Instrumentation and Methods for Astrophysics
SHARP – A spectrograph proposal to fully exploit ELT capabilities and look beyond JWST
P. Saracco, P. Conconi, C. Arcidiacono et al. (+47 more)
The Extremely Large
Telescopes (ELTs), with their large apertures and cutting-edge Multi-Conjugate Adaptive Optics (MCAO) systems, promise to deliver data that is both sharper and deeper than even the James Webb Space
Telescope (JWST) across large fields. SHARP is a concept study for a near-IR (0.95-2.45 $\mu$m) spectrograph specifically designed to fully exploit the collecting area and angular resolution capabilities of the upcoming ESO's ELT. The instrument concept is driven by the goal of tackling the most important questions in astrophysics and cosmology, from exploring
primordial galaxies to studying the formation of young
stellar object and planetary systems in the nearby
dust-enshrouded regions, bridging the gap between the local and the distant Universe. This requires versatility to accommodate diverse observational needs. SHARP is composed of two main units: NEXUS, a Multi-Object Spectrograph (MOS) optimized for detecting the faintest sources, and VESPER, a multi-object Integral Field Unit (multi-IFU) designed for brighter ones. This article provides an overview of the scientific design drivers, the solutions developed to meet them, and the resulting optical design that achieves the required performance.
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All authors P. Saracco, P. Conconi, C. Arcidiacono, H. Mahmoodzadeh, I. Di Antonio, E. Portaluri, P. Franzetti, A. Gargiulo, I. Arosio, L. Barbalini, G. Lops, E. Molinari, J. M. Alcala, S. Bisogni, R. Bonito, E. Bortolas, M. Cantiello, A. Caratti o Garatti, E. Cascone, V. Cianniello, E. M. Corsini, F. Damiani, F. D'Ammando, F. D'Alessio, E. Dalla Bonta, M. DallOra, V. De Caprio, G. De Lucia, B. Di Francesco, G. Di Rico, V. D'Orazi, C. Eredia, A. R. Gallazzi, M. G. Guarcello, L. Izzo, F. La Barbera, M. M. Lippi, M. Longhetti, A. Longobardo, C. Mancini, M. Mirabile, E. Piconcelli, A. Pizzella, L. Podio, L. Prisinzano, C. Tortora, G. Vietri, F. Vitali, H.-F. Wang, S. Zibetti
High Energy Physics (Theory)
Yuma Furuta, Wataru Harada, Yuya Kusuki et al. (+1 more)
Complex conformal field theories (CFTs) have recently emerged as essential frameworks for understanding non-Hermitian criticality, weakly first-order phase transitions, and walking renormalization group flows, while their general structures remain largely unknown. In this work, we propose a systematic construction of complex CFTs by analytically continuing exactly marginal couplings into the complex plane. This procedure applies uniformly to bulk, boundary, and defect deformations, preserving conformal
symmetry while generically complexifying operator spectra and other universal data. Using the compact free
boson as a solvable laboratory, we uncover the global structure of the complexified Gaussian conformal
manifold. More generally, we demonstrate that genuinely complex rational CFTs do not exist: rational points remain confined to the real regime, providing a sharp distinction between real and complex theories. In the defect case, we investigate the one-parameter family of conformal defects in the Ising CFT and derive exact expressions for the defect spectrum, energy transmission coefficient, and effective central charge from analytic continuation. The theoretical predictions are precisely verified in non-Hermitian critical Ising and free
fermion chains using bulk-defect correlators,
entanglement entropy, and complex energy transport, providing concrete evidence for the complex defect conformal
manifold. Finally, we study complex boundary renormalization-group flows through the AdS/BCFT correspondence. Our results establish complex conformal
manifolds as a controlled bridge between solvable
lattice models, complex CFTs, and holography, while providing stringent analytic
benchmarks for the nonunitary conformal bootstrap.
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All authors Yuma Furuta, Wataru Harada, Yuya Kusuki, Yin Tang
Astrophysics of Galaxies
Global trends in morphology from massive to dwarf galaxies
Ilin Lazar, Sugata Kaviraj, Christopher J. Conselice et al. (+7 more)
The morphological properties of
dwarf galaxies (Mstar < 10^9.5 MSun) remain largely unexplored, particularly outside the local neighbourhood. We explore how morphology changes across the massive to
dwarf-
galaxy regimes, using a mass-complete sample of ~1000
galaxies, with
stellar masses and
redshifts in the ranges 10^7 MSun < Mstar < 10^12 MSun and z < 0.15 respectively. By combining JWST-derived morphological parameters (concentration, asymmetry and clumpiness; `CAS') and visual morphological classifications, we explore: (1) how morphology changes with
stellar mass and effective surface brightness, (2) the connection between morphology and recent
star formation history, as a function of
stellar mass, (3) how bar frequency changes between the massive and
dwarf regimes and (4) how well the CAS parameters perform in separating early- and late-type
galaxies, as a function of
stellar mass. We demonstrate that
galaxies become less concentrated, more asymmetric and less clumpy with decreasing
stellar mass. In both mass regimes,
galaxies that are more concentrated and less asymmetric are more likely to be red (i.e. quenched). The decrease in concentration towards lower
stellar masses results in a loss of the leverage that this parameter can provide in separating early- and late-type
galaxies. Thus, while the CAS system successfully separates early- and late-type systems in the massive-
galaxy regime, these morphological classes become significantly more difficult to separate, using these parameters, in the
dwarf regime. Finally, the bar fraction declines steadily with decreasing
stellar mass and becomes consistent with zero at Mstar ~ 10^8 MSun, suggesting a lower limit for the
galaxy mass needed to induce bar formation.
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All authors Ilin Lazar, Sugata Kaviraj, Christopher J. Conselice, Lewi Westcott, Aaron E. Watkins, Sophie Koudmani, Garreth Martin, Thomas M. Sedgwick, Darshan Kakkad, Brian Bichang'a
Astrophysics of Galaxies
Tidal origin of dark-matter free dwarf galaxies in the NGC 1052 group
Francois Hammer and Yanbin Yang
The discovery of dark matter-free (DM-free)
dwarf galaxies in the NGC 1052 neighborhood has had a considerable impact on modern cosmology. The
galaxies have been explained through a
dwarf–
dwarf head-on collision, a rare event. We find that they could alternatively be associated with a head-on 1:1 merger after it was tuned to generate the E4 morphology of NGC 1052. Our simulations show that such mergers produce long-lived
tidal features, are associated with the remnant
galaxy, and are in the form of large
tidal tails, including
tidal dwarf galaxies (TDGs). We emphasise that such
tidal features are predicted by the hierarchical scenario in which massive
galaxies are formed by
galaxy mergers. The latter can reproduce both the
tidal features in the NGC1052 outskirts and the observed
dwarf galaxies. The simulated TDGs have sizes similar to those observed, while they are ten times smaller in the bullet
dwarf scenario. However, we cannot reproduce the luminous globular cluster systems due to resolution limitations. Resolving the radial distance between the DM-free
dwarfs is necessary to identify the scenario of their formation. We suggest that there should be many other examples of DM-free
dwarf galaxies in the neighbourhood of local massive
galaxies and
galaxy groups.
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High Energy Physics (Theory)
The auxiliary-deformed Breitenlohner-Maison model: duality frames and higher-dimensional origin
Daniele Bielli and Mattia Cesàro
The two-dimensional Breitenlohner-Maison (BM) model is a classically integrable subsector of $D=4$ general relativity endowed with two commuting Killing isometries, obtained via Kaluza-Klein reduction to $D=2$. Integrable deformations of such a theory have recently been constructed via auxiliary fields in the so-called $\nu$-frame. In this work we first extend this point of view by deriving the complementary auxiliary field perspective known as $\mu$-frame, and then explicitly construct the uplift to $D=4$ of both descriptions, relying on an ansatz inspired by duality-invariant Lagrangian formulations of Einstein theory. The resulting four-dimensional deformed model thus obtained is a higher-derivative theory which lacks manifest diffeomorphism invariance in both frames. We comment on possible resolutions of this puzzling feature and on the physical interpretation of the model in $D=4$.
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High Energy Physics (Theory)
CFTs on Squashed Spheres and the Thermal Effective Action
Klaas Parmentier and Nikolay Bobev
We study three-dimensional CFTs on compact Euclidean
manifolds in two complementary limits: small deformations of the round $S^3$ and the small-fiber, large-squashing limit of Seifert
manifolds. Near the round sphere, conformal perturbation theory expresses the free-energy response through integrated stress-tensor correlators. We derive a harmonic-space formula for the universal quadratic response to arbitrary metric squashing and show that it is proportional to the $c_T$ coefficient of the stress-tensor two-point function. For
unitary CFTs this establishes that the sphere free energy is a local maximum in the space of metric deformations. This result extends to conserved
spin-$s$ currents, whose quadratic response alternates in sign. For the specific case of squashing the
Hopf fiber, we find an explicit form for the cubic response, and in addition obtain the leading correction to the two-point function of scalar operators. In the small-fiber limit, corresponding to the large temperature regime of the CFT, the partition function is governed by a two-dimensional thermal effective action constructed out of the Weyl-rescaled base metric and a Kaluza–Klein field strength. The thermal effective action relates CFT free energies on different backgrounds, including squashed Lens spaces, which we discuss in detail. We also explicitly determine the Wilson coefficients of this effective action, to various orders in the high-temperature expansion, for free fields, the large-$N$ critical O($N$) model, and
holographic CFTs.
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Astrophysics of Galaxies
Hunting Wandering 3<z<8 Black Holes: Spatial Offsets in Ionization Ratio and Continuum Emission
Urvi Thakurdesai, Anthony J. Taylor, Steven L. Finkelstein et al. (+14 more)
The early growth and assembly of supermassive black holes (SMBHs) remain key topics of interest in
galaxy evolution. One of the scenarios predicted by theoretical models is that frequent minor mergers and asymmetric gas inflows may cause SMBHs to temporarily reside off-center within their host
galaxies in the early universe. To observationally test this scenario, we investigate whether spatially offset ionization signatures-which may be indicative of active
galactic nuclei (AGN)-can be identified. Using JWST NIRSpec PRISM spectroscopy from the
Cosmic Evolution Early Release Science (CEERS) survey, we analyze the 2D spectra of 90 high-
redshift galaxies (3 < z < 8), including two known broad-line AGN. By measuring key emission lines such as H{\alpha}, H{\beta}, [OIII]{\lambda}5007, [NeIII]{\lambda}3868, and [OII]{\lambda}{\lambda}3727, 3729 we derive spatial flux ratio profiles, and focus on [OIII]/H{\beta} as a tracer of high-ionization mechanisms that may indicate AGN activity. We identify 26
galaxies (~30% of the sample) with significant localized peaks in [OIII]/H{\beta}. Out of these 26
galaxies, 12 sources (~46%) exhibit significant spatial offsets between the peak [OIII]/H{\beta} ratio and the
stellar continuum center. Six of these sources show the highest amount (> 1.5) pixel spatial offsets. This spatial offset between ionization structure and
stellar centers offers a promising avenue to probe early SMBH
evolution and its connection to
galaxy formation.
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All authors Urvi Thakurdesai, Anthony J. Taylor, Steven L. Finkelstein, Gene C. K. Leung, Oscar A. Chavez Ortiz, Jonathan R. Trump, Bren E. Backhaus, Nikko J. Cleri, Francesco D'Eugenio, Fabio Pacucci, Anton M. Koekemoer, Pablo Arrabal Haro, Micaela Bagley, Mark Dickinson, Jeyhan Kartaltepe, Casey Papovich, Nor Pirzkal
Cosmology and Nongalactic Astrophysics
The magnetic mayhem in Abell 2199: discovery of synchrotron threads and homogeneous diffuse radio lobes
R. Timmerman, L. Rudnick, A. Botteon et al. (+2 more)
Sensitive low-frequency
radio observations have started uncovering examples of synchrotron-emitting threads, isolated from the rest of
radio emission in
galaxy clusters. As the bridge of
radio emission previously detected between the
radio lobes of 3C 338 in Abell 2199 is a candidate of such a structure, we observed this
galaxy cluster using the International LOFAR
Telescope. These observations revealed the presence of multiple narrow isolated synchrotron threads in 3C 338: east, west and north of the AGN and its
radio lobes. Chandra X-ray observations show that these structures most likely do not reside within cavities in the intracluster medium (ICM), and are therefore considered to be distinct structures from the
radio lobes. Non-detections in 1.5 GHz Very Large Array observations imply that the spectral index of these newly-discovered isolated threads is likely $\alpha_{1500}^{144} < -3.0$ or steeper. We consider these isolated synchrotron threads to most likely display examples of
magnetic threads within the ICM that have captured synchrotron-emitting
plasma, as has recently been proposed. Furthermore, our observations reveal the
radio lobes to show an almost perfectly uniform spectral index, unlike what would be expected if substantial age differences are present in the
radio lobes according to standard spectral ageing models. We find that the relativistic
plasma in 3C 338 is consistent with a homogeneous
cosmic ray electron population, with the spectral variations dependent on the local
magnetic field strength. Finally, we explore the various models that could explain this trend in the
radio lobes.
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All authors R. Timmerman, L. Rudnick, A. Botteon, G. Brunetti, R. Kale
Cosmology and Nongalactic Astrophysics
Galaxy Power Spectrum at Two-Loop Order: Implications for Weak Lensing Surveys and New Physics
Mikhail M. Ivanov
We compute the
galaxy power spectrum at two-loop order in cosmological perturbation theory (effective field theory, EFT). We derive
galaxy bias operators through the fifth order and obtain two-loop renormalization conditions for their bias coefficients. We also derive the relevant higher-derivative and
stochastic contributions, and implement IR resummation using time-sliced perturbation theory. We obtain the complete dark-matter and
galaxy renormalization conditions for the higher-derivative operators at the power spectrum, bispectrum, and trispectrum level. Having identified the redundant operators, we find that the two-loop
galaxy power spectrum requires 21 additional bias, higher derivative and
stochastic parameters per
galaxy sample relative to the one-loop model. We compare our computation with the
galaxy-
galaxy and
galaxy-matter power spectra from the PT Challenge N-body simulation at $z=0.61$ and find a per mille-level agreement up to $k=0.85~h$Mpc$^{-1}$. We show that even with conservative priors on all EFT parameters, the two-loop model produces an unbiased measurement of the mass fluctuation amplitude $\sigma_8$ with three times narrower error-bars than the linear theory model. The improvement over the one-loop model is $\simeq 40\%$. This suggests significant gains in the two-loop EFT analyses of
galaxy clustering and
galaxy–
lensing two-point functions (“$2\times2$ pt”) from CMB
lensing maps and imaging surveys like Euclid, LSST, and Roman. In addition, our two-loop computation offers a probe of new physics scenarios that modify the shape of the matter power spectrum at wavenumbers $(0.4-0.8)~h$Mpc$^{-1}$ such as the presence of ultra-light
axion dark matter sub-components with masses $m_a\sim 10^{-24}$ eV.
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High Energy Physics (Theory)
Non-supersymmetric dualities beyond the gauge algebra
Bernardo Fraiman, Vittorio Larotonda, Ling Lin et al. (+1 more)
We provide a testing ground for dualities of non-supersymmetric type 0 orientifolds by finding the global forms of their gauge groups. As an example, we consider the Bergman–Gaberdiel proposal for a duality of theories with $\mathfrak{so}(32) \oplus \mathfrak{so}(32)$ gauge
algebra. On the orientifold side, we perform a scan of brane states, similar to the case of the D0-brane in type I string theory, and identify spinorial states that constrain the gauge group. Comparing with the bosonic string side, where the gauge group is determined by the internal momentum
lattice as in heterotic strings, our analysis shows that the gauge groups match, hence supporting the duality beyond the perturbative string spectrum.
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All authors Bernardo Fraiman, Vittorio Larotonda, Ling Lin, Salvatore Raucci
Astrophysics of Galaxies
Little Red Dots as Intermediate Mass, Super-Eddington Engines: Insights from Type IIn Supernovae and The 1837-1856 Great Eruption of $\eta$ Carinae
Rohan P. Naidu, Jorryt Matthee, Anna de Graaff et al. (+20 more)
JWST's Little Red Dots (LRDs) display a unique constellation of features that do not occur simultaneously in any other class of
galaxies or AGN. Here we observe that many of these features find parallels in the 19th century Great Eruption (GE) of $\eta$ Carinae and a sub-class of
supernovae (Type IIn). Drawing on these
stellar phenomena –
outflows trapped by dense circumstellar gas envelopes – we sketch a possible scenario for LRDs.
Outflows from the central engine produce an enshrouding envelope of gas that may be thought of as a slow wind. This dense wind and its enormous extent produce an opacity so high that a pseudo-photosphere forms within the wind, obscuring the central engine and manifesting as a blackbody-like continuum. Radiation from the buried engine powers the system. The engine may also launch fast winds that crash into the existing envelope to generate shocks. Lines form within the wind above the photosphere – electron scattering and absorption in the clumpy (ionized + neutral) medium account for broad wings and P-Cygni cores. A key implication is that inferences of “overmassive black holes" may be interpreting this wind-like physics as a virial broad-line region. We propose an escape velocity argument to constrain the mass of the engine, which yields $M<10^{5} M_\odot$ for the typical LRD. The lack of variability and low surface
gravity of the photosphere provide further support for intermediate mass ($M\approx10^{3-6} M_\odot$), but very luminous super-Eddington ($L_{\rm{bol}}/L_{\rm{edd}}\gtrsim5$) systems harboring a supermassive
star or intermediate mass black hole. Paralleling the
evolution of IIn SNe,
dust production in the envelope may mark the beginnings of classical AGN. This paper explores a possible self-consistent explanation for the entire life-cycle of LRDs, from their enshrouding in dense gas to their fates as seeds of massive black holes.
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All authors Rohan P. Naidu, Jorryt Matthee, Anna de Graaff, Alberto Torralba, Chris Ashall, Harley Katz, John Chisholm, Gabriel Brammer, Luc Dessart, Anna-Christina Eilers, Raphael E. Hviding, David O. Jones, Vasily Kokorev, Joel Leja, Hanpu Liu, Zhaoran Liu, Devesh Nandal, Pascal A. Oesch, Conor L. Ransome, Robert A. Simcoe, Wendy Q. Sun, Andrea Weibel, Mengyuan Xiao
Astrophysics of Galaxies
Morpho-kinematic of galaxies at cosmic noon
F. Rigamonti and F. R. Ditrani
Recent studies of local
galaxies highlight the need for high-resolution photometry and kinematics to accurately characterize
galactic structures. From this, limitations emerged in the standard two-phase evolutionary scenario, where
galaxies first form dispersion-supported bulges followed by secular disk growth. IFS surveys, combining photometry and kinematics, demonstrated that morphology and dynamics correlate weakly, with bulges and disks forming a continuum in their kinematic properties. This scenario is further supported by JWST observations. From analyses based on visual morphology emerged that mature
galaxies with distinct morphological features exist at earlier times than expected. This, however, needs to be confirmed with high-resolution
stellar kinematics observations. We, therefore, propose to measure
stellar kinematics at high spatial resolution for massive
galaxies at
cosmic noon to probe the build-up of central regions and to disentangle the true nature of structures inferred from visual morphology (e.g., disks and bulges with different degrees of rotation). This will enable studying how
galaxy mass, kinematics, and
star formation co-evolve, providing a complete census of
galactic structures and their formation pathways. In this regard, the VESPER-SHARP instrument on the E-ELT is uniquely suited for this program, offering, within reasonable exposure times, rest-frame optical coverage at $z\sim2$, high spatial resolution, a suitable field of view, and multiplexing for simultaneous observations.
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High Energy Physics (Phenomenology)
LinApart3: efficient algorithm for multivariate partial fraction decomposition with linear denominators
L. Fekésházy and A. Kardos
We present LinApart3, an efficient multivariate partial fraction decomposition
algorithm for rational functions with linear denominators. Our decomposition
algorithm guarantees that each term contains at most as many distinct denominators from the original set as partial fraction variables, introduces no spurious singularities, is independent of variable ordering, and is insensitive to the presence of spectator variables. While general multivariate approaches based on Gröbner bases or Leinartas' method handle arbitrary
polynomial denominators, they suffer from intermediate expression swell. LinApart3 replaces
polynomial-ideal computations with linear
algebra and residue extraction by exploiting the geometry of the hyperplane arrangement defined by the denominators, circumventing this issue just as LinApart did in the univariate case. Because the individual basis contributions are independent, the
algorithm is moreover naturally parallelizable. To showcase the utility of our
algorithm we implemented the
algorithm both in Wolfram Mathematica and FORM.
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General Relativity and Quantum Cosmology
Dynamical Completion of Coupling-Charge Thermodynamics
Kamal Hajian and Bayram Tekin
The scalar-gauge pair formulation promotes gravitational coupling constants to conserved charges, clarifying their role in extended black hole thermodynamics. However, its original incarnation restricts these auxiliary scalar fields to rigid, non-dynamical configurations. In this paper, we introduce a local, dynamical completion of this framework. By constructing the kinetic sector from a defect, which is the difference between the top-form field strength and the associated gravitational Lagrangian density, we allow the scalar to propagate as a genuine massive degree of freedom. Crucially, this local sector acts as a charge-preserving massive scalar backreaction, ensuring the thermodynamic coupling remains a conserved integration constant rather than a locally varying field. When evaluated on constant-coupling configurations, the auxiliary stress-energy contributions vanish entirely, perfectly preserving the original black hole solutions, the first law, and the Smarr relation. We illustrate this construction using the cosmological constant and the Gauss-Bonnet coupling.
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Instrumentation and Methods for Astrophysics
Mapping Stellar Heterogeneities with the Nautilus Space Observatory
Adina D. Feinstein, Jeff Valenti, Julien de Wit et al. (+9 more)
Stellar photospheric heterogeneities, such as starspots and faculae, are a fundamental limitation for
exoplanet transmission spectroscopy. Inhomogeneous surfaces can imprint wavelength-dependent signals during transits that may mimic or mask atmospheric absorption features, especially for
planets orbiting cool low-mass
stars. Recent work has shown that the information content of transmission spectroscopy observations can be sufficient to correct for
stellar contamination, but only if
stellar photosphere and active-region models have adequate fidelity. This requires empirical benchmarking with observations that validate next-generation
stellar models and identify which spectral diagnostics best encode heterogeneity properties as a function of spectral type, activity level, and time. We propose a two-generation Nautilus program that leverages the scalable architecture of the observatory concept. Generation 1 would use broad-wavelength time-series observations of transiting
exoplanet systems to connect starspot-crossing events and out-of-transit variability to localized and disk-integrated heterogeneity properties. Generation 2 would use the optimized spectral diagnostics identified in Generation 1 to conduct slitless spectroscopic monitoring of large samples of GKM
stars on different timescales. Generation 2 instrumentation would include activity tracers of both the photosphere and chromosphere. This program would provide the
benchmark data and population-level framework needed to turn
stellar contamination into a calibrated input for
exoplanet atmospheric
retrievals.
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All authors Adina D. Feinstein, Jeff Valenti, Julien de Wit, Valeriy Vasilyev, Chia-Lung Lin, Daniel Apai, Ana Glidden, Prajwal Niraula, Peter Plavchan, Benjamin V. Rackham, Noah Tuchow, Luis Welbanks
Computational Physics · Cross-listed from cs.LG
Joint discovery of governing partial differential equations from multi-source datasets by competitive optimization
Hao Xu, Siyu Lou, Yuntian Chen et al. (+1 more)
Discovering governing equations directly from observational data is a key step towards interpretable scientific machine learning. Current data-driven approaches typically operate on a single
dataset, inherently limiting their performance when faced with restricted observations. In practice, multiple
datasets are often available for the same physical system, distinguished only by distinct initial conditions or boundary configurations. Here, we present a competitive optimization framework designed to discover shared partial differential equations (PDEs) from multi-source
datasets, termed MCO-PDE. The framework first trains independent neural surrogates for each data source, and then employs a soft-competitive weighting mechanism to dynamically assess
dataset credibility and aggregate a consensus global coefficient. Integrated with a genetic
algorithm for structural search, this approach simultaneously identifies the functional forms and parameters of the governing laws. We demonstrate that fusing as few as 50 observations per
dataset across seven cases recovers canonical equations with high accuracy. The framework inherently handles two- and three-dimensional domains characterized by irregular boundaries and heterogeneous coefficients, and successfully extracts physically meaningful laws from real-world wave-tank experiments. Overall, this work establishes a promising route for automated scientific discovery via heterogeneous data fusion.
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All authors Hao Xu, Siyu Lou, Yuntian Chen, Dongxiao Zhang
Earth and Planetary Astrophysics
Testing the prevalence of hydrogen-silicate miscibility in young sub-Neptunes
James G. Rogers and Hilke E. Schlichting
Hydrogen-silicate miscibility can significantly alter the interior structure and thermal
evolution of sub-Neptunes. We consider the interplay between this miscibility and
stellar-driven atmospheric escape. We find that, for the first $\sim 100$ Myr, sub-Neptunes store most of their hydrogen content within their miscible interiors, protecting it from escape. As hydrogen is removed from the top of the atmosphere, more hydrogen is exsolved from the miscible interior, resupplying the envelope mass and delaying the
planet's contraction when compared with models that do not account for miscibility. We construct a population-level
Bayesian hierarchical inference model which tests for the prevalence of fully miscible sub-Neptunes. With conservative measurement uncertainty and no completeness corrections, we predict that $\sim 100-200$ observed young sub-Neptunes with measured radii, masses and ages $\lesssim 1$ Gyr are required to differentiate between fully miscible and immiscible models. This survey size requirement decreases with improved measurement uncertainty. Furthermore, one can reliably infer the underlying distributions of planetary initial conditions if completeness corrections are included in the analysis.
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High Energy Astrophysical Phenomena
Expansion rate of the young, oxygen-rich supernova remnant G292.0+1.8
Maria Aslanidou, Manan Agarwal and Jacco Vink
Core-collapse
supernova remnants (CCSNRs) are ideal targets for studying ejecta–interstellar-medium interactions, shock dynamics, and explosion characteristics. G292.0+1.8 is a classic CCSNR featuring oxygen-rich ejecta, circumstellar material, a rapidly moving
pulsar, and a
pulsar wind nebula (PWN). We examine its expansion rate using deep Chandra ACIS-I observations over two nearly independent $\sim$10 yr baselines (2006–2016). After applying astrometric corrections based on
Gaia DR3 sources, we extracted radial profiles in 19 sectors around the forward shock. The weighted-mean expansion rate is $0.016\% \pm 0.001\%\,\mathrm{yr^{-1}}$ in the broadband, implying an expansion age of ${\sim}2500$ yr for a uniform ambient medium, consistent with previous estimates of 2000–3700 yr. For a $1/r^2$ circumstellar density profile (Wolf-Rayet progenitor wind), the inferred age is ${\sim}4100$ yr. Narrow-band analysis of $\alpha$ elements (O-Ne, Mg, Si-S) shows that lighter elements follow the broadband behaviour, while heavier elements expand more slowly, consistent with their origin in deeper
stellar layers. We discuss the pronounced azimuthal asymmetry of the expansion, the apparent paradox that some sectors expand (with $\sim$2500 km/s) preferentially in the direction of the
neutron-
star kick, and the role of reflected shocks from the reverse-shock–PWN interaction.
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Cosmology and Nongalactic Astrophysics
Primordial Black Holes in a Radiation-Dominated Universe
Thomas W. Baumgarte, Katy Clough, Mary Gerhardinger et al. (+2 more)
Primordial fluctuations frozen out during inflation re-enter the cosmological horizon and can collapse, leading to the formation of
primordial black holes. We perform simulations of the direct collapse of over-dense regions re-entering the horizon during a radiation-dominated epoch, using full 3+1 general relativistic simulations with the BSSN formalism. Building on previous studies, we impose periodic boundary conditions and allow the matter content of the Universe to self-consistently drive its dynamics. We analyze the
evolution of over-densities in both the collapse and dispersal regimes and find a threshold, $0.77<\delta_c<0.83$, above which over-densities collapse and form
primordial black holes. Our findings are consistent with previous analytic predictions as well as numerical studies that use different formalisms and computational approaches, and hence provide independent validation of those results.
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All authors Thomas W. Baumgarte, Katy Clough, Mary Gerhardinger, John T. Giblin Jr., Amanda Miller
High Energy Physics (Theory) · Cross-listed from math.AG
Lagrangian correspondences of nonabelian Hodge type and shifted twistor structures
Jacob Kryczka, Yuuji Tanaka and Shing-Tung Yau
Classical nonabelian Hodge theory identifies Dolbeault and de Rham
moduli spaces by providing a real-analytic isomorphism. In this paper, motivated by the Kapustin–Witten theory, we study this correspondence in the more general framework of perfect complexes on proper varieties, paying special
attention to the surface case. We establish a Lagrangian correspondence which relates the shifted
symplectic geometries by Pantev–Toën–Vaquié–Vezzosi (PTVV) between the derived stacks of flat and
Higgs perfect complexes. We investigate the existence of derived twistor structures of hyperkähler type on the
moduli stack of perfect complexes endowed with $\lambda$-connections by Deligne–Hitchin–Simpson. We establish a version of the AKSZ/PTVV transgression, Lagrangian intersection, and (hyperkähler)
symplectic reduction
theorems in this context. Moreover, we prove that the derived Riemann–
Hilbert correspondence of Porta and Holstein–Porta, which states an equivalence of derived analytic stacks of perfect complexes on $X_{\mathrm{Betti}}$ and $X_{\mathrm{DR}}$, is compatible with the natural shifted–
symplectic structures. We then study the relation between the shifted (pre-)twistor structures and the shifted
symplectic forms on the fibers, and prove that the analytic Deligne–Hitchin–Simpson
moduli stack on a smooth projective variety $X$ has a canonical $2(1-\dim X)$ shifted pretwistor structure over $\mathbb{P}^1_{\mathbb{C}}$, a result which has been anticipated for some time. In particular, the
moduli stack of solutions to the Kapustin–Witten equations modulo gauge equivalence on a smooth proper complex algebraic surface exibits a $(-2)$-shifted (pre)twistor structure as a family over $\mathbb{P}^1_{\mathbb{C}}$.
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Quantum Physics
Authentication in Quantum Networks
Christopher Battarbee, Suchetana Goswami, Elham Kashefi et al. (+1 more)
In this review, we survey the cryptographic task of authentication from the perspective of
quantum communication. We review three main flavours of authentication that are often conflated in the literature: authentication of classical messages, authentication of
quantum messages, and entity authentication, also covering recent hardware-assisted approaches. We compare representative protocols for each functionality in terms of their security assumptions, set-up requirements, composability, and scalability in large or dynamic networks, and use these criteria to identify and recommend suitable candidates. Finally, applications are surveyed: we provide a detailed case study of authentication and
quantum key distribution (QKD), then extend the discussion to protocols beyond QKD, where the role of authentication is more complex. Our take-home message is that an authentication requirement is not an intrinsic limitation of
quantum networks: as with all secure communication, each protocol relies on a particular authentication resource, and the security claim of that protocol is meaningful only once the authentication resource and its deployment assumptions are made explicit. At the same time, the existing classical and
quantum literature already offers a range of
quantum-secure authentication schemes, which can support different applications when carefully matched to the required functionality, assumptions, and security guarantees.
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All authors Christopher Battarbee, Suchetana Goswami, Elham Kashefi, Mina Doosti
Quantum Physics
Provable random-matrix spectral ramp in a static, geometrically local Hamiltonian
Matteo Ippoliti
Quantum chaos is commonly associated with the emergence of random-
matrix statistics in the spectra of
quantum systems. A useful diagnostic is provided by the spectral form factor (SFF), which for random
matrix ensembles displays a universal linear-growth regime (`ramp'). In the last decade, a landmark result by Bertini, Kos and Prosen (BKP) identified for the first time a class of geometrically local
quantum dynamics of finite-dimensional particles where the SFF provably exhibits a random-
matrix ramp: periodically driven (Floquet) qudit chains whose
evolution is described by `dual-
unitary'
circuits. Here, building on the BKP result and on a recently proposed variant of the Feynman-Kitaev clock construction, we obtain a spectral ramp in a class of static, geometrically local
Hamiltonians. Our strategy is to embed the Floquet quasienergy spectrum of a dual-
unitary circuit into the energy spectrum of a static local
Hamiltonian, and to prove that the latter's connected SFF inherits the BKP ramp within a
symmetry sector. This is to our knowledge the first proof of a spectral ramp in a time-independent, geometrically local many-body system with finite local
Hilbert space dimension.
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Cosmology and Nongalactic Astrophysics
GIGA-Lens 2.0: Strong-Lens Modeling on Multiple GPU Nodes
Xiaosheng Huang, Linus Upson, Nicolas Ratier-Werbin et al. (+12 more)
We present GIGA-Lens 2.0: a major upgrade to the GPU-accelerated
Bayesian framework for modeling strong
lensing systems that allows it to be run across multiple GPU nodes. We have succeeded in running GIGA-Lens 2.0 on 128 nodes or 512 A100 GPUs. We demonstrate the speed benefits of this new version, and apply them to modeling 100 simulated systems and a real system, DESI J238.5690+04.7276. We also present other changes to the framework that have yielded further improvement on performance.
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All authors Xiaosheng Huang, Linus Upson, Nicolas Ratier-Werbin, Harry Lu, Sean Xu, Elden Yap, Evan Odell, Ansel Parke, Harsh Ambardekar, Saul Baltasar, Nestor Demeure, Bradley Richardson, Andi Gu, Yuan-Ming Hsu, Junyi Liu
High Energy Physics (Theory)
D-brane tension as central charge
Vinícius Bernardes, Theodore Erler and Atakan Hilmi F{\i}rat
Using
Hamiltonian methods in open bosonic string field theory, we derive the mass of a D0-brane as the central charge of the spontaneously broken Poincaré
algebra in 26 dimensions. Though the formulas originate from string field theory, the calculation can be carried out completely on-shell. This illustrates a general procedure for computing spacetime central charges in string theory.
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High Energy Physics (Theory)
Poisson bracket and $L_\infty$ algebras
Vinícius Bernardes, Theodore Erler, Atakan Hilmi F{\i}rat et al. (+1 more)
We describe the Poisson bracket of a Lagrangian field theory expressed in the framework of $L_\infty$
algebras. If the
symplectic structure on phase space is defined following recent work, we show that the Poisson bracket can be computed with the Peierls formula, confirming the well-known result of the covariant phase space formalism. Of particular interest is the Poisson bracket in nonlocal theories. In $p$-adic string theory we find that a straightforward construction of the Poisson bracket is obstructed by higher derivative instabilities. We also discuss the inverse relation between the Poisson bracket and
symplectic structure in the
language of homological
algebra, extending some ideas in the mathematical physics literature.
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All authors Vinícius Bernardes, Theodore Erler, Atakan Hilmi F{\i}rat, Igor Khavkine
Quantum Physics
Cavity-mediated probabilistic magic $T$-gate injection
Sofia Cocciaretto, Roberto Menta and Vittorio Giovannetti
Non-Clifford gates are a necessary resource for universal
quantum computation, yet their fault-tolerant implementation typically relies on magic-state
distillation, which incurs significant overhead in
qubit count and
circuit depth. In this work, we propose a probabilistic cavity-based magic-state injection protocol. Our scheme exploits controlled atom-cavity interactions and conditional measurements to probabilistically prepare an effective magic state encoded in the first two level Fock subspace of a single cavity mode, achieving a success probability of $0.74$ per attempt, independent of the target magic phase. The cavity-encoded magic state is subsequently injected into a computational atom via a teleportation-based protocol mediated by dressed-state transitions, requiring only Clifford operations and a single auxiliary atom for readout. We show that all required operations – state preparation, two-
qubit exchange gates, and projective measurement – can be implemented with experimentally available techniques in Rydberg atom-cavity platforms. We further discuss how the scheme can in principle be adapted to operate at the logical level, where collective Rydberg interactions and optical nonlinearities provide a route toward cavity-mediated $T$-gate injection directly into code-encoded
qubits.
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Astrophysics of Galaxies
Prescriptions for the stochasticity effect on the integrated X-ray luminosity of star-forming galaxies:Implications for selecting star-forming galaxies and AGN in X-ray surveys
Elias Kyritsis, Andreas Zezas and Konstantinos Kovlakas
(abridged) The integrated X-ray luminosity (Lx) of
star-forming
galaxies is dominated by high-mass X-ray binary (HMXB) populations. The discrete nature of these populations introduces
stochastic sampling effects that distort the X-ray Luminosity Function (XLF) and bias observed scaling relations. We investigate how
stochastic sampling of the HMXB XLF affects the predicted integrated Lx across a wide range of
star-formation and
metallicity conditions, quantifying the scatter to provide a statistical framework for interpreting X-ray observations. Using Monte Carlo simulations, we derive Lx distributions over a broad grid of
star-formation rate (SFR) and
metallicity values. By measuring statistical quantities describing these distributions, we parametrize the luminosity scatter by fitting surfaces to the upper and lower Lx bounds as functions of SFR and
metallicity. We provide practical prescriptions to compute the expected Lx for given SFR and
metallicity, fully accounting for
stochastic effects without rerunning costly XLF sampling. Applying these to local and high-
redshift samples shows stochasticity must be considered before attributing Lx differences to intrinsic properties. A simulation study across z=0.5-5 reveals mild
redshift evolution of
stochastic scatter, with minimum scatter at z~2.5. Our prescriptions quantify biases in scaling relations introduced by flux-limited surveys. At low
redshifts,
stochastic effects can raise Lx by up to 1 dex, overlapping with the low-luminosity AGN regime and biasing source classification in deep surveys. These prescriptions offer a framework for constraining scatter, quantifying extreme outliers, and refining X-ray source classification in current and future surveys.
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Computational Physics
A neural delta-$f$ particle-in-cell method: evolving the background with learned backward flows
Victor Fournet, Martin Campos Pinto, Emmanuel Franck et al. (+1 more)
We present a novel {\delta}f particle-in-
cell (PIC) method for the kinetic simulation of electrostatic
plasmas in which the bulk density, acting as a control variate, is evolved using
symplectic neural networks (SympNets). The SympNets are used as an approximation of the backward flow and trained using the particle trajectories. We introduce a periodic variant of the SympNet architecture that encodes the spatial periodicity of the problem into the network itself. We validate the approach with numerical results in 1D1V and 3D3V for the Vlasov-Poisson system.
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All authors Victor Fournet, Martin Campos Pinto, Emmanuel Franck, Victor Michel-Dansac
Instrumentation and Methods for Astrophysics
Gaussian processes on ray-guided transformed uniform grids for fast, flexible, and auto-differentiable adaptive source reconstruction in lens modelling
Wolfgang J. R. Enzi, Coleman M. Krawczyk, Tian Li et al. (+1 more)
Strong gravitational
lensing constrains cosmology and dark matter, but robust inference requires accurate source reconstruction. The achievable source resolution is highly position-dependent. Adaptive meshes can place resolution where needed, but typically rely on discontinuous operations, such as Delaunay tessellations or Voronoi binning, which can restrict regularization choices and break differentiability. In this paper, we present a novel approach for modelling the source on a ray-guided transformed uniform grid (RTU grid), that is adaptive to the lens mass model, auto-differentiable and flexible with respect to the regularization by allowing for an arbitrary choice of power spectrum. We achieve this by defining the source as a Gaussian process on a uniform grid, which is then transformed based on the cumulative distributions of rays traced back to the source plane. This approach ensures that source pixels contain a more uniform number of rays. The approach is fast by leveraging the fast
Fourier transform to describe the Gaussian process in
Fourier space. We apply this new approach to mock data and show that it achieves comparable fit quality with fewer source pixels, typically corresponding to about a factor of two fewer pixels per dimension, and increases Evidence Lower Bounds (ELBOs) for the same number of pixels. Using the RTU grid only mildly affects the difference in ELBO for models with and without substructures within lens
galaxies. A fast, flexible, and auto-differentiable source reconstruction can greatly benefit the analysis of large samples of lens systems, e.g. those found within the Euclid survey
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All authors Wolfgang J. R. Enzi, Coleman M. Krawczyk, Tian Li, Thomas E. Collett
Statistical Mechanics
Why can genetic algorithms work in high-dimensional search spaces?
Stephen Whitelam
We show that the effective dynamics of the elitist $(1+M)$ genetic
algorithm is, in the limit of small mutations, normalized gradient descent on the loss in the presence of anisotropic Gaussian white noise. In expectation, therefore, a simple mutation-selection genetic
algorithm follows the gradient of the loss, without explicit calculation of gradients and without averaging over loss evaluations. The genetic
algorithm is slower than gradient descent because of the noise that acts in directions transverse to the gradient. However, this slowdown is controlled not by the number of parameters of the search space but by the effective rank of the Hessian of the loss function. For the concentrated Hessian spectra observed in neural-network loss functions the effective rank can be far smaller than the number of parameters, which may explain why genetic
algorithms can scale to large search spaces.
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