High Energy Physics (Theory)
Higgsless Lagrangian SCFTs and Strongly Finite VOAs
Siqi Chen, Anirudh Deb and Leonardo Rastelli
Vertex operator
algebras (VOAs) are well studied in both mathematics and physics. The best understood class is that of strongly rational VOAs, whose representation category is maximally well behaved: indeed, it is a modular tensor category. At the next level of complexity are strongly finite but non-rational VOAs. Their representation category is not semisimple (it is “logarithmic”), but maintains nice structural properties. Only a few families of examples in this class are known, a fact that may have hindered the development of a comprehensive mathematical theory. The SCFT/VOA correspondence provides a natural way to generate more examples: strongly finite but non-rational VOAs are expected to arise from four-dimensional ${\cal N}=2$ Lagrangian superconformal field theories (SCFTs) that do not admit a
Higgs branch
moduli space of
vacua. We tackle the combinatorial task of classifying all such “Higgsless” Lagrangian SCFTs. To our surprise, this set turns out to be rather sparse. Free vector multiplets and their discrete gaugings are immediate examples. The interacting Higgsless theories comprise one infinite sequence of SO/USp quivers and three sporadic examples. We construct and study the novel VOAs associated to two of the sporadic examples, and confirm that they are indeed strongly finite and logarithmic.
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Astrophysics of Galaxies
Magnetogenesis by galactic processes: impact on circumgalactic and intergalactic fields
Rahul Ramesh, Enrico Garaldi and Chris Byrohl
We investigate the origin and
evolution of
cosmic magnetic fields using a suite of large-volume cosmological magnetohydrodynamic simulations (L$_\mathrm{box}=25$ Mpc/h) run with the moving-mesh code AREPO. Atop the IllustrisTNG
galaxy formation model, we implement additional recipes for magnetogenesis in which
magnetic energy is injected during
supernovae (SNe) and supermassive black hole (SMBH) feedback events, and compare these to simulations initialized with uniform
primordial seed fields.
Halo magnetic field strengths at $z=0$ are largely similar across seeding models and are primarily amplified and sustained by small-scale and
halo-scale dynamo action. Nevertheless, we find differences in
magnetic field
topology, with SMBH-driven models exhibiting systematically smaller coherence lengths than
primordial-only and SNe-only runs. We find that feedback-driven injection accelerates the onset of dynamo growth, leading to more rapid convergence of
magnetic field strengths with numerical resolution, particularly in low-mass
halos. In the intergalactic medium (IGM), SNe-only injection underproduces
magnetic fields relative to inferred lower limits from $\gamma$-ray cascade constraints at both $z=0$ and $z \sim 3$, whereas our specific SMBH-based injection prescription satisfies present-day constraints but remains in mild tension at high
redshifts. Reconciling these specific high-$z$ constraints therefore likely requires either modified feedback prescriptions or an additional
primordial seeding component.
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Quantum Physics
Comment on "Beyond-classical computation in quantum simulation"
Wladislaw Krinitsin, Nikita Alert, Matteo Rizzi et al. (+1 more)
A recent article [Science 388, 199-204 (2025)] investigates the applicability of numerical methods and a
quantum processor unit in simulating a
quantum annealing protocol. One of the findings indicates that Neural
Quantum States - a versatile variational ansatz for the many-body wave function based on artificial neural networks - fail to reach the same accuracy as the
quantum processor. In this comment we revisit these concerns, demonstrating that NQS can provide competitive results in some of the cases when accounting for the Monte-Carlo noise and large autocorrelation times between samples obtained from the final state.
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All authors Wladislaw Krinitsin, Nikita Alert, Matteo Rizzi, Markus Schmitt
General Relativity and Quantum Cosmology
Einstein–Gauss–Bonnet Inflationary Cosmology in Phase-$\theta$ Formalism
Gevorg D. Manucharyan, Igor V. Fomin, Shivam Kumar Mishra et al. (+1 more)
A central challenge in testing inflationary scenarios with
cosmic microwave background (CMB) data is to derive predictions for cosmological observables that remain accurate beyond the slow-roll regime, where the standard consistency relations are no longer applicable. We address this issue in the context of Einstein–Gauss–Bonnet (EGB)
gravity by introducing a phase-$\theta$ parametrization of the inflationary dynamics. Within this framework, the background
evolution and the coefficients governing scalar and tensor perturbations are expressed entirely in terms of a single monotonic phase variable and the Hubble parameter. This construction provides a closed, analytical mapping between the background parameters of a given model and the associated inflationary observables. A notable advantage of the proposed parametrization is that it remains regular throughout the inflationary epoch, including the end-of-inflation regime, in which the conventional slow-roll consistency relations no longer hold. As an illustrative application, we consider a Starobinsky-type potential supplemented by a linear coupling between the inflaton and the Gauss–Bonnet invariant. Using the proposed formalism, we demonstrate that the resulting predictions of the Starobinsky model are consistent with the most recent constraints from ACT DR6 and BICEP/Keck, explicitly incorporating the impact of the non-minimal Gauss–Bonnet coupling on the expected values of the cosmological perturbation parameters. Finally, we compute the corresponding relic
stochastic gravitational-wave background and evaluate its detectability with current and forthcoming gravitational-wave observatories.
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All authors Gevorg D. Manucharyan, Igor V. Fomin, Shivam Kumar Mishra, B.Mishra
Quantum Physics
Plaquette: A hardware-aware design platform for fault-tolerant quantum computers
Raul Conchello Vendrell, Carlos Díaz López, Ish Dhand et al. (+12 more)
Hardware teams building fault-tolerant
quantum computers (FTQCs) must decide which imperfections to suppress, and that decision requires the logical performance of the architecture under the device's actual noise. Hardware noise often departs from the
stochastic Pauli models used by scalable stabilizer simulators: superconducting transmons leak out of the computational subspace, neutral atoms scatter through intermediate states, trapped ions heat as their motional modes absorb
phonons, and miscalibrated controls over-rotate coherently. We present Plaquette, a theoretical framework and software suite that computes the logical performance of fault-tolerant architectures directly from the physics of such imperfections. In Plaquette, a hardware error model is specified once, as Kraus operators,
Hamiltonian-Lindblad dynamics, or an experimentally reconstructed
quantum channel, and is compiled automatically into the exact or approximate representation required by each of four sampler classes: stabilizer sampling for Pauli noise, the new XPauli sampler for leakage and environment sectors, near-Clifford samplers for coherent errors, and full-state simulation for exact reference calculations. We validate the XPauli and near-Clifford samplers against full-state simulation, which they can match within statistical uncertainty while Pauli twirling can fall short depending on the error model. We demonstrate the framework on three error models: leakage in superconducting
qubits, intermediate-state scattering in neutral atoms, and heating in trapped ions. The size of the discrepancy between Plaquette and Clifford-only simulations varies with platform and noise process, so reliable thresholds, error budgets, and overhead estimates require the most accurate simulation available. Plaquette provides a direct path from the open-system physics of a device to the logical performance of the FTQC built on it.
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All authors Raul Conchello Vendrell, Carlos Díaz López, Ish Dhand, Kshitij Kapoor, Davide Laureti, Marcello Massaro, Pranjal Nayak, Ivan Ogloblin, Martin B. Plenio, Shreya Prasanna Kumar, Matteo Santandrea, Varun Seshadri, Antal Száva, Trevor Vincent, Raphael Weber
Quantum Physics
Typicality of Steering for Two-qubit States
Gerard Anglès Munné, Paweł Cieśliński, Tamás Vértesi et al. (+1 more)
Phenomena that slip beyond the grasp of our classical intuition reveal uniquely
quantum effects that deepen our understanding of the physical world and enable advances in information processing, particularly in
quantum communication and computation. One such phenomenon is
quantum steering, whereby measurements performed by one party influence the conditional states of another when the two share an entangled
quantum system. If the observed correlations cannot be explained by a local hidden state model, the state is said to be steerable. In this work, we investigate the typicality of this behavior: given a generic two-
qubit state and $m$ Haar-random projective measurements, what is the probability of observing steering? We derive analytical expressions for the steering probability $\mathcal{P}_S$ of Werner states in two- and three-setting scenarios, the latter restricted to coplanar projective measurements on the Bloch sphere. For larger numbers of settings and various random states ensembles, we perform numerical analyses showing that $\mathcal{P}_S$ increases systematically with the number of measurements and substantially exceeds the corresponding probabilities associated with Bell nonlocality. Our results demonstrate that random states with minimal environmental coupling exhibit a high probability of steering for finite $m$ and approach genuine typicality, $\mathcal{P}_S=100\%$, as the number of settings increases. We provide a detailed characterization of $\mathcal{P}_S$ across different state ensembles and specific families, including Bell-diagonal and Werner states, identifying those with the greatest non-classical potential and highlighting their relevance for protocols in which steering serves as a key resource.
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All authors Gerard Anglès Munné, Paweł Cieśliński, Tamás Vértesi, Wiesław Laskowski
Quantum Physics
Irreducible Geometry of Higher-Order Correlator Families
Kaito Kobayashi
Programmable
quantum simulators are beginning to access correlators of increasing complexity, ranging from four-point out-of-time-ordered correlators to even higher-order many-body correlators. The theoretical framework for interpreting such data, however, remains comparatively underdeveloped. Although a variety of higher-order correlators can be constructed straightforwardly, their physical meaning is often difficult to infer. A further complication is that different correlators are generally not independent: some may be mutually redundant, while others may encode genuinely distinct information. These features make it necessary to analyze correlators not as isolated quantities, but as a structured family. In this work, we develop a
geometric framework for the collective analysis of higher-order correlator families. By representing correlators as inner products between operator words, we recast each family as a geometry in operator space. The key idea is to introduce conditioning subspaces that separate this geometry into reducible information, already explained by a chosen resolved sector, and irreducible information, encoded in the residual correlator geometry. Focusing on the latter component, we define irreducible volume profiles that quantify how broadly the unexplained part of a correlator family spreads over independent
geometric directions. This perspective leads to several complementary forms of conditioning. Canonical conditioning optimally explains a correlator family. Targeted conditioning fixes the resolved sector to isolate a chosen physical feature. Krylov and cross conditioning extend the framework from a single correlator family to comparisons among correlator geometries. Our framework reveals irreducible structures hidden at the level of individual correlator values and establishes correlator geometry as a higher-level description of
quantum many-body dynamics.
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Quantum Physics
Hockey stick $f$-divergences
Fumio Hiai, Milán Mosonyi and Marco Tomamichel
In this paper we give a systematic and unified treatment and extensions of various results on a new notion of
quantum $f$-divergences defined from
quantum hockey stick divergences, the theory of which has been developed recently in \cite{BHT_fdiv,HircheTomamichel_integral,LiuHircheCheng2025}. In particular, we consider non-normalized states and hockey stick $f$-divergences defined from more general notions of
quantum hockey stick divergences, as well as a somewhat more general form of the integral representation defined in terms of an additional real parameter. We also consider the extension of the theory to general von Neumann
algebras, and extend various results from \cite{HircheTomamichel_integral,LiuHircheCheng2025} to this setting. Our main results here are the representation of the hockey stick $f$-divergences in terms of Neyman-Pearson error probabilities, which was given in the finite-dimensional case in \cite{LiuHircheCheng2025}, an extension of Jen\v cová's result \cite{Jencova2023} on the detection of reversibility of a
quantum channel on a pair of states in terms of the hockey stick divergences, and an extension of a result in \cite{HircheTomamichel_integral} showing that the regularized hockey stick Rényi $\alpha$-divergences coincide with the Petz-type Rényi divergences for $\alpha\in(0,1)$ and with the sandwiched Rényi divergences for $\alpha>1$. Moreover, we give some partial results on the characterization of when different notions of
quantum $f$-divergences give the same value on a pair of
quantum states.
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Instrumentation and Methods for Astrophysics
DegenDetector: Symbolic Recovery of Parameter Degeneracies in Bayesian Posteriors
Chaipat Tirapongprasert and Matthew Ho
We introduce DegenDetector, a framework for identifying and characterizing parameter degeneracies in posterior distributions as closed-form symbolic equations. By combining mutual information screening with alternating symbolic regression, we facilitate automated and interpretable identification of degenerate relationships without domain-specific input. While standard tools such as corner plots can indicate that correlations exist, they do not reveal the underlying functional form. DegenDetector fills this gap by expressing multi-parameter degeneracies as closed-form equations, providing interpretable structure that scales to high-order parameter spaces.
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High Energy Physics (Theory)
Phase-dependent kink collisions and dual critical-velocity branches in the complex sine-Gordon model
Mohammad Mohammadi, Farnaz Eizadbaksh and Vahideh Bagheri
The complex sine-Gordon (CSG) model contains an internal phase degree of freedom that strongly modifies the dynamics of its solitary-wave solutions. We present a numerical study of complex kink–kink collisions and determine how the final state depends jointly on the initial velocity and relative phase. In contrast with the elastic collisions of the real sine-Gordon model, the CSG system exhibits scattering, capture, long-lived bion formation, breather-like states, and emission of radiative profiles. The simulations reveal two distinct phase-dependent branches of critical velocity. In one branch, increasing the initial velocity promotes capture, whereas in the other it restores scattering. This dual structure highlights the rich velocity–phase dependence of the collision dynamics. We also compute the energy carried by radiative profiles and examine extreme values of the energy density, kinetic and gradient contributions, and field modulus at the collision center. These quantities show sharp transitions at critical points and provide sensitive diagnostics of phase-controlled dynamics. These results suggest that the relative phase behaves as an effective internal degree of freedom that plays an important role in the collision dynamics of complex
solitons.
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Earth and Planetary Astrophysics
Debris Disc Substructures Induced by Secular Planetary Perturbations
Roman R. Rafikov, Deniz Akansoy and Antranik A. Sefilian
Observations of debris discs have the potential to provide valuable information about massive
planets perturbing them gravitationally. In this work, we explore the
evolution of the azimuthally-averaged (or axisymmetric) surface density (ASD) — a characteristic routinely derived from observations — in a disc that is secularly perturbed by an inner
planet. We develop a detailed analytical understanding of ASD
evolution and verify it using a novel numerical framework debrispy, which we make publicly available. With these tools we show that in a secularly evolving disc ASD develops a set of sharp features — sharp peaks at eccentricity nulls and finite discontinuities at caustic points where particle periastra or apoastra pile up — marching out through the disc as it ages. We probe the dependence of these features on planetary eccentricity, ratio of the free to forced particle eccentricity, and underlying radial mass distribution, showing in particular that more eccentric
planets produce more prominent ASD features. Convolution with the PSF of realistic observations (as well as the non-zero random free eccentricity of debris) smooths out these features, but they can still be detectable in high-resolution observations. The radial locations of secular ASD peaks follow a particular, well-defined pattern, which should unambiguously point to their secular nature in observations. We illustrate how both detection and non-detection of such secular features in observed discs can be used (in combination with other constraints) to measure or constrain key parameters of perturbing
planets (even those not yet detected) — mass, semi-major axis and eccentricity.
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Astrophysics of Galaxies
Deep Spectroscopic Follow-Up of Maisie's Galaxy – A Typical Galaxy in the Early Universe
Rebecca L. Larson, Taylor A. Hutchison, Steven L. Finkelstein et al. (+26 more)
The first several years of JWST observations have yielded surprisingly large numbers of bright $z>10$
galaxies, with follow-up spectroscopy of many of these sources implying extreme
star formation activity and/or AGN content. Here, we present a combination of two deep Cycle 3 NIRSpec G395M programs, totaling over 19 hours of exposure time, plus MIRI/LRS observations for one such high-
redshift source: Maisie's
Galaxy. We provide an updated
redshift measurement of $z = 11.408 \pm 0.005$ for this source. Measurements of the [OII] doublet in these data yield an electron density ($n_e = 108.56^{+873.9}_{-35.37}$) and a
star-formation rate (SFR$_{[OII]} = 1.3 \pm 0.35$), placing it along the
star-formation main sequence (SFMS) and indicating that this is a much more typical, rather than extreme, source in the early Universe. We also report fluxes for the [OIII]$\lambda$5008 and [NeIII]$\lambda$3869 lines that provide us with a $\log$(Ne3O2) $= -0.219 \pm 0.145$ and a $\log$(O32) $=0.724 \pm 0.191$. We estimate the
metallicity ($Z/Z_{\odot} = 0.17 \pm 0.05$) and ionization parameter ($\log$(U) $= -2.26 \pm 0.13$) from the Ne3O2 ratio. We place this
galaxy in the context of other $z>10$ sources with similar line detections and compare the results to those obtained from SED fitting. The results suggest that we should go deeper with our observations to better understand the average
galaxy population at these early times.
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All authors Rebecca L. Larson, Taylor A. Hutchison, Steven L. Finkelstein, Pablo Arrabal Haro, Casey Papovich, Weida Hu, Javier Álvarez-Márquez, Ruqiu Lin, Jorge A. Zavala, Volker Bromm, Nikko J. Cleri, Abdurro'uf, Brittany Vanderhoof, Bren E. Backhaus, Dan Coe, Henry C. Ferguson, Ananya Ganapathy, Norman A. Grogin, Michaela Hirschmann, Intae Jung, Jeyhan S. Kartaltepe, Anton M. Koekemoer, Dale D. Kocevski, Ray A. Lucas, Alexa M. Morales, Pablo G. Pérez-González, Nor Pirzkal, Jonathan R. Trump, L. Y. Aaron Yung
High Energy Physics (Theory)
Decoupling Limit of Quiver Theories and the Angular Spectra of Extreme C-metrics
Peng Yang and Kilar Zhang
We investigate the angular
eigenvalue problem of the extreme charged C-metric. Starting from a constrained five-point Fuchsian description of the non-extremal angular equation, we obtain its extreme limit by decoupling a hypermultiplet in the dual four-dimensional $\mathcal{N}=2$, $\mathrm{SU(2)}\times \mathrm{SU(2)}$ linear quiver gauge theory. We derive the parameter dictionary and renormalized Matone relations, and connect the physical limit $Q\to M$ to the quiver decoupling by an explicit coordinate transformation. Regular endpoint conditions give an algebraic quantization condition.
Eigenvalues obtained from the truncated instanton prepotential are tested against independent angular spectra near extremality and at larger acceleration. The axisymmetric sector recovers the known exact spectrum.
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High Energy Astrophysical Phenomena
SACRA-K: A Performance-Portable Numerical Relativity Code with Kokkos
Ming-Zhe Han, Kenta Kiuchi and Masaru Shibata
We present SACRA-K (SimulAtor for Compact objects in Relativistic Astrophysics with Kokkos), a performance-portable numerical relativity code ported from the Fortran code SACRA-MPI to C++ with the Kokkos library. SACRA-K retains the physics and numerical methods of SACRA-MPI, namely a Baumgarte-Shapiro-Shibata-Nakamura (BSSN) spacetime
evolution with Z4c constraint propagation and a box-in-box Berger-Oliger adaptive mesh refinement, together with the high resolution shock capturing scheme for the general relativistic hydrodynamics from NANASI, while gaining cross vendor portability. We validate the port against SACRA-MPI across binary black hole, black hole
neutron star, and binary
neutron star configurations. Across these tests, the waveform discrepancies are well below both the scatter among independent numerical relativity codes and the resolution dependent variation within a given code, and remain at or below the distinguishability threshold of current gravitational-wave detectors; the $\pi$
symmetry is preserved exactly at the bitwise level; and the gravitational wave phase of the binary
neutron star merger exhibits second order convergence. In the smallest test configuration, SACRA-K runs about an order of magnitude faster on the NVIDIA A100 GPU cluster or the AMD MI300A APU cluster than the Fortran SACRA-MPI on the CPU cluster, and we measure its scaling up to 256 accelerator devices.
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High Energy Physics (Phenomenology)
Internal pseudospin, lepton-number superselection, and neutrino–antineutrino coherence in massive neutral-fermion one-particle states
Ricardo Romero
At fixed three-momentum, massive Dirac
neutrino one-particle states span a 4D space of particle–antiparticle identity and helicity. We show that helicity flip, charge conjugation, and their product close an internal $SU(2)$ pseudospin subalgebra within $SU(4)$, distinct from the Wigner little group. Its helicity generator is the
lepton-number-weighted
spin rotation $U_1=2LJ_2$. The
lepton-number $L$ and helicity $\mathcal H_h$ grade the 16 generators $\tau_\mu\otimes\sigma_\nu$, organizing the $\Delta L=2$ sector. Helicity-preserving directions $\tau_{1,2}\otimes\sigma_{0,3}$ carry the pseudo-Dirac mixing $\kappa_{\rm pD}=\Delta m^2/4E$ (active–sterile), while helicity-flipping directions $\tau_{1,2}\otimes\sigma_{1,2}$ carry the neutrinoless double-beta decay mass factor (active–active). Furthermore, charge conjugation matches the $U_2$ generator. The Majorana condition is thus a projection onto the $U_2=+1$ eigenspace, where only the Wigner
algebra survives. This framework algebraically classifies Majorana masses and pseudo-Dirac splittings without assuming
neutrinos are Majorana particles.
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Cosmology and Nongalactic Astrophysics
The statistics of curvature-profile dispersion in primordial black hole formation
Albert Escrivà
In the standard
curvature-perturbation scenario, PBHs form from the collapse of superhorizon
curvature fluctuations after horizon re-entry. The predicted abundance is exponentially sensitive to the collapse threshold and hence to the shape of the
primordial curvature profile. In this work we develop a finite-action framework to describe
curvature-profile dispersion around representative peak profiles. Using a multipolar
Fourier-Bessel decomposition, we separate the local peak variables of the Gaussian field from residual radial and angular deformations, normalized by their Gaussian action. We apply the formalism to spherical numerical-collapse examples in order to isolate the effect of radial shape dispersion. For finite-width spectra, and in the presence of logarithmic local non-Gaussianity, we compute the collapse threshold as a function of a coherent shape variable and combine the result with peak statistics. We find that the dominant contribution to the PBH abundance is not necessarily the conditional-mean reference profile, nor simply the profile with the lowest threshold. Instead, it is selected by a competition between the Gaussian cost of realizing a coherent deformation and the exponential gain associated with lowering the collapse threshold. Broad spectra and negative non-Gaussianity can make rare shape deformations dominate the abundance. In the examples studied here, the dominant branches can correspond to several-sigma coherent shape fluctuations while enhancing the integrated abundance by orders of magnitude. Equivalently, including shape dispersion can reduce the power-spectrum amplitude required to obtain a fixed PBH abundance. Our results show that residual profile dispersion is a genuine statistical ingredient in PBH formation and can be quantitatively important for accurate abundance estimates.
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High Energy Physics (Theory)
The mini-Page Curve in Cosmology
Ricardo Espíndola and Shoichiro Miyashita
The black hole information paradox has motivated extensive study of how and when information escapes from evaporating black holes. Here we address the analogous question for cosmological horizons: when does an individual Hawking pair begin to carry information out of a de Sitter horizon? We study this problem in a class of two-dimensional flow geometries that interpolate smoothly between an asymptotic AdS$ _2 $ boundary and a dS$ _2 $ static patch. Modeling the emission of a Hawking pair via a probe state constructed from local operators and their modular conjugates, we promote the centaur
algebra of observables to a Type II$ _\infty $ factor through the crossed-product construction. This allows us to compute the
entropy difference between the thermofield-double reference state and the Hawking-pair state. We find that this difference traces a characteristic mini-Page curve for the cosmological horizon: it starts near zero, reaches a minimum near $ \tau \approx \beta/8 $ before increasing again. We interpret the location of the minimum as the time at which
quantum information begins to escape the cosmological horizon. Extending the analysis to the microcanonical ensemble, we show that the algebraic
entropy coincides with the generalized
entropy of an
entanglement wedge cut that tracks the emitted particle along the horizon. Furthermore, the relative modular flow generated between the two states yields a Lyapunov exponent $\lambda =2\pi/\beta$, identifying the scrambling time as the scale at which the information carried by the pair becomes accessible to a static-patch observer.
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High Energy Astrophysical Phenomena
Tilted thin accretion disks in the full Kerr spacetime and their implications
K. S. Sruthy, Chandrachur Chakraborty and Sudip Bhattacharyya
We derive a steady-state warped-disk equation in the full Kerr spacetime to study the tilt dynamics of a thin, viscous
accretion disk around a spinning collapsed object. The formulation, based on Pringle's framework, remains valid for all values of the Kerr parameter $a$, thereby encompassing both Kerr black holes (BHs; $0 < a \le 1$) and Kerr naked singularities ($a > 1$). By incorporating the exact Keplerian and Lense-Thirring precession frequencies, we analytically obtain the radial tilt equations of the disk without invoking slow-
spin or weak-field approximations. Numerical solutions of the resulting equations, obtained under realistic boundary conditions, reveal significant deviations from slow-
spin approximations, particularly in the inner disk where the relativistic effects dominate. In the diffusive regime, we find that for Kerr naked singularities the tilt profile exhibits distinct inner hump(s) near the radius where the specific angular momentum vanishes – a feature absent for Kerr BHs. Consideration of a tilt in the inner disk could significantly influence the interpretations from observed X-ray spectral, timing, and polarization features, which are crucial to probe the strong
gravity regime and to infer the
spin of the central object. While such a distinct hump feature alone does not uniquely distinguish Kerr BHs from Kerr naked singularities, their interpretation in conjunction with constraints on the disk regime may provide a potential observational handle on the nature of the accreting collapsed object.
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Solar and Stellar Astrophysics
Cataclysmic Variables Photometric Periods from TESS
S. O. Kepler, Alejandra Daniela Romero, Larissa Luciano Amorim et al. (+1 more)
We present a sample of coherent and stable photometric period determinations for cataclysmic variables, based on TESS photometry through sector 102. We analyzed a total of 1554 cataclysmic variable
stars and detected periodic variations in 1362 objects, including 286 eclipsing or ellipsoidal-variation systems, 63 polars, and 135 intermediate polars. In particular, we present the first determination of the optical variability period for 564 cataclysmic variables. Due to the 21x21" pixel size of TESS, we tested whether the variability was coming from the cataclysmic variable and not from a nearby
star. For the intermediate polars, we detected
spin periods in addition to orbital periods for 83 systems. We detect a clear period gap between ~2 and ~3 h in the eclipsing sample, consistent with previous work. The gap remains for the complete sample of photometric variability periods. There is no apparent gap in the orbital period distribution for intermediate polars. Finally, the median of the photometric period distribution of our complete sample of cataclysmic variables is 3.681 h. Comparing this to the distribution of rotation periods for likely single white
dwarfs, we find a similar range, with a median photometric period of 6.803~h.
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All authors S. O. Kepler, Alejandra Daniela Romero, Larissa Luciano Amorim, Marcos Perez Diaz
Astrophysics of Galaxies
Force convergence in Monte Carlo Lyman-alpha radiative transfer
Joshua Kasiri, Aaron Smith, Kevin Lorinc et al. (+2 more)
Monte Carlo radiative transfer (MCRT) is widely used to model Lyman-alpha (Lya) resonant-line transport, but convergence is difficult to assess in optically thick media where
photons undergo many scatterings before escape. This is especially important for internal quantities such as radiative acceleration and the force multiplier, which depend on momentum deposition throughout the gas rather than only on emergent spectra. We study the convergence of Lya MCRT momentum-transfer
estimators in static spherical clouds. We first establish
diffusion-limit
benchmarks for radial acceleration profiles and integrated force multipliers, then develop a moment-based framework for diagnosing convergence from the
photon-packet contribution distribution. This framework separates three distinct questions: whether the
estimator converges to the correct mean, how large its finite-sampling uncertainty is, and whether the estimated uncertainty is itself stable. We apply this hierarchy to the direct event-based scattering
estimator, a gradient-of-energy-density
estimator, and a divergence-of-radiation-pressure
estimator. Zeroth-order convergence is assessed with profile comparisons, integrated force-multiplier bias, and finite-group relative error. First-order convergence is quantified with fractional error, the
photon number required to reach a target precision, and the corresponding runtime requirement. Second-order convergence is tested with the coefficient of variation of variance, which measures the reliability of the variance estimate used in the first-order diagnostics. Core-skipping prescriptions, source geometry,
estimator construction, and spatial resolution enter this hierarchy in different ways. Our results provide a practical convergence framework for internal Lya MCRT force calculations and show why statistical precision, computational cost, and physical accuracy must be evaluated separately.
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All authors Joshua Kasiri, Aaron Smith, Kevin Lorinc, Olof Nebrin, Kazutaka Kimura
High Energy Physics (Phenomenology)
Optimal-Transport-Based Cell Resampling for Negative and Pathological Event Weights
Regan Doherty, Lauren Hay, Rishabh Jain et al. (+4 more)
Negative and pathologically large Monte Carlo event weights strain the computing budgets of experiments at the Large
Hadron Collider.
Cell resampling
algorithms locally redistribute event weights among nearby events in a metric space. We study the performance of metrics defined in terms of Optimal Transport, namely the Energy Mover's Distance and a spectral variant, in the context of such
algorithms. As these metrics are insensitive to the addition of soft and collinear radiation, they may be applied directly to particles at any stage of event generation. When applied to samples simulated at next-to-leading-order in
quantum chromodynamics, this approach reduces the observed bias relative to other
cell resampling techniques presented in the literature. We also study the Cross-Section Mover's Distance as an unbinned, broadly-applicable figure of merit for quantifying the bias introduced by any full-phase-space reweighting.
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All authors Regan Doherty, Lauren Hay, Rishabh Jain, Matt LeBlanc, Julia Marrinan, Camille Mauceri, Jennifer Roloff
Astrophysics of Galaxies
Thermal Sunyaev-Zel'dovich Measurements of Locally Bright Galaxies with ACT DR6: Radio Source Contamination and Excess Compton-y Signal
Nicholas Battaglia, Jean-Baptiste Melin, J. Colin Hill et al. (+1 more)
The Planck collaboration found a remarkable power-law relation between
stellar mass and the thermal Sunyaev-Zeldovich (tSZ) signal for the Locally Bright
Galaxy (LBG) sample, spanning over a decade in
stellar mass. We re-examine this measurement using the Atacama Cosmology
Telescope (ACT) DR6 component-separated Compton-$y$ maps, which provide lower noise and higher angular resolution than Planck, on a footprint spanning one-third of the sky. We recover a consistent power-law scaling between the cylindrical Compton-$y$ signal and
stellar mass. Additionally, we identify residual contamination in the tSZ signal from
radio sources at the few percent-level, which has not been considered previously. In parallel, we identify a factor-of-two excess in the Compton-$y$ signal in LBGs hosting co-spatial
radio sources relative to those without, at fixed
stellar mass. This excess persists to radii of at least 6 arcminutes, suggesting a
halo-scale effect, and is recovered in the original Planck results when the same
radio source subselection is applied. We consider two physical explanations: a systematic difference in
halo mass at fixed
stellar mass, or thermal energy injected into the circumgalactic medium by Active
Galactic Nuclei, although we cannot currently distinguish between the two. This result has direct implications for tSZ cross-correlation measurements more broadly, and necessitates careful characterization of the
radio source fraction in
galaxy samples in future analyses.
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All authors Nicholas Battaglia, Jean-Baptiste Melin, J. Colin Hill, James Bartlett
Optics
Asymmetric high-harmonic generation from subwavelength bianisotropic resonators
Albert Mathew, Piyush Jangid, Rebecca Aschwanden et al. (+3 more)
High-harmonic generation (HHG) enables attosecond light pulses and table-top sources of coherent extreme-ultraviolet and soft X-ray radiation. Although HHG has long been associated with gases and
plasma, nanostructured solids are emerging as new alternative sources enabling both the enhancement and control of HHG. Here, we experimentally demonstrate and theoretically describe that a single dielectric subwavelength resonator can act as a direction-selective high-harmonic source, enabling control over multiple harmonic orders through the excitation and hybridization of Mie modes. The resonator's geometrical volume is $0.12 \lambda^3$, and its optical mode volume is $0.03 \lambda^3$ at its pump wavelength. Structural asymmetry of the resonator along the propagation direction translates into different mode coupling under opposite illumination directions, resulting in pronounced forward-backward asymmetry in the generation of the third, fifth, and seventh harmonics. These results establish bianisotropic subwavelength resonators as a platform for flexible asymmetric generation of high harmonics, expanding the toolbox for controlling strong-field light-matter interactions with Mie-resonant nanophotonics.
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All authors Albert Mathew, Piyush Jangid, Rebecca Aschwanden, Yves Köppeler, Thomas Zentgraf, Sergey Kruk
Quantum Physics
Approaching Carnot Efficiency at Finite Power in an Experimentally Feasible Quantum Heat Engine
Shogo Toma, Atsushi Noguchi, Ken Funo et al. (+1 more)
Whether a heat engine can approach Carnot efficiency while maintaining finite power is a fundamental question in finite-time thermodynamics. For classical Markovian heat engines with local interactions, the power-efficiency trade-off forbids an asymptotic approach to Carnot efficiency at finite power. In
quantum systems, by contrast, degeneracy,
symmetry, and collective jumps have been theoretically predicted to enable such an asymptotic attainment by enhancing activity. It has remained open, however, whether this mechanism can be realized in an experimentally implementable heat engine. In this Letter, we propose a superconducting-
circuit heat engine that emulates the collective enhancement, thereby enabling an asymptotic approach to Carnot efficiency at finite power. This result demonstrates that, in an implementable model, such an enhanced dissipative mechanism circumvents the power-efficiency trade-off of classical Markovian engines. Our work connects abstract bounds in finite-time thermodynamics to a concrete
circuit-QED platform and suggests a route toward
quantum-device design based on collectively enhanced dissipative processes.
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All authors Shogo Toma, Atsushi Noguchi, Ken Funo, Hiroyasu Tajima
Mesoscale and Nanoscale Physics
Competing Chern states revealed by quasiparticle charging in moiré rhombohedral graphene
Hongyuan Li, Zuhan Geng, Junseok Seo et al. (+13 more)
Moiré materials realize a versatile platform for exploring the physics of fractional Chern
insulators (FCIs). The recently observed
evolution from FCIs to an extended
quantum anomalous
Hall background upon lowering the electronic temperature in moiré rhombohedral
graphene (mRG)8 raises a fundamental question: Is it caused by a failure to equilibrate the edge states of an FCI or by a genuine phase transition in the bulk from an FCI to a generalized anomalous
Hall crystal? Here we address this question by probing quasiparticle charging in a mesoscopic mRG antidot device and by bulk resistance measurements, both of which are bulk-sensitive and free from complications from edge states. Tunneling to the mRG antidot reveals quasiparticles carrying one electron charge for both Chern states at filling factors {\nu}=1 and 2/3 at low temperatures. Temperature dependence measurements of the bulk resistance near {\nu}=2/3 further suggest a thermodynamic phase transition from an FCI to a generalized anomalous
Hall crystal at temperatures below about 150mK. The results clearly exclude the edge state equilibration scenario and favor the phase transition scenario. Our work establishes mesoscopic probes as a powerful approach to uncover competing ground states in moiré materials and provides a basis for probing fractionalized excitations in FCIs.
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All authors Hongyuan Li, Zuhan Geng, Junseok Seo, Chenxi Xu, Yifan Jiang, Shenyong Ye, Zhenqi Hua, Jiabin Xie, Lujin Min, Kenji Watanabe, Takashi Taniguchi, Kenji Yasuda, Xiaomeng Liu, Long Ju, Jie Shan, Kin Fai Mak
Quantum Physics
Robust One-Sided Device-Independent Quantum Key Distribution via High-Dimensional Steering
Monika Mothsara, Suraj Goel, Bohnishikha Ghosh et al. (+4 more)
Quantum key distribution (QKD) brings the promise of communication with information-theoretic security but is limited in practice due to its susceptibility to noise, losses, and device imperfections. To address these challenges, we propose a robust high-dimensional (HD) one-sided device-independent QKD (1sDI-QKD) protocol and present a proof-of-principle experimental implementation using
photons entangled in the transverse-spatial degree-of-freedom. We develop a systematic security analysis of HD 1sDI-QKD protocols, leveraging
quantum steering to certify security, and evaluate achievable secret key rates for different measurement configurations and system dimensions using reverse reconciliation. Our analysis shows that increasing the dimension enhances robustness against both noise and loss. We then demonstrate the key experimental building blocks required for implementing the protocol: (a) a high-quality source of high-dimensional photonic
entanglement, and (b) a fully programmable, high-dimensional multi-outcome measurement device operating in up to dimension 11. Using these components, we obtain positive key rates for all investigated dimensions under the fair-sampling assumption, with the highest key rates achieved for dimension d=7. Finally, we discuss the steps required for a practical, loophole-free implementation of 1sDI-QKD in realistic regimes of loss and noise.
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All authors Monika Mothsara, Suraj Goel, Bohnishikha Ghosh, Vatshal Srivastav, Will McCutcheon, Mehul Malik, Gláucia Murta
Quantum Physics
Absence of quantum advantage for approximate spin glass optimization
Dries Sels and Flaviano Morone
We perform a semiclassical, large-
spin S, analysis of the
quantum approximate optimization
algorithm (QAOA) on the Sherrington-Kirkpatrick (SK) model, using the truncated Wigner approximation. Fixing the QAOA angles to their previously determined optimal S=1/2 values, we observe a non-monotonic dependence of the final energy on the
spin. At small S the semiclassics is dominated by noise, while the large-S limit is constrained by the exponential growth of the initial fluctuations. For a depth-p QAOA one achieves the optimal balance at S of order p, resulting in a convergence of the final energy to the Parisi value like log(p)/p. We find that the semiclassics slightly outperforms the true
spin-1/2 QAOA, and thus suggest they both converge to the Parisi value in the same way. Finally, removing all the initial noise, and re-optimizing the parameters to account for that change, results in superior performance with 1/p convergence.
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High Energy Physics (Phenomenology)
Heavy quark coalescence probability in the presence of a potential
Taesoo Song and Jiaxing Zhao
In this study, we explore the role of the heavy
quark potential in heavy
quark coalescence, whose probability is expected to be unity at low momentum. To this end, we develop a phenomenological heavy
quark potential based on the constituent
quark model that reproduces the
vacuum masses of pseudoscalar and vector heavy
mesons. Using this potential, we demonstrate its enhancement effect on the coalescence probability. We also investigate how medium-induced modifications of the heavy
quark potential in the
quark gluon plasma affect the coalescence process. Our results indicate that the coalescence probability remains close to unity as long as the modification of the potential is sufficiently moderate.
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Mesoscale and Nanoscale Physics
Bohao Li and Fengcheng Wu
We design
lattice models with tailored
quantum geometry, including generalized Landau levels (LLs) satisfying the integrated trace condition and higher-Chern bands with ideal
quantum geometry. Our models with $N=2$, $3$, and $4$ sublattices include a generalized Haldane model ($N=2$ honeycomb
lattice model) with Gaussian-decaying hoppings realizable in twisted
bilayer MoTe$_2$, and $N \geq 3$ models with exponentially decaying hoppings. Exact diagonalization reveals fractional Chern
insulators in the generalized zeroth LL bands of all three models, a Moore-Read state in the generalized first LL band of the $N=4$ model, and various interaction-driven topological phases$\unicode{x2013}$including integer and fractional anomalous
Hall crystals and a multicomponent Halperin state$\unicode{x2013}$in the ideal higher-Chern band of the $N=3$ model. Informed by
quantum geometry, our work provides a pathway for
lattice realizations of Landau-level and beyond-Landau-level physics.
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Earth and Planetary Astrophysics
The Impact of Planetary Phase Functions on Exo-Earth Detectability with EXOSIMS
Searra Foote, Tyler D. Robinson, Rhonda Morgan et al. (+3 more)
The under-development NASA Habitable Worlds Observatory (HWO) aims to provide breakthroughs in
exoplanet science, yet the most effective approaches to modeling the detection and characterization of potentially Earth-like worlds with HWO remain uncertain despite being essential considerations for mission design. In this work, we aim to better model and understand detection metrics through the use of EXOSIMS (
Exoplanet Open-Source Imaging Mission Simulator), an
exoplanet yield modeling tool. Yield modeling requires representing planetary brightness via a planetary phase curve. Earth's true visual phase curve is non-Lambertian, deviating from the idealized Lambertian model in EXOSIMS, particularly at phase angles beyond 90 degrees (i.e., quadrature). This leads to underestimating Earth's brightness. To address this, we incorporate phase-dependent reflectance from a high-fidelity Earth model into EXOSIMS for physically motivated simulations. We explore and quantify differences in phase-dependent detections, finding that the realistic Earth phase function produces modest changes in the median number of detected exo-Earths and systematically redistributes detections towards medium to high phase angles where Earth is intrinsically brighter than a Lambertian approximation. Additionally, we explore the role of coronagraph inner working angle (IWA) by running simulations across multiple IWA values with both phase functions, revealing that smaller IWAs expand access to a broader range of orbital phases, altering the resulting phase-angle distribution of detections. Together, these results demonstrate that realistic phase functions and IWA parameters both have measurable impacts on yield estimates for an HWO-like mission and highlight the need to more realistically represent Earth-like worlds in yield modeling.
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All authors Searra Foote, Tyler D. Robinson, Rhonda Morgan, Dmitry Savransky, Mario Damiano, Armen Tokadjian