Optics
DO-CGI: deep-optimized illumination patterns for computational ghost imaging at low sampling ratios
Mor Hale, Ofir Lindenbaum and Eliahu Cohen
Computational ghost imaging (CGI) reconstructs objects from known illumination patterns and bucket-detector measurements, but quality deteriorates at low sampling ratios (SRs). We present a deep-learning framework that optimizes grayscale diffuser patterns before reconstruction. In simulations using CIFAR-10 and MNIST images with Split Bregman reconstruction, the learned patterns outperform random patterns in peak signal-to-noise ratio and structural similarity, including at SRs below 5%. Patterns trained on CIFAR-10 also transfer to MNIST and remain effective under moderate perturbations of the sensing
matrix. These results support learned pattern design as a route to fewer CGI measurements.
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Quantum Physics
Minimal Counterexamples of the MacWilliams Extension Theorem for Stabilizer Codes
Ali Assem Mahmoud
The MacWilliams extension
theorem fails for module alphabets with non-cyclic socle, and the label alphabet of qudit stabilizer codes, $\F_{q^2}$ over $\F_q$, is such an alphabet.
Quantum error correction, however, only ever sees self-orthogonal additive codes, and whether that
rigidity rescues the
theorem—equivalently, whether every weight-preserving isomorphism of stabilizer groups is implemented by local Cliffords and a qudit permutation—was asked by Gluesing-Luerssen and Pllaha and answered negatively by Pllaha for particular
qubit codes. We develop the negative answer systematically and at the smallest possible scales. For every
prime power $q$ we construct a pair of $[[q+1,q-1]]_q$ stabilizer codes and a weight-preserving isomorphism between them extending to no monomial transformation; the codespaces are inequivalent even under arbitrary local
unitaries combined with permutations, though they share Shor–Laflamme enumerators. Self-orthogonality is automatic here, by two elementary lemmas which also show that Dyshko's threshold-length counterexamples were already self-orthogonal, unremarked. For
qubits we prove by exhaustive search that length $3$ is minimal and the counterexample essentially unique. Dropping the “idle qudit” invariant that detects these, we find the minimal full-support lengths: $4$ for a non-extendable isometry, $5$ for a weight-isometric pair that is not monomially equivalent, realized by explicit $[[5,2]]$ codes; at length $6$ all nontrivial stabilizer elements can have weight $\ge 4$. Whether these codespaces are locally unitarily equivalent is posed as an open problem, connecting the extension problem to the LU–LC circle of questions.
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Computational Physics
Astroid Spinodal Boundary in Phase-Based Ising Machines
Malihe Farasat and Nikhil Shukla
Oscillator Ising machines (OIMs) and dynamical Ising machines (DIMs) encode binary
spins in phase states stabilized by second-harmonic injection (SHI). In a coupled network, the competition between SHI and the instantaneous local network field reshapes each oscillator's conditional energy landscape. We show that this competition drives a transition between monostable and bistable regimes through an astroid spinodal boundary. Near this boundary, the barrier scales as $\Delta E_i\propto\mu_i^{3/2}$ at generic smooth points and as $\Delta E_i\propto\mu_i^{2}$ at the longitudinal cusp. OIMs and DIMs obey the same spinodal geometry, with their conditional landscapes related by a reversal of the transverse field. Finally, the first-harmonic conditional landscape is mathematically equivalent, up to an additive constant, to the Stoner–Wohlfarth energy of a uniaxial
magnetic particle.
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Mesoscale and Nanoscale Physics · Cross-listed from cs.ET
MEDA: Measurement-Efficient Disorder-Aware Majorana Zero Mode Detection in Realistic Devices
Nathan Jones, Binayyak Roy, Valentine Mohaugen et al. (+4 more)
Fault-tolerant topological
quantum computing relies on identifying Majorana zero modes (MZMs), but reliable detection in realistic devices remains challenging. Conventional topological indicators are inherently biased in finite, disordered systems, blurring the distinction between true MZMs and trivial states. Furthermore, attempts to map these indicators to real observables via machine learning require dense, expensive conductance measurements, creating a severe scaling bottleneck. To simultaneously address topological bias and measurement limitations, we present MEDA: a Measurement-Efficient, Disorder-Aware framework for MZM detection in realistic devices. MEDA maps sparse, practically obtainable observables directly to the robust periodic disorder invariant (PDI). Using a novel sparse parameter regime, MEDA reduces measurement volume by 10x while maintaining predictive quality, even in moderate to strong disorder regimes that limit conventional methods. Furthermore, MEDA naturally prioritizes input features consistent with the topological gap protocol, demonstrating strong physical interpretability.
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All authors Nathan Jones, Binayyak Roy, Valentine Mohaugen, Ian Lewis, Toby Cox, Sumanta Tewari, Rong Ge
Astrophysics of Galaxies
Binary disruptions driven by massive disks around massive black holes
Mark Dodici
Accretion disks around massive black holes (MBHs) in
galactic nuclei can contain significant mass, in which case their non-spherical potentials exert significant torques on single and binary
stars orbiting the MBHs. These torques can drive orbits to very large eccentricities. Previous works have shown that this driving can cause disruptions of single
stars by the
tidal gravity of the MBH. Here, we characterize the ability of these torques to drive binary
stars to the point of disruption via the Hills mechanism. We derive semi-analytical estimates, validated with numerical simulations, of the number of binary disruptions driven by a generic disk in a generic
nucleus. Using these results, we estimate that the formation of the ~5-Myr-old disk of
stars in the
Galactic Center drove a burst of ~10^2 binary disruptions. These disruptions produced an excess of S-cluster
stars and hypervelocity
stars — possibly including S5-HVS1, the fastest-known hypervelocity
star. In other
galaxies, analogues of S-cluster
stars produced by this process may evolve into
tidal disruption events following a disk phase. Hypervelocity
star observations may help clarify the importance of disk-driven disruptions, which eject
stars nearly isotropically and in temporal bursts — a unique combination among processes driving binary disruptions.
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Optics
Sideband-Resolved 4H-SiC Optomechanical Resonators with Interference-Engineered Anchor-Loss Suppression
Xirui Gou, William Privratsky, Wenhan Sun et al. (+4 more)
Sideband-resolved cavity optomechanical resonators provide a powerful platform for coherent
photon–
phonon interactions, enabling applications ranging from
quantum state transduction and optomechanically induced transparency to precision sensing and microwave photonics. Achieving this regime in integrated microresonators, however, requires simultaneously realizing a narrow optical cavity linewidth, a high-frequency mechanical mode, and low mechanical dissipation. Here, we report the first sideband-resolved optomechanical resonators based on the 4H silicon carbide (4H-SiC) platform. By combining compact microdisk geometries with interference-engineered anchor-loss suppression, we simultaneously achieve intrinsic optical quality factors exceeding $1\times10^6$, room-temperature mechanical quality factors up to $1.51\times10^4$, and a sideband-resolution factor greater than seven. Systematic numerical and experimental studies reveal that a local minimum in anchor loss enables high mechanical quality factors without requiring aggressive undercutting, substantially improving fabrication yield and device robustness. We further demonstrate the first observation of optomechanically induced transparency in integrated 4H-SiC resonators, confirming coherent cavity optomechanical interactions in this material platform. These results establish 4H-SiC as a promising platform for integrated cavity optomechanics and provide a practical route toward scalable
photon–
phonon devices for classical and
quantum photonic technologies.
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All authors Xirui Gou, William Privratsky, Wenhan Sun, Yuncong Liu, Hamed Abiri, Philip X.-L.Feng, Qing Li
High Energy Physics (Theory)
Intersection Bounds for BPS Strings in Six-Dimensional Supergravity
Hee-Cheol Kim and Kai Xu
In six-dimensional $\mathcal{N}=(1,0)$ supergravity, the structure of tensor
moduli space is governed by primitive BPS string charges known as BPS generators and their intersection pairing. We derive bounds on the intersection numbers of these generators from a purely effective field theory (EFT) perspective. Although gauge anomaly cancellation constrains intersections between generators supporting gauge
algebras, bounds for E-strings intersecting generators with self-intersection numbers $-2$ and $-3$ have previously remained incomplete. We show that the Zariski decomposition, interpreted as the charge
lattice counterpart of the attractor mechanism, together with current
algebra embeddings on the E-string worldsheet theory, yields strong universal bounds on these intersection numbers. These results establish the finiteness of tensor charge intersection numbers up to duality. The underlying structure was identified through AI-guided investigation and is proven here analytically using EFT arguments.
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High Energy Physics (Experiment)
First Search for Quirks at the LHC with FASER
FASER Collaboration
We present the first LHC search for quirks, particles with Standard Model and QCD-like infracolor (IC) interactions. The analysis uses data collected in 2022–2024 by FASER, with a $186\,\mathrm{fb}^{-1}$ integrated luminosity of
proton-
proton collisions at a center-of-mass energy $\sqrt{s} = 13.6\,\mathrm{TeV}$. Scintillator charge and timing information are used to search for slow pairs of quirks with no QCD color and electric charge $\pm 1$. No events are seen in this nearly background-free search, resulting in the first exclusion of quirks with masses above the weak scale for IC confinement scales in the broad range of $300 \,\mathrm{eV}<\Lambda<100\,\mathrm{keV}$.
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High Energy Physics (Theory)
Toward an Observable Algebra for de Sitter Space: Gap Protection and Modular Dressings
Hassan ElSayed
We investigate the relation between fundamental complements and regional operator
algebras in global de Sitter space. For a finite union of open arcs on the time-symmetric circle of global dS$_2$, we show that the fundamental complement is determined by the largest complementary gap: a gap contributes precisely when its angular length is at least $\pi$, and at most one gap can do so. In higher-dimensional global de Sitter space, the corresponding criterion is containment of an open hemisphere. We then study the operator-algebraic consequences in an abstract Möbius-covariant
chiral conformal net. Each regional
algebra is crossed with its
vacuum modular flow using a shared auxiliary clock. We derive an exact criterion for inclusions between the resulting continuous cores and show that
vacuum correlations obstruct this criterion when the larger region contains an additional spacelike arc. A compatible family can nevertheless be obtained on the finite Boolean
algebra generated by a fixed collection of separated arcs by using a split product state. Motivated by the holograms prescription of Bousso and Penington, we introduce a representation-dependent commutant model for regional
algebras. When the protected gap overlaps a fixed reference arc, the assigned
algebra is a proper von Neumann subalgebra of the reference Type-II$_1$ factor. For an explicit two-arc family, adding an arbitrarily short antipodal component removes the fundamental complement and changes the assigned
algebra discontinuously to the full reference
algebra.
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Cosmology and Nongalactic Astrophysics
Cosmology beyond standard sirens: cross-correlation of gravitational waves and neutral hydrogen intensity mapping
Matteo Schulz, Ulyana Dupletsa, Andrea Cozzumbo et al. (+8 more)
We explore the potential of cross-correlation between gravitational wave (GW) events and neutral hydrogen (HI) intensity mapping surveys to serve as an independent cosmological probe. Focusing on the ET and the SKAO, and assuming that binary black hole mergers and HI emission are biased tracers of the underlying dark matter distribution, we use their angular auto- and cross-correlation spectra to constrain cosmological parameters. We test three different GW detector networks: ET alone, both in its $\Delta$ and 2L configuration, and ET-2L together with
Cosmic Explorer. We show that the cross-correlation method, by naturally mitigating tracer-specific systematics, yields robust cosmological bounds, allowing for a sub-percent ($\sim 0.5\%$) precision on the Hubble constant $H_\mathrm{0}$. Furthermore, this approach robustly constrains the
cosmic expansion history throughout the post-reionization era of the Universe and, unlike conventional standard sirens, simultaneously probes the large scale distribution of matter perturbations, achieving relative uncertainties of approximately 1.3% on the total matter density $\Omega_\mathrm{m}$ and 1.6% on the late-time clustering amplitude $\sigma_8$.
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All authors Matteo Schulz, Ulyana Dupletsa, Andrea Cozzumbo, Giona Sala, Tommaso Ronconi, Marta Spinelli, Riccardo Murgia, Simone Mastrogiovanni, Jan Harms, Erik de la Haye, Felicitas Keil
Solar and Stellar Astrophysics
HCO$^+$ and the Effect of Mixing in SN 1987A
H. M. Davies, M. Matsuura, H. L. Gomez et al. (+8 more)
We present high angular resolution observations of the HCO$^+$ emission in the central ejecta of the
supernova remnant SN 1987A using the Atacama Large Millimeter Array (ALMA). We use this to infer the degree and type of mixing required within the ejecta in order to form HCO$^+$. The distribution of the $J=3-2$ HCO$^+$ emission is co-spatial with that of the $J=2-1$ CO emission, with an overlap between their brightest peaks. The correlation between the two molecules is strong and suggests that HCO$^+$ could form from reactions involving CO. We obtain additional observations of the $J=4-3$ HCO$^+$ emission to calculate the mass of HCO$^+$. The estimated HCO$^+$ mass is $3\text{--}9 \times 10^{-6}\,M_{\odot}$. The relatively large fractional abundance of HCO$^+$ with respect to CO ($M_{\mathrm{HCO}^+}/M_{\mathrm{CO}} = 3 \times 10^{-6}\text{--}3 \times 10^{-4}$) suggests that a moderate amount of hydrogen was mixed into the carbon- and oxygen-rich
nuclear zones of the ejecta prior to and during the
supernova explosion, in addition to large-scale macroscopic mixing.
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All authors H. M. Davies, M. Matsuura, H. L. Gomez, A. M. S. Richards, P. Cigan, R. Indebetouw, F. D. Priestley, R. Wesson, M. J. Barlow, J. Larsson, C. Fransson
Solar and Stellar Astrophysics
A tale of two isotopes: Spatial variation in HCN fractionation toward young cores
Sigurd S. Jensen, Silvia Spezzano, Olli Sipilä et al. (+3 more)
Context. Isotopic fractionation can serve as a powerful tracer of the chemical
evolution during
star and
planet formation. To accurately interpret observations, it is crucial to identify the dominant pathways of nitrogen and carbon fractionation at different evolutionary stages. Aims. We aim to study nitrogen and carbon fractionation in a sample of young cores at the onset of
star formation. Methods. We map H$^{13}$CN and HC$^{15}$N around one starless and three pre-
stellar cores. We compute the $N$(H$^{13}$CN)/$N$(HC$^{15}$N) column density ratio across the cores and compare the distribution with $N$(H$_2$) maps from $\textit{Herschel}$/SPIRE. In addition, we calculate $^{14}$N/$^{15}$N maps using the double isotope method for comparison with earlier studies. The results are compared with astrochemical modeling of carbon and nitrogen fractionation for a one-dimensional pre-
stellar core model. Results. The computed $N$(H$^{13}$CN)/$N$(HC$^{15}$N) ratio exhibit clear spatial variation across the maps. This variation is correlated with $N$(H$_2$) in three out of four cores. Conclusions. Our analysis reveals a correlation between the H$^{13}$CN/HC$^{15}$N ratios and the $N$(H$_2$) maps. According to the astrochemical model, the correlation is mainly due to variations in the $^{12}$C/$^{13}$C ratio. Consequently, the results caution against applying the double-isotope method to derive $^{14}$N/$^{15}$N ratios without independently assessing possible spatial variations in the $^{12}$C/$^{13}$C ratio. Furthermore, the leading cause of the isotopic variation in the model is not isotope-selective photodissociation, but rather more efficient fractionation through exchange reactions at lower temperatures in the denser regions of the cores.
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All authors Sigurd S. Jensen, Silvia Spezzano, Olli Sipilä, Paola Caselli, Laura Colzi, Elena Redaelli
Astrophysics of Galaxies
A Supermassive Black Hole Mass Measurement in NGC 5102 with Schwarzschild Orbit-superposition Modeling
Thomas K. Waters, Kayhan Gultekin, Karl Gebhardt et al. (+2 more)
We present a
stellar-dynamical mass measurement of the central black hole in the lenticular
galaxy NGC~5102 (SA0$^-$). Our analysis combines high-quality integral-field spectroscopy from the VLT Multi Unit Spectroscopic Explorer with high-spatial- and high-spectral-resolution Hubble Space
Telescope Imaging Spectrograph observations, using the Ca II triplet as a
stellar kinematic tracer. We constrain the black hole mass with axisymmetric, three-integral Schwarzschild orbit-superposition models, incorporating surface brightness measurements from HST F547M WFPC2 imaging. Assuming a distance of $3.66\,\mathrm{Mpc}$, we find a black hole mass of $(1.30^{+0.19}_{-0.18})\times10^6\,\mathrm{M_{\scriptscriptstyle\odot}}$, which is within $1.7\sigma$ of a previous CO band-head-based Jeans Anisotropic Modeling result ($M_{\bullet}=(9.1^{+1.8}_{-1.5})\times10^5\,\mathrm{M_{\scriptscriptstyle\odot}}$). Our measurement is also consistent with literature extrapolations of the $M_{\bullet}$-$\sigma_e$ relation into the currently under-sampled low-mass regime. The close agreement between these independent dynamical approaches provides external validation of the Jeans Anisotropic Modeling framework and supports the robustness of our Schwarzschild orbit-superposition result, bolstering confidence in future black hole mass measurements with this framework.
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All authors Thomas K. Waters, Kayhan Gultekin, Karl Gebhardt, Soch Foskic, Ahmad Kadri
High Energy Physics (Phenomenology)
Lepton-Number Violation in Higgs Effective Field Theory: Complete Operator Basis and Type-II Seesaw Matching
Zizhou Ge, Huayang Song and Xia Wan
We construct a complete and nonredundant basis of
lepton-number-violating (LNV) operators in the
Higgs effective field theory (HEFT) through $\mathcal{O}(p^4)$, including their full
flavor multiplicities. Using a complex dressed spurion that encodes the $B-L$ charge, we classify the $\Delta L=2$ and $\Delta L=4$ sectors, including
baryon-number-violating operators, and independently validate the counting using
Hilbert-series methods. As a concrete application, we present the first complete tree-level matching of the type-II seesaw model onto HEFT through $\mathcal{O}(p^4)$, covering the bosonic,
lepton-number-conserving, and LNV sectors. Using the nonlinear field representation and primary-HEFT power counting, we retain the full dependence of the matching coefficients on the independent scalar masses, the neutral-scalar mixing, and the doublet and triplet
vacuum expectation values. We compare our results with the corresponding real-triplet matching and a broken-phase effective field theory. We further discuss implications for LNV processes,
Higgs physics, and electroweak observables.
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Earth and Planetary Astrophysics
The JWST weather report: Unravelling the atmospheric variability of isolated worlds using principal component analysis
Merle A. Schrader, Johanna M. Vos, Evert Nasedkin et al. (+17 more)
Brown
dwarf variability directly probes atmospheric dynamics beyond the
Solar System, and recent JWST time-resolved spectroscopy has opened a new window into these processes. Principal component analysis (PCA) offers a data-driven framework to identify the dominant, independent patterns of spectral variability of variable targets without relying on prior atmospheric assumptions. SIMP 0136 is a young, T2.5, brown
dwarf at the planetary-mass boundary, making it an ideal analogue for directly imaged
exoplanets. We analysed one rotation of JWST/NIRSpec PRISM time-series spectroscopy to investigate the drivers of its variability using PCA. Two principal components are sufficient to reduce the residual spectra to the propagated noise floor, indicating that they capture the detectable coherent spectroscopic variability. The leading principal component captures broadband variability consistent with temperature changes, while the second traces chromatic variability linked to vertical cloud structure. The dominance of two components implies that the spectra can be described as mixtures of three distinct atmospheric states, whose relative contributions we mapped as a function of rotational phase. The observed spectra are described as evolving linear combinations of these states, indicating that the variability arises from the changing visibility of spatially distinct atmospheric regions. By projecting Sonora Diamondback forward models into the same principal component space, we found that the principal components capture a large fraction of the model variance, demonstrating that the same physical processes that govern SIMP-0136's observed variability also capture much of the model grid's variation. Our results establish PCA as a computationally efficient, physically interpretable framework for analysing JWST time-resolved spectroscopy of substellar atmospheres.
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All authors Merle A. Schrader, Johanna M. Vos, Evert Nasedkin, Jennifer Kestell, Nicolas B. Cowan, Roman Akhmetshyn, Samuel Beiler, Beth A. Biller, Ben Burningham, Jacqueline Faherty, Eileen C. Gonzales, Allison M. McCarthy, Caroline V. Morley, Barry O'Donovan, Cian O'Toole, Genaro Suarez, Xianyu Tan, Channon Visscher, Niall Whiteford, Yifan Zhou
Cosmology and Nongalactic Astrophysics
Radio Recombination Line Contamination in Post-Reionization 21 cm Intensity Mapping
Pip Petersen, Yakov Faerman and Matthew McQuinn
We explore
radio recombination line (RRL) contamination in post-reionization 21 cm intensity mapping observations. We develop a formalism to estimate the contamination of the 21 cm auto-power spectrum from the myriad of RRL lines that
redshift into a 21 cm map and predict contamination of the 21 cm power spectrum at all
redshifts. At $z\lesssim 2$, extrapolation of the conservative upper-bound model of Petrovic & Oh (2011) predicts high contamination to the 21 cm power spectrum, whereas our empirically-calibrated models suggest contamination several orders of magnitude smaller. We also estimate the contribution from carbon RRLs and find it to be subdominant. We find the RRL contamination is highly oscillatory in wavenumber, owing to the dominant contamination from RRLs emitted close in physical space to the 21 cm emission. These oscillations could in principle bias distance measurements derived from
Baryon Acoustic Oscillations (BAO), a key science driver of post-reionization 21 cm intensity mapping. We find the shift in the BAO extrema is at least two orders of magnitude smaller than relevant for percent-precision cosmology from BAO.
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Astrophysics of Galaxies
How to raise a supermassive black hole: interpreting early JWST AGN with the AESOPICA simulations
Sophie Koudmani, Jan Scholtz, Anthony J. Taylor et al. (+11 more)
The active
galactic nuclei (AGN) uncovered by JWST in the early Universe are highly abundant and seemingly overmassive with respect to local scaling relations, challenging standard models of black hole formation and growth. Yet it remains unclear whether they trace an efficient early growth channel, represent the observable tail of a broader population, or reflect systematic uncertainties in mass estimates. We introduce the AESOPICA project, a suite of twelve mid-volume ($L = 60\,\mathrm{cMpc}$) cosmological simulations based on the FABLE
galaxy formation model, varying the black hole seed mass across the theoretical formation channels ($M_\mathrm{seed} = 10^{2}$-$10^{5} \,\mathrm{M_{\odot}}$), the
accretion efficiency, including super-Eddington bursts, and the
supernova feedback strength. We forward-model observational selection with BALMERSOPICA, a mock JWST broad-line survey pipeline that assesses the detectability of each simulated AGN for a given grating and exposure time. We find that the bulk of the JWST AGN population can be assembled from any seed mass provided the
accretion efficiency is high, although light seeds require the most favourable
accretion conditions explored. Applying broad-line selection naturally recovers the apparently overmassive population, with the detected AGN lying furthest above the intrinsic $M_\mathrm{BH}$-$M_\mathrm{stellar}$ relation for inefficient
accretion models. The selected AGN lie on the local, weakly evolving $M_\mathrm{BH}$-$\sigma_\mathrm{stellar}$ relation, supporting a scenario where black holes assemble before the
stellar component is fully established. Since efficient
accretion rapidly erases the imprint of the initial seed mass, the low-mass end of the black hole mass function and host gas-phase
metallicities offer the most promising discriminants between seeding channels.
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All authors Sophie Koudmani, Jan Scholtz, Anthony J. Taylor, Ignas Juodžbalis, Debora Sijacki, Rachel S. Somerville, Roberto Maiolino, Emma Curtis-Lake, Steven L. Finkelstein, Martin A. Bourne, Francesco D'Eugenio, Sophia Geris, Lucy R. Ivey, Hannah Übler
High Energy Astrophysical Phenomena
Spectroscopic Analysis of Fermi-detected Blazars using SDSS-V
Mohammed Iddrisu Nlowie, James Aird, Eli Kasai et al. (+17 more)
The automated spectroscopic pipeline of the Sloan Digital Sky Survey (SDSS) systematically assigns
Galactic star,
galaxy, or typical
quasar classifications to jet-dominated blazars, owing to the absence of a non-thermal jet continuum component in its template library. In this study, we present a new, physically motivated, multi-component spectral fitting pipeline that we apply to 746 optical counterparts of
Fermi/4FGL-DR4 $\gamma$-ray sources in the SDSS-V Data Release 20 spectroscopic database, yielding 707 well-fitted blazar candidates dominated by Power-law+
Galaxy (59.4%), Power-law+Lines (22.6%), and Power-law+QSO (15.0%) model families. Independent WISE infrared (IR) photometry confirms that 96.6% of the 88 sources originally misclassified as
Galactic stars by SDSS fall within the canonical blazar region, with 90.9% reclassified as BL Lacertae object (BL Lac) candidates, demonstrating the success of our new pipeline. The new classification scheme naturally recovers the known cosmological separation between BL Lac and Flat Spectrum
Radio Quasar (FSRQ) candidates and a separation of approximately one order of magnitude in median $\gamma$-ray luminosity. We compare our
redshift estimates to a validation sample of 111 sources in the Third
Fermi-LAT Catalogue of High-Energy Sources (3FHL), finding a 10.4% reduction in catastrophic failures ($\eta = 0.387$ vs 0.432) over the SDSS pipeline. The equivalent width analysis validates the traditional |EW| = 5 Ang classification boundary at the population level (BL Lac: 4.47 $\pm$ 0.15 Ang; FSRQ: 22.86 $\pm$ 0.86 Ang), although 49.5% of individual BL Lac candidates exceed this threshold and 51.4% show simultaneous emission and absorption features. This hybrid population challenges the traditional binary blazar classification and points towards a more physically continuous description of blazar properties.
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All authors Mohammed Iddrisu Nlowie, James Aird, Eli Kasai, Amy L. Rankine, Paloma Guetzoyan, Scott Anderson, Catarina Aydar, William N. Brandt, Joel R. Brownstein, Xinyu Dai, Lorena Hernández-García, Paola Rodríguez Hidalgo, Pranavi Hiremath, Anton Koekemoer, Andrea Merloni, Sean Morrison, Mara Salvato, Donald P. Schneider, Axel Schwope, Benny Trakhtenbrot
Cosmology and Nongalactic Astrophysics
A Periodically Interacting Dark Sector: Signatures and Constraints from CMB and Cosmic Expansion Data
Marco Antonio Cardoso Alvarez, Micol Benetti, Leila Graef et al. (+1 more)
We introduce a novel cosmological model that provides an effective description of the back-reaction of super-Hubble fluctuations on the cosmological background, a generic effect expected to arise in any cosmological scenario without requiring additional ingredients. At the phenomenological level, it can be interpreted as an interacting dark sector scenario in which the sign of the energy transfer changes periodically over time. We constrain the model using CMB, BAO, and Type Ia
supernova data. We find that a significant amplitude of the oscillatory interaction is allowed by the data, although there is no statistically significant preference for this model over $\Lambda$CDM.
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All authors Marco Antonio Cardoso Alvarez, Micol Benetti, Leila Graef, Robert Brandenberger
Solar and Stellar Astrophysics
Multi-Wavelength Diagnostics of Pre-Flare Evolution with Aditya-L1: From the Solar Chromosphere to the Corona
Adithya H.N., Sreejith Padinhatteeri, Soumya Roy et al. (+13 more)
The pre-
flare phase of
solar flares provides important insight into the processes that drive active regions toward instability. We investigate chromospheric pre-
flare activity using observations from the
Solar Ultraviolet Imaging
Telescope (SUIT) onboard Aditya-L1, complemented with X-ray measurements from High Energy L1 Orbiting X-ray Spectrometer (HEL1OS) and
Solar Low Energy X-ray Spectrometer (SoLEXS). We analyse seven M- and X-class
flares, focusing on spatially resolved Mg II h (2803~Å) observations from SUIT. We identify 102 pre-
flare transients within regions of interest prior to
flare onset. These transients are detected in the Mg II h channel, with no counterparts in continuum filters, confirming their chromospheric origin. In most cases, the transients are co-spatial with polarity inversion lines (PILs) and the eventual flaring region. Approximately 28~% of transients have X-ray counterparts in HEL1OS (10-30~keV); The Spectrometer
Telescope for Imaging X-rays (STIX) spectral analysis reveals non-thermal emission in a subset, indicating that some transients are small-scale
flare-like events. A hot X-ray onset is identified in four cases. For the remaining three cases, the signal-to-noise ratio above the background is insufficient to determine whether a hot-onset phase is present. The peak-flux distribution of the transients follows a broken power law with indices $\alpha_1 = 1.64^{+0.59}_{-0.57}$ and $\alpha_2 = 3.12^{+0.64}_{-0.61}$, with the higher-energy slope consistent with the Ly-$\alpha$
flare distribution. These results suggest that chromospheric pre-
flare transients represent small-scale
magnetic energy-release events that contribute to the progressive destabilisation of active regions prior to major
flare onset.
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All authors Adithya H.N., Sreejith Padinhatteeri, Soumya Roy, K. Sankarasubramanian, Durgesh Tripathi, Abhilash R Sarwade, Srikar Paavan Tadepalli, Harshavardhan G Hegde, Nived V. N, Janmejoy Sarkar, Rahul Gopalakrishnan, Rushikesh Deogaonkar, A. N. Ramaprakash, Sami K. Solanki, Dibyendu Nandy, Dipankar Banerjee
Instrumentation and Methods for Astrophysics
Tricouplers for nulling interferometry with photonic integrated circuits
Anusha Pai Asnodkar, Nemanja Jovanovic, Harry-Dean Kenchington Goldsmith et al. (+7 more)
Solar System analog gas
giants and habitable-zone terrestrial
planets are observationally elusive to conventional
exoplanet detection and characterization techniques, i.e. transits, radial velocities, and direct imaging. Long baseline nulling interferometry across multiple apertures suppresses starlight and enables detection of faint planetary signals at higher spatial resolution than traditional coronagraphs on single-aperture
telescopes. Leveraging technological advancements from the telecommunications industry, photonic integrated
circuits (PICs) offer a promising platform for performing the optical operations necessary for astronomical applications, including phasing and beam combination for nulling interferometry in both long-baseline and cross-aperture configurations. PICs provide compact, scalable architectures with reduced sensitivity to
alignment as well as thermal and mechanical perturbations compared to bulk optics. However, their design and manufacturing precision remain insufficient for the stringent requirements of
exoplanet instrumentation. Here, we investigate the nulling capabilities of photonic tricouplers, devices composed of three equal-width waveguides that are geometrically predisposed to produce achromatic nulls upon beam combination through their symmetric construction. In the laboratory, we characterize null depths in monochromatic light at 1.55 $\mathrm{\mu}$m with devices on a planar silica-on-silicon platform. In broadband $H$-band light, we explore chromatic effects from components such as thermo-optic phase modulators used for fine-phasing. Our ongoing efforts towards maturation of PICs for direct detection and atmospheric characterization of
exoplanets will support scalable testing and deployment of high-contrast technologies for future space-based observatories, such as the Habitable Worlds Observatory.
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All authors Anusha Pai Asnodkar, Nemanja Jovanovic, Harry-Dean Kenchington Goldsmith, Ahmed Sanny, Yoo Jung Kim, Hani Nejadriahi, Isabelle Rivera, Michael P. Fitzgerald, Dimitri Mawet, Pradip Gatkine
Instrumentation and Methods for Astrophysics
High-statistics simulations of NewAthena WFI background using Geant4
Matthew K. Heine, Catherine E. Grant, Marshall W. Bautz et al. (+14 more)
The observation of hot gas structures is one science goal of the Wide Field Imager (WFI) on ESA's NewAthena X-ray observatory. Because the measurement of these faint diffuse sources is limited by background from
cosmic ray particle interactions within the instrument, understanding and reducing this background is critical. To this end, we employ a two-pronged approach, performing high-fidelity Geant4 simulations on both detailed, realistic geometry models as well as complementary simple geometry models. The former can reveal subtle sensitivities of background to details of the instrument design. The latter allows for fast iteration, useful in guiding and understanding the larger simulations. We show how we leverage High Performance Computing (HPC) resources to achieve simultaneously high throughput and fast time to result. We discuss our recent results, which are applicable not only to WFI, but also other X-ray missions.
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All authors Matthew K. Heine, Catherine E. Grant, Marshall W. Bautz, Beverly J. LaMarr, Eric D. Miller, Michael W. J. Hubbard, David Hall, Joan Requena, Emanuele Perinati, Steven W. Allen, Artem Poliszczuk, Dan Wilkins, Fabio Gastaldello, Silvano Molendi, Ralph P. Kraft, Gerrit Schellenberger, Arnab Sarkar
Mesoscale and Nanoscale Physics
Dirac Fermion Scattering and Conductance Response in Asymmetric Graphene Wormholes
Arián Gorza, Facundo Arreyes and Juan Sebastián Ardenghi
We calculate massless Dirac scattering and the conductance response to a localized scalar ring gate in a
graphene wormhole with two independent
curvature scales and no axial
magnetic flux. Matching Hankel and Gauss hypergeometric spinors gives the unperturbed scattering states. Interchanging the throat segments preserves the total Landauer conductance, while a gate at a fixed displaced position produces different conductance changes in the two mirror configurations. For $a=5$~nm and $r_L+r_R=13.68$~nm, a $1$~meV gate of width $1$~nm centered at $u_0=7$~nm gives relative conductance changes of $+0.0718\%$ and $-0.0918\%$ at $E=200$~meV for $\eta=0.5$ and $2$, respectively. Energy–position maps show how asymmetry redistributes the electrical response. Gates centered well inside both curved segments can give different response magnitudes; opposite signs occur near the mouths and farther out. We also find opposite response signs in the fixed-length comparison at the chosen operating point. For equally occupied opposite angular channels, the sublattice imbalances cancel and the conductance responses add. A spatially controlled gate thus probes throat orientation through conductance even when the unperturbed two-terminal measurement cannot distinguish the two configurations.
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Quantum Physics
A two-dimensional piezo-optomechanical transducer
Tian Xie, Nelson Ooi, Linus Woodard et al. (+7 more)
Optical
quantum networks provide a natural route for connecting distant superconducting
quantum processors, enabling distributed
quantum computation, sensing, and communication. Piezo-optomechanical transducers are among the leading candidates for scalable microwave-to-optical
quantum interfaces. However, prior one-dimensional piezo-optomechanical transducers remain limited by optical-absorption-induced heating and the resulting thermal noise. Two-dimensional optomechanical
crystals offer substantially improved thermalization from better thermal anchoring, but their structural complexity has so far hindered the realization of a fully integrated two-dimensional transducer. Here, we overcome this challenge with a new design strategy based on band structure engineering. We fabricate the devices and experimentally characterize the response, measuring an electromechanical damping rate of 4.6 kHz at room temperature and electromechanical coupling rate of 0.17 MHz by wire-bonding to a multi-mode microwave resonator at 10 mK. Bidirectional transduction is performed with a calibrated internal efficiency of 0.85% in the continuous-wave operation, alongside pulsed
photon-
phonon pair generation near its
quantum ground state. Our results represent a significant step toward high-efficiency and low-noise transducers for entangling remote superconducting
qubits.
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All authors Tian Xie, Nelson Ooi, Linus Woodard, Sultan Malik, Felix Mayor, Oliver A. Hitchcock, André G. Primo, Wentao Jiang, Samuel Gyger, Amir H. Safavi-Naeini
Quantum Physics
Algebraic paradoxes in adaptive quantum computation
Samson Abramsky, Rui Soares Barbosa, Carmen Constantin et al. (+1 more)
Measurement-based
quantum computation (MBQC) is a universal model of
quantum computation whose full power requires adaptivity. Contextuality is known to power
quantum advantage in MBQC, yet it has resisted algebraic analysis in the adaptive setting. We show that if an adaptive $\mathbb{Z}_2$-linear measurement-based
quantum computing protocol deterministically computes a non-affine Boolean function, then the underlying
quantum resource satisfies an inconsistent set of linear equations. This witnesses an algebraic form of strong contextuality generalising Mermin's All-versus-Nothing arguments. Such algebraic contextuality can be detected cohomologically, resolving an open question posed by Raussendorf, who had established cohomological witnesses of contextuality for non-adaptive protocols, but left the adaptive case open. We prove this result constructively: we model adaptive measurement protocols as ordinary measurements on a larger scenario of tree-like measurements, and explicitly build the inconsistent equations inductively.
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All authors Samson Abramsky, Rui Soares Barbosa, Carmen Constantin, Martti Karvonen
Quantum Physics
Role of flavor degrees of freedom in quantum simulations of disorder-free localization
Yizhuo Tian, Jared Jeyaretnam, Tanmay Bhore et al. (+2 more)
A recent Google
Quantum AI experiment [\href{https://www.science.org/doi/10.1126/science.adr9680}{Gyawali et al., Science 393, 71 (2026)}] has exploited
quantum parallelism to emulate disorder-averaged many-body dynamics, with conserved local degrees of freedom generating an effective disorder potential. We investigate how the local spectrum of these static variables controls localization in a
flavor-extended ${\mathbb Z}_2$
lattice gauge theory, which maps onto a mixed-field Ising chain with $n$-level bond disorder. Combining finite-size spectral and
entanglement diagnostics with infinite
matrix-product state dynamics, we find a qualitative distinction between binary and multilevel disorder. For $n=2$, apparent localization ultimately gives way to thermalization; the long-lived transient arises from energy-scale separation, degenerate spectral towers, and approximate
Hilbert-space fragmentation. By contrast, $n=4$ displays consistent localization signatures, including Poissonian level statistics, area-law eigenstate
entanglement, nonthermal
entanglement spectra, and persistent local
memory over accessible times in the thermodynamic limit. Our results show that, despite its larger variance, binary disorder lacks the local amplitude diversity needed to suppress resonances. Thus, localization is governed not simply by disorder strength, but by the local disorder spectrum and the resulting resonant connectivity of the many-body
Hilbert space.
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All authors Yizhuo Tian, Jared Jeyaretnam, Tanmay Bhore, Zlatko Papić, Jad C. Halimeh
Quantum Physics
Graph Theoretic Approach to Quantum Nonstabilizerness
Yingjian Liu, Albert Gasull, Mengyao Hu et al. (+3 more)
Detecting nonstabilizerness requires full
tomography and an optimization over exponentially many stabilizer states. A limited Pauli measurement set promises resource-efficient magic certification, yet the resulting reduced stabilizer polytope is generally difficult to characterize. We trace this difficulty into two coupled obstructions: the simultaneous measurability of measurements captured by their frustration graph structure, and the consistency of sign dependencies from stabilizer formalism. We show that the sign dependencies can be discarded exactly whenever active dependencies are absent, and that perfect frustration graphs then make this reduced polytope efficiently solvable. This solvable regime derives a closed form bounded by the clique number of the frustration graph, revealing a tradeoff between witness capacity and simultaneous measurability. Clifford covariance allows rotated measurement sets to enlarge the detectable state space without raising the capacity. Graph structure therefore emerges as both a certificate of tractability and a design principle for scalable magic resource detection.
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All authors Yingjian Liu, Albert Gasull, Mengyao Hu, Ruiyun Zhang, Flavio Baccari, Jordi Tura
Astrophysics of Galaxies
The extended globular cluster system of the archetypal "failed galaxy" Dragonfly-44 from deep white-light Hubble Space Telescope imaging
Maria Luisa Buzzo, Pieter van Dokkum, Roberto Abraham et al. (+2 more)
For nearly a decade, Dragonfly-44 (DF44, $M_{\star} = 3\times10^8\,{\rm M}_\odot$) has been considered an archetypal “failed
galaxy”, a system so rich in globular clusters (GCs) and dark matter that it challenges standard
dwarf galaxy formation scenarios. Yet a key measurement underpinning this classification has remained controversial, with published GC counts differing by a factor of four. Here we present new ultra-deep Hubble Space
Telescope WFC3/UVIS imaging of DF44 in the F350LP filter, reaching more than one magnitude below the canonical turnover of the GC luminosity function. We find that DF44 hosts $N_{\rm GC}=73.1\pm8.6$ GCs in a spatially extended system with a half-number radius of $R_{\rm gc}=1.48^{+0.39}_{-0.51}R_{\rm e}$, at the high end of previously published values. The GC system comprises ${\sim}3.9\%$ of the total
stellar mass and, if DF44 follows the empirical GC number–
halo mass relation, implies $\log(M_{\rm vir}/M_\odot)=11.5\pm0.3$, consistent within the uncertainties with the cored
halo mass inferred from
stellar kinematics by van Dokkum et al. 2019. Together with a specific frequency of $S_N=42.1\pm4.9$, the rich GC population strongly supports the interpretation of DF44 as a failed-
galaxy candidate that assembled a massive
halo and rich GC population early, but never formed the field
stellar mass expected for its
halo. Current formation models reproduce several individual properties of DF44, but its combination of GC richness, early quenching, and high inferred
halo mass remains an important constraint on models of
dwarf-
galaxy formation.
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All authors Maria Luisa Buzzo, Pieter van Dokkum, Roberto Abraham, Shany Danieli, Aaron J. Romanowsky
Strongly Correlated Electrons
Quantum spin-glass criticality in disordered frustrated dimer magnets
Darshan G. Joshi and Matthias Vojta
We study
quantum phase transitions of Mott
insulators between
spin-glass and featureless paramagnetic phases. Specifically, we consider a triangular-
lattice bilayer Heisenberg model with bond disorder. The clean system has two phases, a dimer
quantum paramagnet and a non-collinear antiferromagnet, separated by a
quantum critical point. Bond disorder destroys the
antiferromagnetic phase via the interference of dipolar textures and results in
spin-glass order, such that the system features a
quantum phase transition between
spin-glass and dimer phases. We study the vicinity of this transition using a variant of bond-operator theory and calculate thermodynamic observables as well as excitation spectra. Bond disorder leads to strong inhomogeneities near the transition which suppresses non-collinearities and leads to anomalously weak glassiness in the near-critical
quantum spin glass. We characterize the low-energy excitations which have a strong tendency towards spatial localization, and we track the behavior of the amplitude (i.e.
Higgs) mode across the glass phase whose spectral weight we find to be strongly suppressed due to interference effects.
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Materials Science
Isolation of spin-valley locked nodal-line fermions in $d$-wave $\mathrm{AV_2X_2O}$ altermagnets
Pritesh Srivastava, Rahul Verma and Bahadur Singh
Crystalline
symmetries stabilize topological states with distinct electronic properties, while altermagnets exhibit momentum-dependent
spin splitting without net magnetization. Here, we combine first-principles calculations with a minimal tight-binding model to realize $C$-paired
spin-valley-locked nodal-line
fermions in the $d$-wave altermagnet $\mathrm{AV_2X_2O}$ (A = Rb, Cs, or K; X = Te, Se, or S). The low-energy electronic structure hosts coexisting
spin-degenerate and
spin-polarized nodal lines around $C_{4z}$-paired valleys near the
Fermi level. The
spin-polarized nodal lines are protected by the out-of-plane mirror
symmetry $\mathcal{M}_z$ and remain robust against
spin-orbit coupling. The minimal model reveals their microscopic origin and establishes a general design principle for their isolation. Layer engineering and electronic correlations serve as material-specific knobs for realizing these isolated
spin-valley-locked nodal lines near the
Fermi level. Our results establish the $\mathrm{AV_2X_2O}$ family as a versatile platform for exploring topological
spin-valley locking in $d$-wave altermagnets.
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