Materials Science
Compositional gradient engineering for enhanced ferroelectricity in ultrathin AlScN
Zekun Hu, Haiwen Zhang, Rajeev Kumar Rai et al. (+12 more)
Ferroelectric AlScN is promising for CMOS-compatible non-volatile
memory, but thickness scaling is limited by leakage, premature breakdown, and defect-mediated failure. Here we show that compositional grading within a continuous wurtzite AlN-AlScN
lattice mitigates these limitations by distributing structural and polarization discontinuities across the film thickness, reducing defect formation and local field concentration. In a 20 nm graded
heterostructure, monotonic Sc incorporation and AlN-rich boundaries produce reversible ferroelectric switching, an as-grown metal-polar state, a 21% higher breakdown field, 10% enhanced remanent polarization, and 40x higher resistivity relative to homogeneous AlScN. Time-domain PUND measurements reveal strongly suppressed post-switching leakage, consistent with reduced defect-assisted and polarization-coupled conduction. This improved dielectric robustness enables ferroelectric functionality in 5 nm graded stacks containing only a 2 nm $\mathrm{Al}_{0.64}\mathrm{Sc}_{0.36}\mathrm{N}$ region, with measurable switching near 1 V. These results establish compositional grading as a defect- and field-management strategy for scalable ultrathin wurtzite ferroelectrics.
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All authors Zekun Hu, Haiwen Zhang, Rajeev Kumar Rai, Yuhong Cao, Xiaolei Tong, Pedram Yousefian, Hyunmin Cho, Bongjun Choi, Chao-Chuan Chen, Yunfei He, Kefei Bao, Chloe Leblanc, Eric A. Stach, Roy Olsson, Deep Jariwala
Plasma Physics
Hierarchical Framework of Runaway Electrons using Deep Learning
Tyler Mark and Christopher McDevitt
We present an adjoint deep learning framework describing the
evolution of fluid moments and the energy distribution of the runaway electron (RE) population. We demonstrate that a careful formulation of the adjoint problem allows for the temporal
evolution of these quantities for arbitrary initial electron distributions, and in combination with a physics-informed neural network (PINN), we show that the resulting surrogates can resolve a broad range of
plasma parameters. This combination of the adjoint formulation and rapid inference of neural networks enables orders of magnitude faster predictions of RE kinetics than traditional methods. Here, we detail the mathematical formulation and the design of three PINNs which recover the temporal
evolution of the RE current, average energy and energy distribution. Predictions are validated against a traditional RE solver, with good agreement across a broad range of scenarios.
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Cosmology and Nongalactic Astrophysics
Galaxy formation in modified gravity – II. galaxy halo connection and assembly bias
Michael Collier, Sownak Bose and Baojiu Li
Modern surveys such as DESI and Euclid, which collect data for hundreds of millions of
galaxies to map the large-scale structure (LSS) of the Universe, hold the key to determining the cosmological parameters and testing new physics. This ambition, however, is limited by uncertainties in the
galaxy-
halo connection: the link between observed
galaxies and the underlying, unobservable matter field, by accounting for effects such as
galaxy bias and assembly bias (AB). These are particularly poorly-understood for modified
gravity (MG) models, which are popular alternatives to the cosmological constant to explain accelerated expansion. We approach this problem using mock emission line
galaxy (ELG) and luminous red
galaxy (LRG) catalogues in $f(R)$
gravity matching the specifications of ongoing Stage-IV
galaxy surveys, generated from state-of-the-art MG hydrodynamical simulations. While the interplay between MG – especially the chameleon screening mechanism – and
galaxy formation leaves complicated imprints in the
galaxy-
halo connection, a simple physical picture emerges in which
halo and
galaxy formation are enhanced for progressively more massive
haloes over time. We confirm that the basic
galaxy-
halo connection model, the
halo occupation distribution (HOD), in which
galaxy occupation is determined solely by
halo mass, underestimates
galaxy clustering strength in $\Lambda$CDM by $10$–$20\%$ at $z\lesssim1$ when neglecting AB, and demonstrate that MG introduces further complexity. Extending this model with a suitably-chosen environment density as a secondary HOD variable reduces the AB effect in all models to $2$–$3\%$ for $z\lesssim0.5$. This provides a well-motivated starting point for further works on minimising the impact of AB when testing non-standard cosmological models with LSS.
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Physics and Society
SCAR dynamics of adolescent substance use: peer influence, dropout, and bifurcation structure in a school-based model
Tamantha Pizarro, Jinni Su, Yixuan He et al. (+1 more)
We develop a four-compartment susceptible–casual–addicted–resistant (SCAR) model for adolescent substance use in a high-school setting. The model divides students into susceptible non-users, casual or experimental users, students with sustained or substance-use-disorder (SUD)-level involvement, and resistant students in protective anti-use environments. It includes peer-driven initiation, escalation from casual to problematic use, protective peer influence, school disengagement, and partial re-entry after rehabilitation. Qualitative analysis and bifurcation diagrams show three main results. First, the return parameter \(\phi\) separates two regimes: when \(\phi=1\), the total population is conserved and interior
equilibria may exist; when \(\phi<1\), problematic use causes net school-population loss, so positive scaled
equilibria may not represent true endemic
equilibria. Second, initiation and escalation are governed by distinct thresholds, meaning first use and progression to problematic use are dynamically different. Third, the model can exhibit multistability, including bistability between a substance-free state and a stable high-use state, so long-term outcomes may depend on initial conditions. These findings suggest that effective school policy should combine universal prevention, early intervention for casual users, targeted support for students at risk of problematic use, recovery-supportive environments, and strong school re-engagement pathways.
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All authors Tamantha Pizarro, Jinni Su, Yixuan He, Yun Kang
High Energy Physics (Theory)
The state/defect correspondence
Adrien Arbalestrier, Elise Paznokas and Stathis Vitouladitis
We formulate a one-to-one correspondence between states and defects for higher-form gauge theories in arbitrary dimensions. The correspondence is not predicated on conformal invariance, as these theories are in general not conformal. Instead, it relies on the existence of infinitely many conserved charges associated with the mixed anomaly of electric and
magnetic higher-form
symmetries. In $p$-form Maxwell theory, these charges generate an extended Kac-Moody
algebra that acts simultaneously on states and on extended operators. We show that this
algebra organizes the
Hilbert space on $S^p \times S^{d-p-1}$ into highest-weight representations allowing for a direct identification between states and $p$-dimensional defects. In particular, Wilson-'t Hooft defects dressed with local gauge-invariant operators are mapped to squeezed energy eigenstates. We further relate these novel
symmetries to higher-
spin currents and demonstrate that their construction persists in a class of interacting non-linear electrodynamics theories.
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Computational Physics
Feature-preserving Latent-EnKF for Data Assimilation of Flows with Shocks
Hemanth Chandravamsi, Hangchuan Hu, Ponkrshnan Thiagarajan et al. (+1 more)
The ensemble Kalman filter (EnKF) is widely adopted for sequential data assimilation, but fails for solutions with discontinuities, such as shocks in compressible flows. For ensembles with uncertainty in discontinuity location, the EnKF analysis can lose physical consistency, which can be viewed through three lenses: (i) bimodal pointwise statistics in the forecast ensemble, (ii) mixed-sign analysis weights in the affine superposition of forecast members, and (iii) spatially distributed Kalman-gain profiles that modify the state around a discontinuity rather than translating it coherently. In order to preserve flow features in the analysis state and, as such, maintain physical consistency, a feature-preserving latent-EnKF is introduced. The proposed method performs the ensemble update in a low-dimensional latent space learned by a coordinate-conditioned auto-decoder. The latent representation retains near-Gaussian ensemble statistics and provides coordinates in which flow features vary coherently across the forecast ensemble. The EnKF updates performed on the latent codes are decoded into coherent changes in the represented flow features, translating shocks through coordinate morphing rather than superposing them at displaced locations. The corresponding Kalman-gain profiles generated by the latent-EnKF exhibit an approximately step-like variation across the discontinuities, allowing the fronts to translate while preserving sharp features and monotonicity. Sod shock-tube, Mach~2 shock-cylinder, and immersed-body shape-inference tests with sparse, noisy observations demonstrate accurate recovery of shocks and contact discontinuities without spurious oscillations.
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All authors Hemanth Chandravamsi, Hangchuan Hu, Ponkrshnan Thiagarajan, Tamer A. Zaki
Quantum Physics
New bounds on private simultaneous quantum message passing
Uma Girish, Alex May, Natalie Parham et al. (+1 more)
In the private simultaneous message (PSM) setting, $k$ players obtain inputs $x_i\in\{0,1\}^n$ and then each send messages to a referee, who should learn $f(x_1,...,x_k)$ but no other information about $(x_1,...,x_k)$. The PSM setting was introduced as a minimal model for secure multiparty computation and has connections to Boolean function complexity. In the
quantum setting, PSM has been related to non-local
quantum computation (NLQC). The communication and correlation cost of implementing PSM remains poorly understood. Here, we give new upper and lower bounds on the (
quantum) PSM model. For lower bounds, we show: 1) Nečiporuk's measure lower bounds the
entanglement required for $k$-player
quantum PSM with perfect correctness. This leads to quadratic lower bounds for explicit functions. 2) The rank of the communication
matrix of $f(x_1,x_2)$ lower bounds 2-player
quantum PSM with perfect
privacy but imperfect correctness. This implies a previously unknown lower bound on classical PSM with imperfect correctness. When allowing
quantum communication and shared
entanglement, these are the first lower bounds on
quantum PSM that make use of the
privacy condition. For upper bounds, we show: 1) Letting $s$ be the size of a
quantum circuit computing $f$, $d_f$ be the
circuit depth, $k$ the number of players, $n$ the number of bits received by each player, and $\epsilon$ a correctness parameter, we obtain $\mathsf{PSM}_k^*(f) \leq (kn +s) \cdot \log^{O(d_f)}(s/\epsilon)$. 2) The square of the
Fourier 1 norm of $f$, $\Vert \hat{f}\Vert_1^2$, upper bounds the classical PSM complexity, $\mathsf{PSM}(f)\leq O(\Vert \hat{f} \Vert^2_1)$. In proving the first upper bound, we generalize existing $T$-depth based techniques for NLQC from $2$ to $k\geq 2$ parties, and consider cases where the Clifford layers are restricted to having small light cones.
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All authors Uma Girish, Alex May, Natalie Parham, Henry Yuen
Materials Science
Hierarchical Interdiffusion Kinetics in Nanoscale Ni/Al Multilayers
S.S. Riegler, I. Gallino, N.J. Peter et al. (+11 more)
Reactive metallic multilayers store chemical energy that can be released rapidly through interdiffusion and intermetallic formation. Predictive control of this heat release requires distinguishing transport and phase-formation processes that occur in rapid succession. Here we combine free-standing nanoscale Ni/Al multilayers with chip-based flash calorimetry and isoconversional kinetic analysis over five orders of magnitude in heating rate. Selected reaction states are quenched and examined by scanning transmission electron microscopy. This workflow separates pre-ignition interdiffusion into two regimes and quantifies activation energies of (81 $\pm$ 24) and (168 $\pm$ 17) kJ/mol, consistent with grain-boundary and
lattice diffusion of Ni in Al, respectively. Microscopy supports this assignment: no significant compositional changes are observed after the first regime, whereas the second increases the Ni content of the Al layers and produces Ni-enriched features spaced by 5$-$10 nm, matching the Al grain size. These results identify the Al grain-boundary network as the dominant low-barrier pathway, providing rapid transport across the Al layers and priming
lattice-mediated mixing and intermetallic phase formation. More broadly, the workflow links calorimetric signatures to pathway-specific kinetics and transient microstructures, enabling direct assessment of how microstructural design redirects coupled transport and reaction pathways in reactive multilayers and other materials driven far from
equilibrium.
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All authors S.S. Riegler, I. Gallino, N.J. Peter, A. Tarasov, T. Meyer, J. Schmauch, C. Pauly, M. Frey, Y.H. Sauni Camposano, H. Bartsch, R. Schwaiger, P. Schaaf, R. Busch, J. Arlt
Cosmology and Nongalactic Astrophysics
Complex yet Hermitian: Gaussian covariance of cross-correlation and multi-tracer power spectra
Federico Montano, Stefano Camera, Emiliano Sefusatti et al. (+1 more)
Accurate modelling of the covariance of clustering observables is essential to fully exploit current and future survey data, which is expected to constrain large-scale clustering signals with unprecedented precision. Computational costs of simulation-based estimates motivate analytical approaches, especially in light of the growing interest towards multi-tracer analyses and parity-odd signatures in two-point statistics, which respectively mitigate
cosmic variance and probe relativistic projection effects on cosmological scales. In this work, we generalise previous theoretical results for the Gaussian covariance of multi-tracer power spectrum measurements, providing a general expression applicable to both real (even-parity) and complex (both even- and odd-parity) power spectra. We focus on a generic weighted
estimator at first, and then showcase how our general formalism applies to Legendre power spectrum multipoles and two-dimensional power spectrum, recovering known limits in appropriate cases. We validate our predictions against Gaussian Monte Carlo simulations and investigate the structure of the covariance
matrix, including the Hermitian properties of its imaginary part.
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All authors Federico Montano, Stefano Camera, Emiliano Sefusatti, Mohamed Yousry Elkhashab
High Energy Physics (Theory)
Tachyonic Encore: A universal shift of inflationary observables
Diogo S. Gorgulho, Margherita Putti, Rodrigo Gonzalez Quaglia et al. (+3 more)
We propose a generic mechanism applicable to single-field inflaton models in which a light
axion spectator, initialized near the hilltop of its potential, reshapes inflationary observables through purely gravitational multi-field dynamics. During inflation the
axion is frozen and the background follows an effectively single-field trajectory. After inflation ends, the
axion rolls, inducing a turn in field space and transient tachyonic phases of the isocurvature mode. The resulting “tachyonic encore” occurs entirely on super-horizon scales. These phases generate a nearly scale-invariant enhancement of the
curvature power spectrum, suppressing the tensor-to-scalar ratio and shifting the scalar tilt to a weighted combination of adiabatic and entropic tilts at horizon crossing. We show that these effects can reconcile otherwise disfavored inflaton potentials with current CMB constraints. The same dynamics predict local non-Gaussianity, $f_{\rm NL}^{\rm loc.}\sim \mathcal{O}(1)$, within reach of upcoming surveys.
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All authors Diogo S. Gorgulho, Margherita Putti, Rodrigo Gonzalez Quaglia, Ema Dimastrogiovanni, Matteo Fasiello, Diederik Roest
Astrophysics of Galaxies
Constraining the Geometry of Galactic Dark Matter with Gaia Data Release 3
Francesco Sylos Labini and Roberto Capuzzo-Dolcetta
We derive both the mid-plane and off-plane rotation curves, $v_c(R,z)$, and the vertical acceleration, $a_z(R,z)$, of the Milky Way (MW) using
Gaia~DR3 data over the ranges of vertical heights $z \in (-2,2)\,$ kpc and galactocentric distances $R \in (8.5,14)$ kpc where the velocity components are determined with high precision, i.e., with an error $< 5\%$. In contrast, the vertical acceleration $a_z(R,z)$ is dominated by model-dependent systematics, with uncertainties of up to $\sim 20\%$. This level of accuracy allows us to place stringent constraints on the geometry of the MW's dark matter (DM) distribution, as the vertical gradients of the gravitational potential attain their maximum within this range of radial and vertical distances corresponding to the characteristic scales of the disk. We find that models including the observed
stellar components together with a spherical DM
halo fail to reproduce both the pronounced variation of $v_c(R,z)$ with height and the observed behavior of $a_z(R,z)$. In particular, spherical
halos with a scale radius of $r_s \sim 15$ kpc contribute negligibly to the off-plane rotation curve and vertical acceleration in the inner disk, leaving these features primarily determined by the
stellar mass distribution. Conversely, models in which DM is confined to a flattened, disk-like configuration predict substantial contributions to both $v_c(R,z)$ and $a_z(R,z)$, resulting in a markedly better agreement with the data. We conclude that disk-like DM distributions are strongly favored over spherical
halo models. Forthcoming
Gaia data releases will enable even more stringent tests of the geometry and distribution of the MW's DM component.
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High Energy Physics (Theory)
Vacuum photon emission and mean electromagnetic field in pair-creating external backgrounds
I. A. Aleksandrov, E. V. Perelygin and D. V. Chubukov
We develop a perturbative description of
vacuum radiative processes in
quantum electrodynamics with a prescribed external electromagnetic background capable of producing electron-positron pairs. Since the initial
vacuum is then unstable and the in- and out-
vacua are inequivalent, radiative observables require a real-time formulation beyond the ordinary in-out approach of
vacuum-stable QED. Using the Keldysh-Schwinger-Fradkin nonequilibrium technique, we derive the mean number density of emitted
photons through the second nonvanishing order in the fine-structure constant. The leading term, of order $\alpha$, reproduces the known vertex and tadpole mechanisms, while the complete order-$\alpha^2$ correction contains interference, loop, and induced-current contributions. We also give an independent derivation based on the spectral decomposition of the identity operator in the in-Fock space, where the
photon number density is represented as a sum of squared transition amplitudes and
vacuum-disconnected terms are canceled by the optical
theorem generalized to an unstable
vacuum. In addition, we compute the mean electromagnetic field through order $e^3$, including the electromagnetic dressing of the induced
vacuum current, and verify it using the corresponding Schwinger-Dyson equations. The final formulas are expressed in terms of exact solutions and propagators of the Dirac equation in the external background and apply to general spacetime-dependent field configurations.
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High Energy Physics (Phenomenology)
Polarization Formalism for Photon-Gravitational Wave Mixing Around Magnetars
Jean-Simon Côté and Jean-François Fortin
The Gertsenshtein effect can be used to probe the
stochastic gravitational wave background at high frequencies, well above the range of standard cosmological sources. In this paper, we revisit the conversion between electromagnetic and gravitational waves in the magnetosphere of magnetars by solving the
evolution equations of the associated Stokes parameters. In the process, we point out that the adiabatic approximation usually taken in the literature is not generally justified in the context of the Gertsenshtein effect. To derive analytical results, we focus our
attention on two specific geometries where the adiabatic approximation is valid. From these, we derive a lower bound on the
stochastic gravitational wave background from the conversion of magnetar electromagnetic emission into gravitational waves, and an upper bound by requiring that the conversion of background gravitational waves into electromagnetic radiation does not exceed the observed magnetar flux in the X-ray band. Our results demonstrate that gravitational waves generated through the Gertsenshtein conversion of magnetar electromagnetic emission produce a negligible
stochastic background, as anticipated.
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Quantum Physics
Spectral analysis of equilibration: information leakage in isolated quantum systems
André T. Cesário, Marcos G. Alpino, Reinaldo O. Vianna et al. (+1 more)
We develop a unified dynamical-spectral framework for equilibration in isolated
quantum systems based on a subspace coarse-graining approach. Central to our formulation is the Leakage Fidelity Function (LFF), defined as the probability that a unitarily evolving state escapes the support of its initial subspace. This quantity provides a direct, operational measure of information flow and
memory loss without invoking ensemble assumptions or perturbative arguments. We derive universal bounds on temporal fluctuations of the LFF, in terms of the spectral gap structure and the square of the effective dimension, evincing that large spectral delocalization suppresses fluctuations and guarantees equilibration on average. By introducing spectral power distributions and associated entropic measures, we establish a quantitative link between phase mixing, gap participation, and dynamical stability. We further investigate the equilibration timescale by connecting the LFF to
quantum speed limits, thereby revealing the average time required for equilibration. Our results provide a state-dependent, geometrically transparent perspective on how spectral complexity and subspace information leakage jointly govern irreversibility in closed
quantum many-body systems.
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All authors André T. Cesário, Marcos G. Alpino, Reinaldo O. Vianna, Tiago Debarba
Superconductivity
Dynamical Control of Superconductivity in Superconductor-Ferromagnet Bilayers
Dimitri Pimenov, Nicholas R. Poniatowski, Charlotte G. L. Bøttcher et al. (+2 more)
We study a simplified model of a
ferromagnetic metal proximitized by a fully-gapped $s-$wave
superconductor and integrated with a microwave resonator. The low-energy excitations in the combined system consist of
ferromagnetic magnons, Bogoliubov excitations of the
superconductor, and cavity
photons. We show here that when the
magnons and
photons have comparable frequencies and are subject to an external drive, the hybridized driven
magnon-polaritons induce a non-
equilibrium crossover from the expected proximitized nodal $p-$wave
superconductor to a fully gapped $(p_x+ip_y)-$
superconductor. Moreover, the characteristic crossover temperature is inversely related to the
magnon-
photon detuning. We compute the temperature-dependent renormalization of the cavity
photon frequencies across this nodal to nodeless
evolution, which modifies the kinetic inductance of the resonator, and find a number of non-trivial features tied to the non-
equilibrium (i.e., driven) nature of the problem. We compare and contrast these results with a recent
circuit quantum electrodynamics (cQED) based experiment studying a permalloy-niobium
bilayer, where a non-trivial dependence of the low-temperature cavity response on the
magnon-
photon detuning was observed. Our results pave the way for a principled exploration of engineering novel states of matter by coupling cavity
photons to electronic collective modes in correlated two-dimensional materials and interfaces.
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All authors Dimitri Pimenov, Nicholas R. Poniatowski, Charlotte G. L. Bøttcher, Amir Yacoby, Debanjan Chowdhury
High Energy Astrophysical Phenomena
Spectral analysis of magnetized advective accretion flows around rotating black holes
Mayank Pathak, Shubhrangshu Ghosh and Banibrata Mukhopadhyay
The spectra of an
accretion disk around black holes are the basic diagnostic tool to enlighten the underlying flows and then black holes.
Accretion flows around black holes, however, are controlled by parameters like the
magnetic field,
spin of the black hole,
accretion rate and temperature of the flow. These quantities affect the (magneto)hydrodynamics of the flow thus consequently lead to variations in the spectrum. We first consider numerical steady state magnetohydrodynamic (MHD) solutions of magnetized
accretion flows around black holes to study the dependence of the spectra on these disk properties. The spectrum exhibits strong dependence on the
spin of the black hole,
accretion rate,
magnetic field and the electron temperature of the flow. Variations in these quantities influence the emission peaks and overall luminosity, which can be a tell-tale sign to extract physics of observed spectra. We further validate our results with general relativistic MHD (GRMHD) simulations using the standard and normal
evolution (SANE) and magnetically arrested disk (MAD) vector potentials. We consider two black hole
spins ($a=0.5$ and $a=0.9375$) to model the
magnetic field configurations and study the resulting spectra by comparing MAD and SANE results. We find a large difference in the bolometric luminosities and the location of the emission peaks between SANE and MAD flows. Certain properties of the spectra, like, the ratio of synchrotron radiation to synchrotron self-Comptonization peaks in SANE and MAD, show drastically distinct features. The overall luminosity combined with such metrics can distinguish the
magnetic field characteristics in astrophysical systems.
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High Energy Astrophysical Phenomena
Implementation of multi-grid Poisson solver in numerical relativity and its application to gravitational collapse of massive star
Kenta Kiuchi and Hirotada Okawa
We develop a new grid-based multi-grid Poisson solver in numerical relativity. We report the performance of the multi-grid Poisson solver in the initial value problems for two-puncture black holes, a static spherical
neutron star, a uniformly rotating
neutron star in
equilibrium, and a gravitationally collapsing massive
star. As a demonstration, we conduct a numerical-relativity
neutrino-radiation-transfer hydrodynamics simulation of the gravitational collapse of the $9M_\odot$ massive
star in Ref.~\cite{Aguilera-Dena:2020mfh} up to the core bounce. During the simulation, we employ the constraint-preserving regird prescription with the newly developed multi-grid Poisson solver to improve the resolution. It shows that the baryonic mass, the Arnowit-Deser-Misner (ADM) mass, and the ADM-like angular momentum are, respectively, preserved with $O(10^{-3})\%$ and $O(10^{-2})$–$O(10^{-1})$% accuracy.
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Astrophysics of Galaxies
DESI as sparse Integral Field Spectrograph I: Spatially resolved chemical enrichment in star-forming galaxies at $z\leq0.1$
Vibhore Negi, Ravi Joshi, B. Vishnupriya et al. (+8 more)
We present a spatially resolved chemical abundance analysis of 2291
star-forming
galaxies at $z \leq 0.1$, spanning nearly four orders of magnitude in
stellar mass ($8 \le \rm log (M_{\star}/M_{\odot}) \le 11.5$), by exploiting the multi-fibre spectra from the Dark Energy Spectroscopic Instrument (DESI) as a sparse integral field spectrograph. In the inner regions ($<2R_e$), the radial gas-phase
metallicity profiles show an outward-declining trend for massive
galaxies, with the steepest gradient ($\nabla_{log(O/H)}$) $\sim-0.08$ dex/R$_{e}$, whereas low-mass
dwarf galaxies exhibit nearly flat profiles ($\nabla_{log(O/H)}\sim-0.02$ dex/R$_{e}$). The large galactocentric radii ($\sim$5 R$_{e}$) probed in this study, reveal flat
metallicity profiles near the disk-
halo interface. Strikingly, these flat
metallicity values are consistent across a wide
stellar mass range, likely reflecting the influence of low SFR and metal poor inflows in the outer regions. The
metallicity gradient -
stellar mass relation exhibits a turnover at $\log(M_\star/M_\odot) \sim 10.5$, beyond which gradients become shallower, possibly driven by the chemical
equilibrium in the inner disk of massive
galaxies and/or dilution from
cosmic gas
accretion. At fixed
stellar mass, a strong size dependence is observed, where compact
galaxies show flatter gradients and higher central enrichment than their extended counterparts. The abundance gradients are further linked with the
stellar age distribution within the
galactic disk, where
galaxies with younger outskirts show steeper gradients than the ones with older outskirts, consistent with ongoing inside-out disc growth sustaining centrally concentrated chemical enrichment. These results underscore the interplay of
star formation efficiency,
stellar feedback, and metal-poor gas
accretion in governing the radial chemical structure in
galaxies.
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All authors Vibhore Negi, Ravi Joshi, B. Vishnupriya, Xue-Bing Wu, Hassen M. Yesuf, Luis C. Ho, Ayan Acharyya, Ramya Sethuram, Abhijeet Anand, Michele Fumagalli, Celine Peroux
High Energy Physics (Theory)
Toward Entanglement Bootstrap for Conformal Field Theory in Any Dimension
Rolando Ramirez Camasca, Xiang Li, Ting-Chun Lin et al. (+1 more)
Given a
quantum critical wavefunction in any dimension, we propose a reconstructed
Hamiltonian, analogous to the ones previously found for 1+1d CFT and for 2+1d bosonic
liquid topologically-ordered states. We test numerically that, for known regularized approximate CFT groundstates (on the icosahedron and the fuzzy sphere), (1) they are close to the groundstate of their reconstructed
Hamiltonian, and (2) the spectrum of their reconstructed
Hamiltonian on the unit sphere has CFT properties (integer spacing of descendants) and matches known low-lying energies. We show that this provides an automated method to improve the finite-size effects in a fixed
Hilbert space.
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All authors Rolando Ramirez Camasca, Xiang Li, Ting-Chun Lin, John McGreevy
Quantum Physics
Unifying spacetime approaches to quantum mechanics
N. L. Diaz, M. Cerezo and Paolo Braccia
Recent efforts to formulate
quantum mechanics in a way that treats space and time on a more equal footing have led to a large variety of spacetime-oriented approaches. In this work we present a detailed study of spacetime states, the objects that play the role of
quantum states in the recently introduced framework of spacetime
quantum mechanics, and show that the main proposals in the literature are different manifestations of the same underlying object. Path integrals,
quantum states over time, pseudo-density
matrices, the Page and Wootters mechanism, superdensity operators, and timelike-
entanglement proposals all arise from spacetime states through particular evaluations, reduced information, linear maps, or
quantum channels. This unification provides explicit mathematical representations of these formalisms, reveals relations among them, and clarifies the spacetime information each one captures. We also study the broader relevance of the spacetime-state point of view for Leggett-Garg inequalities, OTOCs, temporal tensor networks, fermionic systems, relativistic QFTs,
quantum reference frames, and classical physics, together with additional insights and perspectives revealed by the common unifying framework.
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Statistical Mechanics
Influence-solvability: a systematic theory of $(1+1)D$ solvability and its application to brickwork circuits
Friedrich Hübner and Sun Woo P. Kim
`Solvable'
circuits, such as dual
unitaries and its generalisations, have arisen as paradigmatic examples of tractable chaotic non-
equilibrium dynamics, both in classical and
quantum systems. However, while increasingly complicated sufficient conditions have been proposed, a systematic theory classifying and understanding general features of Solvable
circuits is missing. In this work we develop such a theory by deriving the most general local necessary and sufficient conditions under which a $(1+1)D$
circuit is Solvable. Concretely, we define a
circuit to be influence-solvable if its influence
matrix, representing the `bath' generated by its own
evolution, is given by a uniform MPS with finite bond-dimension $\chi$. This property allows for efficient computation of subsystem dynamics and essentially contains all known examples of Solvable
circuits. The set of necessary and sufficient local conditions follows from a new version of the fundamental
theorem of MPS for open boundary conditions. Next, we apply our theory to brickwork
circuits with $\chi=1$ influence-solvability and perform a systematic classification of classical brickwork
circuits with local dimension up to $d=3$ and
quantum brickwork
circuits with $d=2$. Our search reveals new Solvable
circuits that are not captured by known conditions.
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High Energy Physics (Theory)
Wigner continuous-spin equations in $\mathbf{AdS_D}$: bosonic and fermionic cases
Lev N. Astrakhantsev, Anastasia A. Golubtsova and Mikhail A. Podoinitsyn
We construct Wigner-like equations of motion for symmetric continuous-
spin fields in anti-de Sitter space of arbitrary dimension, treating both the bosonic and fermionic cases. We generalise the classical flat-space Wigner constraints for bosonic continuous-
spin fields, and for the fermionic case we adopt the equations proposed by Bekaert and Mourad as our starting point. This is achieved by covariantising the ordinary derivatives and deforming the resulting constraints so that they form a closed
algebra. The construction is carried out in a metric-like formalism and yields a system of first-class constraints that define a representation of the $\mathfrak{so}(2,D-1)$ isometry
algebra, realised via the Lie-Lorentz derivative. Using these constraints, we compute the
eigenvalues of the quadratic and quartic Casimir operators and compare the obtained values with Metsaev's classification of continuous-
spin representations for both the bosonic and fermionic cases. A crucial algebraic role is played by special operators of the (super)
algebra Howe-dual to the Lorentz subalgebra $\mathfrak{so}(1,D-1)$: the $\mathfrak{sl}(2)$ Casimir operator in the bosonic case, and the Casimir's ghost of the $\mathfrak{osp}(1|2)$ superalgebra in the fermionic case. Both objects naturally organise the constraint
algebra and ensure its consistency.
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Astrophysics of Galaxies
Getting to know the Stellar Clusters in NGC 1569: Bayesian inference of stellar cluster properties in a dwarf starburst galaxy
Bjarki Björgvinsson, Anna F. McLeod, Bronwyn Reichardt Chu et al. (+3 more)
We present a
Bayesian analysis of
star clusters in the
dwarf starburst
galaxy NGC 1569 based on high-resolution Hubble Space
Telescope imaging combined with integral-field spectroscopy from the Keck
Cosmic Web Imager, obtained as part of the DUVET survey. For each cluster identified, we infer posterior probability distributions for mass and age using a forward modelling method that properly accounts for uncertainties due to
stochastic sampling of the IMF. We investigate how the inferred properties depend on photometric coverage by repeating the analysis with different filter combinations, including mock extensions to the ultraviolet and near-infrared that emulate the addition of HST UV bands and James Webb Space
Telescope imaging. We find that, while inclusion of these wavelength regimes further breaks age and mass degeneracies, the currently available data yields reasonably strong constraints on cluster parameters. We compare inferred cluster properties to the conditions of the local interstellar medium, and find evidence for multiple interesting correlations. The truncation mass of the cluster mass function varies with galactocentric distance, particularly moving off the disk, consistent with a dependence on the density of the interstellar medium. Cluster mass positively correlates with
metallicity, suggesting that massive clusters preferentially form in pre-enriched gas, and the ionisation state of the gas, reflecting the increased prevalence of high-mass
stars in high-mass clusters. These results demonstrate the power of
Bayesian, initial mass function-aware modelling for resolving cluster populations in nearby starburst
dwarfs and provide new insight into how cluster formation and feedback respond to local
galactic conditions.
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All authors Bjarki Björgvinsson, Anna F. McLeod, Bronwyn Reichardt Chu, Magdalena J. Hamel-Bravo, Deanne B. Fisher, Mark R. Krumholz
High Energy Physics (Phenomenology)
Directional dark matter signatures of the Large Magellanic Cloud
Javier Reynoso-Cordova, Nassim Bozorgnia and Marie-Cécile Piro
The Large Magellanic Cloud (LMC), the most massive satellite of the Milky Way (MW), can significantly perturb the local dark matter (DM) distribution. We study its impact on directional DM detection using the Auriga cosmological simulations of a MW analogue hosting an LMC analogue. We find that the LMC induces strong anisotropies in directional
recoil signals, driven primarily by the non-zero mean azimuthal velocity of the local DM distribution. The characteristic ring-like feature predicted in the Standard
Halo Model (SHM) for heavy DM and low
recoil energies is strongly distorted, producing an asymmetric
recoil pattern concentrated at preferred azimuthal angles. Differences between
recoil maps for the MW-LMC analogue and the SHM reach up to $\sim80\%$ near the signal maximum. These distortions significantly enhance directional discovery prospects, reducing the number of events required to reject isotropy by nearly a factor of five for a 100 GeV DM particle in a near-future CYGNUS-like experiment, and by even larger factors for heavier DM. Our results highlight the importance of the LMC for interpreting and optimizing future directional DM searches.
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High Energy Physics (Theory)
Higher Gauge Theory via Differential Nonabelian Cohomology
Hisham Sati and Urs Schreiber
This is a streamlined introduction to the global (infrared) completion of Maxwell-type higher gauge fields (as in the higher gauge sectors of higher dimensional supergravity and its brane probes) by electromagnetic flux quantization in differential nonabelian
cohomology, using cohesive homotopy theory. Applications include D/NS brane charge in (unstable) K-theory, M-brane charge in unstable Cohomotopy and
geometric engineering of topological
quantum order on probe M5-branes.
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High Energy Physics (Phenomenology)
Constraining the real scalar singlet extension of the SM
Moritz Bosse, Gudrun Hiller, Daniel Litim et al. (+4 more)
The real scalar singlet extension of the standard model provides a minimal framework in which the
Higgs sector can realise a strong first-order electroweak phase transition and improve the stability of the electroweak
vacuum. We combine the electroweak phase transition and high-scale
vacuum stability with current and projected
collider probes, including precision
Higgs measurements, the
Higgs trilinear coupling, EWPO and resonant searches for a heavy singlet-like scalar in $ZZ$ and di-
Higgs final states. Focusing on a singlet heavier than the standard model
Higgs, we find that there is parameter space compatible with a strong first-order electroweak phase transition for singlet-like scalar masses up to nearly 1 TeV. Deviations in the
Higgs self-coupling can be larger than those in the
Higgs–$Z$ coupling, making
Higgs-potential measurements a key probe. We find that the HL-LHC will test a large fraction of the parameter space, while the FCC will provide ultimate discovery and model-discrimination capabilities.
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All authors Moritz Bosse, Gudrun Hiller, Daniel Litim, Fabio Maltoni, Michael J. Ramsey-Musolf, Simone Tentori, Guotao Xia
Solar and Stellar Astrophysics
TESS detection of periodic brightness variations during the rise of classical nova PGIR22akgylf
Kirill V. Sokolovsky, Elias Aydi, Konstantin Malanchev et al. (+14 more)
Classical novae are transient events powered by thermonuclear burning in a layer of hydrogen-rich material accreted by a white
dwarf from its binary companion. Most classical novae reach optical maximum within ~1 d, but a rare few rise far more slowly. We probe the envelope structure and ejection mechanism of the slowly-rising nova PGIR22akgylf with TESS photometry spanning 3 to 16 d after the nova discovery, supplemented by ground-based observations that cover its full ~133 d ascent to maximum. We detect a 0.1802 +/-0.0012 d periodic brightness modulation with a peak-to-peak amplitude of ~0.02 mag, identified with PGIR22akgylf via temporal and spatial coincidence. The period is stable over the two weeks of TESS coverage, suggesting an orbital origin. Whether this period corresponds to the full or half orbital period, it implies a
dwarf donor companion. At the time of the TESS observations the nova was >~6 mag above quiescence (but still 4 mag below peak), so its light should be dominated by the expanding photosphere. We interpret the periodic signal as arising from the binary orbital motion distorting the nova envelope while its size remains comparable to the binary separation. This interpretation points to common-envelope interaction as a contributor to shell ejection in PGIR22akgylf and demonstrates that the slow-rise phenomenon is not exclusive to thermonuclear eruptions in symbiotic binaries, where the large orbital separation of the
giant companion inhibits such interaction.
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All authors Kirill V. Sokolovsky, Elias Aydi, Konstantin Malanchev, Koji Mukai, Jennifer L. Sokoloski, Laura Chomiuk, Peter Allen Craig, Rebekah A. Hounsell, Justin D. Linford, Isabella Molina, Montana N. Williams, Kishalay De, Mansi M. Kasliwal, Nicholas Earley, David J. Lane, Filipp D. Romanov, Richard Schmidt
General Relativity and Quantum Cosmology
Gotta light? Illuminating AGN disks with LISA EMRIs
Federico Fantoccoli, Francisco Duque and Jonathan Gair
We study the ability of the upcoming
Laser Interferometer Space
Antenna (LISA) to constrain gas torques acting on extreme-mass-ratio inspirals (EMRIs) when these are embedded in
accretion disks, using recently developed relativistic models for the binary-disk interaction. Using a fully
Bayesian setup, we find that, contrary to previous forecasts based on Newtonian results, these observations can provide simultaneous estimates of the disk surface density and the
accretion rate (or, equivalently, its total luminosity) without the need for an electromagnetic counterpart. Our analysis also indicates that simpler measurement constraints based on the linear-signal (Fisher
matrix) approximation are not valid for these systems. For typical EMRI observations, the torque amplitude can be constrained to within ~10%, strengthening the prospect of probing
accretion physics at (sub)microparsec scales, deep in the strong-field
gravity regime and complementing electromagnetic observations. This also strengthens LISA's ability to help answering questions such as how massive black holes grow and coevolve with their host
galaxies and, by helping to identify the EMRI's host
galaxy through cross-correlation with AGN catalogues, to improve the use of these sources as (dark) sirens for cosmology.
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Strongly Correlated Electrons
Hidden antiferromagnetism, persistent valley fluctuations, and $U(6)$ crossovers in triangular-lattice M-point moiré materials via determinantal quantum Monte Carlo
Konstantinos Vasiliou, Dumitru Călugăru, Johannes S. Hofmann et al. (+1 more)
A new moiré material platform was recently proposed based on twisting two-dimensional atomic monolayers whose low-energy states lie at the three M-points of the Brillouin Zone. Continuum and ab initio modeling suggest that electrons in the conduction bands of these materials realize three-valley Hubbard models with valley-selective, quasi-one-dimensional hopping. Remarkably, the onsite Hubbard repulsion is almost $U(6)$-symmetric without fine-tuning. Here, we show that this class of systems naturally admits sign-free determinantal
Quantum Monte Carlo simulations at a filling of three electrons per moiré unit
cell. We use these to explore the phase diagram for interactions of various strengths and $U(6)$-breaking anisotropies. We show that for near-isotropic interactions as relevant to, e.g., AA-stacked twisted SnSe$_2$, the system exhibits an extended intermediate-coupling regime in which local-moment formation and itinerancy compete, and the crossover to a putative low-temperature ordered state can be understood in terms of fluctuating $U(6)$ local moments. We argue that many of these features persist beyond the idealized sign-problem-free limit.
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All authors Konstantinos Vasiliou, Dumitru Călugăru, Johannes S. Hofmann, S.A. Parameswaran
High Energy Physics (Theory)
Analytic approaches to perturbations of strongly coupled Yang-Mills plasma
Inês Aniceto, Paolo Arnaudo, Alex Ratcliffe et al. (+1 more)
We study perturbations of Yang-Mills
plasma, represented by scalar quasinormal modes of AdS black branes, as functions of the wave number $q$ in the entire range from zero to infinity. At finite $q$, these modes can be computed by classical spectral methods based on truncating the boundary value problem. We show that this truncation admits a natural analytic interpretation in terms of
quantum Seiberg–Witten periods in the Nekrasov–Shatashvili limit, with the spectral condition organised as an instanton expansion around small values of the counting parameter. The physical black-brane problem corresponds to evaluating this series at a finite value of the counting parameter, and the Seiberg–Witten formulation provides a systematic way to analyse when the truncation is under control. In particular, it reveals that, as $q$ or the mode number $N$ increases, the physical point approaches the boundary of the domain of convergence of the instanton expansion, limiting the validity of the truncation approach. We overcome this limitation through an exact WKB analysis in which $q^{-1}$ acts as the expansion parameter. The resulting exact quantisation conditions, expressed in terms of period integrals and the associated Stokes geometry, incorporate both perturbative and non-perturbative corrections. The resummed quasinormal modes remain accurate far beyond the strict large-$q$ regime and can be analytically continued all the way to $q=0$, notably by using the Seiberg–Witten approach, providing a consistent description of the QNM spectrum.
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All authors Inês Aniceto, Paolo Arnaudo, Alex Ratcliffe, Michał Spaliński