equivalent threshold is $D^2_{M(\mu)}<7.097$. The final criteria combine this with the parallax condition and $\mathrm{ruwe}<1.4$. Applying the new criteria to the SDSS DR16Q confirmed quasars, the recovery rate is $90.25\%$. The suggested purely astrometric selection significantly improves both completeness and purity compared to other strategies used in the literature, reaching a quasar purity of approximately $95\%$ ($\sim2\sigma$ Gaussian-equivalent). It can be used to improve the selection purity and completeness for future quasar surveys. As an example, we use the suggested strategi to locate 24 very bright $z>2$ quasars without redshifts in the literature. Our proposed astrometric selection strategy recovers 95% of known quasars. Its potential use for new discoveries is demonstrated by the identification of 24 very luminous $z>2$ quasars. Ten of these are new discoveries and for an additional seven we correct the redshifts determined by other methods.}
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Cosmology and Nongalactic Astrophysics

Relaxation Dark Energy: Compositional Dynamics and the Future of Cosmic Acceleration

Gianmassimo Tasinato

If cosmic acceleration is driven by a positive cosmological constant, the universe approaches an eternally accelerating de Sitter state, whose interpretation in quantum gravity remains elusive. We develop a framework in which acceleration is instead a transient stage of dark-sector relaxation towards compositional equilibrium: matter and dark energy approach a stationary density ratio, eventually diluting like pressureless matter. Guided by linear response theory and Onsager's near-equilibrium regression hypothesis, we describe this evolution through a composition variable measuring departure from equilibrium. Extending constant fractional relaxation to the full background evolution yields the dark-energy equation of state $w=w_0a^{-n}$, where $n$ is the relaxation rate per e-fold of expansion. This history connects early dark-energy suppression, an upward phantom crossing and a density maximum to a pressureless scaling future. Using DESI DR2 BAO and Planck distance priors, with and without three alternative supernova compilations, we find a nominal $2.6$–$3.6\sigma$ preference for nonzero relaxation over constant $w$. The composition framework also motivates a constitutive prescription for linear perturbations that remains regular at phantom crossing. Near equilibrium, regular long-wavelength composition disturbances relax at the background rate to leading order, while small-scale fluctuations propagate as damped sound waves. We prove, however, that for separately conserved matter and dark energy, the pointwise constitutive relation cannot sustain a regular, gradient-stable negative-pressure branch throughout its full past evolution. We explore modifications of the pressure response and their consistency with neighbouring homogeneous histories, identifying requirements for extending the near-equilibrium description to the full cosmological evolution.
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Soft Condensed Matter

Shear-driven arrest of dip-coating film entrainment

Theo Witkamp, Stéphane Zaleski and Federico Toschi

A plate withdrawn from a bath of partially wetting liquid entrains a film above a critical velocity. Here, we show that this critical threshold can be substantially increased by the presence of a laminar gas flow opposed to the plate velocity that exerts a tangential shear stress on the liquid-gas interface. Using two-phase immiscible Navier-Stokes simulations and confining the gas to a narrow channel, we derive a closed-form expression for the interfacial stress, which combined with lubrication theory relates the thickness of the film and the contact line velocity to the applied shear stress. As the gas velocity is increased, the film thins and the contact line velocity slows down, until the imposed shear overcomes the drag of the moving plate and entrainment is arrested. As in the quiescent case, the velocity mismatch between plate and contact line is independent of the plate velocity and is set by the applied shear alone. We find that one set of varying gas flow simulations, with constant critical plate velocity, therefore determines the critical gas flow for every smaller plate velocity.
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Optics

Chiroptical Nonlinearity Found in Covalent Organic Frameworks

Yile Zhang, Lei Wei, Sixue Tang et al. (+4 more)

Chiroptical nonlinearity is vital for modern optics and photonics. However, it remains a central challenge to obtain a material simultaneously with large second-order nonlinearity and strong nonlinear optical chirality. Here we uncover the strong chiroptical nonlinearity in COF-330-a, owing to the formation of unique chiral, polar structure with large p-electron conjugation via structural transformation. A large effective second-order nonlinear susceptibility of ~ 101 pm/V and a strong nonlinear chiroptical response (SHG-CD: -1.60 to +1.66) have been demonstrated in individual COF-330-a microcrystals, transcending the performance trade-off limitation in conventional chiroptical materials. These findings open a new avenue for designing nonlinear chiroptical materials which harness the duality of polarity and chirality and chemical versatility of COFs.
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All authors Yile Zhang, Lei Wei, Sixue Tang, Yuhang Li, Yanhang Ma, Yue-Biao Zhang, Xiaoqin Shen

High Energy Physics (Theory)

Anomaly induced transport in holographic superconductors

Ashis Tamang, Nishal Rai, Javier Esteban et al. (+1 more)

We investigate the anomaly-induced transport properties of a holographic superconductor exhibiting spontaneous symmetry breaking. The holographic model incorporates vector and axial gauge fields, an additional non-anomalous $U(1)$ symmetry, and a charged scalar field that drives the phase transition. Working in the probe limit, we numerically construct the superconducting background under two alternative scalar field quantizations, corresponding to operators with scaling dimensions $\Delta=1$ and $\Delta=3$ (denoted as the $O_1$ and $O_2$ theories, respectively). Using Kubo formulae, we compute the chiral magnetic conductivities and examine their response to the scalar condensate. Our findings demonstrate that spontaneous symmetry breaking allows anomaly-induced transport to extend beyond anomalous currents, significantly impacting the non-anomalous sector as well. Remarkably, this effect appears in both theories, indicating that the influence on the non-anomalous sector is independent of the chosen quantization. The comparison of our numerical results with the analytical limits for $O_i \to 0$ and $O_i \to \infty$ $(i=1,2)$ reveals consistent behavior across both theories.
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All authors Ashis Tamang, Nishal Rai, Javier Esteban, Eugenio Megias

Astrophysics of Galaxies

Turbulence modes in molecular clouds in M33: a challenging test of the Brunt-Federrath framework

Raffaele Rani, Ayu Konishi, Kazuyuki Muraoka et al. (+5 more)

Understanding the turbulent structure of molecular clouds is essential for linking galactic environment to the regulation of star formation. Although Galactic molecular clouds have been studied extensively, extending turbulence-mode analysis beyond the Milky Way remains challenging because of the limited spatial resolution and dynamic range of extragalactic observations. We assess the applicability of the Brunt & Federrath (2014; BF14) framework to molecular clouds in M33. We apply BF14 to 128 $^{13}$CO(2-1) clouds, selecting a primary quality-controlled sample of 54 clouds and a more restrictive 25-cloud subsample defined using a stricter extraction-padding criterion (PAD=2) for quantitative analysis.Tests of cloud and noise power spectra, Fourier-space cutoffs, extraction padding, and Monte Carlo uncertainties demonstrate that the retained spatial frequencies are dominated by astrophysical signal and that the inferred turbulence-mode fractions are robust against reasonable analysis choices. Both samples yield consistent distributions of the solenoidal fraction, with mean values of $R \simeq 0.22$ for both samples and median values of $R \simeq 0.18$ and $0.17$, respectively, indicating that compressive motions dominate the turbulent energy budget. No strong systematic variations of $R$ are found with galactocentric distance or tracers of recent star formation. These results demonstrate that, despite the challenging spatial resolution of current extragalactic molecular-line observations, the BF14 framework can be applied reliably to nearby galaxies using spectroscopic observations alone. To our knowledge, this constitutes the first application of the full BF14 formalism to extragalactic molecular-cloud observations.
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All authors Raffaele Rani, Ayu Konishi, Kazuyuki Muraoka, Toby J. T. Moore, David J. Eden, Karan Fernandes, Yueh-Ning Lee, Shih-Ping Lai

Astrophysics of Galaxies

High Resolution Spectro-Polarimetric Observations of the Optical Filaments surrounding NGC 1275 with ESPaDOnS

Benjamin Vigneron, Julie Hlavacek-Larrondo, Luca Fabiani et al. (+6 more)

We analyze archival high spectral resolution ESPaDOnS spectropolarimetric observations (R = $\lambda/\Delta\lambda$ = 68000) of three targeted locations within the filamentary nebula surrounding NGC 1275. We present here the analysis of the main filaments emission lines, namely: [NII]$\lambda6584$, H$\alpha$, and [NII]$\lambda6548$, across our three pointings displaying clear detectable emission, with one also showing additional [SII]$\lambda6716$ and [SII]$\lambda6731$ emission line doublet. Using a Markov Chain Monte-Carlo (MCMC) algorithm and thanks to the exceptionally high spectral resolution of the observations, we resolve for the first time each of the emission lines within one of the pointings into a set of three emission components with a remarkable velocity dispersion contrast ($\sigma_1 \sim 25$ km/s, $\sigma_2 \sim 90$ km/s and $\sigma_3 \sim 208$ km/s). We also perform flux ratios of the three detected emission components, which reveal differences in electron density and ionization sources. Consequently, the ESPaDOnS observations appear to reveal for the first time the overlap of an outer quiescent filament and a central turbulent filament likely affected by the AGN activity at a distance of $\sim 6.8''$ ($\sim 2.5$ kpc) from the central BCG. Finally, ESPaDOnS polarimetric data of one of the pointing allows us to confirm an average linear polarization degree of $\sim 0.15-0.14\%$ and an angle of polarization of $5.3\pm25.7^\circ$ for the optical emission of the filaments, as well as polarization dips associated with the H$\alpha$ emission line and its multiple emission components. We interpret these features and measurements as tentative polarization due to dust scattering.
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All authors Benjamin Vigneron, Julie Hlavacek-Larrondo, Luca Fabiani, Lison Malo, Carter Lee Rhea, Megan Donahue, Jorge Karolt Barrera Ballesteros, Hyunseop Choi, Nadine Manset

Materials Science

Dislocation mediated twin boundary faceting in $\beta$-Sn

John Israel, Ian Chesser, Khanh Dang et al. (+1 more)

Grain boundaries (GBs), including twin boundaries (TBs), play a critical role in plastic deformation by interacting with dislocations. The deformation and strengthening mechanisms in $\beta$-Sn are of significant interest because Sn-based alloys are widely used as solder materials. Recent experiments have shown deformation-induced faceting in $\beta$-Sn arising from twin-dislocation interactions. Using molecular dynamics (MD) simulations informed by a recently developed machine-learned interatomic potential (MLIP), we demonstrate a $\langle c\rangle$ dislocation-absorption mediated faceting reaction along $(301)$ TBs in $\beta$-Sn in which facet length grows with the number of absorbed dislocations. We show that the predicted facet length is consistent with isotropic elasticity theory only when the disclination character of the asymmetric twin facet is taken into account. We discuss analogies to faceting reactions in other low symmetry metals and hypothesize that the ubiquity of $(301)$ twins in $\beta$-Sn stems from their ability to grow rapidly through a forest of dislocation obstacles.
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All authors John Israel, Ian Chesser, Khanh Dang, Vinamra Agrawal

Quantum Physics

Dynamical Lie Algebras for Fixed-Gate Quantum Ansätze

Orlane Zang, Daniel Juteau, Tony Quertier et al. (+1 more)

Parameterized Quantum Circuits have emerged as a central framework for variational quantum algorithms in the NISQ regime, with major applications in quantum simulation, combinatorial optimization, and, more recently, quantum machine learning (QML). By developing a new approach for computing dynamical Lie algebras associated with quantum circuits combining parametrized gates and non-parametrized entangling gates, we aim to extend the applicability of recent algebraic results to architectures that are actually used in quantum machine learning.
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All authors Orlane Zang, Daniel Juteau, Tony Quertier, Grégoire Barrué