General Relativity and Quantum Cosmology
How Much Geometry Does Horizon Entropy Determine? A Discourse on Entropy, Gravity, and Observable Quantities
Yen Chin Ong
Building on Jacobson's thermodynamics derivation of Einstein field equations, the "generalized
entropy and varying-G" (GEVAG) framework was proposed to consistently incorporate generalized horizon
entropy $S=f(A)/4G$ into both the thermodynamics and the geometry of spacetime. This leads to an effective gravitational coupling $G_\text{eff}=G/f'(A)$. A related "
entropy-
gravity correspondence" (EGC) instead is equivalent to promoting this horizon relation to a radially varying bulk coupling $G_\text{eff}(r)$. We clarify the similarities and fundamental distinctions between these approaches. Although they share the same horizon consistency relation, their global causal structures and asymptotic geometries can differ substantially. In addition, the radial prescription of EGC introduces an additional ambiguity for multi-center configurations. We further examine a near-horizon extension of GEVAG, which restores the equivalence between thermodynamic and ADM masses that is absent in the horizon-only formulation. We then discuss the implications of these different prescriptions for the Bekenstein bound. The Bekenstein bound provides a surprising link between $G_\text{eff}$ in near horizon GEVAG, EGC, and the one obtained in the recent $f(R)$-reconstruction approach of generalized
entropy geometry via Wald
entropy. Finally, we raise the most important question: what exactly is the $G$ measured in laboratories?
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Quantum Physics
Numerical simulation of D-Wave's quantum advantage experiment with time-dependent variational Monte Carlo
Roeland Wiersema
Programmable
quantum annealers can realize real-time dynamics of frustrated transverse-field Ising models on large, nontrivial graphs. Recent work by King et al. argued that the classical simulation of such experiments would require exponential computational resources for classical methods such as tensor networks and neural
quantum states. Here, we numerically simulate the D-Wave
spin-glass annealing protocol with time-dependent variational Monte Carlo (t-VMC) using a correlator state tailored to
spin-glass dynamics. For the two-dimensional cylinder, three-dimensional dimer, diamond, and biclique instances considered, at annealing times of 7 and 20 ns, we show that systematically increasing the variational ansatz size enables t-VMC to approximate the final two-
spin correlation errors of the
quantum processing unit (QPU). We also perform an accurate large-scale simulation of a challenging biclique instance for which no other variational method is known to work, and we find close agreement with the
quantum annealer. Through ablation studies, we identify poor Markov-chain mixing, high-variance local-energy
estimators, and
stochastic Runge-Kutta error estimates as the principal numerical failure modes. We address these numerical issues by using parallel tempering, blurred sampling and an importance-weighted differential equation solver, thereby clarifying the numerical requirements for stable, large-scale t-VMC simulations. Our results extend the frontier of classical simulation while providing a realistic assessment of the computational costs of simulating
quantum dynamics at this scale.
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High Energy Physics (Phenomenology)
Electromagnetic tails of $B$-meson light-cone distribution amplitudes
Max Ferré and Matthias Neubert
We investigate electromagnetic corrections to the $B$-
meson decay constant and light-cone distribution amplitudes (LCDAs) within the framework of heavy-
quark effective theory. The inclusion of QED effects extends the support of the LCDAs to negative values of the light-cone momentum. We clarify the relation between this region and QED-generalized decay constants sensitive to electromagnetic final-state radiation. We derive model-independent expressions for the asymptotic behavior in the large negative-momentum region of the QED-generalized LCDAs $\Phi_\pm(\omega,\mu)$ in terms of integrals over the two- and three-particle LCDAs defined in pure QCD. We show that our result for $\Phi_+$ is consistent with the renormalization-group equation satisfied by this object and study its
evolution using the known one-loop anomalous dimension. Finally, we propose a phenomenological model consistent with these constraints
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High Energy Physics (Phenomenology)
Primordial Black Hole Assisted Dirac Leptogenesis
Marco Manno and Anish Ghoshal
Dirac leptogenesis offers a qualitatively different route to the
baryon asymmetry: total
lepton number is conserved, but equal and opposite asymmetries are stored in the Standard Model and right handed
neutrino sectors, with only the visible component processed by electroweak sphalerons. We present the first dedicated study of how evaporating
primordial black holes (PBHs) modify this mechanism. In a minimal charged-scalar mediator setup, we solve the coupled Boltzmann system including thermal production, Hawking emission of the mediator $X$ and of right handed
neutrinos, the PBH contribution to the expansion rate, and
entropy injection. We find that Hawking emission can populate $X$ in regions where thermal production is inefficient, allowing its subsequent CP-violating decays to enhance the
baryon asymmetry. For representative
benchmarks, PBHs extend the successful region from mediator masses around $10^9\,{\rm GeV}$ down to about $10^6\,{\rm GeV}$ and can compensate for smaller effective CP asymmetries. This effect is not universal: where thermal Dirac leptogenesis is already efficient, PBHs can instead reduce the final asymmetry. Their evaporation also deposits energy in the right handed
neutrino sector and contributes to $\Delta N_{\rm eff}$. In the PBH parameter scan, part of the region that reproduces the observed
baryon asymmetry lies below the Planck reference level $\Delta N_{\rm eff}=0.284$ and above the projected CMB-S4 sensitivity $\Delta N_{\rm eff}=0.06$.
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High Energy Physics (Phenomenology)
SN1987A constraints on the neutrino-dark-fermion interaction from resonant scattering with C$\nu$B
Christina Gao, Ke Hu, Kun-Feng Lyu et al. (+1 more)
Neutrino self-interactions mediated by a light scalar offer a compelling resolution to cosmological tensions and may naturally arise in
neutrino mass generation mechanisms. When the scalar also couples to a light dark-sector
fermion,
supernova neutrinos can resonantly annihilate with the
cosmic neutrino background (C$\nu$B) into invisible dark radiation, depleting the flux en route to Earth. We use this depletion to constrain the
neutrino-scalar coupling from the SN1987A data. Within a
Bayesian framework we analyze the data for two
supernova neutrino emission models, a parameterized model and a 2D hydrodynamic simulation, and for two coupling types, a mass-independent one and a mass-proportional one. Our results show that new-physics limits from SN1987A cannot be quoted independently of the heavy-
flavor emission, the
flavor conversion, or the coupling structure. Finally, we forecast that a future high-statistics burst recorded by Hyper-Kamiokande would restore a meaningful upper bound even when
flavor conversion is included.
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All authors Christina Gao, Ke Hu, Kun-Feng Lyu, Vincent Zou
High Energy Astrophysical Phenomena
Measuring Small-scale Turbulence in Supernova Remnants with Jitter Radiation
Emily Simon, Damiano Caprioli, Niccolò Bucciantini et al. (+2 more)
Hard X-ray emission from Cas A has been attributed to jitter radiation, implying
magnetic turbulence on scales near or below the ion Larmor radius. We propose these fields arise from ion-scale micro-instabilities (e.g., mirror and firehose) in the shock downstream, and use high-resolution hybrid simulations to demonstrate the generation of such small-scale
turbulence. Its spectral index, once numerical dissipation is accounted for, is consistent with that inferred for Cas A, suggesting that jitter radiation is a direct probe of ion-scale
turbulence in
supernova remnants.
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All authors Emily Simon, Damiano Caprioli, Niccolò Bucciantini, Emanuele Greco, Marco Miceli
High Energy Physics (Theory)
On-shell recursion and soft theorems for worldline quantum field theory
Nathan Castet and Vincent F. He
We derive a set of on-shell recursion relations for amplitudes in worldline
quantum field theory (WQFT), an effective theory of
gravity coupled to a massive worldline which is relevant for computing classical gravitational observables. We overcome the poor large-$z$ falloff of amplitudes under an all-line complex momentum deformation by deriving and exploiting a new soft-graviton
theorem in the presence of a worldline. This
theorem generalizes the leading (Weinberg) and subleading soft
theorems with additional contributions due to soft emission from the worldline. Our main result is a $d$-dimensional recursion formula, expressing any $n$-graviton rational amplitude in terms of lower-point amplitudes from WQFT and pure
gravity. Using the soft-worldline
theorem, we can obtain amplitudes with any number of external worldline fluctuations from the corresponding all-graviton amplitudes, making the recursion sufficient to construct any rational amplitude of the theory. We verify our results by explicitly computing two-graviton and three-graviton amplitudes.
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General Relativity and Quantum Cosmology
One-cycle radiation-reaction Magnusian for eccentric binaries through relative 1PN order
Andrea Placidi
We derive the one-cycle first Magnusian for nonspinning compact binaries on planar, bound eccentric orbits through relative first post-Newtonian (1PN) order and linear order in radiation reaction, and construct the associated first-order periastron return map. Combining the conservative 1PN dynamics and its Jacobi transport with the 2.5PN and 3.5PN radiation-reaction forces, we obtain all four components in closed form for \(0<e<1\), without expanding in eccentricity. The dependence on all eight Iyer–Will radiation-reaction gauge parameters reduces to periodic coboundaries and therefore cancels over a radial cycle. The result reproduces the averaged energy and angular-momentum losses, their circular limit, and the secular
evolution of the 1PN radial orbital elements. The two remaining components encode the dissipative angle-sector information. Projecting the resulting phase-space update onto the perturbed periastron return section yields the corrections to the return time and apsidal phase. We then compare the strict first-order map with a partially exponentiated map built from the same Magnusian. The comparison is observable dependent: at fixed periastron index, the strict map gives smaller residuals for a representative
evolution over 40 radial cycles, whereas partial exponentiation reduces the accumulated periastron-timing residual by about an order of magnitude. Across a representative one-cycle grid at equal masses, partial exponentiation improves the radial-action and energy updates at every sampled point.
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High Energy Physics (Phenomenology)
Axion Quality from Exact Proton Stability
Joe Davighi, Admir Greljo and Xavier Ponce Díaz
A discrete, anomaly-free $\mathbb Z_9$ gauge
symmetry may persist to the deep infrared, exactly forbidding
proton decay. This $\mathbb Z_9$ can emerge from Higgsing a
lepton-flavour non-universal $U(1)_X$ that generates realistic
neutrino masses and mixings through a high-scale seesaw and predicts an additional light Goldstone. Adding an anomaly-free
chiral heavy-
quark sector turns this mode into the QCD
axion. The same selection rules that ban
proton decay also forbid PQ-violating operators below a suitably high dimension, $d_{\rm PQ}\gtrsim10$, including operators involving the heavy
quarks that radiatively match onto the scalar potential. We construct explicit models viable when PQ breaking occurs before or after inflation; in the latter case, avoiding stable heavy relics and eliminating the string-wall network tightly constrain the heavy-
quark spectrum. We identify restricted regions of parameter space where thermal leptogenesis remains viable and, for $d_{\rm PQ}\geq13$, can coexist with a high-quality
axion constituting all of the dark matter.
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Astrophysics of Galaxies
JWST Reveals a Candidate Supermassive Black Hole Binary at z=4.3 in the Brightest Sub-millimeter Galaxy in COSMOS-Web
Jed McKinney, Ansh Gupta, Julian B. Munoz et al. (+13 more)
We present JWST/NIRSpec PRISM and G395M grating spectroscopy for AzTEC-1, a massive sub-mm bright
galaxy at $z=4.34$ in the COSMOS extragalactic field. The PRISM spectrum reveals strong H$\alpha$, a significant Balmer break, and no H$\beta$ detection, indicating a $100-400$ Myr-old
stellar population and high
dust attenuation. BPT line ratios indicate the presence of an Active
Galactic Nucleus (AGN). Decomposing narrow and broad line components, we recover broad, blueshifted H$\alpha$ with a velocity offset of $1245{\,\rm km\,s^{-1}}$ from the systemic narrow line velocity and with FWHM$\,\sim2500\,{\rm km\,s^{-1}}$. AzTEC-1's smooth morphology and
stellar age is suggestive of a past merger-induced starburst period that would have brought in a second supermassive black hole, raising the possibility for a binary supermassive black hole system. In this scenario, we assume that the lower mass black hole hosts a broad line region orbiting a quiescent primary. Evidence for an extended
outflow is not found in the 2D spectrum, NIRCam imaging, resolved ALMA observations of
dust continuum, or CO, [C II]$_{157\,\mu \rm m}$ and [N II]$_{\rm 205\,\mu m}$ kinematics. AzTEC-1's high central gas mass surface density and dynamically unstable gas disk indicates that massive gas clouds external to the candidate binary SMBH's orbit might have played a role in stalling infall from $\sim10$ Myr to $\sim100$ Myr through dynamical torques, which has been theorized to occur in the
nuclei of massive
galaxies like AzTEC-1. If the supermassive black hole binary is confirmed, AzTEC-1 would be an excellent laboratory into the astrophysics driving low-frequency gravitational wave detections.
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All authors Jed McKinney, Ansh Gupta, Julian B. Munoz, John Chisholm, Caitlin M. Casey, Stephanie M. Urbano Stawinski, Olivia Cooper, Erini Lambrides, Hollis Akins, Maximilien Franco, Archana Aravindan, Seiji Fujimoto, Kohei Inayoshi, Andreas L. Faisst, Jeyhan S. Kartaltepe, Michael Boylan-Kolchin
Quantum Physics
Purification of photonic graph states
Matthias C. Löbl, Aliki A. Capatos, Ming Lai Chan et al. (+3 more)
Graph states constitute the main building block for
quantum computing with
photons.
Quantum emitters with a hosted
spin can deterministically generate photonic graph states, strongly lowering the overhead of multiplexing highly probabilistic linear-optics graph state generation. However, they generally suffer from various noise sources, resulting in reduced fidelities of the produced states. To mitigate this issue, we develop purification schemes for entangled photonic states. We first develop purification schemes to purify arbitrary photonic GHZ and other CSS states, which we generalize to all photonic graph states and stabilizer states. The proposed purification schemes have a high success probability of up to $1/2$ and require only linear optics and
photon detectors. We optimize cascaded purification schemes for various graph states, taking into account phenomenological Pauli errors or physical noise in time-bin-encoded graph state generation with
quantum emitters.
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All authors Matthias C. Löbl, Aliki A. Capatos, Ming Lai Chan, Peter Lodahl, Anders Søndberg Sørensen, Stefano Paesani
Astrophysics of Galaxies
The Comprehensive Investigations of the NGC 7419 Open Cluster and the New Perspective on Mass Populations
Nasser M. Ahmed, Remziye Canbay and Deniz Cennet Ç{\i}nar
We present a structural, kinematic, and photometric analysis of the young, red supergiant- and Be
star-rich open cluster NGC 7419 using
Gaia DR3 and 2MASS data. Using the HDBSCAN
algorithm and conservative membership criteria, we identify 734 high-probability cluster members, separating the cluster from the dense Perseus Arm background. Isochrone fitting to the
Gaia DR3 color-magnitude diagram, treating classical Be
stars separately to account for their circumstellar excess, yields an age of 15 +/- 2 Myr, a distance of 3161 +/- 261 pc, a distance modulus of 12.50 +/- 0.08 mag, and a color excess E(GBP-GRP) = 2.58 +/- 0.06 mag. An independent 2MASS analysis gives a consistent distance modulus of 12.53 mag and E(J-Ks) = 0.99 mag. The Be
stars show a prominent infrared excess in J-Ks, consistent with free-free and bound-free emission from circumstellar disks. We derive mean proper motions of -2.738 +/- 0.115 and -1.604 +/- 0.149 mas yr^-1 and a mean parallax of 0.288 +/- 0.062 mas, corresponding to a trigonometric distance of 3316 +/- 317 pc. The photometric distance is adopted as the primary estimate. A generalized King profile gives a core radius of 1.53 +/- 0.08 arcmin and a limiting radius of 8.16 +/- 1.1 arcmin. The
stellar mass distribution is best described by a three-component Gaussian model, which we interpret as three distinct mass populations. Their coexistence and incomplete mixing are consistent with the young dynamical state of NGC 7419. Hierarchical formation provides a plausible framework for their origin.
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Astrophysics of Galaxies
The HERON Coma Project: Exploring the low-surface-brightness frontiers in the Coma cluster
Javier Román, R. Michael Rich, Pablo M. Sánchez-Alarcón et al. (+3 more)
The technical complexity of data processing and residual instrumental systematics remain among the main barriers to reaching the faintest low-surface-brightness (LSB) regimes in the local Universe. Here, we present the HERON Coma Project, a deep $g$- and $r$-band imaging campaign on the Coma cluster carried out with the LSB-optimized 71-cm Jeanne Rich
Telescope. The observing and processing strategy combines accurate flat-fielding, sky-background modeling and extended point spread function (PSF) characterization. As representative scientific applications, we explore the complex associated with the
giant elliptical
galaxies NGC 4839 and NGC 4816, in the southwestern region of Coma. Spatially coherent emission is recovered in direct imaging to $\mu_{\overline{g+r}}\simeq30~\mathrm{mag\,arcsec^{-2}}$, consistent with the nominal sensitivity inferred from the scaling of the background fluctuations. The PSF-deconvolved photometric profiles of NGC 4839 and NGC 4816 are traced to generalized isophotal radii of 705 and 329 kpc, reaching $\mu_{\overline{g+r}}=32.2$ and $31.6~\mathrm{mag\,arcsec^{-2}}$, with data-derived signal-to-noise ratios of 4.1 and 7.0, respectively. The agreement between direct detection and the predictions from background fluctuations provides no clear evidence of a systematics-dominated detection floor over the surface brightness range and spatial scales examined. We also assess the observational challenges involved in extending reliable measurements to still fainter surface brightness levels. The HERON Coma Project opens a new window onto the faint
stellar record of the complex and ongoing assembly of Coma, while demonstrating the potential of modest ground-based
telescopes with suppressed instrumental reflections to provide highly competitive measurements of extended diffuse structures. We make the final calibrated images publicly available to the community.
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All authors Javier Román, R. Michael Rich, Pablo M. Sánchez-Alarcón, Yolanda Jiménez-Teja, Chester Li, Mónica Esquide
Astrophysics of Galaxies
Linking neutral gas inflows and outflows to offsets in the star-forming main sequence and mass-metallicity relation
S. Weng, M. Pieri, A. Saintonge et al. (+40 more)
Gas inflows and
outflows regulate
galaxy growth, but direct observational links between measured gas flows and
galaxy scaling relations remain limited. Using ~6,000
star-forming
galaxies with down-the-barrel Na I D absorption from DESI DR2, we examine how systems with detected neutral-gas inflows and
outflows populate the
star-forming main sequence (SFMS) and mass-
metallicity relation (MZR). Inflow and
outflow hosts are compared with
stellar-mass- and
redshift-matched controls, and with SFMS and MZR fits derived from
galaxies without detected gas flows.
Outflow hosts (v_flow $\leq$ -50 km s$^{-1}$) show enhanced sSFRs by 0.25-0.40 dex and elevated central
metallicities by 0.04-0.06 dex in the lower-
redshift sample. Slow inflow hosts (0 $<$ v_flow $<$ 100 km s$^{-1}$) show similarly enhanced sSFRs of 0.20-0.30 dex, but no significant
metallicity offset, while fast inflow hosts (v_flow $\geq$ 100 km s$^{-1}$) show weaker SFR enhancement and modestly lower
metallicities. Together, these trends support a regulator picture in which neutral gas flows trace different phases of the
baryon cycle. Slow inflow hosts lie above the SFMS, consistent with
accretion sustaining enhanced
star formation without strong central
metallicity dilution. This may indicate that inflowing gas is already metal-enriched or has mixed or enriched over extended timescales. By contrast,
outflow hosts lie near the upper 1{$\sigma$} SFMS envelope, consistent with feedback regulating subsequent growth. Gas-flow hosts also show small but systematic offsets in the narrow 4000 Å break strength ($D_n$4000) relative to controls matched in
redshift,
stellar mass and SFR. Our results show that neutral gas flows are associated with population-level offsets from the SFMS and MZR, consistent with a
baryon-cycle contribution to scaling-relation scatter.
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All authors S. Weng, M. Pieri, A. Saintonge, D. Scholte, D. Muñoz Santos, T. Hu, J. Aguilar, S. Ahlen, F. Beutler, D. Bianchi, D. Brooks, A. Carnero Rosell, F. J. Castander, T. Claybaugh, A. de la Macorra, B. Dey, P. Doel, V. A. Fawcett, J. E. Forero-Romero, E. Gaztañaga, S. Gontcho A Gontcho, G. Gutierrez, A. Kremin, M. Landriau, L. Le Guillou, A. Meisner, R. Miquel, J. Moustakas, S. Nadathur, W. J. Percival, F. Prada, I. Pérez-Ràfols, C. Ravoux, G. Rossi, R. Ruggeri, E. Sanchez, C. Saulder, D. Schlegel, J. Silber, M. Siudek, G. Tarlé, B. A. Weaver, H. Zou
High Energy Physics (Theory)
Chang-Han Chen, Geoff Penington, Gautam Satishchandran et al. (+1 more)
We construct an
algebra of observables associated to a cut of null infinity in asymptotically flat spacetimes. The Bondi mass associated with a sharp cut of future null infinity is not a well-defined
quantum operator: its fluctuations diverge even after smearing in retarded time. We instead introduce a finite-radius, time-smeared version of the Bondi mass and adjoin this operator to the matter and graviton observables in an arbitrarily small asymptotic neighborhood of the cut. We separately analyze spacetimes with and without black holes and find, in both cases, Type III$_1$ von Neumann
algebras that satisfy non-trivial nesting relations. In Minkowski spacetime, the resulting
algebra reconstructs the spacelike wedge associated with the cut. In a stationary black hole spacetime, it reconstructs the region bounded by the cut and the black hole bifurcation surface, providing an asymptotically flat analogue of an
entanglement wedge. In the limit as the cut is moved to past infinity, we recover a Type I$_{\infty}$
algebra for spacetimes without black holes and a Type II$_{\infty}$
algebra for black hole spacetimes. For
algebras at finite cuts of retarded time, we construct a Type II$_\infty$ regularization of the black hole
algebra whose renormalized von Neumann
entropy agrees with the generalized
entropy. In appendices, we prove two technical results about
quantum fields, in a Schwarzschild spacetime, that asymptote to the Minkowski
vacuum at infinity: a split property for unbounded, spacelike separated regions and the construction of a faithful, normal, and semifinite Hartle-Hawking weight whose modular flow is Schwarzschild time
evolution.
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All authors Chang-Han Chen, Geoff Penington, Gautam Satishchandran, Elisa Tabor
Instrumentation and Methods for Astrophysics · Cross-listed from cs.LG
Generative Diffusion Surrogates with Analytical Variance Schedule
Patrick Reichherzer, Gianluca Gregori, David N. Hosking et al. (+1 more)
Stochastic transport describes physical systems in which an initially structured distribution spreads under unresolved forcing, scattering, or heterogeneous media. Useful surrogates for such systems should be probabilistic, time-resolved, and able to represent non-Gaussian distributional structure. Generative
diffusion models, which corrupt data with Gaussian noise and learn a reverse flow back to structured states, have these properties. Their noise schedules, however, are usually chosen heuristically: image and audio generation—the canonical use cases—provide no physical clock. In transport, by contrast, the variance, or mean-square displacement, is often known from macroscopic theory or empirical scaling even when the full distribution is not. Here we prescribe the forward noising rate as the time derivative of this variance, turning generative time into a calibrated transport clock. The variance path is enforced by construction, while the learned score field represents how non-Gaussian structure inherited from entrance data is smoothed along that path, requiring no intermediate-time physical transport data. For ballistic-to-diffusive transport in turbulent
plasmas, the surrogate matches test-particle distributions, reproduces the laboratory-measured variance scale, and tracks the simulated kurtosis
evolution without schedule tuning, enabling calibrated emulation and likelihood-based inference.
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All authors Patrick Reichherzer, Gianluca Gregori, David N. Hosking, Subir Sarkar
General Relativity and Quantum Cosmology
Geodesics and thermodynamics of a $\kappa$-deformed anti-de Sitter black hole surrounded by a quintessence field
Faizuddin Ahmed, Ahmad Al-Badawi, Izzet Sakalli et al. (+1 more)
We investigate the geodesic structure and thermodynamics of a $\kappa$-deformed Schwarzschild-anti-de Sitter black hole in a Kiselev quintessence field, where dynamics are governed by a mass-dependent lapse deformation. This term produces an inner Cauchy horizon without requiring charge or
spin, yet it fails to resolve the central singularity; instead, the Kretschmann scalar diverges more strongly as $r^{-10}$. Because the deformation amplitude couples to the mass, the standard Bekenstein-Hawking area law violates the first law of thermodynamics. We resolve this by either deriving a modified
entropy or rescaling the mass, both of which restore the first law and yield a consistent Smarr relation. Optically, an increasing deformation parameter shrinks both the
photon sphere and the critical impact parameter. We also derive a closed-form Joule-Thomson coefficient, revealing that the $\kappa$-deformation triggers an inversion curve a feature absent in standard neutral SAdS. Notably, this occurs without generating a van der Waals critical point, demonstrating that Joule-Thomson inversion and van der Waals criticality can be cleanly decoupled. Finally, the deformation suppresses peak Hawking emission by a factor of roughly four and increases flux sparsity, an effect driven almost entirely by a drop in temperature rather than changes to the black hole shadow.
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All authors Faizuddin Ahmed, Ahmad Al-Badawi, Izzet Sakalli, Erdem Sucu
Optics
Multidimensional Double Refraction Microscopy
Jörg König and Christian Cierpka
Multidimensional optical microscopy - extracting 3D location, orientation, and spectral information from nanoscale emitters - is key to modern nanoscience. However, this multidimensional capability requires complex instrumental setups, demanding exceptional stability and specialized expertise in optics. Here, we overcome these barriers by introducing Double Refraction Microscopy (DRM), a passive imaging method providing a straightforward pathway to multidimensional super-resolution imaging. Based on bifocal imaging via a birefringent microscope slide, DRM splits nanoprobe light into a characteristic double image encoding 3D location, orientation, and spectral signature, while requiring zero hardware modifications to standard wide-field microscopes. To showcase its robustness, we implement DRM across three distinct slides of varying materials and thicknesses, calibrating 3D localization with 450-nm nanoparticles and demonstrating high orientation sensitivity using polarization-controlled emitters. Furthermore, we confirm spectral readout using a pinhole array acting as a grid of point emitters back-illuminated at various wavelengths to generate distinct spectral signatures. Finally, we showcase practical utility by performing a two-colour 3D localization measurement within a $10\,\mu\text{m}$ gap, utilizing the single optical pathway of a standard epi-fluorescence microscope. Ultimately, DRM provides the missing optical hardware simplicity to complement established computational tools, promising to transfer advanced super-resolution capabilities from specialized facilities to every laboratory bench.
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Fluid Dynamics
A reconfigurable multi-axis cyber-physical framework for multi-regime fluid–structure interaction experiments
Zihan Zhang, Alex Sorensen, Qimin Feng et al. (+3 more)
Fluid–structure interaction (FSI) experiments are typically built around mechanical dynamics and constraints imposed by the physical apparatus, so changing mass, stiffness, damping, or allowable motion often requires hardware reconfiguration. Here we present a reconfigurable cyber-physical framework in which these properties are instead assigned through software-defined dynamics. The system provides three translational and one rotational degree of freedom, each independently configurable as prescribed, load-responsive, or locked, with operating roles that can also be reassigned during a running experiment. Measured forces and torques are incorporated into real-time virtual dynamic models, while a common supervisory architecture coordinates multi-axis motion, mode switching, synchronized data acquisition, and diagnostic positioning. The prescribed-motion pathway is validated using a pitching hydrofoil by comparison with published thrust and power scaling trends, while the load-responsive pathway is evaluated using an active-heave/passive-pitch
benchmark that reproduces the expected frequency-dependent resonant response over the tested conditions. The same platform is then reconfigured for intra-cycle active–passive pitching, coordinated vertical-axis turbine-surrogate motion, force-driven passive surge, and automated multilayer stereoscopic particle image velocimetry. These results demonstrate that distinct FSI boundary conditions and measurement requirements can be implemented within a common motion, sensing, and control architecture. By treating mechanical roles and constraints as software-defined experimental variables, the framework provides a reusable basis for reconfigurable FSI experiments without redesigning the underlying platform for each application.
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All authors Zihan Zhang, Alex Sorensen, Qimin Feng, Orion Roberts, Linhao Jin, Qiang Zhong
Quantum Physics
Tunneling assisted interference in double-well levitodynamics
Yue Ma, Endre Bokor and M. S. Kim
Levitated particles trapped in double-well potentials provide a promising platform for exploring
quantum dynamics beyond the harmonic regime. We show that such systems exhibit a distinctive
quantum signature arising from tunneling-assisted interference. Unlike classical dynamics, where the two wells are disconnected, in the
quantum case,
quantum tunneling enables eigenstates to delocalize into the other well, creating nonzero overlaps between adjacent eigenstates that introduce low-frequency components into the
evolution of the mean particle position. By comparing
quantum and classical dynamics of particles in one-dimensional double-well potentials, we demonstrate that this interference is uniquely
quantum and can be identified through the oscillation of the average position alone. We further relate the observed spectral peaks to the structure of the energy
eigenvalues. The effect provides a promising probe of the
quantum signature of levitated particle motion, and has fundamental importance as it predicts the demonstration of two major phenomena of
quantum mechanics,
quantum tunneling and
quantum interference, at the same time and on the same system.
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Instrumentation and Methods for Astrophysics
CosmicPAH-IRDB: A Web Application for Including Anharmonicity in Simulated PAH Spectra for Astrophysics
Louan de Bentzmann, Christine Joblin, Karine Demyk et al. (+6 more)
Advances in infrared observations with the James Webb Space
Telescope (JWST) call for new tools to exploit the information associated with the Aromatic Infrared Bands (AIBs), now observed in both distant
galaxies and the embryos of planetary systems. The AIBs contain information about their carriers as well as the excitation conditions, making them powerful probes of the chemical and physical conditions of their environments - if their spectral information can be decoded. While large
datasets of theoretical infrared spectra are becoming available, efforts have primarily focused on the contribution of chemical diversity to the AIBs. However, the results remain limited by the impact of the excitation process on the band profiles. The AIB carriers, thought to be polycyclic aromatic hydrocarbons (PAHs), are hot molecules, which affects their spectral characteristics. We report here our approach to quantify these effects empirically by collecting IR spectra - both experimental and theoretical - and studying the
evolution of band positions and widths with temperature. We present our methodology, including the development of the CosmicPAH-IRDB web application and spectral database, along with the associated cosmicPAHmfit multi-component spectral fitting tool. Our philosophy emphasizes open sharing, user-friendly access, and machine readability. The web application, tool and their update are accessible via the
Cosmic PAH portal (https://
cosmic-pah.irap.omp.eu/)
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All authors Louan de Bentzmann, Christine Joblin, Karine Demyk, Giacomo Mulas, Dominique Toublanc, Vincent Marty, Axel Pérignon, Mickaël Boiziot, Jean-Michel Glorian
General Relativity and Quantum Cosmology
Dark-Sector Effects on the Phase Structure of Nonlinear Magnetic AdS Black Holes
Carlos E. Romero-Figueroa and J. R. Villanueva
We investigate the effects of perfect fluid dark matter (PFDM) and a dark-energy field on the phase structure of a nonlinear magnetically charged Anti–de Sitter (NLMC–AdS) black hole. The full thermodynamic system is analyzed numerically, while exact critical points are obtained for the limiting cases. Small–large black hole (SBH/LBH) phase transitions emerge in both the limiting geometries and the full solution within the quintessence regime. Moreover, the critical ratio $\rho_c=P_c v_c/T_c$ differs from the standard Reissner–Nordström–AdS (RN–AdS)/van der Waals (vdW) value, $\rho_c=3/8$. Our results show that the dark-sector parameters significantly influence the strength and persistence of the first-order transition. In the quintessence regime, a stronger dark-energy contribution enhances the swallow-tail structure of the Gibbs free energy and increases the latent heat associated with SBH/LBH coexistence. In contrast, a larger magnitude of the PFDM parameter $|\lambda|$ progressively suppresses the swallow-tail structure and the corresponding first-order transition, eventually leading to a single-phase regime. In the phantom regime, the system instead exhibits spinodal behavior without phase coexistence. We also find that any nonzero $\lambda$ prevents the formation of a regular
magnetic core. Finally, geometrothermodynamics (GTD) reproduces the phase structure through singularities of the thermodynamic
curvature, while the associated critical scaling is consistent with results reported for black holes, cosmological horizons, and real fluids, pointing toward a broader universality of thermodynamic critical behavior.
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Atomic Physics
A monolithic segmented 3D ion trap fabricated from fused silica by selective laser-induced etching
Edgar Brucke, Martin Wagener, Moritz Fontboté-Schmidt et al. (+10 more)
We present the design, fabrication, and characterization of a monolithic, segmented, three-dimensional linear Paul ion trap for
quantum science applications. The trap is fabricated from a single fused-silica block using selective
laser-induced etching (SLE) and is subsequently metallized, forming electrodes isolated by self-shadowing trench structures without the need for layer
alignment or external shadow masks. The segmented electrodes allow for shaping of the axial potential, enabling the creation of anharmonic potential wells, such as those required for equidistant ion strings. In addition, they enable shuttling and splitting of ion chains. We discuss key design choices and SLE-imposed constraints on achievable feature sizes, and evaluate electron-beam evaporation and magnetron sputtering as metallization approaches. Across two independent experimental setups, we demonstrate stable trapping and control of linear chains of up to 33 $^{40}$Ca$^+$ ions, including approximately equally spaced configurations. The measured secular frequencies in both traps agree with boundary-element simulations at the percent level, with residual deviations attributed to stray electric fields in the presence of anharmonic axial potentials, rather than fabrication imperfections. We measure axial micromotion field strengths on the order of 100 V/m along the trap axis, in approximate agreement with simulations. For radial mode frequencies near 2 MHz and an ion-electrode distance of 300 um, we measure heating rates of the order of 10 quanta/s in all but one motional mode, which is elevated by a technical noise source. The presented trap design is thus suitable for a wide range of
quantum science applications and demonstrates the viability of SLE for the fabrication of finely segmented, monolithic, three-dimensional ion traps.
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All authors Edgar Brucke, Martin Wagener, Moritz Fontboté-Schmidt, Philip Leindecker, Matteo Marinelli, Vlad Negnevitsky, Ilia Sergachev, Grégoire F. M. Tomassi, Paul Venetz, Stephan Welte, Jonathan Home, Daniel Kienzler, Cornelius Hempel
Atmospheric and Oceanic Physics
Baseline Climatology of Tornadoes and Waterspouts in the Philippine Archipelago
Generich H. Capuli
Tornadoes are documented on every inhabited continent, yet the environmental conditions used to anticipate them were developed and validated overwhelmingly on mid-latitude records, leaving tropical regimes largely unexamined. Here, we collected 1,186 combined tornado and waterspout reports in the Philippines spanning the early 1900s to 2025 and paired each with an ERA5 proximity sounding to construct the first baseline climatology and environmental characterization of these events in the archipelago. Activity concentrates in three corridors, mostly flanked by mountain ranges, one in each major island group, and is sharply phased within a May-October window that closely tracks the annual cycle of thunderstorm frequency, peaking in August and lagging into October for waterspouts alongside the tropical cyclone season. These events cluster in the mid-to-late afternoon, consistent with a daytime heating regime rather than nocturnal convection. The environments are thermodynamically permissive but kinematically shallow, with convective available potential energy (CAPE) exceeding typical Great Plains values, while the 0-6 km bulk wind difference (BWD; DLS) remains weak at $\sim$10-14 kt, departing from the mid-latitude covariance in which instability and shear increase together. Although streamwise vorticity is modest in magnitude, nearly all discriminating variance resides in the lowest kilometer, where 68-79% of near-surface horizontal vorticity is streamwise, reaching $>$0.005 s$^{-1}$ and 96% streamwiseness in the most organized profiles, and the hodographs retain low-level
curvature. Consequently, composite indices remain low even as tornadoes and waterspouts recur. Mid-latitude-calibrated parameters can therefore misdiagnose tropical-maritime regimes, and recalibration toward shallow-layer, orientation-aware kinematic discriminators may recover the diagnostic signal.
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Quantum Physics
Comment on "Environmental memory effects and quantum resource hierarchies in polarized hyperon–antihyperon systems"
Saeed Haddadi
We comment on the recent work [Eur. Phys. J. C 86, 988 (2026)], which investigates
quantum resources in polarized hyperon–antihyperon systems using correlated dephasing channels with
memory. Although the use of experimentally reconstructed
spin-density
matrices to characterize
quantum correlations in hyperon production may be a good motivation, we argue that the interpretation of the hyperon–antihyperon pair as an open
quantum system undergoing correlated environmental decoherence is not physically established. In particular, no physical environment or system–environment interaction responsible for the assumed correlated dephasing channel is identified, and hadronization cannot simply be interpreted as such an environmental dephasing process. Consequently, the claimed non-Markovianity, information backflow, and
memory-assisted protection of
quantum resources should be regarded as properties of a phenomenological channel rather than established physical effects in hyperon–antihyperon production. We also identify several technical and conceptual issues concerning the dephasing dynamics,
entanglement quantification, basis dependence of coherence, and the claimed hierarchy of
quantum resources. These issues call for a substantial revision of the physical interpretation and quantitative conclusions of the work. We hope that the present Comment will help clarify the distinction between phenomenological
quantum-channel modeling and physically established dynamical mechanisms in high-energy particle systems, and thereby provide useful guidance for future studies and help avoid similar conceptual and technical issues.
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Data Analysis and Statistics
Multi-fidelity Monte Carlo estimation of floor response spectra under combined seismic and structural parameter uncertainties
Nils Baillie, Baptiste Kerleguer, Cyril Feau et al. (+2 more)
Floor response spectra (FRS) are essential tools for the design of non-structural elements (such as equipment or components). Given the various physical phenomena influencing FRS, high-fidelity (HF) mechanical models of the primary structure may be required to estimate them. Since numerical simulations based on such models are generally computationally expensive, this paper proposes using a multi-fidelity Monte Carlo (MFMC) approach for the efficient estimation of FRS. The method relies on using observations from a fast low-fidelity (LF) model as control variables. If the absolute value of the correlation between LF and HF samples is close to 1, this approach reduces both variance and estimation error compared to a standard Monte Carlo estimate based solely on HF data samples. Through a case study involving the reactor building of the Kashiwazaki-Kariwa
nuclear power plant, we demonstrate the suitability of this method for FRS estimation. It effectively reduces variance and estimation error, even when using a LF model as simple as a single-degree-of-freedom system. We also show that the method accounts for modeling uncertainties while maintaining comparable performance. Its ease of use makes it a valuable tool for practitioners.
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All authors Nils Baillie, Baptiste Kerleguer, Cyril Feau, Josselin Garnier, Fan Wang
Adaptation and Self-Organizing Systems
Arithmetic of the sync basin for pulse-coupled oscillators
K. P. O'Keeffe
A population of $N$ identical pulse-coupled oscillators ultimately settles into one of two outcomes: full synchrony or a state of co-existing synchronized clusters. We show that which outcome occurs is controlled by the
prime factorization of $N$. At the critical charging curve — linear, the boundary between the synchronizing and clustering regimes — the synchronization basin acquires exact arithmetic structure. The synchronization probability is $\Psync=A_{N,1}/N^N$ for all $N$, where $A_{N,1}$ satisfies an exact recurrence relation. For
prime $N$, $A_{N,1}=N^N-1$ giving the closed form $\Psync=1-1/N^N$; for composite $N$, the observed asymptotic scaling is $1-\Psync\sim C_m N^{-(m-1)}$, where $m$ is the smallest
prime divisor. The result adds a new member to the atlas of exotic basin geometries: alongside fractal, riddled, and tentacled basins, we now have a basin that is arithmetic.
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Instrumentation and Methods for Astrophysics
Amortized Opacity Marginalization Improves C/O Interval Calibration for Brown-Dwarf Retrievals
Kellen Heraty
Molecular line lists disagree at a level that measurably shifts retrieved C/O, so
retrievals conditioned on a single list omit a dominant systematic from their error bars. Classical marginalization re-runs a full
retrieval under K opacity realizations per object. We move that cost into simulation: while generating the training set we randomize opacities (smooth multiplicative
Fourier fields in $\log\nu$ plus a discrete line-list mixture, under a deliberately broad prior informed by measured inter-list differences), so a neural posterior
estimator learns an already-marginalized posterior. Conceptually, this is the amortized analogue of repeating a conventional
retrieval under many plausible opacity realizations and averaging the resulting posteriors. On perturbed held-out spectra (n=2048) a standard NPE covers nominal 90% C/O intervals 43.3% of the time against 82.4% for a compute-matched marginalized network; three-seed control ensembles reach 93.2% on clean data but 61.4% under perturbation, against 89.4% marginalized, isolating the deficit as opacity-induced (TARP joint expected-coverage deviation 0.005 against 0.035 for a single control network). An axis ablation traces the gain to the continuous field (45.4% for the discrete swaps alone, 79.3% for the field alone). Applying the 105 real bad-pixel masks with median filling then collapsed the ensemble's C/O coverage from 0.901 to 0.479; retraining on the same mask distribution and pooling three such seeds returns a nominal 0.905 C/O and 0.891 overall under the full deployment path, still in simulation (n=1024, same 105 masks), at 0.21 to 0.31 of the prior width. On 105 JWST/G395H spectral products of 13 late-T/Y
dwarfs, single marginalized networks bracket the Hood et al. (2024) T8
benchmark C/O where the control excludes it, a consistency check rather than a validation, at 1.6-2.6x wider intervals.
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Quantum Physics
Observable- and state-selective prethermalization and bounds on prethermal lifetimes
C. L. Sriram, Soumya Kanti Pal and Lea F. Santos
Prethermalization describes long-lived intermediate regimes that precede
equilibrium and can dominate experimentally accessible dynamics. Here, we show that a separation of spectral energy scales, despite giving rise to a hierarchy of dynamical timescales, does not by itself guarantee the appearance of a prethermal plateau. Under the same
Hamiltonian, some observables may exhibit prethermal behavior, while others relax directly toward
equilibrium. We uncover the mechanism governing this selectivity, showing that the emergence of a prethermal plateau depends not only on the
Hamiltonian, but also on the observable and the initial state. Our results apply broadly to systems close to a fully permutation-symmetric limit and are illustrated with a long-range interacting
spin model. We further prove that the Loschmidt echo provides a lower bound on the prethermal lifetime of any bounded observable whenever the prethermal and exact dynamics are
unitary.
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Quantum Physics
Depth-1 expanders on the unitary group and applications
Anurag Anshu, Shankar Balasubramanian, Jonas Haferkamp et al. (+2 more)
We construct a constant-degree and constant-gap
quantum expander on $n$
qubits where each
unitary can be implemented by a depth-$1$ and 1D
circuit of Pauli or CNOT gates. We provide two applications of this expander. First, we use it to construct a family of frustration-free 1D
Hamiltonians whose ground states obey the
entanglement-gap relation $S = \Theta(\Delta^{-1/2})$; this is believed to be optimal, but achieving it had been open. Second, we use it to provide a streaming protocol that tests for closeness to a class of 1D volume-law entangled states. Moreover, we extend our
quantum expander to a constant-degree and constant-gap expander on the
unitary group where each
unitary is a single $T$ gate, a single $T^{\dagger}$ gate, or a depth-$1$ Clifford
circuit. This implies that a random sequence of
unitaries from the expander yields a gapped walk on a dense subgroup of the
unitary group. This improves upon previous work by Bourgain and Gamburd which did not control the dependence of the gap on the dimension.
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All authors Anurag Anshu, Shankar Balasubramanian, Jonas Haferkamp, Aram W. Harrow, Xinyu Tan