Soft Condensed Matter
Collective Behavior of Intelligent Active Brownian Particles in the Presence of a Static Obstacle
Surya Narayan Sahoo, Arabinda Bera and Jiarul Midya
Using computer simulations, we investigate the collective behavior of two-dimensional active Brownian particles (ABPs) with excluded-volume interactions in the bulk and in the presence of a single static circular obstacle. Perception-mediated interactions are introduced through a
vision-based steering mechanism that enables each particle to reorient its propulsion direction according to the instantaneous positions of neighboring particles within a prescribed
vision cone. In the bulk, these intelligent active Brownian particles (iABPs) exhibit distinct collective states, including aggregated clusters, worm-like chains, worm-aggregate coexistence, and dilute gas phases. We characterize these states using a shape anisotropy parameter and construct the corresponding phase diagrams. The presence of a static obstacle, which interacts with the particles through purely repulsive forces, qualitatively alters their collective behavior. In contrast to conventional ABPs, whose isotropic accumulation around the obstacle increases with activity, iABPs exhibit the opposite trend, with boundary accumulation decreasing as the activity increases. We further identify empirical scaling relations that describe particle accumulation and cluster formation at the obstacle boundary. Consequently, the relative effective
diffusion coefficient of iABPs displays a nonmonotonic dependence on self-propulsion speed, whereas that of conventional ABPs decreases monotonically with increasing activity. In addition, we show that the residence times of iABPs are orders of magnitude shorter than those of conventional ABPs, indicating that perception-mediated interactions can be useful for controlling the organization and transport of active particles in complex environments.
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Cosmology and Nongalactic Astrophysics
Probabilistic characterization of blending with LSST and application to cluster lensing cosmology
Manon Ramel, Cyrille Doux, Marine Kuna et al. (+9 more)
Next-generation
galaxy surveys, like the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST), will deliver unprecedented depth and sky coverage, enabling precise measurements of
cosmic probes such as weak
lensing and
galaxy clustering. However, increased imaging depth leads to significant blending of
galaxy images, particularly in dense fields like
galaxy clusters. This blending, exacerbated by atmospheric blurring in ground-based observations, contaminates
galaxy property measurements and causes source confusion. To simultaneously capture these effects, we develop a probabilistic framework introducing the blending
entropy, a metric quantifying the ambiguity in matching detected objects to true
galaxies or external reference sources. Using simulated data from the DESC Data Challenge 2 (DC2), we characterize blending in LSST data and quantify its impact on cluster
lensing cosmology around cosmoDC2
halos. We demonstrate that imposing a blending
entropy threshold of $S_b<0.2$ effectively filters out highly blended objects (around 25%), which are especially prevalent near the survey's magnitude limit and are associated with higher errors in shape measurements and photometric
redshifts. Applying this cut substantially reduces blending-induced biases in cluster
lensing profiles and mass estimates, thereby mitigating systematic errors in cosmological parameters—most notably reducing tension in $\sigma_8$ estimates. Our method is readily generalizable to other static probes and offers a practical path forward for real data analyses, particularly when leveraging overlapping high-resolution
datasets from spaced-based missions such as Euclid or the Roman Space
Telescope, where these external
datasets can act as reference catalogs to improve the identification of blended sources in LSST data.
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All authors Manon Ramel, Cyrille Doux, Marine Kuna, Michel Aguena, Céline Combet, Shuang Liang, Constantin Payerne, Camille Avestruz, Alex I. Malz, Marina Ricci, Nikolina Šarčević, the LSST Dark Energy Science Collaboration
Instrumentation and Methods for Astrophysics
A Proliferated Space Architecture for Time-Domain Astrophysics
Daniel Kocevski, Eric Burns, Thomas Barclay et al. (+58 more)
Time-Domain and Multi-Messenger Astrophysics (TDAMM) is entering a discovery-rich but follow-up-limited era, creating an urgent need for responsive, multiwavelength space-based capabilities. The Hydra constellation is a concept for a proliferated space architecture for time-domain astrophysics. The constellation would act as a disaggregated observatory composed of coordinated, relatively low-cost spacecraft that collectively provide capabilities traditionally concentrated within a single large mission. The architecture would combine persistent wide-field gamma-ray monitoring, wide-field and focused X-ray observations, and rapid-response ultraviolet, optical, and infrared imaging and spectroscopy. The constellation would both discover high-energy transients and respond to external alerts from gravitational-wave detectors,
neutrino observatories, and ground- and space-based surveys, using low-latency communications, automated event prioritization, and community coordination frameworks to rapidly assign observing resources. A proliferated architecture would offer operational advantages over a single larger mission, including simultaneous observations of multiple targets, graceful degradation following individual spacecraft failures, recurring technology refresh, and opportunities for commercial, international, and philanthropic contributed nodes to join the network. The constellation would address fundamental questions concerning
cosmic accelerators, the origin and
evolution of the elements, the behavior of matter at extreme density, and the nature of dark energy through gravitational-wave standard sirens. This white paper presents the Hydra concept description that was submitted to NASA's ASTRA initiative for consideration by the
Cosmic Origins Program Analysis Group (CoPAG) and Physics of the Cosmos Program Analysis Group (PhysPAG).
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All authors Daniel Kocevski, Eric Burns, Thomas Barclay, Nicholas E. White, Massimiliano Galeazzi, Brendan O'Connor, Amy Lien, Chris Fryer, Hallie Fausey, Fe McBride, Neil Cornish, Dheeraj Pasham, Kip Kuntz, Anya Nugent, Scott Porter, Tzu-Ching Chang, Adam Lidz, Alexander van der Horst, Sylvain Guiriec, Ed Cackett, Dieter Hartmann, Brad Cenko, C. Michelle Hui, Tyler Parsotan, Michael W. Coughlin, Eliza Neights, Zorawar Wadiasingh, Catherine Grant, Oindabi Mukherjee, Francesco Longo, Eric Bellm, Alec Habig, George Younes, Kim Page, Shivam Kumar Sharma, Oliver J. Roberts, Rachel Hamburg, Rahul Gupta, Colleen A. Wilson-Hodge, William Cleveland, Breann Sitarski, Vikas Chand, Raffaella Margutti, Adam Goldstein, Ryan J. Foley, Vidushi Sharma, Yi-Jung Yang, Elisabetta Bissaldi, M. Coleman Miller, T. A. Pritchard, D. J. Sand, Tomas Ahumada, Judith Racusin, Noah Franz, Kate D. Alexander, Brenna Mockler, D. Andrew Howell, Elisa Quintana, Chin-Ping Hu, Igor Andreoni, Boyan Hristov
Quantum Physics
Benchmarking the computational power of quantum computers
Timothy Proctor, Oliver Hart, Oliver Widzowski Maupin et al. (+27 more)
Quantum computing hardware is advancing rapidly toward utility-scale machines that will enable scientific breakthroughs. Many teams are pursuing distinct and difficult-to-compare routes to this goal, using different
qubit technologies and logical architectures. Tracking progress toward
quantum utility therefore requires rigorous
benchmarks that measure computational capability relative to utility-scale challenge problems and enable fair comparison across disparate platforms. Here we demonstrate direct, cross-platform measurement of
quantum computational capability using a new
benchmark that quantifies the size of the largest computationally relevant
quantum circuits that a machine can execute successfully and the speed at which it can execute them. We apply this
quantum universal operation performance system (QUOPS) experimentally to leading processors from Quantinuum, Google, and IBM, computing directly on physical
qubits. Translating state-of-the-art resource requirements for recognized challenge problems that represent useful
quantum computation into effective QUOPS
circuit sizes shows that computational capability must grow by 5 orders of magnitude, motivating fault-tolerant approaches. We use the same
benchmark to assess the performance of a simple fault-tolerant logical-
qubit processor implemented on up to eight [[7,1,3]]-encoded logical
qubits using Quantinuum Helios-1, and project the growth of capability across successive generations of fault-tolerant
quantum computers to show how QUOPS can track progress toward
quantum scientific utility.
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All authors Timothy Proctor, Oliver Hart, Oliver Widzowski Maupin, Matthew Girling, Daniel Hothem, Daniel Mills, Jordan Hines, Karl Mayer, Jacob S. Nelson, Tyler LeBlond, Zohim Chandani, Diego Forlivesi, Piper C. Wysocki, Boldizsár Poór, Joan M. Dreiling, Annie Park, Adam P. Reed, Brian Estey, Cameron Foltz, Akhil Isanaka, M. S. Allman, Michael Mills, Maxwell D. Urmey, Peter E. Siegfried, Audrey Faricy, Jin-Sung Kim, Cristina Cîrstoiu, Andrew D. Baczewski, Charles H. Baldwin, Robin Blume-Kohout
Materials Science · Cross-listed from cs.AI
Mined from Scientific Literature: Process Schemas for Atomic Layer Deposition and Etching in Materials Science
Sameer Sadruddin, Eleni Poupaki, Alex Watkins et al. (+5 more)
Atomic layer deposition (ALD) and atomic layer etching (ALE) are reported heterogeneously across experimental and simulation literature in materials science, hindering comparison and machine-actionable reuse. We present four domain-expert-reviewed JSON Schemas for ALD and ALE experimental and simulation processes. Curated with schema-miner and grounded in QUDT using schema-miner pro, the schemas structure materials, process conditions, configurations , and measured or predicted results. We compare their scope, structure, and semantic grounding, and demonstrate their use for schema-guided literature extraction and publication of structured records through ORKG templates.
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All authors Sameer Sadruddin, Eleni Poupaki, Alex Watkins, Bora Karasulu, Adriaan J. M. Mackus, Erwin Kessels, Sören Auer, Jennifer D'Souza
Soft Condensed Matter
Colloidal shadows reveal hidden solute transport
Haoyu Liu, Zehao Chen and Amir A. Pahlavan
An object releasing a chemical into a surrounding flow leaves behind a plume that encodes the rate of release, but for most solutes, that plume is invisible. Classical transport theory describes this configuration through a self-similar concentration boundary layer whose structure has never been resolved experimentally in forced flow at low Reynolds number: a century of measurements at these conditions has returned integrated transfer rates rather than the field itself. Here we show that both the field and the information it carries are experimentally accessible. Around hydrogel posts photopatterned inside a microfluidic channel, a released solute drives suspended colloidal particles away by diffusiophoresis, i.e., their drift along chemical gradients, carving a particle-free “shadow” downstream. Using a fluorescent solute, we resolve the concentration field around the post and recover the classical self-similar structure of convective mass transfer. For an invisible surfactant, the width of the shadow, benchmarked against a directly imaged solute on the same platform, then serves as a proxy for the dimensionless rate of mass transfer from the post. Finally, comparing two orientations of a triangular post tests a classical prediction by Brenner: the local concentration fields rearrange, yet no orientation dependence of the integrated transfer rate is resolved. For solute–tracer pairs whose diffusiophoretic response is known, colloidal shadows thus turn ordinary tracer particles into quantitative reporters of chemical exchange that cannot be observed directly.
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Quantum Gases
Topological chirality of dissipative limit cycles in an open Dicke model
Nikolay Yegovtsev, Sayan Choudhury and W. Vincent Liu
In an open, $U(1)$-symmetric Dicke model with
chiral atom-cavity couplings, we show that dissipation drives two limit-cycle phases of opposite chirality in the thermodynamic limit, obtaining exact analytical solutions. These phases are separated by a $U(1)$-broken superradiant state, lending the phase diagram a topological character, and persist under $U(1)$-preserving perturbations, making them candidates for
chiral continuous time
crystals. In addition to stable normal and inverted steady states, the model also exhibits multistability, where the long-time dynamics is set by the initial state. Our results establish dissipation as a resource for inducing
chiral dynamical order in light-matter coupled systems.
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Quantum Physics
Evidencing Macroscopic Quantum Coherence using Confined Uniform Magnetic Field
Dipankar Home, Harsh Talwar, Nilaj Saha et al. (+2 more)
A previously unexplored scheme is devised for creating and certifying coherent
quantum superposition of distinctly separated states of a
spin-tagged massive object passing through a confined uniform
magnetic field. This results in entangling the spatial and
spin parts of a two-component Pauli wavefunction such that the entailed coherence can be conveniently certified by
spin measurements alone. The implementability of this scheme is analysed using NV-centre nanodiamonds of masses $\sim 10^{10}$ amu based on the current technological capabilities.
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All authors Dipankar Home, Harsh Talwar, Nilaj Saha, Sougato Bose, Arka Banerjee
High Energy Astrophysical Phenomena
Probing Lorentz Invariance Violation in Cosmogenic Neutrino Propagation with KM3-230213A
Rodrigo Sasse, Rodrigo Guedes Lang and Rita de Cássia dos Anjos
We investigate superluminal Lorentz invariance violation (LIV) in the
neutrino sector using cosmogenic
neutrino fluxes generated with ultrahigh-energy
cosmic-ray propagation models. Standard fluxes are calculated with CRPropa 3.2 and subsequently modified using a prescription based on LIV-induced
neutrino splitting. Superluminal LIV suppresses the flux at the highest energies while producing an enhancement at PeV - EeV energies. We use the KM3-230213A event as a
benchmark to evaluate the sensitivity of current observations to these spectral modifications. Although the available statistics do not allow a formal constraint, the predicted fluxes are particularly sensitive to coefficients in the range $10^{-24} \mathrm{eV}^{-1} \lesssim \delta_{\nu,1} \lesssim 10^{-22}\,\mathrm{eV}^{-1}$, with the results strongly depending on the assumed
cosmic-ray source properties. Intermediate coefficients can enhance the expected event rate within the reconstructed energy range of KM3-230213A, whereas larger coefficients may overproduce
neutrinos in energy intervals constrained by IceCube and the Pierre Auger Observatory. These results identify a region of observational sensitivity to LIV and provide testable predictions for future
neutrino telescopes.
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Mathematical Physics
Division Algebras, Triality, and Exceptional Magic
A. Garrett Lisi
We describe in explicit detail the rich relationship between division
algebras, split composition
algebras, triality, Clifford
algebras, spinors, triality Lie
algebras, generalized reflections, exceptional magic square Lie
algebras, triality eigenspaces, 3-symmetric spaces, Vinberg theta
algebras, and Exceptional Unification in particle physics.
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Statistical Mechanics
Models and Measures of Statistical Physics and Sociophysics for Fracture Mechanics and Earthquake Dynamics: An Introduction
Sudip Sarkar, Soumyajyoti Biswas and Bikas K. Chakrabarti
The breaking or fracture of materials and damages or devastations due to earthquakes have caught our
attention since the earliest stage of human civilization. In fact, at around 1500, Leonardo Da Vinci made the pioneering observation that, unlike elastic constants (formalized later by Hooke in 1678) of the materials, the tensile (breaking) strengths of nominally identical iron wires decrease drastically with their length, indicating the vanishing breaking strength of materials in the large size limit, suggesting the impossibility of constructing arbitrarily large structures. This was the first observation that unlike the elasticity of disordered materials, which remains defined in the thermodynamic limit (self averaging statistics), the breaking properties of the disordered materials have extreme (non self averaging) statistics. In spite of major and some precise developments in statistical physical modelling and characterizing the fracture mechanics (starting with Allan Griffith's crack nucleation theory in 1921 and the weakest link failure Fibre Bundle Model of Frederick Thomas Peirce in 1926) and of earthquake dynamics (starting with Robert Burridge and Leon Knopoff's continuum dynamical model in 1967 and later other discrete or
lattice train models or fractal overlap models of stick slip earthquakes), no graduate level textbook in condensed matter physics or in statistical physics introduces the basic models and their properties. And now computer scientists and social scientists (coming with their social inequality measures applied to the avalanche statistics in precursor failures) are joining their efforts to explore the new precursory inequality measures for big avalanches or failures. This introductory review is designed to fill this gap with a view to introducing these to this wider audience and to take them to the current frontiers in these fields.
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High Energy Physics (Phenomenology)
The devil in the transition: NLO nucleation and the particle physics behind the PTA signal
Cristina Puchades-Ibáñez and Pedro Schwaller
We quantify how the treatment of a strongly supercooled phase transition affects the particle-physics interpretation of a nanohertz gravitational-wave signal. For the classically conformal Abelian
Higgs model, we calculate the nucleation rate at NLO in the dimensionally reduced theory and test the gradient expansion against explicit fluctuation determinants. A calibrated correction reproduces the determinant exponent with a mean absolute relative difference of $0.8\%$ and allows this information to be included throughout the parameter scan. We propagate the corrected rate through percolation, reheating and gravitational-wave production, and confront the resulting spectra with the NANOGrav 15-year and IPTA DR2 data. The corrected NLO calculation shifts the preferred gauge coupling by $9\%$ and $13\%$, respectively, and the input scale by $18\%$ for NANOGrav. After the determinant calibration, the largest theoretical uncertainties arise from uncertainties in the gravitational-wave spectra and the relation between $R_\star$ and $\beta/H$.
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High Energy Physics (Phenomenology)
Driver and damping of the directed-flow response in heavy-ion collisions
Kishora Nayak and Vipul Bairathi
The initial-state geometry plays a crucial role in driving directed flow, while the dissipative response of the medium dampens it. Both of these factors influence how the directed-flow slope varies with system size. We developed a method to differentiate between these driving and damping effects on charged-
hadron directed flow in O+O, Cu+Cu, Ru+Ru, Au+Au, and U+U collisions at $\sqrt{s_{\mathrm{NN}}} = 200$~GeV using an improved version of the string-melting AMPT model. We formulated three scaling observables based on the
entropy density, the number of participants, and the mass number. A dimensionless ratio was constructed, revealing the threshold mass number $A \approx 35$ in central collisions from the
entropy and participant scaling, indicating the onset of collective behavior. We constructed a kinetic-theory Knudsen-number ($\mathrm{Kn}$) map to analyze the contributions of the initial-state driver, which grows as $\mathrm{Kn}^{\kappa}$ with $\kappa \approx 2$, and a final-state viscous damping of the hydrodynamic response with characteristic scale $\mathrm{Kn}_0 \approx 0.27$ for the directed flow slope. This damping scale is found to be about a factor of 2.5 smaller than the $\mathrm{Kn}_0 \approx 0.7$ extracted from the
elliptic flow. Furthermore, we determined the ratio of shear viscosity to
entropy density, $\eta/s$, to be between 0.10 and 0.20, using an alternative method that does not rely on fitting flow harmonics.
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Mesoscale and Nanoscale Physics
Orbital-geometric spin response: inter-band coherence versus orbital-to-spin conversion
Dimitrie Culcer
Orbitronics seeks to convert orbital angular momentum (OAM) into
spin, but its microscopic dynamics is not understood. Here I show that, at moderate
spin-orbit coupling, an electrically induced
spin density contains a direct term and an orbital-
geometric spin response (OGSR) due to inter-band coherence of the spinless parent
Hamiltonian—related to OAM but not descended from it. In massive Dirac
fermions the OGSR survives as the net OAM vanishes, and generates counterflow, opposing the direct response. These results provide guidelines for optimising orbitronic systems.
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Chaotic Dynamics
Mechanisms for extreme events in position-dependent mass systems
Wasif Ahamed M, Chithiika Ruby V, Sathish Aravindh M et al. (+2 more)
Oscillators defined on curved spaces provide a natural framework for exploring geometry-induced nonlinear dynamics. The two-dimensional Mathews-Lakshmanan oscillator and
Higgs oscillator are prominent examples of geometrically induced nonlinear oscillators. The two-dimensional
Higgs oscillator in flat space arises from a conformal (stereographic) projection of the harmonic oscillator on the sphere S2 onto the two-dimensional plane. Its one-dimensional counterpart, defined by a non-Euclidean geometry with
curvature parameter, exhibits chaotic dynamics and extreme events (EEs) when subjected to damping and external driving forces [1]. In this work, we introduce coupling through mass interaction among multiple one-dimensional damped and forced
Higgs oscillators and investigate the resulting collective nonlinear dynamics within a many-particle framework. More importantly, we establish the connection between the conformal mass m(x) and the extrema of velocity through a power-law relation, demonstrating how the conformal mass regulates the turning points leading to the emergence of extreme events (EEs). Furthermore, to provide additional insight into the underlying mechanism, we quantify the energy synchronization error among the oscillators, thereby revealing how energy synchronization evolves during the onset of EEs.
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All authors Wasif Ahamed M, Chithiika Ruby V, Sathish Aravindh M, Venkatesan A, Lakshmanan M
High Energy Physics (Theory)
Ladder Operators and Fermionic Tensor Fields on Maximally Symmetric Spaces
Facundo L. Cruz, Matias N. Sempé and Guillermo A. Silva
We construct first-order ladder operators for
spin-$\frac{1}{2}$ Dirac fields and transverse, $\gamma$-traceless
spin-$\frac{3}{2}$ Rarita–Schwinger fields on maximally symmetric spaces using non-isometric closed conformal Killing vectors. For both
spins, we find three distinct operators: two of them, $\mathcal{D}$ and $\mathcal{D}^{s}$, shift the conformal label as $\Delta \to \Delta \pm 1$, while a third operator, $\widetilde{\mathcal{D}}$, reverses the sign of the Dirac
eigenvalue at fixed $\Delta$. The latter exists in arbitrary dimensions and reduces to the standard infinitesimal conformal transformation of a primary spinor when acting on massless
spin-$\frac{1}{2}$ fields. On $S^N$, the ladder operators relate neighboring fermionic harmonics and generate the spinor tower from Killing-spinor seeds. In Lorentzian signature, we study their action on de Sitter mode spaces. In $dS_4$, the
spin-$\frac{3}{2}$ ladders connect the zero-Dirac-mass sector with the fermionic gauge points $M=\pm i/\ell$, while $\widetilde{\mathcal{D}}$ extends to arbitrary mass the conformal-like transformation previously identified for the gauge field. We explicitly present the
spin-$\frac{1}{2}$ and
spin-$\frac{3}{2}$ fermionic harmonics on spheres as well as the de Sitter mode solutions. Finally, we derive the Casimir operators on $S^3$, $dS_3$, and $dS_4$ corresponding to SO(4), SO(3,1) and SO(4,1), and relate their
eigenvalues for UIRs to the allowed masses in the fermionic field equations. These results provide a unified
geometric framework relating conformal Killing geometry, fermionic Dirac-type spectra, and the representation theory of maximally symmetric spaces.
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High Energy Astrophysical Phenomena
Which Type Ia supernova observables best indicate the ages of their progenitor stars?
Young-Lo Kim, Chul Chung, Young-Wook Lee et al. (+3 more)
Type Ia
supernovae (SNe Ia) observables, such as the light-curve shape and the colour, are expected to contain information about the progenitor
star. In this work, we explore this information, with a particular focus on the age of the SN Ia progenitor
star. For this, we construct the SN Ia progenitor age distribution (SPAD) and compare it to the observed distributions of light-curve shape (x1) and the colour (c) parameters in a volume-limited SN Ia sample. We find that SPAD and the x1 distribution share a common shape: a young/high-x1 peak and an old/low-x1 bump in the tail, and this shape varies systematically with
redshift. In contrast, this behaviour is not evident in the c distribution. We then examine the correlation of the local age at the SN Ia explosion site, used as a proxy for the progenitor age, with x1 and c. The local age and x1 are well correlated (the linear correlation coefficient ~ -0.71), whereas the local age and c show no significant correlation (the coefficient ~ 0.08). Furthermore, we find that the x1 distribution systematically evolves with the local age. Lastly, we demonstrate that an empirical mapping approach based on SPAD successfully reproduces the observed x1 distribution across different
redshift bins. Taken together, our results suggest that the light-curve shape distribution indicates progenitor age at the population level more robustly than the colour does. In particular, younger progenitors are more likely to have higher-x1 SNe Ia. We discuss an application for creating a more homogeneous sample of SNe Ia in terms of progenitor age across a wide
redshift range without the Malmquist bias, thereby improving the accuracy of cosmological constraints derived from SNe Ia.
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All authors Young-Lo Kim, Chul Chung, Young-Wook Lee, Seunghyun Park, Junhyuk Son, Suk-Jin Yoon
High Energy Physics (Theory)
Emergent Conformal Symmetry on Superfluid Vortices in Two-Color QCD and Pseudoreal Gauge Theories
Muneto Nitta
Two-color QCD provides a unique first-principles laboratory for strongly interacting matter at finite
baryon density, where a diquark condensate realizes a baryonic superfluid. We investigate the internal physics of its quantized superfluid
vortices in the
chiral limit. We find that a
vortex localizes an exact and normalizable $S^3\simeq SU(2)$ family of pion modes. Remarkably, the bulk Wess–Zumino–Witten (WZW) term induces a quantized WZW term for these modes, driving the
vortex theory in the infrared to the $SU(2)_1$ WZW conformal field theory with central charge $c=1$. Thus a strongly coupled conformal theory emerges on a
vortex in a nonconformal bulk theory. The mechanism extends to pseudoreal $Sp(2N)$ gauge theories, where the corresponding minimal
vortex theory flows to $SU(2)_N$, with the level directly encoding the microscopic anomaly coefficient.
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Disordered Systems and Neural Networks
Hierarchical Prototype Emergence in Modern Hopfield Models
Aditya Cowsik and Adithya Sriram
Hierarchical correlations are a universal feature of any realistic model of data, and the question of how associative
memory models may learn these correlations and generalize beyond them to construct new sensible images is an important step towards understanding more complex modern architectures such as
diffusion models. We consider a hierarchical model for
memories which are sampled and stored in a dense Hopfield network with
polynomial activation. We analytically derive conditions for each level of this hierarchy to be locally stable - that is they are local energy minima. We use prototype reconstruction as a minimal model of generalization and we find that it takes only a quasi-
polynomial amount of information to generalize beyond particular
memories and even particular groups in the hierarchy. We observe a qualitatively analogous phase diagram in the number of
memories, sharpness of the activation function (
polynomial degree) for data from Fashion-MNIST.
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Quantum Physics
Modeling Quantum Error Detection with Transition Matrices
Rohan S. Kumar, Ben Foxman and Yongshan Ding
We construct an explicit transition
matrix that exactly describes code-adapted basis-population dynamics of stabilizer codes under
circuit-level
stochastic Pauli noise. The
matrix is expressed in a code-adapted basis that captures probability flow between logical-basis labels and syndrome sectors. For
quantum error detection (QED), we incorporate post-selection by aggregating rejected outcomes into an absorbing state, so that a single transition
matrix represents a full clock cycle of gates, syndrome extraction, and post-selection. Additionally, we characterize when protocol
symmetries permit exact lumping to simpler, more interpretable models. The transition
matrix framework enables direct application of classical
stochastic-
matrix techniques to analyze multi-cycle QED protocols. First, we identify a leading-order obstruction to a stationary logical-only accepted-map description, and quantify the accepted leakage injection from QED-check imperfections that causes it. Second, we express leading-order QED efficiency as a function of check frequency in terms of physically meaningful parameters, and prove that less frequent checks improve efficiency to leading order. We evaluate the framework on the $[[4,2,2]]$ and $[[5,1,3]]$ codes under depolarizing gate noise and readout errors: transition-
matrix predictions agree with million-shot Stim Monte Carlo at the scale of the reported confidence intervals, and
matrix-computed results illustrate the first-cycle transient and interval-dependent efficiency. More broadly, the transition-
matrix formalism provides both an analytical foundation for QED analysis and an interpretable tool for understanding code behavior under realistic noise.
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High Energy Astrophysical Phenomena
Long-term X-ray spectral analysis of Cygnus X-1 using AstroSat
H Lalthantluanga, Akash Garg, Ranjeev Misra et al. (+2 more)
We performed a spectral analysis of long-term observations (2016-2019) of the black hole binary Cygnus X-1 using AstroSat, covering its hard, intermediate, and soft states. During soft states, we found that a typical spectrum fitted with a single Comptonization, a thermal disc, and an iron line yields poor fits and unphysically small disk radii (R_in < 1 R_g). While adding a relativistic disk component (kerrbb) improved the fit but required high color factors (f_col ~ 3.35-5.08), indicating additional Comptonization. We therefore adopted a dual-Comptonization model with hot (optically thin) and warm (optically thick) coronae. This provided consistent good fits across all soft and hard states of Cygnus X-1. The spectral
evolution reveals the critical role of dual Comptonization in shaping the broadband emission of Cygnus X-1.
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All authors H Lalthantluanga, Akash Garg, Ranjeev Misra, Vanzarmawii Chhangte, Lalthakimi Zadeng
Materials Science
Unusual phase coexistence regime across the ferroelectric - paraelectric transition
M. Kopecký, J. Kub, E. de Prado et al. (+1 more)
A PbTiO3 epitaxial thin film grown on a DyScO3 substrate was studied by x-ray diffraction in the temperature range of 20-500 degrees Celsius. It is found that the ferroelectric to paraelectric phase transition proceeds through a peculiar transitional coexistence state extending between 402 degrees Celsius and 414 degrees Celsius. Within this temperature interval, at a temperature of 405 degrees Celsius, a domain structure transition occurs, at which the three-domain c/a1/a2 polytwin phase transforms into an ordinary c/a2 twinned phase. It is proposed that the coexistence of two independent twinned phases with the paraelectric phase is enabled by vertical strain gradients in the film.
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All authors M. Kopecký, J. Kub, E. de Prado, J. Hlinka
Quantum Physics
Dephasing-driven suppression of superradiance and metastable dynamics in the anisotropic open Rabi model
Jivyanshu Priya, Pragna Das and Auditya Sharma
Finite-component light-matter systems realize dissipative phase transitions in a single controllable atom-cavity setup, but how atomic dephasing - ubiquitous in real cavity- and
circuit-QED devices - affects this criticality remains unknown. We study the anisotropic open Rabi model under cavity decay, spontaneous emission, and atomic dephasing together. We show that when spontaneous emission stabilizes a long-lived metastable superradiant phase, atomic dephasing actively competes with it - eroding its coherence and shortening the lifetime. This direct competition reveals that a dissipation channel's microscopic character, not its strength, controls its nonequilibrium criticality - a distinction directly tunable via independent spontaneous-emission and dephasing rates in
circuit-QED and trapped-ion platforms.
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Cosmology and Nongalactic Astrophysics
The Role of Big Bang Nucleosynthesis in Joint Cosmological Analyses
Mehmet Akharman, Nicholas DePorzio, Cara Giovanetti et al. (+1 more)
We perform joint
Baryon Acoustic Oscillation (BAO) + Big Bang Nucleosynthesis (BBN) and BAO+BBN+
Cosmic Microwave Background (CMB) analyses with Planck CMB and DESI DR2 BAO data, explicitly marginalizing over BBN nuisance parameters for the first time with these data combinations and paying particular
attention to the impact of BBN on these results. We find in our fiducial analyses $h=0.6833^{+0.0048}_{-0.0053}$ ($\Lambda$CDM, BAO+BBN), $h=0.6823^{+0.0027}_{-0.0026}$ ($\Lambda$CDM, BAO+BBN+CMB), as well as $h=0.6791^{+0.0069}_{-0.0075},N_{\rm{eff}}=2.974^{+0.098}_{-0.099}$ ($\Lambda$CDM+$N_{\rm{eff}}$, BAO+BBN), and $h=0.6838^{+0.0052}_{-0.0054},N_{\rm{eff}}=3.065^{+0.078}_{-0.076}$ ($\Lambda$CDM+$N_{\rm{eff}}$, BAO+BBN+CMB). We demonstrate how investigator choices can impact results of joint analyses involving BBN. We provide recommendations for the treatment of BBN in light of recent work, and demonstrate a pipeline that accurately accounts for prediction uncertainties in BBN.
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All authors Mehmet Akharman, Nicholas DePorzio, Cara Giovanetti, Hongwan Liu
High Energy Physics (Phenomenology)
One-point charge correlator as a probe for the odderon
Haotian Cao, Zhong-Bo Kang, Diego Padilla et al. (+1 more)
We propose the one-point charge correlator (OPCC) in transversely polarized deep inelastic scattering as a new probe of the
spin-dependent odderon. The OPCC is an infrared and collinear safe observable constructed solely from the charge and angular information of final-state charged particles. Because the charge weight is odd under charge conjugation, the contribution of the C-even pomeron to the OPCC vanishes identically in the small-$x$ eikonal limit, whereas the contribution of the C-odd
spin-dependent odderon survives. We define a transverse single-
spin asymmetry by normalizing the
spin-dependent OPCC to the unpolarized charged-
hadron one-point energy correlator. At small $x$, this asymmetry reduces to a ratio of
spin-dependent odderon and pomeron contributions. We provide illustrative estimates of this asymmetry for Electron-Ion
Collider kinematics within the small-$x$ dipole framework with Balitsky–Kovchegov
evolution to guide experimental studies. Dedicated measurements of the OPCC asymmetry with a transversely polarized
proton beam would provide new quantitative constraints on the currently unconstrained
spin-dependent odderon.
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All authors Haotian Cao, Zhong-Bo Kang, Diego Padilla, Jani Penttala
Statistical Mechanics
Breakdown of Multipole Expansion in Emergent Electromagnetism
Tom Ben-Ami, Markus Heyl and Roderich Moessner
We find a striking departure from simple electrostatics in a family of two-dimensional
lattice models whose effective description takes the form of an emergent electromagnetism: a high-order multipolar charge configuration can induce an electric field characteristic of a lower-order multipole. Studying the archetypical hardcore dimer and U(1)
spin-1/2 link models, we trace this to a breakdown of the superposition principle: for dense charge configurations, there can be a nonlinear suppression, or even enhancement, of the far field compared to the linear expectation. Our work establishes that microscopic
lattice-scale constraints in models for emergent electromagnetism can change the far-field behaviour to differ from often utilized long-wavelength descriptions in standard effective continuum models.
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Astrophysics of Galaxies
Unified modelling of broad and narrow optical-UV emission lines from massive black holes: interpreting high-redshift JWST observations
Adele Plat, Michaela Hirschmann, Emma Curtis-Lake et al. (+10 more)
JWST is uncovering a large population of active
galactic nuclei (AGN) at high
redshift, motivating the extension of models calibrated on local sources to a broader range of physical conditions. We present a consistent suite of broad- and narrow-line photoionisation models based on ionising spectra that vary with black-hole mass and Eddington ratio, spanning sub- to super-Eddington
accretion. For the broad-line region (BLR), we investigate the detectability of low-mass accreting black holes. At z=6, broad H{\alpha} may be detectable down to $M_{BH}\approx10^{5.7} M\odot$ for a BH accreting at the Eddington limit under favourable assumptions. We derive line-to-
accretion-luminosity corrections, with hydrogen and helium recombination lines providing more robust tracers than metal lines. We also explore which changes in black-hole properties and BLR conditions can contribute to the large H{\alpha} equivalent widths, elevated Balmer decrements, and weak high-ionisation lines observed in some high-
redshift sources, finding that variations in BLR structure can substantially modify the emergent spectrum. For the narrow-line region (NLR), H{\alpha} and [O III] {\lambda}5007 are among the most promising tracers of low-mass accreting black holes, probing $M_{BH}\approx10^{5.5} M\odot$ at the Eddington limit. Many classical diagnostic diagrams miss low-
metallicity AGN; we identify alternative UV and optical diagnostics that more robustly separate AGN from Pop. II and Pop. III
stellar photoionisation over the conditions explored. Nevertheless, NLR line ratios are driven primarily by
metallicity and ionisation parameter, with only a weak dependence on black-hole mass and Eddington ratio. Looking ahead, these models are intended for
Bayesian interpretation of JWST spectra and connection to cosmological simulations through physically motivated priors.
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All authors Adele Plat, Michaela Hirschmann, Emma Curtis-Lake, Anna Feltre, Stephane Charlot, Steven L. Finkelstein, Lorenzo Napolitano, Fabio Pacucci, Norbert Pirzkal, Sandra Raimundo, Anthony Taylor, Alba Vidal-Garcia, L. Y. Aaron Yung
Astrophysics of Galaxies
BAQARO: Tracing Stochastic Black Hole Growth Histories and Quasar Lightcurves in a Cosmological Context
Elia Pizzati, Joseph F. Hennawi and Joop Schaye
How supermassive black holes (BHs) assemble their mass and power the luminous
quasars we observe across
cosmic time remain central open questions in
galaxy evolution. We present BAQARO, a semi-empirical framework for BH growth. Built on subhalo merger trees extracted from the FLAMINGO-10k simulation, the model links BH growth histories to those of their host subhalos through prescriptions that capture both average trends and
stochastic variability. BAQARO is constrained by the bolometric
quasar luminosity function, the clustering of UV-luminous
quasars, and the conditional Eddington ratio distribution function. With six free parameters controlling BH seeding, the coupling between gas
accretion and
halo growth, and the stochasticity and temporal coherence of
accretion, the model reproduces the available observational constraints over $0 \lesssim z \lesssim 7$. Using emulators, we perform
Bayesian inference and quantify the constraining power of each observable. Our main findings are: (i) BH
accretion is well described by the assembly of cold gas reservoirs in
halos, without requiring an explicit dependence on
cosmic time. (ii) BHs rapidly assemble their mass at high
redshift through
stochastic episodes of super-Eddington
accretion. (iii) These episodes are radiatively inefficient and persist for timescales of $\sim1\,\mathrm{Myr}$, imprinting observable signatures on
quasar lightcurves, proximity zones, and clustering measurements. (iv) The merger growth channel is always subdominant, but becomes increasingly important at $z \lesssim 1$, particularly for massive BHs. BAQARO growth histories and
quasar lightcurves provide a flexible framework for interpreting the rapidly expanding landscape of
quasar observations, from high-$z$
accretion probed by JWST to low-$z$ mergers constrained by
pulsar timing arrays.
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Astrophysics of Galaxies
Galaxies in the first two billion years: Earlier formation and quenching with surface-density modulated star formation and feedback
Akash Vani, Mohammadreza Ayromlou, Guinevere Kauffmann et al. (+1 more)
JWST has revealed massive, UV-bright, compact, and in some cases quenched
galaxies in the first two billion years of
cosmic history, challenging current
galaxy formation models. We develop an extended L-
Galaxies semi-analytic model, run on the MillenniumTNG dark-matter-only simulation, and follow
galaxy evolution over $0 \le z \lesssim 15$. The model ties the
star formation efficiency and the coupling of
stellar feedback energy to the local cold gas surface density, making
star formation efficient and feedback ineffective in dense gas. We include dissipative gas-rich mergers and disc instabilities in
stellar and gaseous discs. All parameters are calibrated simultaneously against
stellar mass functions and quenched fractions at $z\simeq0-4$ and UV luminosity functions at $z\simeq11-12$ with a new parallelised Markov chain Monte Carlo framework. The model reproduces the
stellar mass function up to $z\approx 11$ and increases the abundance of massive and UV-bright
galaxies at $z\gtrsim9$ by up to two orders of magnitude over the legacy version. Although the AGN feedback prescription is unchanged, the enhanced bulge growth and black hole fuelling make massive quenched
galaxies at $z\simeq3-8$ two orders of magnitude more abundant, while dissipative mergers produce compact remnants with UV size-luminosity relations matching observations at $z\simeq10-13$. At low
redshift,
galaxy sizes, cold-gas content,
metallicities, radial profiles, and morphologies remain consistent with observations. Our results indicate that the tension between models and JWST observations at
cosmic dawn can be substantially reduced by regulating
star formation and feedback through the local gas surface density, without a modified initial mass function, non-standard cosmology, or new AGN physics.
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All authors Akash Vani, Mohammadreza Ayromlou, Guinevere Kauffmann, Volker Springel
Astrophysics of Galaxies
Resolved SED modelling with JWST and ALMA: the role of stellar mass surface density in regulating star formation in cosmic noon galaxies
Cheng-Lin Liao, Leindert A. Boogaard, Jacqueline A. Hodge et al. (+27 more)
We present kpc-scale ($0.2''-0.5''$) physical property maps of 35 main-sequence
galaxies at $z \approx 0.5-3.7$, with
stellar masses of $\log(M_*/M_\odot) \sim 9.7-11.7$ and
star formation rates of $\mathrm{SFR} \sim 1.4-280\,\mathrm{M_\odot\,yr^{-1}}$, selected from the ALMA Spectroscopic Survey (ASPECS) in the Hubble Ultra Deep Field. Leveraging the unique HST, JWST (NIRCam and MIRI), and ALMA observations, we perform spatially resolved spectral energy distribution (SED) modeling across the UV-to-FIR regime. We find that incorporating MIRI and/or ALMA data reduces the overestimation of
dust luminosity (by up to $\sim0.8$ dex), while ALMA observations further mitigate the age-
dust degeneracy. In the absence of such data, restricting the SED model library based on the observed unresolved colors can partially mitigate these biases. The
stellar masses ($M_{*}$) derived from resolved and unresolved modeling are consistent within $\sim0.05$ dex, suggesting that mass discrepancies (attributed to outshining) are less significant for
cosmic noon main-sequence
galaxies when rest-frame near-infrared (NIR; e.g., $\sim1-3\,\mu\mathrm{m}$) data are included. After normalization to the same reference, the composite SED of our sample closely resembles that of local starburst
galaxies such as M82, suggesting similar
dust attenuation and re-emission properties. Finally, we find that the molecular gas fraction and depletion time correlate with the effective
stellar mass surface density ($\Sigma_{\rm eff,*} = M_{*}/2\pi R_{\rm eff,M_*}^2$) similarly to that observed in local
galaxies. These results provide a first qualitative view of how the
stellar gravitational potential influences gas regulation and
star formation in
galaxies beyond the local Universe.
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All authors Cheng-Lin Liao, Leindert A. Boogaard, Jacqueline A. Hodge, J. Li, E. da Cunha, P. Sharda, A. Battisti, C. Lagos, M. Kaasinen, I. Smail, M. Aravena, F. E. Bauer, R. K. Cochrane, L. Colina, P. Cox, R. Decarli, T. Díaz-Santos, R. Fernández Aranda, N. N. Geesink, H. Inami, B. Magnelli, J. Melinder, M. Neeleman, G. Östlin, G. Popping, D. A. Riechers, I. Shivaei, P. van der Werf, F. Walter, A. Weiss