Astrophysics of Galaxies
Supernovae Ia ejecta velocities and host galaxy environments: the role of survey-selection effects
L. V. Barkhudaryan, A. A. Hakobyan, M. H. Gevorgyan et al. (+6 more)
The origin of the near-maximum-light Si II $\lambda$6355 velocity diversity among
supernovae Ia (SNe Ia) remains uncertain. Previous studies have suggested that high-velocity (HV) and normal-velocity (NV) SNe Ia occupy systematically different host
galaxy environments, implying differences in their progenitor populations. We re-examine this hypothesis using a sample of 354 nearby ($z\leq0.04$) spectroscopically normal SNe Ia, comprising 239 NV and 115 HV events, identified in targeted and untargeted surveys. For each SN, we determine the host
galaxy morphology, galactocentric distance, and physical size, and obtain homogeneous
stellar mass estimates while assessing the influence of survey-selection effects. The Si II velocity distribution is well described by two Gaussian components, confirming the NV and HV populations. We find no statistically significant differences between the galactocentric distance, host
galaxy size, or
stellar mass distributions of the two velocity subgroups. The environmental trends reported in previous studies are recovered only with marginal statistical significance in the targeted subsample, whereas they disappear almost entirely in the untargeted subsample, consistent with survey-selection effects playing a major role in the previously inferred environmental differences between the NV and HV events. Our results weaken the interpretation that the observed Si II velocity diversity is primarily driven by systematic differences in the global host properties examined here. Instead, they favour a scenario in which intrinsic explosion asymmetries and viewing-angle effects account for a substantial fraction of the observed velocity diversity, without excluding a possible contribution from local environmental conditions or progenitor properties.
Read the full abstract ▾
All authors L. V. Barkhudaryan, A. A. Hakobyan, M. H. Gevorgyan, D. Kunth, G. A. Mamon, U. Burgaz, V. Adibekyan, Zh. R. Martirosyan, A. G. Karapetyan
High Energy Physics (Phenomenology)
Photon production from gluon splitting and fusion induced by a magnetic field of arbitrary strength in relativistic heavy-ion collisions
Alejandro Ayala, Santiago Bernal-Langarica, José Jorge Medina-Serna et al. (+1 more)
We compute the yield and
elliptic flow coefficient for
photons produced during the pre-
equilibrium stage of semi-central relativistic heavy-ion collisions from the
gluon fusion and splitting processes induced by the presence of a
magnetic field. The calculation is performed for arbitrary values of the field strength. The pre-
equilibrium gluon distribution is modeled with a glasma-inspired Bose-Einstein occupation factor, as well as with an anisotropic distribution that accounts for the rapid initial expansion along the beam axis. In both cases, we find a very good agreement between the calculation and the experimental data from PHENIX. Most notably, the shape and strength of the
elliptic flow coefficient are described quite well, representing a step towards solving the outstanding
photon puzzle.
Read the full abstract ▾
All authors Alejandro Ayala, Santiago Bernal-Langarica, José Jorge Medina-Serna, Ana Julia Mizher
General Relativity and Quantum Cosmology
Dual entropy gain by radiation at the zero temperature limit
Koray Düztaş
Recently we have demonstrated that black hole radiation can be smoothly extended to the zero-temperature limit. Here we analyse
entropy variations at the zero temperature limit and evaluate the validity of the Generalized Second Law (GSL). Typically one verifies that the
entropy gain in the exterior region compensates for the
entropy loss of the black hole due to evaporation. However an anomalous feature emerges at the zero temperature limit. The fact that the emission is restricted to the modes $\omega <m\Omega$, renders the variation of the horizon area of a Kerr black hole positive definite. Simultaneously the von Neumann
entropy of the exterior region increases both for bosonic and fermionic modes. The dual
entropy gain at the zero temperature limit marks a robust conservation of the GSL. We demonstrate that the dual increase also applies to Kerr-Taub-NUT black holes whose
entropy is neither directly proportional to the horizon area nor analytically integrable.
Read the full abstract ▾
General Relativity and Quantum Cosmology
Black hole singularity is a surface not a point
Andrew J. S. Hamilton and Tyler McMaken
It is widely repeated in the popular literature and elsewhere that the singularity at the center of a black hole is a point. It is not true. Two observers who free-fall into a spherical black hole along two different angular trajectories at the same time $t$ do not encounter each other at the central singularity; rather, they lose causal contact with each other already well away from the singularity. Counterintuitively, in general relativity two points can be spatially close yet causally distant. The singularity is a surface, not a point. The story for rotating black holes is more complicated, but the same conclusion holds. For a rotating black hole, the singular surface almost certainly resides at its inner horizon, where even the tiniest classical or
quantum perturbations ignite the exponential mass inflation instability, precipitating collapse to a spacelike singular surface. There are implications for
quantum gravity. We argue that, whatever the ultimate theory of
quantum gravity may be, the
quantum states of a black hole probably reside at its effectively 2-dimensional singular surface, which coevolves unitarily with, and in thermodynamic
equilibrium with, the hot atmosphere of trapped Hawking radiation that the black hole generates within its event horizon.
Read the full abstract ▾
High Energy Physics (Theory)
Neural Network Field Theory at Finite Width
Christian Ferko and Aaron Mutchler
Under mild assumptions, any
quantum mechanical (QM) model or
quantum field theory (QFT) admits a representation in terms of an ensemble of neural networks with countably many random parameters. We investigate the features of NN-QM and NN-FT models with finitely many parameters, such as a feedforward network of width $N < \infty$. We find that, generically, such models must violate one of the properties of conventional Euclidean QFTs, such as reflection positivity or cluster decomposition. We present several complementary ways of understanding which features can and cannot be preserved at finite $N$, both in QM and in QFT.
Read the full abstract ▾
Disordered Systems and Neural Networks
A minimal mechanism to generate long timescales without fine tuning
Kathryn McClain, Shivang Rawat, Mia Morrell et al. (+3 more)
Long timescales in
brain dynamics give rise to power law correlations measured in experiments. A simple linear recurrent neural network model can reproduce this power law behavior, but the recurrent interaction strength needs to be fine tuned in order to sit at the edge of stability. We show that by adding a dynamical recurrent feedback gain to the simple linear model removes the need for fine tuning, because the gain self-organizes so that the spectrum of the effective recurrent
matrix is always gapless with the top
eigenvalue landing on the stability edge for any recurrent strength. As a consequence, long timescales and scale free correlations arise generically, as we demonstrate both analytically and numerically.
Read the full abstract ▾
All authors Kathryn McClain, Shivang Rawat, Mia Morrell, Stefano Martiniani, David J. Heeger, Flaviano Morone
Instrumentation and Detectors
Reconstructing High-Fidelity Light Yield Maps for Surface LArTPCs Using Crossing Cosmic Muons
Alex Heindel, Wei Shi, Angelo Ralaikoto et al. (+5 more)
Photon detection systems in
liquid argon time projection chambers provide
prompt scintillation light information that can improve triggering, timing, calorimetry, and interaction reconstruction. These applications require an understanding of the spatial dependence of the detected light yield (LY), which is not adequately described by a single detector-wide average. We present a method for reconstructing voxelized 3D light yield maps in surface LArTPCs using crossing
cosmic muons. For each selected
muon, the path length through every crossed voxel is converted to deposited energy using a minimum ionizing particle approximation, producing a linear system relating the unknown voxel light yields to the total detected
photon signal. The resulting inverse problem is solved using nonnegative least squares, with an additional $L_2$ smoothness penalty used to stabilize weakly constrained voxel values. The method is studied in simulation using the ProtoDUNE-VD detector geometry and
photon detection system. Reconstructed maps recover the dominant spatial structure of a visibility-based truth reference and respond as expected to changes in the
photon detector configuration. Smoothness regularization reduces zero-valued voxels and localized fluctuations while leaving the detector-average light yield approximately unchanged at the selected regularization strengths. The voxel-wise RMSE relative to the truth reference is reduced by approximately 44% for the regularized reconstruction.
Read the full abstract ▾
All authors Alex Heindel, Wei Shi, Angelo Ralaikoto, Shuaixiang Zhang, Laura Paulucci, Franciole Marinho, Maressa Pimenta Sampaio, Sanskar Jain
Quantum Physics
Scaling vs entanglement in measurement-induced phase transition for non-integrable systems
Paranjoy Chaki, Protyush Nandi, Subinay Dasgupta et al. (+1 more)
We find that the measurement-induced phase transition generated by deterministic global measurements, previously observed in the integrable transverse-field Ising model (TFIM), persists in non-integrable variants of the same. To address this question, we consider the TFIM with longitudinal field and the axial next-nearest-neighbor Ising (ANNNI) model. We show that both the survival probability and the bipartite
entanglement entropy consistently capture a transition between area-law and volume-law entangled phases for two distinct initial states: a product state with all
spins polarized along the transverse direction and a Greenberger-Horne-Zeilinger (GHZ) state. Finite-size scaling reveals a pronounced initial state dependence: for the polarized product state, the transition point follows an inverse-square-root scaling with system size in both non-integrable models, consistent with the integrable TFIM, whereas for the GHZ initial state, it deviates from this scaling and approaches zero considerably more slowly in the non-integrable models than in the integrable TFIM. These results establish the robustness of measurement-induced transitions under deterministic measurements against integrability breaking while highlighting the crucial role of the initial state in governing their scaling behavior.
Read the full abstract ▾
All authors Paranjoy Chaki, Protyush Nandi, Subinay Dasgupta, Ujjwal Sen
High Energy Astrophysical Phenomena
Relativistic blob signatures in the M87 jet at sub-parsec scales
Donaldo Mora, Alejandro Cruz-Osorio, Erika Benítez et al. (+1 more)
In this work, we present results from general-relativistic radiative-transfer calculations of black hole
accretion and jet launching to reproduce the observed properties of the M\,87 jet at sub-parsec scales. For the first time, in the simulations we have included a blob component at the launching region of the jet that allowed us to reproduce the quasi-simultaneous low-energy spectral energy distribution ($10^{10} \text{ Hz} \leq \nu \leq 10^{16} \text{ Hz}$). Moreover, we obtain a better fit of the synchrotron emission in the self-absorption region ($\nu \leq 10^{11} \text{ Hz}$), showing that the inclusion of a blob component in our radiative transfer calculations results in a flatter spectrum ($\alpha_{22-86\ \text{GHz}}=0.08$). Additionally, our simulations improved the accuracy of the observed morphology of M\,87's jet, matching the data up to a distance of 0.6 mas from the core at 86 GHz. Our results reproduce the edge-brightened structure up to $\sim1.3$ mas, i.e., in a more extended region compared with previous studies, with a brighter southern edge. The obtained synthetic image of the jet reproduces additional observed
knots along the southern edge.
Read the full abstract ▾
All authors Donaldo Mora, Alejandro Cruz-Osorio, Erika Benítez, Yosuke Mizuno
Quantum Physics
Emulating non-Markovian system-bath dynamics with parametrically driven cavities
Valentin Boettcher, Félix Pellerin, Philippe St-Jean et al. (+1 more)
We introduce and characterize a scheme for emulating non-Markovian
quantum system-bath dynamics using the discrete electromagnetic field modes of a parametrically driven cavity. In this scheme, the character of a bosonic bath (the form of the bath spectral density) is tied directly to the shape of the real-time waveform describing periodic parametric cavity modulation. As an explicit example, we demonstrate the feasibility of this scheme for a fiber-loop experiment with currently achievable parameters, supported by numerical simulations and analytical estimates. In particular, we show that a localization transition of the
spin-
boson model can be accurately emulated in this fiber-loop cavity system. This localization effect is characterized by a sharp transition from partial decay to complete decay for a two-level system coupled to a bosonic bath as the bath spectral density $J(\omega)\propto \omega^{s}$ is continously tuned from the sub-ohmic ($s<1$) to the super-ohmic ($s>1$) regime. The transition is only exactly realized in the thermodynamic limit (for an infinite number of bath modes) and for sufficiently weak system-bath coupling. We highlight a competition between the weak-coupling and thermodynamic limits in this problem and show that challenges in approximately realizing the transition can nevertheless be overcome. Finally, we provide bounds on the systematic error introduced when emulating non-Markovian dynamics for arbitrary system observables. The scheme presented here can enable the realization of a modular platform for engineering custom non-Markovian baths, with potential applications in
quantum thermodynamics, thermalization of many-body systems, and resource-efficient
quantum simulations of open
quantum systems.
Read the full abstract ▾
All authors Valentin Boettcher, Félix Pellerin, Philippe St-Jean, William A. Coish
Optics
Weyl Points and Fermi Arc Surface States in a Self-assemblable Zinc-Blende Photonic Crystal
Johnathon P. Gales, Hengbin Cheng, David J. Pine et al. (+1 more)
Colloidal self-assembly has long been proposed as a method for growing large-scale three-dimensional photonic
crystals with important optical properties in visible and near-infrared wavelength regimes, where top down lithographic fabrication fails. While much of the focus in these systems has been on producing a photonic band gap, such
lattices can also give rise to topological features of photonic bands. To date, there has been no proposal for realizing topological photonic features in photonic
crystals that may be self-assembled. In 3D, Weyl points are topological band degeneracies that are of particular interest due to their robustness to perturbations and their corresponding
Fermi arc surface states. In order to realize Weyl points, either time-reversal or inversion
symmetry must be broken, and no previous self-assembled colloidal photonic
crystal has exhibited either property. Here, we propose a new zinc-blende structure, built off of recent progress in self-assembling diamond photonic
crystals, which lacks inversion
symmetry and supports photonic Weyl points. Furthermore, we show that the geometry can be optimized to make the Weyl point and its
Fermi arc surface states experimentally observable in the photonic
crystal's projected band structure. Finally, we perform molecular dynamics simulations to demonstrate that the geometry we propose for observing Weyl points is capable of being self-assembled with realistic interparticle interactions. Together, these results provide a platform for the assembly of large-scale photonic
crystals supporting topological degeneracies and robust
Fermi arc surface states in the visible and near-infrared.
Read the full abstract ▾
All authors Johnathon P. Gales, Hengbin Cheng, David J. Pine, Mikael C. Rechtsman
Earth and Planetary Astrophysics
Assessing the Impact of High-Resolution Imaging on Statistical Validation of TESS Planet Candidates
Michael Collier, Steven Giacalone, Brian Derfer et al. (+38 more)
High-resolution imaging is widely used to constrain false-positive scenarios in
exoplanet validation, but it is a finite follow-up resource that reaches only a subset of candidates, and its population-level impact on validation outcomes has not been quantified through controlled removal experiments. Using an automated pipeline built on TRICERATOPS, we compute the false-positive probability (FPP) of 443 TESS
planet candidates. For the 264
planet candidates with high-resolution imaging observations, we compute FPP with and without the corresponding contrast curves, allowing us to quantify the impact of the additional data. We find that 72% of 68 contrast-curve bearing validated
planets would fail validation without their adopted contrast curves. The fraction requiring imaging decreases with increasing
planet size, from 100% below $1.7~R_\oplus$ to $33\%$ above $4~R_\oplus$: within our sample and TRICERATOPS-based analysis, the availability of high-resolution imaging directly limits the yield of small-
planet validation and the supply of validated targets for atmospheric characterization. Our analysis statistically validates 64 new TESS
planets with sizes spanning 0.94 to 7.83 $R_\oplus$ across hosts of spectral type M through F. Four of these are highly amenable to JWST observations based on the transmission and emission spectroscopy metrics, and each achieves validation only with its imaging constraint.
Read the full abstract ▾
All authors Michael Collier, Steven Giacalone, Brian Derfer, David R. Ciardi, Catherine A. Clark, Ian J. M. Crossfield, Sarah Deveny, Sergio B. Fajardo-Acosta, Elise Furlan, Emily A. Gilbert, Steve B. Howell, Adam L. Kraus, Rachel A. Matson, Joshua E. Schlieder, Julian C. van Eyken, David Baker, Khalid Barkaoui, Özgür Baştürk, Mario Basilicata, Izuru Fukuda, Akihiko Fukui, Mourad Ghachoui, Michaël Gillon, Emmanuel Jehin, Jerome de Leon, Luigi Mancini, Francesca Manni, Gabriel Murawski, Bob Massey, Luca Naponiello, Norio Narita, Justus Randolph, Roberto Zambelli, Richard P. Schwarz, Abderahmane Soubkiou, Gregor Srdoc, Chris Stockdale, Toshi Suganuma, Jiaqi Wang, Francis P. Wilkin, Selçuk Yalç{\i}nkaya
Optics
Optical injection locking of white light cavity based superluminal lasers
Jacob Scheuer, Zifan Zhou, Yael Sternfeld et al. (+2 more)
Optical injection locking is a simple method for synchronizing a
laser to an external
laser source by injecting part of the external
laser light into the cavity of the other
laser. This approach received significant interest due to its potential applications in telecommunications, precision metrology, and more. We study and analyze the steady-state and dynamic properties of optical injection locking in white light cavity (WLC)
lasers. We derive the steady-state injection locking range of the WLC
laser and the dynamic (Adler) equation for the phase-difference between the injected signal and the locked
laser output. The analysis shows that WLC
lasers can exhibit an order of magnitude broader locking range and three order of magnitudes faster dynamics compared to conventional
lasers with similar thresholds and free spectral ranges.
Read the full abstract ▾
All authors Jacob Scheuer, Zifan Zhou, Yael Sternfeld, Michal Hazan, Selim M. Shahriar
Atmospheric and Oceanic Physics
Probabilistic inference of surface parameters for Monin-Obukhov similarity theory
Ethan YoungIn Shin and Michael F. Howland
In simulations of atmospheric flow, the grid spacing typically exceeds the size of the roughness elements at the surface by an order of magnitude. The unresolved effects of surface morphology and roughness on the flow are represented by effective surface parameters and specified as a surface flux boundary condition, most often through a formulation based on Monin-Obukhov similarity theory (MOST). These surface parameters are known to depend on both surface and flow properties, yet they are generally estimated as deterministic quantities with no characterization of associated uncertainty. In this study, we use a
Bayesian approach to infer surface parameters for MOST and quantify their uncertainties. For the aerodynamic roughness length $z_0$ inferred in isolation, a normal-normal conjugate update yields the posterior and posterior predictive distributions in closed form. We first demonstrate our method on idealized conventionally neutral boundary layers generated by large-eddy simulation, where $z_0$ is prescribed, and quantify how prior- and observation-related choices shape the inferred posterior. We then apply the method to field observations from the Atmospheric Radiation Measurement Southern Great Plains observatory, from which we infer $z_0$ distributions conditioned on month, on wind direction, and on both jointly. By leveraging a prior informed by sample statistics of all near-neutral observations in the training years, we demonstrate the advantage of the
Bayesian inference method for $z_0$ relative to the state-of-practice least-squares profile-fitting method in conditions of data sparsity. Predictions for unseen observations-evaluated at the posterior mean-reduce root mean squared error and mean absolute error in data-sparse wind directions, while posterior predictive distributions consistently reduce the continuous ranked probability score by approximately $20$-$30\%$.
Read the full abstract ▾
Astrophysics of Galaxies
The Milky Way Joins the Extragalactic World: I. PHANGS
Neal J. Evans II, Davide Elia, Jiayi Sun et al. (+2 more)
Complete catalogs of molecular clouds in the Milky Way allow analysis of the molecular medium and the
star formation properties of the Milky Way that closely follows the method used for nearby
galaxies, in particular in the PHANGS project. The dependencies of the depletion time on other properties of molecular gas in the Milky Way are similar to those of other
galaxies when analyzed in an analogous way. They exhibit a large scatter and relatively weak correlations. The strongest correlation is a decrease in depletion time with increasing velocity dispersion. We explore the effects of spatial resolution, sensitivity, cloud identificaton method, averaging method, and tracer choice on our results.
Metallicity effects in converting observations to mass can have a substantial impact. Somewhat fortuitously, differences in conversion methods between PHANGS and the Milky Way do not affect the current comparison. Inadequate spatial resolution, resulting in unresolved cloud structure, has the most important effect on interpretation of both extragalactic observations and existing catalogs of Milky Way clouds.
Read the full abstract ▾
All authors Neal J. Evans II, Davide Elia, Jiayi Sun, Sophia Stuber, Adam K. Leroy
General Relativity and Quantum Cosmology
Study of Dynamical Instability of Collapsing Charged Spherically Symmetric Anisotropic Matter Configurations within Non-Minimally Coupled Gravity
A. Rehman, M. Yousaf, Mohammed Zakarya et al. (+2 more)
We investigate the dynamical instability and gravitational collapse of charged, spherically symmetric anisotropic matter configurations within $f(R,\mathcal{L}_{m})$
gravity. The analysis focuses on the combined effects of anisotropic pressure, perturbations, electric charge, and modified-
gravity source terms on the stability of compact objects. A specific equation of state is adopted to relate the static and perturbed variables through the adiabatic index. Using a perturbation scheme, we derive the modified hydrostatic
equilibrium and collapse equations and obtain instability constraints in both Newtonian and post-Newtonian regimes. The results show that the stability of the system is governed by the competition between inward gravitational attraction and outward pressure support. In addition, the dark source terms generated by the non-minimal matter-geometry coupling modify the collapse conditions and can enhance the stability of the charged fluid. These findings provide a useful framework for understanding the
evolution and collapse of dense self-gravitating compact objects in non-minimally coupled
gravity.
Read the full abstract ▾
All authors A. Rehman, M. Yousaf, Mohammed Zakarya, M. Aslam, Maram Ali
Computational Physics · Cross-listed from math.NA
A Memory-Efficient Adjoint State Optimization Method Based on Time-Reversible Dynamical Low-Rank Approximation
Lukas Einkemmer and Julian Mangott
The primary challenge of conducting PDE-constrained optimization for high-dimensional problems, such as kinetic equations, is the often prohibitive
memory cost. Computing gradients using the adjoint state method would require the storage of the entire time history of the forward solution. For such problems, where the
memory cost for storing a single instance of the forward solution can already be a limiting factor, this is clearly not feasible. In this paper, we propose a
memory-efficient adjoint state method that compresses the forward and adjoint solution with a dynamical low-rank approximation (a model order reduction technique) and bypasses the need to store the entire forward solution by employing a time-reversible low-rank integrator. The dynamical low-rank approach introduces a number of challenges: reversibility can fail in the rank-deficient case and the low-rank trajectories can show chaotic behavior. In particular, the latter has a number of important consequences for the optimization problem. We address those challenges and show that our method can drastically reduce the
memory requirement for gradient-based optimization of kinetic equations. In particular, we consider two examples from kinetic
plasma physics: optimizing beam profiles to suppress a bump-on-tail instability and shaping a particle beam using external electric fields.
Read the full abstract ▾
Mesoscale and Nanoscale Physics
Noise-Robust Spin-Orbit Qubit in Germanium Holes via p-Orbital Encoding
Yasuo Oda and Jason P. Kestner
Germanium hole
spin qubits are a leading platform for
semiconductor quantum computation due to their strong
spin-orbit coupling, all-electrical operability, and absence of valley degeneracy. A central obstacle is charge noise, which couples to the
qubit through the same
spin-orbit interaction that enables fast electrical control. In this work, we propose a new operational mode of a three-hole
quantum dot in a planar Ge/SiGe
heterostructure, modeled within a four-band Luttinger-Kohn–Bir-Pikus framework: a
spin-$p$-orbital (SpO)
qubit encoded in the $p$-shell of the topmost hole. We characterize charge noise sweet spots in the parameter space of electrostatic confinement and
magnetic field, and estimate that relaxation rates of the SpO
qubit are comparable to those of
spin qubits hosted in single holes. We then design and optimize an all-electrical Landau-Zener state-transfer protocol that induces logical
qubit state transitions without microwave driving, and we show that the quadrupole-quadrupole Coulomb interaction between neighboring dots enables fast two-
qubit entangling gates operated by adiabatic shuttling.
Read the full abstract ▾
Materials Science
Automated Analysis to Reveal Grain Boundary Phase Microstructures
R. Daniel Moore, Ian S. Winter, Robert E. Rudd et al. (+2 more)
We develop a method for analyzing grain boundary (GB) microstructures that identifies distinct interfacial phases and the dislocation line defects separating them. Similar to bulk materials, GBs can adopt multiple distinct interfacial phases and undergo first-order phase transitions. When these phases coexist, their spatial arrangement and phase junctions constitute a GB microstructure, characterized by variations in excess properties and line defects with associated dislocation content. Despite this intrinsic heterogeneity, our ability to quantitatively characterize GB microstructures remains limited, as it requires identification of individual GB phases, phase-resolved excess properties, and the Burgers content of phase junctions, capabilities not available in existing automated methods. Here, we present an automated tool that performs interfacial microstructure mapping for planar coincidence site
lattice GBs. The method identifies the spatial distribution of GB phases, quantifies phase-specific excess properties, and estimates the Burgers content of GB phase junctions. We demonstrate the approach using three representative cases: (i) quantification of mass transport during
diffusion-limited GB phase transformations; (ii) identification of structurally indistinguishable phases formed by vacancy and interstitial loops; and (iii) characterization of GB microstructures containing phase
nuclei. More broadly, this framework enables quantitative studies of GB
evolution processes, including spinodal decomposition and coarsening with direct implications for GB deformation, creep, and migration.
Read the full abstract ▾
All authors R. Daniel Moore, Ian S. Winter, Robert E. Rudd, Fadi Abdeljawad, Timofey Frolov
General Relativity and Quantum Cosmology
Electrically Charged Non-Abelian Black String in Anti-de Sitter Space
G. Alencar, R. N. Costa Filho, I. Jardim et al. (+1 more)
We construct a new family of static, electrically charged, cylindrically symmetric black-string solutions of four-dimensional Einstein–Yang–Mills theory with a negative cosmological constant, supported by a genuinely non-Abelian $SU(2)$
vortex field. The coexistence of electric and
vortex sectors renders the standard single-function Lemos metric inconsistent with the Einstein equations, requiring a three-function metric compatible with the anisotropic Yang–Mills stress tensor. Regular near-horizon and asymptotic AdS expansions provide boundary data for numerical integration of the complete field equations. Two limiting sectors are recovered: vanishing electric horizon datum yields the neutral Lemos black string with zero Yang–Mills field strength, while switching off the
vortex component gives the embedded $U(1)\subset SU(2)$ charged Lemos–Zanchin solution. Perturbations about the latter show that genuinely non-Abelian hair appears at linear order through the commutator field strength, whereas its backreaction on the electric profile and geometry begins at quadratic order. The horizon equations yield the analytic local non-degeneracy bound $R_1^{\rm crit}=s_0\alpha\sqrt{3/(4\pi G)}$. The asymptotic geometry exhibits a quadratic correction absorbable into an effective Abelian charge and a cubic coefficient giving the first irreducible asymptotic signature of the non-Abelian hair. The
entropy obeys the Bekenstein–Hawking area law, while the temperature difference from the embedded Abelian solution arises through the asymptotic lapse normalization. The fully backreacted numerical solutions are nonlinear realizations of this transverse non-Abelian deformation.
Read the full abstract ▾
All authors G. Alencar, R. N. Costa Filho, I. Jardim, Celio R. Muniz
General Relativity and Quantum Cosmology
Chiral symmetry and black hole isospectrality
Colin Weller, Dongjun Li, Pratik Wagle et al. (+3 more)
We prove that black-hole isospectrality between linearly independent solutions follows whenever radiative metric and matter perturbations are reconstructed from complex master variables obeying a closed, complex-linear system with complex-linear boundary conditions. If a phase rotation maps one parity sector to the other, then the even- and odd-parity QNM spectra coincide, and the perturbations are parity isospectral. A broad class of
chiral-aligned theories satisfies these criteria. As an application, we demonstrate that subextremal Kerr–de Sitter black holes are parity isospectral.
Read the full abstract ▾
All authors Colin Weller, Dongjun Li, Pratik Wagle, Andrew Laeuger, Yanbei Chen, Nicolás Yunes
Mesoscale and Nanoscale Physics
High Speed Contact-Resonance Tracking using Brownian motion
J. Bemis and R. Proksch
Contact-resonance atomic force microscopy (CR-AFM) provides nanoscale maps of contact stiffness, dissipation, and electromechanical response, but conventional piezoacoustic excitation can obscure the cantilever resonance with actuator and sample-holder modes. Pure Brownian excitation avoids this transfer-function background, yet its small amplitude generally requires averaging that is incompatible with routine imaging. We introduce interferometric dual-AC resonance tracking (iDART), which combines quadrature-phase differential interferometry with two-frequency resonance tracking. By positioning the interferometric spot near the displacement maximum of the first contact-resonance mode, the detector noise floor is reduced below the off-resonance thermal displacement of the cantilever. Brownian spectra identify the contact mode and define the tracking frequencies, while active electrical excitation provides the signal-to-noise ratio required for pixel-resolved imaging. Simultaneous low-frequency and resonant measurements show that both electrical and photothermal drive increases contrast in the amplitude and phase channels without appreciably shifting the contact resonance. These results establish a practical route to resonance-enhanced, drive free nanomechanical imaging at conventional AFM scan rates.
Read the full abstract ▾
Optics
Femtosecond Laser Induced Metallization in Silicon via Photon Momentum Mediated Band Transition
Ehatasham Haque, Sunjana Tarannum, Jannatul Shahrin Shoshi et al. (+1 more)
Silicon-based technology has been at the forefront of electronic and photonic research since the dawn of the electronic revolution. However, silicon is fundamentally an indirect-bandgap
semiconductor: the conduction band minimum and valence band maximum occur at different points in momentum space, so optical transitions require
phonon assistance to conserve
crystal momentum. This three-body electron-
photon-
phonon interaction renders silicon an inefficient material for light-absorbing applications such as
solar cells and optoelectronic devices. In this work, we build on an established nanoscale
photon-momentum confinement mechanism, which broadens the
photon momentum distribution and enables
phonon-free absorption in silicon, by subsequently applying a high-intensity femtosecond pulsed excitation that injects hot carriers beyond the Mott density, collapsing the bandgap and inducing a reversible
semiconductor-to-metal transition. While nanoscale
photon-momentum confinement itself has been previously established, the central contribution of this work is this subsequent, carrier density-driven stage, which drives the momentum-enhanced region into a reversible transient metallic phase. Our simulations report highly negative permittivity, enhanced optical power absorption, a large absorption coefficient, and low skin depth, with carrier densities reaching a notable value, far exceeding the Mott threshold. We have shown carrier driven metallization with stable operation below melting threshold of silicon. These results establish a general mechanism for dynamically inducing metallic states in silicon, offering a potential pathway toward monolithically integrated active photonic components and dynamically reconfigurable electro-optical devices within conventional CMOS platforms.
Read the full abstract ▾
All authors Ehatasham Haque, Sunjana Tarannum, Jannatul Shahrin Shoshi, Mahdy Rahman Chowdhury
Quantum Physics
Asymptotic entanglement in circle stabilizer states and states forbidding arbitrary vertex-minors
Kenneth Goodenough and Marcelo Sales
Stabilizer states play a central role in
quantum information theory, and understanding their
entanglement has motivated a large body of work. A well-studied question in particular is when a stabilizer state $|\psi\rangle$ can be transformed into another stabilizer state $|\phi\rangle$ using only single-
qubit Clifford operations and Pauli measurements. If this is possible, we say that $|\phi\rangle$ is a vertex-minor of $|\psi\rangle$. Assuming Geelen's weak structural
conjecture on vertex-minors, we establish the following general statement. For any fixed stabilizer state $|\phi\rangle$, the
entanglement in stabilizer states $|\psi\rangle$ that do not contain $|\phi\rangle$ as a vertex-minor is asymptotically constrained. More concretely, we show that the distance of any sufficiently rank-connected $|\psi\rangle$ not containing $|\phi\rangle$ as a vertex-minor grows as $O(\log n)$, and prove similar results for the so-called locally accessible information, a quantity that captures the amount of information that can be learned through single-
qubit Pauli measurements. Our results rely on (i) connecting the above two
entanglement measures to rank functions of multimatroids, (ii) connecting the rank functions of circle stabilizer states to rank functions on $4$-regular multigraphs, which asymptotically constrains the
entanglement of circle stabilizer states, and (iii) using Geelen's weak structural
conjecture on vertex-minors to `lift' the previous result to sufficiently connected states in proper vertex-minor-closed families of stabilizer states. Our results establish a connection between asymptotic stabilizer
entanglement and forbidden vertex-minors, with direct implications for the
entanglement that can be generated in
quantum devices.
Read the full abstract ▾
Materials Science
Machine-learned exchange-correlation functionals for molecules, solids, and reactive surfaces
Mohamed S. Abdallah, Zhuotao Jin, Boris Kozinsky et al. (+1 more)
The application of density functional theory to heterogeneous catalysis is hindered by the shortcomings of conventional density functional approximations. We combine machine learning with explicitly non-local physically informed descriptors and introduce an exchange-correlation functional (CIDER26SS) framework regularized for wide transferability. CIDER26SS is size-extensive, highly efficient, provides a balanced and accurate description of both molecular and solid-state systems, and is specifically well-optimized for transition metal surface chemistry. Surpassing existing conventional functionals, CIDER26SS resolves the CO/Pt puzzle, identifying the correct binding site for CO adsorption on the Pt(111) surface, along with an accurate adsorption energy, Pt
lattice constant, and surface energy. Predictions agree well with the experimental values, even when all bulk and surface data for Pt are excluded from the training set. Remarkably, CIDER26SS exceeds the accuracy of semilocal approximations even for systems far outside the training domain.
Read the full abstract ▾
All authors Mohamed S. Abdallah, Zhuotao Jin, Boris Kozinsky, Kyle Bystrom
Quantum Physics
Many-body ergodicity breaking from wavefunction snapshots
Riccardo Andreoni, Devendra Singh Bhakuni, Marcello Dalmonte et al. (+2 more)
Modern
quantum experiments can probe many-body wavefunctions through projective measurements, providing snapshots of individual many-body configurations. A fundamental question is whether the intrinsic structure of their measurement distributions can reveal
quantum dynamics beyond predefined observables. Here, we address this question at the many-body ergodicity-breaking transition using two complementary characteristics of nonequilibrium wavefunction snapshots: their binary intrinsic dimension (BID) and the
topology of wavefunction networks constructed from Hamming distances. We show that the critical point is characterized by an extensive but submaximal BID, and scale-free network connectivity with highly connected hubs. These signatures distinguish the ergodic, critical, and nonergodic regimes, and provide experimentally accessible probes of ergodicity breaking from projective measurement snapshots.
Read the full abstract ▾
All authors Riccardo Andreoni, Devendra Singh Bhakuni, Marcello Dalmonte, Lev Vidmar, Miroslav Hopjan
High Energy Physics (Theory)
What Neural Network Field Theory Can and Cannot Realise on a Computer
Thomas R. Harvey
One aim of neural network field theory is to put a
quantum or effective field theory on a computer, with the network ensemble itself as the theory. We ask how far that aim can be pushed for a function class regular enough to be computed with. Our main result is a no-go
theorem with assumptions that hold for standard network architectures. We use it to separate four versions of neural network field theory, according to whether the defining object is the finite width ensemble or its infinite width limit, and whether the target we want to compute is a
quantum or an effective field theory. Neither finite width interpretation is straightforwardly consistent. For finite width ensembles with finite variance at each point, the QFT interpretation fails reflection positivity, while the EFT interpretation establishes no scale separation by which the positivity violation can be placed outside its domain of validity. Of the two limit versions, one can be simulated in full and the other only in part, as only its smeared correlators are computable with a controlled error. As such, at the level of a controlled numerical computation, the QFT and EFT versions cannot be distinguished. One dimension escapes the obstruction, yet reflection positivity is shown to still fail there at every finite width for the cosine network. Two escapes from the
theorem remain, giving up either finite variance at a point or exact rotation invariance, and we discuss both of these possibilities.
Read the full abstract ▾
Astrophysics of Galaxies
Beyond orientation: Evidence for distinct physical regimes among Little Red Dots and Little Blue Dots
L. Barrufet, J. S. Dunlop, M. L. Hamadouche et al. (+6 more)
Little Red Dots (LRDs) and Little Blue Dots (LBDs) may represent the same population of compact active
galactic nuclei (AGN) observed along different lines of sight. We test this scenario using a spectroscopic sample from the DAWN JWST Archive, selected based on common criteria for H$\alpha$ equivalent width, UV continuum slope, and compactness. We use the optical continuum slope to distinguish between samples of 89 LRDs and 191 LBDs spanning $1 \lesssim z \lesssim 7.5$, and compare their continuum properties, H$\alpha$ emission, and Balmer decrements. Consistent with previous studies, we find that LRDs exhibit broader H$\alpha$ profiles than LBDs systematically (with median FWHM values of $2319^{+71}_{-64}$ and $1424^{+56}_{-43}~\mathrm{km\,s^{-1}}$, respectively). We also confirm that LRDs show larger Balmer decrements, with median $\log_{10}(F_{\rm H\alpha}/F_{\rm H\beta})=1.01\pm0.03$, compared with $0.47\pm0.01$ for LBDs. Line-of-sight effects could explain both results. However, most significantly, we find that the LRD fraction increases strongly with H$\alpha$ line luminosity: LRDs are approximately six times more luminous in H$\alpha$ than LBDs. This robust finding is much harder to explain through unification with LBDs by orientation. Despite their higher line luminosities, LRDs have a moderately lower median H$\alpha$ equivalent width than LBDs, consistent with more of the raw emission being reprocessed into the rest-frame optical continuum in LRDs. These results, coupled with the systematically lower [O III]/H$\beta$ ratios found in LRDs and the decline of H$\alpha$ equivalent width towards the reddest optical slopes, disfavour a simple orientation-based link between LRDs and LBDs, and are instead more consistent with the predictions of gas-cocoon models in which increasing gas column density explains the apparent transition from LBDs to LRDs.
Read the full abstract ▾
All authors L. Barrufet, J. S. Dunlop, M. L. Hamadouche, M. Mezcua, D. Herrero-Carrion, M. Santos-Lleo, R. Gottumukkala, D. Spinoso, C. T. Donnan
High Energy Physics (Phenomenology)
Disentangling Charged-Current Scalar NSI from the Solar Sector at JUNO
Adriano Cherchiglia, Pietro Chimenti, Christiane Frigerio Martins et al. (+3 more)
We constrain charged-current scalar non-standard interaction with reactor antineutrinos within a
quantum field theory framework of
neutrino oscillations. We derive an analytical expression up to $\mathcal{O}(\varepsilon^{4})$ for the electron antineutrino survival probability including scalar NSI contributions, and show that these effects induce spectral distortions that admit a large mixing angle solution for $\theta_{12}$. Using the 59.1-day and preliminary 207.2-day JUNO
datasets, we obtain the first
neutrino-oscillation determination of NSI parameters individually, rather than in a
flavor-summed combination, from reactor experiments. Assuming one year of data taken, we show that the only
solar sector analysis breaks the degeneracy with the
solar mixing angle at $3\sigma$ of C.L.
Read the full abstract ▾
All authors Adriano Cherchiglia, Pietro Chimenti, Christiane Frigerio Martins, Guilherme A. Nogueira, Pedro Pasquini, Orlando L.G. Peres
Instrumentation and Methods for Astrophysics
On the performance of pre-trained vision transformers for supernova spectral classification using different spectral representations
J. Serrano Bell, P. Gálvez Molina, V. Contreras Rojas et al. (+4 more)
The spectroscopic classification of
supernovae is a key component of time-domain astronomy and plays an important role in the identification of Type Ia events. The increasing volume and diversity of spectroscopic data motivate the development of automated classification approaches. In this work, we explore the use of
Transformer-based
vision models for
supernova spectral classification, focusing on how different visual representations of spectra and fine-tuning strategies affect classification performance when image-based architectures are applied to intrinsically one-dimensional data. We consider a
dataset of 4,011
supernova spectra, augmented and rebalanced into three astrophysically motivated classes: normal Type Ia, other Type Ia subtypes, and core-collapse
supernovae. Spectra are encoded as line-plot images using direct flux-wavelength visualizations as well as alternative flux-difference versus wavelength-difference heatmap representations designed to emphasize differential spectral structure. We evaluate several pre-trained
Transformer architectures, including
Vision Transformers (ViT), Swin
Transformers, and a DINOv3-pretrained ViT, and examine the effects of fine-tuning depth, visual representation, and hyperparameter choices. We find that a plain flux-wavelength line plot outperforms the purpose-built maps on average, though log-scale maps remain competitive for specific architecture and fine-tuning combinations. On the held-out test set, our best model (vitb-p16) reaches a macro-F1 score of 86.3%, with per-class F1 scores of 94% for normal Ia, 77% for other Ia subtypes, and 88% for core-collapse
supernovae. The dominant misclassification arises from confusion between Ia-91T and normal Ia spectra. These results demonstrate that
Transformer-based
vision models can provide competitive performance for single-spectrum
supernova spectral classification.
Read the full abstract ▾
All authors J. Serrano Bell, P. Gálvez Molina, V. Contreras Rojas, W. Fox Fortino, M. Rojas, P. Protopapas, F. Bianco