High Energy Astrophysical Phenomena
Formation of Merging Black Hole Binaries Inside Massive AGN Stars
Sizheng Ma, Douglas N. C. Lin and David A. Velasco-Romero
Stars embedded in the disks of active
galactic nuclei (AGN) can grow to hundreds of
solar masses, and the same disks are expected to host a population of
stellar-mass black holes. A
star may therefore capture passing black holes, turning its interior into a potential factory for forming compact binary black hole systems and, ultimately, for the gravitational-wave events seen by our detectors. We test how readily this channel operates using three-dimensional hydrodynamic simulations of black hole–
star encounters. As a proof of principle, we adopt a
star-to-black-hole mass ratio of $34\!:\!1$, and find that the capture does not disrupt the structure of the
star: it heats the
star by $10$–$30\%$, and the
star loses only $\lesssim1\%$ of its mass throughout. The captured black hole loses its orbital angular momentum rapidly to dynamical friction, sinking to the
stellar center within a
stellar dynamical time $\lesssim10^{4}\,$s. If the
star already harbors a black hole at its center, the two form a bound binary whose gravitational-wave coalescence time falls below $10^{4}\,$yr. Depending on the geometry and speed of the encounter, the resulting orbit may be nearly circular or retain substantial eccentricity. Our calculations confirm that black hole–
star encounters in AGN disks are indeed a viable channel for assembling
stellar-mass black hole binaries and supplying sources for gravitational-wave detectors.
Read the full abstract ▾
Physics and Society
Higher-order interactions reveal synergistic backbones of cycling infrastructure networks
Christoph Steinacker, Henrik Wolf, Marc Timme et al. (+1 more)
Infrastructure networks essentially underlie human mobility and transport. Improving the quality of single links increases network performance locally. However, efficient transport requires high-quality connected corridors across multi-link paths that do not emerge from independent single-link upgrades. Here, we introduce a framework for evaluating the impact of jointly upgrading multiple links as inherently higher-order interactions, enabling us to quantify link synergies in complex transport networks. Two links are synergistic if an upgrade of one increases the benefit of upgrading the other, promoting upgrades of topologically complementary links along the same path while discouraging upgrades of redundant parallel links. By expressing these synergies as second-order derivatives of overall network performance, we develop an efficient computational framework to identify synergistic links that form a connected network backbone. We apply our theoretical framework by combining empirical street network and cycling demand data for Hamburg, Germany, with a perturbed utility route choice model for urban bicycle traffic. Our results reveal synergies from higher-order interactions, thereby enabling strategic infrastructure planning that goes beyond local link importance in complex transport and flow networks.
Read the full abstract ▾
All authors Christoph Steinacker, Henrik Wolf, Marc Timme, Malte Schröder
Superconductivity
Current - voltage characteristics in magnetic field for layered superconductor with intrinsic pinning of Josephson vortices
T.B. Charikova, V.N. Neverov, M.R. Popov et al. (+3 more)
The results of measurements of the transverse voltage in the
Hall configuration, Uy, under conditions of motion of the charge and
vortex subsystems in orhtogonal
magnetic and electric fields on epitaxial films of the layered high-temperature
superconductor Nd2-xCexCuO4 are presented. the motion of Josephson
vortices across CuO2 layers (along the c-axis) is analyzed considering the effects of intrinsic pinning. An exponential dependence of critical depinning current jc(B) for Josephson
vortices is established in contrast to the power law dependences for Abrikosov
vortices. With increasing external
magnetic field after the depinning by a
magnetic field at B=Bc, the onset of the
vortex creep regime, which evolves into the flux-flow regime at crossover field B=Bf, is observed.
Read the full abstract ▾
All authors T.B. Charikova, V.N. Neverov, M.R. Popov, S.D. Popov, N.G. Shelushinina, A.A. Ivanov
High Energy Physics (Experiment)
Probabilistic, Structure-Intrinsic Clustering with an Hierarchical Embedding (PSICHE) in Time and Space Applied In Particle Physics Jet Reconstruction
Margaret Lazarovits and Christopher Rogan
Jet reconstruction is an active and open area of particle physics research, with questions related to jet size, multiplicity, substructure, and experimental performance in the presence of pileup and noise. Analogous challenges are ubiquitous throughout other applications of unsupervised learning in the context of clustering and association. This paper introduces a new
algorithm for clustering in the context of jet reconstruction: Probabilistic, Structure-Intrinsic Clustering with an Hierarchical
Embedding (PSICHE). PSICHE addresses several challenges and shortcomings of existing jet clustering methods with novel features, including but not limited to: (i) dynamically-learned and variable jet (cluster) sizes, (ii) unsupervised, multi-scale learning of emergent features, like jet substructure and multiplicity, (iii) clustering in space and time, and (iv) incorporation of domain-specific experimental uncertainties. All of these properties are achieved in a self-consistent, probabilistic framework that is computationally tractable. Furthermore, demonstrations of these features are presented for a range of jet clustering examples in LHC scenarios for various physics phenomena, clustering inputs, pileup conditions, and detector performance parameters.
Read the full abstract ▾
Quantum Physics
Towards Surrogate Based Dequantization of Quantum Reinforcement Learning
Pablo Rodriguez-Grasa, Sofiene Jerbi, Mikel Sanz et al. (+1 more)
In recent years, the utility of parameterized
quantum circuits as function approximators has been widely studied. In the context of reinforcement learning, this approach has led to variational
quantum algorithms such as
quantum Q-learning. While these methods show promising empirical results, and can provide provable advantages for artificial problems, it remains unclear whether they can provide a provable
quantum advantage over classical approaches for problems of practical relevance. A natural way to investigate this question is through the lens of dequantization: The construction of efficient classical
algorithms capable of matching the performance of
quantum variational methods. Building on recent kernel-based dequantization results for supervised learning, we take steps towards extending this surrogate-based dequantization program to reinforcement learning. Specifically, we study the simplified setting of reinforcement learning with a uniform generative model in which uniformly random state-action samples are available, which models the regime of sampling from a large experience replay buffer after sufficient exploration. Within this setting, we provide finite sample guarantees for classical kernelized Fitted Q-Iteration, with classical kernels designed to match the inductive bias of particular parameterized
quantum circuits. Using these results, we then provide a set of sufficient conditions, on the data-encoding strategy of a parameterized
quantum circuit, the corresponding classical kernel, and the problem structure, under which kernelized Fitted Q-Iteration provides a meaningful dequantization of
quantum Q-learning, in this simplified setting. Apart from providing rigorous dequantization guarantees when these conditions are met, these results also motivate the use of kernelized fitted Q-iteration as a dequantization heuristic when these sufficient conditions cannot be verified.
Read the full abstract ▾
All authors Pablo Rodriguez-Grasa, Sofiene Jerbi, Mikel Sanz, Ryan Sweke
High Energy Physics (Theory)
Zero- and Finite-Temperature Casimir Effect in a Fracton Gauge Field
Celio R. Muniz
We investigate the zero- and finite-temperature Casimir interaction of the free trace-full scalar-charge fracton gauge field between two parallel reflecting boundaries. A variational analysis determines a consistent boundary-value problem that confines all five physical polarizations of the rank-two field. The spectrum separates into three faster and two slower propagating modes. At zero temperature, the
vacuum interaction weights the modes by their propagation speeds; when the fast-branch speed is set equal to the speed of light, the resulting Casimir pressure is approximately 2.21 times the ideal electromagnetic value. At finite temperature, the two branches acquire different thermal weights and generate a split crossover. The normalized free energy and pressure follow distinct crossover profiles but approach the same classical high-temperature ratio of 2.5 relative to ideal electromagnetism, because the Matsubara zero mode counts the five confined polarizations independently of their propagation speeds. We derive the exact thermal interaction, its low- and high-temperature limits, and the dependence of the crossover scale on the effective gauge-field velocity. The transition from velocity-weighted
quantum fluctuations to classical mode counting provides a direct spectral signature of the multi-branch structure of the higher-rank gauge field.
Read the full abstract ▾
Materials Science
Breaking the Wiedemann-Franz limit in thermoelectrics via separated flat bands
Illia Serhiienko, Fabian Garmroudi, Stefan Enzner et al. (+3 more)
Controlling the charge and
spin degrees of freedom of electrons in solids has been at the heart of condensed-matter science for centuries. One hallmark of metallic conduction is the Wiedemann-Franz law which implies that a moving charge carries
entropy. Despite centuries of dedicated research, disentangling charge and heat transport has remained an unsolved issue so far. Here we present a direct route to reduce thermal conductivity of conduction electrons with respect to their electrical conductivity via energy-dependent scattering. By constraining electronic transport to a boxcar-type distribution asymmetrically around the
Fermi energy, a large Seebeck coefficient and electrical conductivity can be realized simultaneously while electronic heat conduction is suppressed. Based on the case of monolayer Ni$_3$In, which comprises two flat bands around the
Fermi energy, we propose flat-band systems as a promising, tunable platform for scattering phase space engineering. Besides this novel approach, our large-scale assessment of $\approx 5\times 10^4$ data sets in a 'Wiedemann-Franz plot' of $zT$ vs. $S^2$ provides an effective tool to identify reports of $L\ll L_0$ from literature - pointing towards either new and interesting physical mechanisms - or overlooked measurement artifacts.
Read the full abstract ▾
All authors Illia Serhiienko, Fabian Garmroudi, Stefan Enzner, Izem Dural, Giorgio Sangiovanni, Andrej Pustogow
Mathematical Physics · Cross-listed from math.QA
Boundedness in Strict Deformation Quantization
Michael Heins
This paper provides a complex-analytic interpretation of certain
topologies on the tensor
algebra, which are a central tool within strict deformation quantization. We prove that the symmetric tensor
algebra $\operatorname{S}(V)$ of a barelled
nuclear DF-space $V$ endowed with any of these
topologies may be understood as an
algebra of bounded Fréchet holomorphic functions on the strong dual space $V'_\beta$. The coarsest of the
topologies then corresponds to the
topology of uniform convergence on bounded subsets. The finer ones provide an infinite-dimensional generalization of the order of an entire holomorphic function. To facilitate these results, we study the interplay between boundedness and continuity of holomorphic mappings between locally convex spaces. As a byproduct, we establish a simple sufficient criterion for Fréchet holomorphy as well as several completeness results for spaces of bounded functions.
Read the full abstract ▾
General Relativity and Quantum Cosmology
Schwarzschild black holes as low-pass filters of fuzzy dark matter granularity
Flavio Rosales-Infante, Iván Álvarez-Rios and Francisco S. Guzmán
We study the relaxation of a complex massive scalar field around a supermassive black hole, modeling the near-horizon dynamics of Fuzzy Dark Matter (FDM) with spatial granularity. The field is initialized as a broadband, anisotropic multi-mode random field in momentum space with various spectral widths $\sigma$, decomposed into spherical harmonics up to $\ell_{\max}=100$, and numerically evolved on a finite domain using a specialized radial basis adapted to the background spatial geometry. We track the
evolution of each multipole and calculate its Noether flux across both the event horizon and the outer boundary. Since angular momentum barriers suppress the horizon absorption of high-$\ell$ modes, while high-frequency radial components and fine-scale angular structures dissipate via outward radiation and horizon
accretion, the Schwarzschild spacetime acts as an effective low-pass filter. Regardless of the initial spectral width, all configurations converge toward a universal late-time relaxation state dominated almost exclusively by low multipoles ($\ell \le 2$) and small radial wavenumbers, with the initial bandwidth $\sigma$ determining the timescale of global charge depletion. For concrete physical estimates, we set the
boson mass to $m_b=10^{-22}\,\mathrm{eV}/c^2$ and the black hole mass to $M_{\mathrm{BH}}=6.5\times10^9 M_\odot$.
Read the full abstract ▾
Physics Education
Does a Higher Frame Rate Improve the Measurement of g? Precision and Accuracy in Video Analysis
Mauricio Echiburu Fuenzalida and Nicolás Fernández Astudillo
This study investigates the influence of frame rate, expressed in frames per second (FPS), on the experimental estimation of the acceleration due to
gravity, g, using
video analysis with Tracker. Two different dynamical systems were analysed: free fall and a simple pendulum. Starting from original recordings acquired at 120 FPS, equivalent 60, 30, and 10 FPS series were generated by uniform temporal decimation, preserving the same physical trajectory within each realisation. The analysis included ten independent realisations for free fall and eight for the pendulum. For each condition, the mean estimate of g, the standard deviation across realisations, the relative error with respect to g_ref = 9.81 m s^-2, and the RMSE were calculated. For free fall, the 120 FPS condition exhibited the lowest dispersion and RMSE, whereas the mean estimates obtained at 10 and 30 FPS were closer to the reference value. For the simple pendulum, by contrast, the mean value of g, dispersion, relative error, and RMSE remained essentially unchanged between 10 and 120 FPS. An additional analysis of the 12 possible subsampling phases at 10 FPS showed that this stability does not critically depend on a particular choice of decimation phase and that the variability associated with phase is small compared with the dispersion observed across realisations. The results show that a higher temporal sampling rate does not necessarily provide both greater precision and closer agreement with the reference value. The influence of FPS depends on the temporal characteristics of the system and on the procedure used to estimate the physical parameter. In particular, a higher temporal sampling density may reduce dispersion or increase robustness to sampling without necessarily yielding an estimate closer to the expected value.
Read the full abstract ▾
Astrophysics of Galaxies
Cosmic Noon Galaxies in the Hubble Ultra Deep Field with MIRI Wide-Field Slitless Spectroscopy
S. Kendrew, G. Östlin, L. Colina et al. (+29 more)
We present results from a survey of the Hubble Ultra-Deep Field using the Wide-Field Slitless Spectroscopic (WFSS) capability of the Mid-Infrared Instrument (MIRI) on JWST, demonstrating the capabilities of this new mode. We describe the data reduction and calibration methodology, and estimate calibration uncertainties. From our observations we obtain spectra of 47
galaxies with confirmed spectroscopic
redshifts, with a maximum z_spec of 3.712. In the final sample we target in particular the 3.3 um Polycyclic Aromatic Hydrocarbon (PAH) feature, which has recently gathered interest as a
star formation rate indicator and diagnostic for the
dust grain size distribution in
star forming
galaxies from the local Universe to intermediate
redshifts. The feature falls into the WFSS wavelength region for
redshifts 0.67 to 3.1 - providing full coverage of the peak
star formation “
Cosmic Noon” era (1 < z < 3) and connecting
dust properties in this critical
galaxy evolution period with local-Universe and low-
redshift observations. Using the
galaxies in our sample in this
redshift regime, we test correlations identified in lower-
redshift samples in the near-infrared or targeted programs in the mid-infrared, finding the WFSS spectra, even with large calibration uncertainties, show good agreement with complementary samples. The 3.3 um PAH luminosities follow previously established correlations with total IR luminosity and SED-derived
star formation rates, confirming this feature's power as tracer of
dust-obscured
star formation. Our work illustrate the potential of the MIRI WFSS mode for studies of
Cosmic Noon-era
galaxies in particular in an observationally efficient way.
Read the full abstract ▾
All authors S. Kendrew, G. Östlin, L. Colina, P. Rinaldi, J. Álvarez-Márquez, L. A. Boogaard, J. Melinder, J. P. Pye, A. Alonso Herrero, K. I. Caputi, A. Crespo Gómez, M. Garcia Marín, S. Gillman, S. Harish, E. Iani, D. Langeroodi, A. Labiano, P. G. Pérez-González, P. van der Werf, F. Walter, G. Wright, T. Greve, M. Güdel, T. Henning, P.-O. Lagage, T. P. Ray, B. Vandenbussche, E. van Dishoeck, S. Alberts, R. Fernandez Aranda, A. Petric, I. Shivaei
General Relativity and Quantum Cosmology
Bridging the chirp-mass gap: searching for gravitational waves from inspiraling subsolar-mass ultra-compact binaries using LIGO O4ab data
Andrew L. Miller
Gravitational-wave searches for subsolar-mass compact binaries have left a gap between the planetary-mass regime accessible to long-duration searches and the higher masses probed by conventional compact-binary analyses. We close this gap by searching for the inspiral of ultra-compact binaries with chirp masses $10^{-2}$–$10^{-1}\,M_\odot$ in LIGO O4ab data. Using the statistically robust BinaryGFH-v2 method, a time-frequency technique to search for rapidly evolving inspirals lasting minutes to hours, we cover this previously challenging parameter space with a computational cost of only $\sim 350$ CPU-hours, and find no significant candidates. We thus set 90% confidence upper limits on the binary merger-rate density, providing the first gravitational-wave constraints across this chirp-mass range. Assuming that
primordial-black-hole binaries formed in the early Universe with no binary suppression ($f_{\rm sup}=1$), these results provide the first gravitational-wave constraints on the
primordial-black-hole \dmh fraction in this mass range, yielding upper limits with $f_{\rm PBH}<1$ for equal-mass binaries with component masses $10^{-2}$–$10^{-1}\,M_\odot$ and asymmetric binaries with secondary masses $m_2=3\times10^{-4}$–$10^{-2}\,M_\odot$ for a primary mass $m_1=2.5\,M_\odot$.
Read the full abstract ▾
Fluid Dynamics
Improving Reduced-Order Rotating Detonation Engine Models with Data Assimilation and Machine Learning
Ashwin Suriyanarayanan and Romit Maulik
Rotating detonation engines (RDEs) exhibit strongly nonlinear, multiscale wave dynamics that set the observed thermal field. High-fidelity simulations (DNS/LES) resolve these structures but remain computationally prohibitive, while low-order models such as the one-dimensional Koch-Kutz model capture circumferential wave motion yet lack the expressivity for high-frequency content. We use continuous data assimilation (nudging) to synchronize the Koch-Kutz solver with processed high-fidelity temperature data, introducing the prediction-observation mismatch as a relaxation source in the conserved energy equation; where observations are temporally sparse, interpolation supplies a target at every source update. As the nudging strength increases, the reduced model is progressively drawn onto the high-fidelity trajectory, and the forcing recorded along it provides an explicit, state-dependent estimate of the correction the model requires. We then train a Jacobian-regularized closure a priori on this recorded source. With the observation term removed, the corrected model advances autonomously, remains bounded, and recovers the temperature spectrum and the marginal statistics of the conserved variables relative to the baseline.
Read the full abstract ▾
Quantum Physics
Error-corrected function estimation advantage in multiparameter Hamiltonians
Erfan Abbasgholinejad, Lorcán O. Conlon, Sean R. Muleady et al. (+4 more)
We establish the ultimate precision limits for estimating a function of multiple
Hamiltonian parameters in the presence of Markovian noise. By reducing multiparameter function estimation to an optimization over effective single-parameter
embeddings, we derive tight bounds on the
quantum Fisher information. We identify a necessary and sufficient functional
Hamiltonian-not-in-Lindblad-span condition for Heisenberg-limited scaling in time. When this condition holds, we construct a code that simultaneously removes the noise and nuisance
Hamiltonian parameters while preserving the target signal. When it fails, we derive the optimal standard
quantum-limit coefficient and show that it is asymptotically attainable using approximate
quantum error correction. Finally, we demonstrate that direct function estimation can substantially outperform estimating all parameters individually and subsequently evaluating the function. This advantage can scale with both the
evolution time and the number of parameters.
Read the full abstract ▾
All authors Erfan Abbasgholinejad, Lorcán O. Conlon, Sean R. Muleady, Jacob Bringewatt, Ali Fahimniya, Yu-Xin Wang, Alexey V. Gorshkov
Earth and Planetary Astrophysics
What the Solar System Can Teach Us About Rocky Exoplanets
Paul K. Byrne, Claire Marie Guimond, Peter A. Cawood et al. (+9 more)
The number of rocky extrasolar
planets being discovered continues to increase, but so too does the apparent diversity of such worlds. As we work to understand the likely bulk properties and thermal, geological, and climatological attributes we might expect of rocky
exoplanets, we can look to the
Solar System for guidance. Here, we review the interior, surface, and atmospheric characteristics of modern Earth, and discuss how our homeworld has changed through
Solar System history. We then visit in turn Venus, Mars, Mercury and Earth's Moon, and Io, noting how these terrestrial
planets are alike, how they are different, and how they have evolved through time. Finally, we consider some examples of the types of rocky worlds known or suspected to exist without direct
Solar System counterparts — but we argue that even then, for all the variety we might expect, they are still variations on a common theme. Perhaps the most important lesson the
Solar System can teach us is that terrestrial bodies change through time, sometimes dramatically, and that rocky worlds of similar size and mass can have vastly different planetary outcomes.
Read the full abstract ▾
All authors Paul K. Byrne, Claire Marie Guimond, Peter A. Cawood, Michael J. Way, Doris Breuer, Tilman Spohn, João C. Duarte, Diogo L. Lourenço, Francesca Miozzi, Maëlis Arnould, Nicolas Coltice, Stephanie L. Olson
High Energy Physics (Phenomenology)
Enhanced Standard Model bound on charm CP violation from QCD penguins
Ali Mohamed and Maria Laura Piscopo
We investigate the impact of QCD penguin operators on direct CP violation in singly Cabibbo-suppressed $D^0$ decays within the framework of light-cone sum rules (LCSR) using pion and kaon light-cone distribution amplitudes. We determine, for the first time, the hadronic
matrix elements of the QCD penguin operators for $D^0\to K^+K^-$ and $D^0\to\pi^+\pi^-$ at leading order in $\alpha_s$, employing a three-point correlation function with an artificial momentum to avoid unphysical parasitic cuts. We also compute the
matrix elements of the current-current operators using the same framework and compare them with previous LCSR results. We find that the scalar penguin operators $Q_5$ and $Q_6$ can have substantially enhanced
matrix elements. We identify two sources of enhancement:
quark-condensate contributions, which arise already at tree level and are therefore enhanced by a relative factor of $16 \pi^2$ compared to the remaining, loop-induced terms in the sum rule; and an annihilation-type contribution from the $\bar u u$ component of these operators, which enters already through twist-three light-cone distribution amplitudes and is of comparable magnitude. While the impact of QCD penguin operators on the branching ratios is negligible, they can enhance the magnitude of the “penguin-to-tree” amplitude ratios relevant for direct CP violation. The relevant strong phases, however, remain largely unconstrained within the accuracy of our framework. Assuming maximal relative strong phases, we find that the corresponding upper bound on the Standard Model contribution to charm CP violation can be enhanced compared to estimates based on the current-current operators alone, reducing the gap with the experimental measurement.
Read the full abstract ▾
Quantum Physics
$d$-pod realization of nonadiabatic holonomic quantum computation
Oskar Axelsson, Claes Fälth, Elias Henriksson Lindberg et al. (+1 more)
Holonomic
quantum computation (HQC) realizes
quantum gates through non-Abelian
geometric phases, providing an experimentally accessible approach to
quantum control. While the nonadiabatic HQC framework has been extensively developed for three-level $\Lambda$ systems encoding
qubits, its systematic extension to higher-dimensional qudits remains largely unexplored. In this work, we generalize nonadiabatic HQC to a $d$-pod configuration, where a single excited state is coupled to $d$ ground states, the latter forming the computational subspace. This scheme enables universal holonomic single- and two-qudit gates using only optical or microwave pulses on trapped atoms or ions, offering an efficient route to implement a discrete universal gate set with minimal pulse coordination. As an explicit example, we analyze in detail the qutrit ($d=3$) case, demonstrating compact realizations of single- and two-qutrit holonomic gates, each gate requiring at most two loops in the Grassmannian generated by at most three pulses.
Read the full abstract ▾
All authors Oskar Axelsson, Claes Fälth, Elias Henriksson Lindberg, Erik Sjöqvist
Atmospheric and Oceanic Physics
A Self-Diagnosing Structural Error-Aware Parameter Estimation Method for Earth System Models
Qingyuan Yang, Addisu G Semie, Brian Medeiros et al. (+3 more)
We propose a fully automated, structural error-aware, interpretable
climate model parameter estimation method that leverages Perturbed Parameter Ensembles (PPEs). It is based on history matching and aligns with an increasingly-used iterative simulation-emulation-calibration methodology. The method is motivated by the negative impacts of structural error and emulator and observational uncertainties on
climate model parameter estimation efforts, as well as the problems associated with sparsely-sampled PPEs. To address these challenges, the method explicitly builds simpler emulators that avoid overfitting, detect structural error, avoids compensating for structural error through inflated mismatch tolerances, and sequentially excludes structurally inconsistent variables for parameter estimation. The method decomposes the high-dimensional calibration problem into linked low-dimensional subproblems, and integrates their constraints to reconstruct the jointly plausible region of the full parameter space. The method is applied to a 100-member PPE with 34 perturbed parameters generated by a version of CAM6 with machine learning-based warm rain microphysics parameterization. Through iterative application, the method greatly reduces the ensemble spread and improves the matching between simulated and observed zonal climatologies. The method also finds ensemble members that outperform the default CAM6 configuration in root mean square error across multiple diagnostics. Controlled experiments demonstrate that overly-conservative emulator uncertainty could lead to neglect of informative observations, and tolerance of the structural error, in the context of this method, biases the estimated parameters toward compensating for structural error. Our work also emphasizes the value of interpretability for diagnosing structural error and informing parameter estimation in PPE-based calibration.
Read the full abstract ▾
All authors Qingyuan Yang, Addisu G Semie, Brian Medeiros, Gregory S Elsaesser, Da Fan, Wayne Chuang
Astrophysics of Galaxies
Gravitational Wave Bias in IllustrisTNG300 from Machine-Learned Population-Synthesis Calibrated Merger Rates
Dorsa Sadat Hosseini, Taisiia Karasova, Nikshay Chugh et al. (+2 more)
The large scale clustering of gravitational wave (GW) sources offers an independent probe of cosmology and compact-binary astrophysics. Interpreting future GW clustering measurements requires understanding how merger rates depend on host-
galaxy properties and environment. We develop a simulation-based framework to model the clustering of binary black hole (BBH) mergers and estimate the corresponding GW bias. We populate IllustrisTNG300 with GW sources using a machine-learning emulator trained on the GALAXYRATE data set, which provides population-synthesis calibrated merger rates linked to
galaxy formation histories. This enables physically motivated mock GW catalogs with
galaxy-specific BBH merger rates that depend on
stellar mass,
star formation rate,
metallicity, and
redshift. We compare this framework to a simpler phenomenological model in which the merger rate depends only on
stellar mass. In both approaches, GW sources are more strongly biased than the overall
galaxy population, reflecting the preference for BBH mergers to occur in more massive, more strongly clustered
halos. The machine-learned model also produces stronger scale dependence in the GW bias than
stellar-mass weighting alone, indicating that additional host properties affect GW clustering. We further find that
metallicity correlates positively with both GW and
galaxy bias. These results highlight the importance of physically motivated merger rate models for GW large scale structure analyses and provide a framework for interpreting future clustering measurements from experiments such as the Einstein
Telescope and
Cosmic Explorer.
Read the full abstract ▾
All authors Dorsa Sadat Hosseini, Taisiia Karasova, Nikshay Chugh, Alex Krolewski, Ghazal Geshnizjani
Quantum Physics
Link-middle-cut lower bounds for Clifford circuit synthesis
Søren Fuglede Jørgensen
Minimizing the number of CNOT gates required to synthesize a Clifford operator is a central problem in
quantum circuit optimization. We extend the link–middle–cut (LMC) framework for linear reversible
circuits to Clifford operators represented by binary
symplectic tableaux. By introducing block-support connectivity graphs and determinantal invariants, we obtain efficiently computable lower bounds on ancilla-free CNOT complexity. We prove that these bounds are tight for
qubit permutations: a permutation of $n$
qubits with $k$ cycles requires exactly $3(n-k)$ CNOT gates, even when arbitrary one-
qubit Clifford gates are available. We also derive efficiently computable bounds for synthesis up to a permutation of the output
qubits, corresponding to free
qubit relabeling. Finally, we further demonstrate the utility of the bound by using it as an admissible heuristic for $A^*$-based Clifford synthesis and show that, on
benchmark instances, the resulting search can prove optimality beyond what was possible with earlier SAT-based methods, and that it may be used in combination with earlier $A^*$ heuristics to improve the CNOT counts obtained through heuristic search.
Read the full abstract ▾
Astrophysics of Galaxies
Filament Formation via Collision-induced Magnetic Reconnection – Kinematic Features
Shuo Kong, Griselda Arroyo-Chávez, Volker Ossenkopf-Okada et al. (+4 more)
The Collision-induced
Magnetic Reconnection (CMR) mechanism has recently been proposed as a filament formation model that emphasizes the active role of
magnetic fields. To enable better observational tests with data from modern
telescopes, we provide more specific observable predictions for filaments formed via CMR. Two types of CMR kinematics are revealed in position-velocity (PV) diagrams. First, due to the nature of CMR, the midplane contains a converging motion close to the filament and two diverging motions farther from the filament. They exhibit a blueshift,
redshift, blueshift,
redshift (BRBR) velocity pattern along the line-of-sight when the collision midplane is inclined, giving rise to a special pattern in the PV-diagram. Second, the longitudinal PV-diagram along the filament spine exhibits a velocity oscillating pattern, which is currently attributed to the
magnetic transport of gas clumps in the converging motion. The first type of pattern involves emission primarily outside the filament, which can be confused with the environment. The second type, however, mainly emerges from gas inside the filament, thus more robust for observational tests. Both the integral-shaped filament and the Stick filament in the Orion A cloud show the velocity oscillation in PV-diagrams, although the spatial oscillation frequency and their velocity spread differ.
Read the full abstract ▾
All authors Shuo Kong, Griselda Arroyo-Chávez, Volker Ossenkopf-Okada, Héctor G. Arce, Ralf S. Klessen, Duo Xu, Szu-Ting Chen
Earth and Planetary Astrophysics
Rescuing Kepler's False Positives: A Possible Habitable Zone Exoplanet in the Triple Star System KOI-1623
Rita Lanxuan Wang, Daniel Huber, Daniel Hey et al. (+6 more)
The Kepler mission has significantly advanced our understanding of
exoplanet demographics. However, Kepler
planet candidates showing centroid shifts are often classified as false-positives and thus excluded from demographic analyses. Some of these systems may be erroneous false positives, resulting from unresolved binary
stars with
planets orbiting one of the
stars, thereby introducing biases into past
exoplanet demographic studies. Here, we present updated Kepler centroid offset values derived from
Gaia Data Release 3 (DR3) and analyze KOI-1623.01, a Kepler centroid offset false positive (COFP) with a clear transit signal and an orbital period of 111 days. High-contrast imaging with Keck/NIRC2 reveals that KOI-1623A has a close companion with a separation of $0.704 \pm 0.002$ arcsec, consisting of a slightly evolved G-type primary and a K-
dwarf secondary, while
Gaia detects a tertiary companion with common proper motion at a separation of $\sim 8.4$ arcsec. By combining transit photometry, Kepler pixel level data, direct imaging, and
Gaia DR3, we find that the transit signal is consistent with a $10.02 ^{+0.44}_{-0.31} R_{\oplus}$
giant planet located in the habitable zone of the secondary. We furthermore use resolved companions from
Gaia to estimate that another $\approx 70$ out of $515$ of Kepler's centroid false positives were misclassified and instead are real
planets that belong to binary systems.
Read the full abstract ▾
All authors Rita Lanxuan Wang, Daniel Huber, Daniel Hey, Nathanael Burns-Watson, Alexander Larsen, Adam Kraus, Trent J. Dupuy, Steven Giacalone, Justin R. Crepp
Geophysics · Cross-listed from eess.IV
A Sentinel-2 benchmark dataset for deep-learning active-fire segmentation across 25 California wildfires, July 2020-August 2026
Shreyan Mitra, Mohammadreza Narimani and Parastoo Farajpoor
This article describes an open image
dataset for developing and evaluating active-fire
segmentation methods in satellite imagery. The
dataset contains 2,148 image-mask pairs from 25 California wildfires, with acquisitions spanning July 2020 to August 2026. Each image is a 512x512-pixel, three-channel composite derived from Sentinel-2 Level-2A bands B12, B11 and B8A at 20 m spatial sampling. A fixed linear rendering is applied throughout the
dataset. Corresponding masks distinguish background, SWIR-rule active fire and invalid observations. The masks were generated from shortwave-infrared brightness and near-infrared contrast, followed by constrained neighborhood growth. The release includes chip-level metadata and an incident-disjoint partition containing 18 training, three validation and four test fires. Among the image pairs, 841 contain active-fire labels; these labels occupy 0.0766% of all grid
cells. A mask-blind analyst review covers 233 test chips and provides a separate assessment of the rule-generated labels at chip and connected-component levels. Reference training and evaluation code accompanies the data, including a ResNet-34 U-Net implementation with validation-based checkpoint and threshold selection. The archived images, masks, metadata and review annotations support research on rare-class
segmentation, learning from algorithmic labels and transfer across fire incidents. The versioned
dataset is deposited on Zenodo, with preparation and reuse software maintained in a public GitHub repository.
Read the full abstract ▾
Quantum Physics
Utility-Based Path Selection and Configuration in Quantum Networks via Layered Shortest Paths
Leonardo Bacciottini, Subhransu Maji, Don Towsley et al. (+1 more)
A path in a
quantum network is a chain of repeaters that distributes
entanglement between two users. Selecting a path requires balancing the rate and quality (e.g., fidelity) of the delivered
entanglement, but these quantities, unlike standard routing metrics, compose non-additively. The problem is compounded by link-level configuration choices (e.g.,
distillation rounds or emitter brightness tuning), each trading rate against fidelity, so that a path's performance depends jointly on its route and its per-link settings. We cast this joint path selection and configuration problem as a shortest path computation on a layered graph whose layers track discretized end-to-end fidelity. A single run returns the full rate fidelity Pareto frontier, from which the path maximizing any nondecreasing utility function of rate and fidelity can be selected. We prove that for certain utility functions (including the secret key rate of BB84), the method is a fully
polynomial time approximation scheme, returning a near-optimal path within a specified tolerance. We further characterize exactly when cheaper scalarization-based routing suffices: it is optimal for utility functions with convex fidelity profiles, but can be arbitrarily suboptimal otherwise (e.g., for step-like, sigmoidal utilities), whereas the layered method remains reliable in all cases.
Read the full abstract ▾
All authors Leonardo Bacciottini, Subhransu Maji, Don Towsley, Gayane Vardoyan
Nuclear Theory
Obtaining tensor-polarized nuclei with spin $S\ge1$ via spin filtering upon nuclear beam transmission through an unpolarized target (spin dichroism effect)
Sergey Anishchenko, Vladimir Baryshevsky and Alexandra Gurinovich
Upon transmission through an unpolarized target initially unpolarized
nuclei with
spin $S\ge1$ acquire tensor polarization due to
spin dichroism effect. For
nuclei passing several
nuclear lengths in the target, the acquired component $p_{zz}$ can reach substantial values of ~0.2-0.8. The beam obtained in this way can be effectively used to study reactions with tensor-polarized
nuclei.
Read the full abstract ▾
Cosmology and Nongalactic Astrophysics
Peering Beyond the Veil of Last Scattering: A View of the Universe with CMB Spectral Distortions
Bryce Cyr, Nabila Aghanim, Ethan Baker et al. (+37 more)
The frequency spectrum of the
cosmic microwave background is the most precise blackbody ever measured in nature, with deviations constrained at the level of almost one part per million from the COBE satellite. Nevertheless, departures away from a perfect blackbody are present in standard $\Lambda$CDM cosmology, lurking just beneath the surface of our current observational bounds. These spectral distortions provide invaluable information on our thermal history in both the post- and pre-recombination epochs, allowing us to peer beyond last scattering and into the
primordial Universe. Here, we present an overview of the underlying physics responsible for generating CMB spectral distortions at all epochs. As an illustration of this rich physics, we review a comprehensive set of mechanisms capable of generating distortions both within and beyond the standard $\Lambda$CDM paradigm. We also discuss the information that can be gleaned by going beyond the monopole (sky-averaged) spectrum and exploiting the spatial information present in anisotropic spectral distortions. To supplement our discussion of the diverse science of spectral distortions, we provide an overview of the upcoming and proposed experimental landscape. We highlight that the combination of the TMS, COSMO, and BISOU experiments will provide the first discovery of a monopole $y$-type distortion within the coming decade. From space, the proposed FOSSIL experiment is forecasted to improve upon the original COBE/FIRAS measurement by roughly three orders of magnitude in sensitivity, bringing with it the detection of the $\Lambda$CDM $\mu$-type distortion sourced by the dissipation of small scale acoustic modes in the pre-recombination
plasma. With transformational measurements on the horizon, CMB spectral distortions offer a uniquely sensitive probe of the thermal history of the Universe at
redshifts $z \lesssim 2 \times 10^6$.
Read the full abstract ▾
All authors Bryce Cyr, Nabila Aghanim, Ethan Baker, Elia Stefano Battistelli, Richard Battye, José Luis Bernal, Jens Chluba, Xavier Coulon, William Coulton, Paolo de Bernardis, Eleonora Di Valentino, Guillem Domènech, Sara Evangelista, Giulio Fabbian, Fabio Finelli, J. Colin Hill, Rishi Khatri, Alan Kogut, Guilaine Lagache, Hongwan Liu, Bruno Maffei, Fereshteh Majidi, Abhishek S. Maniyar, C. J. A. P. Martins, Silvia Masi, Jeff McMahon, Daniela Paoletti, Vivian Poulin, Wenzer Qin, Mathieu Remazeilles, José Alberto Rubiño-Martín, Alina Sabyr, Mayuri Sathyanarayana Rao, Carlos Sierra, Jack Singal, Tracy R. Slatyer, Elsa M. Teixeira, Leander Thiele, Léo Vacher, Duncan Watts
Astrophysics of Galaxies
JWST Observations of Starbursts: A Young Bubble in NGC 253's Central Starburst
Kaitlyn E. Sheriff, Elisabeth A. C. Mills, Xinyu Mai et al. (+31 more)
We present a multi-wavelength analysis of a young bubble in the
nuclear starburst of NGC 253 using new JWST MIRI-MRS observations together with archival ALMA (100, 350, 690 GHz) and Chandra data. The MIRI maps reveal a prominent bubble-like structure in both ionized and molecular emission lines. The bubble is spatially coincident with one of the least embedded massive young clusters detected with ALMA, suggesting that the cluster is driving the expansion. We measure a radius of $\sim 11.5 \pm 3.4$ pc and an expansion velocity of $\sim 90 \pm 44$ km s$^{-1}$, implying a dynamical age of $\sim 0.1 \pm 0.1$ Myr. Using RADEX modeling of multiple CO transitions, we infer a molecular mass in the range of $(1.3 \pm 0.3) \times 10^4$ to $(2.8 \pm 0.8) \times 10^5$ $M_\odot$. We derive a kinetic energy of order $10^{51}$-$10^{52}$ erg, consistent with mechanical input from Wolf-Rayet
stellar winds or
supernovae in a $\sim 10^6$ $M_\odot$ cluster. The existence of a large population of Wolf-Rayet
stars or past
supernovae is supported by the presence of coincident X-ray emission. Our results provide direct evidence that individual clusters in a
nuclear environment can carve out coherent structures on parsec scales and inject significant energy and momentum into the surrounding interstellar medium, which can contribute to the
nuclear outflow in NGC 253.
Read the full abstract ▾
All authors Kaitlyn E. Sheriff, Elisabeth A. C. Mills, Xinyu Mai, Utsav Siwakoti, Sara E. Duval, Alberto D. Bolatto, Rebecca C. Levy, Jia Wei Teh, Torsten Böker, Serena A. Cronin, Daniel A. Dale, Keaton Donaghue, Kimberly Emig, Simon C. O. Glover, Rodrigo Herrera-Camus, Ralf S. Klessen, Thomas S.-Y Lai, Ashley E. Lieber, Laura Lenkić, Sebastian Lopez, David S. Meier, Jüergen Ott, J. D. T. Smith, Yu-Hsuan Teng, Paul P. van der Werf, Sylvain Veilleux, Vicente Villanueva, Rachel Cionitti, Joseph Havens, Maleah Rhem, Nathan Shaw, Kai Smith, Hazel B. Wright, Md. Abdullah Al Zaman
Astrophysics of Galaxies
Forged in Quenching: Morphological Transformation across Star-forming and Quiescent Galaxies in EAGLE
Kai Wang, Carlton Baugh, Sownak Bose et al. (+15 more)
The connection between morphology and quenching in central
galaxies is well established, but its physical origin remains widely debated. We address this by tracing the main progenitor branches of $z=0$
star-forming and quiescent central
galaxies in the EAGLE cosmological simulation from $z\gtrsim4$. Their disc-to-total ratio and triaxiality tracks are indistinguishable until $z\approx 1$-$2$, when both diverge concurrently with the onset of quenching, whereas the size and supermassive black hole (SMBH) mass differences are established earlier. We identify four physically distinct channels linking
galaxy morphology and quenching. First, mergers cause size growth, rotation suppression, triaxiality increase, and SMBH growth, with the accumulated SMBH mass subsequently causes the quenching of
galaxies. Second, with merger history controlled,
galaxy morphology modulates SMBH growth throughout the
star-forming phase: compact, dispersion-dominated
galaxies grow their SMBHs faster and are preferentially quenched, producing the size and morphology differences between
star-forming and quiescent
galaxies. Third, at fixed
stellar mass and SMBH mass, compactness further facilitates the quenching of
galaxies. Fourth, disc instability transforms compact oblate discs into prolate systems, with substantial size growth and suppressed rotation but negligible
stellar mass growth. This secular channel contributes about half of the prolate
galaxy population around $M_{\rm star}\approx 10^{10.6}\,\rm M_\odot$. Prior to quenching, the progenitors of quiescent
galaxies already have smaller sizes, lower disc-to-total ratios, and more massive SMBHs than
star-forming
galaxies at the same epoch, by amounts comparable to their differences at $z=0$. Morphology therefore plays an active role in growing the SMBH and quenching the
galaxy, rather than being passively inherited through progenitor bias.
Read the full abstract ▾
All authors Kai Wang, Carlton Baugh, Sownak Bose, Shaun Cole, Carlos S. Frenk, Hao Fu, Cedric Lacey, Shengdong Lu, Aaron Ludlow, Peder Norberg, Yingjie Peng, Katy L. Proctor, Isabel Santos-Santos, Francesco Shankar, Tom Theuns, Enci Wang, Tao Wang, Vivienne Wild
Mathematical Physics · Cross-listed from math.OA
A generalization of the Powers-Størmer-Ogata inequality
Markus B. Fröb
We show that for any positive operator monotone function $f$ the inequality $\int_{[0,\infty)} f(t) \, \mathrm{d} \left\lVert E^{\Delta_{\varphi,\psi}}(t) \xi_\psi \right\rVert^2 + f'_\infty \varphi(1-s(\psi)) \geq \frac{f(1)}{2} \Bigl( \varphi(1) + \psi(1) - \lVert \varphi - \psi \rVert \Bigr)$ holds, where $\varphi, \psi \in \mathcal{M}_{*,+}$ are two normal positive linear functionals on a von Neumann
algebra $\mathcal{M}$, and $\Delta_{\varphi,\psi}$ is the associated relative modular operator. Choosing $f(t) = t^s$ with $s \in [0,1]$, the Powers-Størmer-Ogata inequality is recovered.
Read the full abstract ▾
Astrophysics of Galaxies
The Missing Black Hole in the Large Magellanic Cloud: A Dynamical Prediction for Its Present-Day Location
Robin Chisholm, Elena D'Onghia, Niv Drory et al. (+2 more)
There are indications that the Large Magellanic Cloud (LMC) hosts a central supermassive black hole (SMBH), yet no direct detection exists: one reason is that its present-day location need not necessarily coincide with the photometric or kinematic centers. Here we frame a dynamical targeting problem and predict the present-day sky location of the LMC SMBH. We model the recent LMC-Small Magellanic Cloud (SMC) interaction, which induces a bar-disk offset, and integrate SMBH orbits within a realistic, time-dependent LMC-SMC-Milky Way (MW) potential. We show that the MW
tidal field at present epoch exceeds that of the SMC by at least an order of magnitude, setting a preferred direction for coherent, vertical low-amplitude displacements, while the disk asymmetry drives in-plane offsets. Projecting onto the observed LMC frame, the mean of our predicted SMBH probability distribution is located at $(\alpha,\delta)=(80.23^{\circ},-69.55^{\circ})$, with a $1\sigma$ confidence ellipse having semi-major and semi-minor axes of $(a,b)=(1.34^{\circ},0.56^{\circ})$, respectively. This mean is $\sim6$ arcminutes north of the adopted dynamical center, while the mode coincides with the dynamical center and lies well within the $1\sigma$ confidence region. Furthermore, all literature estimates of the LMC center considered here fall within the $2\sigma$ confidence region. This provides a concrete, testable target for ongoing and upcoming spectroscopic surveys, transforming the search for the LMC SMBH from an unconstrained problem into a focused observational strategy.
Read the full abstract ▾
All authors Robin Chisholm, Elena D'Onghia, Niv Drory, Andrew Fox, Noam Libeskind