Accelerator Physics
Anomaly Detection in Bunch Oscillations for Early Warning of Sudden Beam Loss at SuperKEKB
H. Haigh, P. Horak, G. Inguglia et al. (+5 more)
Sudden beam loss (SBL) events at the SuperKEKB
collider result in the loss of a large fraction of the stored beam within just a few revolutions, on a timescale comparable to or shorter than the 20-30 {\mu}s latency of the existing abort system. Such events have damaged collimators and threaten Belle II subdetectors. Bunch Oscillation Recorders (BORs) capture transverse bunch positions at each revolution, which often show sizable oscillations that precede significant beam current loss. We test whether these precursors can be detected earlier than a charge-based reference that mimics the existing abort sensors. We apply several oscillation-based anomaly detection
algorithms to 208 SBL events recorded in the low-energy ring during the 2024 run period, ranging from simple rolling statistics to machine learning models trained to forecast bunch oscillation. On 173 events not used for training or calibration, the best-balanced model (DeepLSTM) triggers before the charge-based reference in 86-90% of events across five training seeds, with a mean lead time of 25-30 {\mu}s. The only trigger classified as a false alarm fires on an oscillation that begins about 60 turns before the abort and persists until the beam is lost, making it more likely an early precursor than a spurious trigger. These results establish bunch oscillations as a viable early abort trigger and motivate a shadow-mode deployment to measure the false-alarm rate in continuous operation.
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All authors H. Haigh, P. Horak, G. Inguglia, C. Krause, G. Mitsuka, H. Nakayama, R. Nomaru, M. Tobiyama
High Energy Physics (Theory)
Holographic Pseudo Entropy from the Rindler Method in AdS and Flat Space
Mehdi Hakami Shalamzari, Zahra Paygozar and Mahdi Kord Zangeneh
Via the Rindler method, we study holographic timelike
entanglement entropy (TEE) for a general timelike interval in AdS$_3$/CFT$_2$ and flat$_3$/CCFT$_2$. The TEE is the pseudo
entropy of a timelike interval. In the bulk, the imaginary part of the TEE comes from a timelike geodesic, but in the Rindler picture this geodesic has not been identified. After a Rindler transformation to a rotating BTZ black hole, the two spacelike extremal curves lie on the inner and outer horizons, and exchanging $l_u\leftrightarrow \ell l_\phi$ takes one to the other. We find the
geometric meaning of the timelike extremal curve: a geodesic stretched between the two horizons. Its length, $i\pi\ell$, is independent of the interval, and it alone produces the imaginary part $i\pi c/6$. We follow the same procedure in flat space holography, where the spacelike curve sits on the cosmological horizon and the timelike curve lies between the cosmological horizon and timelike infinity. Evaluating the holographic TEE for a timelike interval in CCFT$_2$ on the plane, we find that, in contrast with the cylinder, the real and imaginary parts are equal.
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High Energy Physics (Theory)
New analytic Janus and $S^4$ solutions for $\mathcal{N}=2^*$
Fridrik Freyr Gautason
We construct a three-parameter family of regular analytic supergravity solutions which are dual to (a) the $\mathcal{N}=2^*$ gauge theory on the four-sphere, and (b) $\mathrm{U}(1)^2$-invariant Janus interfaces in $\mathcal{N}=4$ SYM with or without the $\mathcal{N}=2^*$ mass turned on. To this end we employ a five-dimensional supergravity model coupled to six scalars which arises as a certain consistent truncation of type IIB supergravity on $S^5$. The curved domain wall solutions feature a hidden integral of motion which allows for their analytic treatment. We relate the three parameters of the solution to field theory sources and vevs and show how regularity of the solutions restricts their range. We briefly discuss the holographic evaluation of the one-point function of the field theory Lagrangian for our family of Janus solutions.
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Quantum Physics
Whither quantum advantage? New classical lower bounds for Max-Cut on large-girth 3-regular graphs
Flaviano Morone, Shivang Rawat and Dries Sels
Every 3-regular graph of girth at least $g$ has a cut containing at least a fraction $M_g$ of its edges, and the best rigorous bounds at large girth are $0.912\le \lim_{g\to\infty}M_g \le 0.92386$. Lower bounds on $M_g$ follow from the performance of local
algorithms: on a graph of girth $g \ge 2p+2$ a depth-$p$ local
algorithm sees the same tree around every edge, so its expected cut fraction on that tree bounds $M_g$ from below. We apply this strategy to the Variational Iterative Rotation
Algorithm (VIRAL), a classical local
algorithm, and evaluate it on the depth-$p$ tree for every even depth up to $p=32$. The resulting bounds exceed those recently obtained from the
Quantum Approximate Optimization
Algorithm (QAOA) for every $p\ge 4$, by $0.005$ to $0.011$, and they extend the range of girths covered from $g=36$ to $g=66$. Notably, at $g=66$ we obtain $M_{66} \ge 0.9127$ at $99.99999\%$ confidence level, which raises the asymptotic lower bound from $0.912$ to $0.9127$.
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Nuclear Theory
Universal relations for hybrid stars and their quark cores: a systematic scan of the quark-matter parameter space
J. P. Carlomagno, G. A. Contrera, A. G. Grunfeld et al. (+1 more)
Universal, equation-of-state (EOS) insensitive relations among the global properties of compact
stars are well established for hadronic
neutron stars and for self-bound strange
stars. We ask whether analogous relations hold for the
quark core of a hybrid
star, and whether the core can be constrained from the surface. Describing
quark matter with the three-flavor MIT bag model with repulsive vector interactions, matched to the hadronic DD2 EOS through a Maxwell construction, we scan the full $(B^{1/4},G_V)$ plane and obtain 1112 hybrid EOSs with maximum masses above $2\,M_\odot$, broadly compatible with current multimessenger constraints. For every stable configuration we evaluate the mass, radius, moment of inertia, and tidal deformability both at the stellar surface and at the boundary of the
quark core. Global quantities follow the relations of hadronic
stars—the $I$–Love relation to within $0.5\%$—while core quantities follow those of self-bound strange
stars with median deviations of $6$–$9\%$. We explain the latter by expanding the structure of the core in powers of its compactness: to first order, the core mass, baryon mass, moment of inertia, and tidal deformability depend only on the compactness and on the properties of the
hadron–
quark interface, chiefly the ratio $\xi=p_{\rm tr}/\varepsilon_+$ of transition pressure to
quark energy density. The strange-
star relations are the $\xi\to0$ member of this family, and the deviations from them measure $\xi$. The fractional core mass and radius of all configurations follow the normalized mass profile of the
star, and no global observable allows the core size to be inferred. Evanescent cores dominate the viable parameter space, while sizable cores require low bag constants and strong vector couplings.
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All authors J. P. Carlomagno, G. A. Contrera, A. G. Grunfeld, G. Lugones
Optics
Observation of Photon Bunching in Broadband Multimode Thermal Light Enabled by Temporal Imaging
Filip Sośnicki, Michał Mikołajczyk, Sanjay Kapoor et al. (+3 more)
Photons emitted by incoherent sources exhibit temporal bunching, a fundamental manifestation of Bose-Einstein statistics first observed by Hanbury Brown and Twiss (HBT). While intensity correlation measurements originated in astronomy and are now central across
quantum technologies, biophysics, and spectroscopy, observing temporal bunching in broadband thermal light remains limited by detector temporal resolution. Conventional approaches - such as streak cameras or optical upconversion - introduce severe trade-offs in efficiency, bandwidth, or setup versatility. Here, we propose and demonstrate a third route: pre-detection temporal magnification of the optical field prior to measuring its intensity autocorrelation function in a conventional HBT setup. Using an electro-optic time lens with a temporal magnification of 660, we resolve the temporal intensity autocorrelation of broadband thermal light generated via non-degenerate spontaneous parametric down-conversion with a bandwidth of 250 GHz. This enables direct observation of thermal
photon bunching on sub-3.5 picosecond timescales without narrow spectral filtering, establishing pre-detection temporal imaging as a general platform for broadband statistical optics, with applications spanning ultrafast
quantum optics, biophysical imaging, and potentially stellar intensity interferometry.
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All authors Filip Sośnicki, Michał Mikołajczyk, Sanjay Kapoor, Dmitri B. Horoshko, Mikhail I. Kolobov, Michał Karpiński
Chemical Physics
Solvating machine-learning interatomic potentials for solution-phase chemistry
Anton Z. Ni and Joonho Lee
Most machine-learning interatomic potentials (MLIPs) are trained on gas-phase data, which limits their use for chemistry in solution. Here, we introduce AnySolv, a transferable implicit solvation potential that provides solvent-dependent energy and force corrections to existing gas-phase potentials without retraining them. It is trained on 1.4 million solvation energies and forces computed with density functional theory (DFT) and SMD in 36 solvents, spanning charged, open-shell, and transition-state structures. Because solvents are represented by continuous physical descriptors, AnySolv supports 179 solvents, including those absent from training. On external
benchmarks, AnySolv reproduces DFT-SMD solvation energies to 2-4 meV mean absolute error at more than three orders of magnitude lower cost, and it matches the accuracy of DFT-SMD against experimental solvation free energies. This enables screening of the mechanisms of 120 nucleophilic aromatic substitution reactions in six phases as well as molecular dynamics simulations that reproduce the experimentally observed solvent-dependent conformational preferences of alanine dipeptide. By providing transferable solvation corrections to existing MLIPs, AnySolv enables scalable simulations of solvent-dependent chemical reactivity and molecular dynamics.
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Quantum Physics
Quantum Reference Frames in terms of Tetrads
Jeremy Butterfield and Daniel A. Turolla Vanzella
We adapt to the context of
quantum theory the treatment, familiar in relativity theory, of a reference frame as a tetrad. Since a tetrad is a set of four orthonormal vectors at a spacetime point, it encodes a timelike direction, three orthogonal spatial directions, and units; and so it gives a configuration in spacetime (a spatial orientation and state of motion) of an idealized infinitesimal apparatus (“rulers and a clock"). So a natural “first guess" is that the state of a
quantum reference frame should be an assignment of complex amplitudes to a set of tetrads. We develop this idea, in terms of bundles over spacetime of bases of the tangent spaces. This paper is a companion to two other papers. It emphasises the main conceptual aspects of our proposal, while the other two papers give physical details. It also explains the main contrast between those two papers. Namely: (i) the first considers a single spacetime geometry, so that a
quantum reference frame, on our proposal, gives a superposition of perspectives on that geometry; while (ii) the second considers the spacetime
manifold with no geometry given a priori, which will imply that a
quantum reference frame, on our proposal, can describe a superposition of perspectives on a superposition of geometries—not “just" a superposition of perspectives on a single geometry. The main mathematical idea for representing this contrast will be choosing between (i) the orthonormal frame bundle, for a given spacetime geometry; (ii) the frame bundle in the usual sense of containing all bases of all spacetime points' tangent spaces.
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Instrumentation and Methods for Astrophysics
Estimating the spectral resolution of a radio data cube from its noise properties
P. Serra, G. Mulas, K. M. Hess et al. (+4 more)
We present a new method to estimate the spectral resolution of a
radio data cube from its noise properties. We assume that the data cube is the result of the convolution of a spectrally-uncorrelated cube with a constant convolution kernel K. We demonstrate that K and the resolution, defined as K's integral, can be estimated thanks to the analytical relation between the autocorrelation of the noise spectra extracted from the cube and the power spectrum of the kernel. We discuss a number of
algorithms that make this method robust in the realistic case of a finite number of spectra and channels, real signal and artefacts, and we present the results obtained for a number of
datasets from the literature. We further highlight that this method is applicable to any data cube that meets our assumptions independently of the observing frequency or the exact nature of the cube's "third" axis, e.g., it could be used to measure the time resolution of transient-search data cubes. We make this method available as part of the open-source software tool spectre.
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All authors P. Serra, G. Mulas, K. M. Hess, P. Kamphuis, T. Westmeier, Y. Ascasibar, J. M. van der Hulst
Strongly Correlated Electrons
Pairing from repulsive interactions in twisted WSe2 from functional renormalization
Hannes Braun, Dumitru Călugăru, Pietro M. Bonetti et al. (+9 more)
Motivated by the observation of superconductivity in twisted bilayer WSe$_2$ over an extended range of displacement fields, reaching from the correlated
insulator down to zero field, we analyze the correlated electron phases of this system at hole filling $\nu = -1$ and twist angle $3.65^\circ$ using Hartree–Fock, random phase approximation, and functional renormalization group calculations. We derive a continuum model with gate-screened Coulomb interaction from first principles and compare its instabilities to those of a realistic three-orbital Wannier model with a Hubbard interaction and an artificial single-orbital Hubbard model. In both cases, we find a superconducting instability of mixed $d$-wave singlet and $p$-wave triplet character, arising adjacent to inter-valley-coherent
spin-density-wave order in the phase diagram spanned by displacement field and interaction strength. Our additional analysis of the pairing mechanism points to inter-valley coherent
spin fluctuations as the pairing glue. The extent of the pairing regime and the associated critical temperatures depend on the model input, and we trace differences to the interaction range entering the projected interaction. Within the continuum model, the gate-screened Coulomb interaction yields pairing down to zero displacement field, bringing theory into agreement with experiment.
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All authors Hannes Braun, Dumitru Călugăru, Pietro M. Bonetti, Haoyu Hu, Yan Zhang, Yi Jiang, Quansheng Wu, Kin Fai Mak, Jie Shan, B. Andrei Bernevig, Michael M. Scherer, Laura Classen
Earth and Planetary Astrophysics
High-resolution transmission spectroscopy of KELT-18b Metastable helium detection at 1083 nm
M. Chella, M. Monticelli, F. Biassoni et al. (+5 more)
We present the first high-resolution transmission spectroscopy of the ultrahot Jupiter KELT-18b, probing its escaping atmosphere by analyzing a single transit obtained with the CARMENES spectrograph. Transmission spectroscopy and Doppler
tomography were utilized to isolate the planetary signal. To mitigate contamination from the strong telluric OH lines overlapping the region of interest, two distinct data analysis procedures were applied: a standard Molecfit and OH-masking approach as well as a PCA-based method. By combining the two complementary approaches, we successfully detect a He\,I triplet absorption feature of $1.10 \pm 0.22\%$ ($5.1\sigma$). The signal exhibits a velocity shift consistent with zero and is attributed to the exoplanetary atmosphere. An injection test reveals that the PCA-based method significantly suppresses the retrieved signal. Additionally, using the ATES and TPM codes, we modeled the atmospheric photoevaporation and the helium triplet profile for different He/H ratios and stellar XUV fluxes, accounting for instrument and planetary rotational broadening. From our simulations we derive a mass-loss rate and an evaporation efficiency for KELT-18b of $10.47 \leq \log_{10}(\dot{M}) \leq 11.68$ and $0.153 \leq \eta \leq 0.321$, demonstrating that the atmosphere of KELT-18b is undergoing photoevaporation. Furthermore, our simulations show good agreement with the observed transmission spectrum, allowing us to exclude very low He/H ratios at a $3\sigma$ confidence level for XUV fluxes up to approximately twice the nominal reconstructed value. Our result expands the known parameter space of
exoplanets with confirmed helium absorption, establishing KELT-18b as the most massive
planet orbiting the hottest host
star with such a detection.
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All authors M. Chella, M. Monticelli, F. Biassoni, F. Borsa, M. Rainer, G. Guilluy, M. Basilicata, L. Cabona
Quantum Physics
Fermionic non-Gaussianity via computable measures and experimentally accessible bounds
Leela Ganesh Chandra Lakkaraju, Naga Dileep Varikuti and Philipp Hauke
Interacting
fermions owe both their non-trivial correlations and their computational power to their departure from Gaussianity. Yet, quantifying that departure geometrically faces two challenges: the Gaussian
manifold is non-convex, and perturbative treatments are confined to weak interactions. Here, we introduce a
geometric measure of fermionic non-Gaussianity, the fidelity distance of a target state to the
manifold of fermionic Gaussian states. We construct an iteration formalism to numerically access it, applicable also at strong coupling. Further, we prove a sharpened operator Jensen inequality, of interest in its own right. We use it to derive a witness that involves only two- and four-point fermionic correlators. Numerical
benchmarks on the one-dimensional Fermi–Hubbard model show that the quality of the witness improves with system size and, for strong coupling, is tighter than antiflatness. Our results open a scalable route to charting non-Gaussianity of strongly-interacting fermionic
quantum simulators.
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Solar and Stellar Astrophysics
From Giant Envelopes to Rapidly Contracting Cores in Rotating Population III Stars from $500$ to $1000 \, M_\odot$
Devesh Nandal, John Chisholm, Daniel J. Whalen et al. (+4 more)
Population III (Pop III)
stars link the chemical enrichment of the early Universe to the formation of the first massive black holes, yet their
evolution remains poorly understood at extreme masses. Using GENEC, we evolve rotating zero
metallicity models from $500$ to $1000\,M_\odot$ at $v/v_{\rm crit}=0.1$ through core Si burning, and a $1000\,M_\odot$, $v/v_{\rm crit}=0.4$ model evolved through He exhaustion. In the fiducial $1000\,M_\odot$ model, convection and rotational transport carry freshly synthesized C and O into H burning layers, producing $62.1\,M_\odot$ of primary N by He exhaustion. Surface mass loss removes $20.2\,M_\odot$, including $1.8\times10^{-3}\,M_\odot$ of N, with $\log(\mathrm{N}/\mathrm{O})=0.68$, $\log(\mathrm{N}/\mathrm{C})=1.48$, and $\log(\mathrm{C}/\mathrm{O})=-0.80$. By the final hydrostatic model, the inner $100\,M_\odot$ is confined within $0.088\,R_\odot$ while the photosphere remains several thousand solar radii away. As C, Ne, O, and Si burning accelerate, chemical mixing freezes out and advanced products remain buried beneath the envelope. At core Si exhaustion, the central angular velocity reaches $4\times10^{-3}\,{\rm s^{-1}}$ while the surface rotates at $5.25\times10^{-8}\,{\rm s^{-1}}$, a contrast of $7.6\times10^4$. Contraction drives this
spin up, while inner specific angular momentum changes by less than $1\%$. The maximum $j_{\rm eq}/j_{\rm ISCO}$ is $0.313$, limiting disk formation in our inside out estimate. These models show that Pop~III
stars can produce strong primary N signatures and rapidly rotating black hole progenitors while their envelopes determine which products enrich the early Universe.
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All authors Devesh Nandal, John Chisholm, Daniel J. Whalen, Andreas A.C. Sander, Volker Bromm, Peixin Zhu, Lisa J. Kewley
Cosmology and Nongalactic Astrophysics
MeV dark matter decay forecasts for the COSI mission
Robin Anthony-Petersen, Orion Ning, Yu Watanabe et al. (+21 more)
The decay of dark matter (DM) is a generic prediction of many particle physics models, producing distinctive monochromatic signatures in environments such as the Galactic
halo. Searches for decaying DM in the elusive 'MeV gap' have remained conspicuously under-explored, despite well-motivated models including
axion-like particles, sterile
neutrinos, and hidden-sector scenarios predicting signatures in this energy range. The upcoming Compton Spectrometer and Imager (COSI)
telescope will help bridge this gap. Designed to probe this energy band with high spectral resolution, low background, and wide field of view, COSI is well-suited for DM line searches at the MeV scale. In this work, we make projections for COSI's 2-year sensitivity for DM decay in the Milky Way
halo using dedicated all-sky simulations incorporating COSI's predicted instrument response. We conclude that COSI will improve the sensitivity to the DM lifetime by more than an order of magnitude over the DM mass range 0.4 to 10 MeV.
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All authors Robin Anthony-Petersen, Orion Ning, Yu Watanabe, Benjamin R. Safdi, Maíra Dutra, Francesca Calore, Savitri Gallego, William Guan, Christopher M. Karwin, Alexander Kusenko, Israel Martinez-Castellanos, Shigeki Matsumoto, Michela Negro, Uwe Oberlack, Field R. Rogers, Thomas Siegert, Tadayuki Takahashi, Haoyu Xie, Hiroki Yoneda, Andreas Zoglauer, Steven E. Boggs, Dieter H. Hartmann, Carolyn A. Kierans, John A. Tomsick
Astrophysics of Galaxies
Yue Samuel Lu, Dušan Kereš, Philip F. Hopkins et al. (+1 more)
Over the last decade,
magnetic fields (B-fields) have become a common ingredient in
galaxy formation simulations. Although seemingly unimportant in matching observational constraints such as the $M_*-M_{\rm halo}$ relations, the B-field influences the circumgalactic medium (CGM) gas and determines
cosmic ray (CR) propagation, making it an indispensable non-thermal component. Nevertheless, the intricate physics of B-fields, particularly how they evolve to the observed $\mu$G-level field, remains largely elusive. In this work, we systematically address the
evolution of B-fields over
cosmic time using the FIRE-2 (Feedback In Realistic Environments) magnetohydrodynamics (MHD) simulations. We present results for both Milky Way (MW)-mass and dwarf
galaxies, with and without CRs. We find that CRs have little impact on B-field properties, while the
halo mass controls the saturated B-field strength at $z\sim 0$. However, all runs reach a
halo-independent
magnetic-to-turbulent ratio of $f_{\rm B}\sim 1-10\%$, though the methods used to measure
turbulence could affect this value. We identify a three-stage evolutionary course for the B-field in tandem with
galaxy formation: i. expansion, ii. amplification, and iii. saturation. The feature is universal, though the timings depend on the initial location and
star formation history of the gas. Flux-freezing is the predominant driver for the first and last stages, exhibiting power relations $B\sim \rho^{2/3}$ and $\rho^{1/2}$, although the latter could also be explained by dynamical and energetic
equilibria. The intermediate amplification stage, potentially driven by “dynamos”, is fuelled by structure formation, feedback, and gas
turbulence. We
conjecture a numerically triggered,
turbulence-driven amplification process to explain this phenomenon.
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All authors Yue Samuel Lu, Dušan Kereš, Philip F. Hopkins, Sam B. Ponnada
High Energy Physics (Theory)
On the analytic continuation and asymptotic behaviour of the two-point function in massless $\phi^4$-theory in Euclidean de Sitter space
Martin Beneke and Andrea F. Sanfilippo
For the two-point function of the massless, minimally-coupled, real scalar field in Euclidean de Sitter space with $\lambda\phi^4$-interaction, we compute the leading-logarithmic terms in the invariant distance of the two-point function to $O(\lambda^2)$, which counts as the fifth subleading order (N$^5$LO) in the $\sqrt{\lambda}$-expansion. We show that the analytic continuation to Lorentzian signature coincides with the expansion of the analogous quantity computed in the
stochastic formalism. We determine the large-order behaviour of the
stochastic series expansion and prove its Borel summability, which suggests that the Euclidean theory can be used to extract the late-time behaviour of massless correlation functions in Lorentzian de Sitter space.
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High Energy Physics (Phenomenology)
What Do Event Generators Compute? Flux Functionals from Detector Operators
Jack Holguin
Every physical prediction of an event generator is a statement about the hadronic fluxes that can be recorded by particle detectors. By contrast, the formal backbone of modern event-generator precision is provided by the unobservable partonic final states of the parton shower, with hadronisation included as a model. We construct the probability distribution of the hadronic fluxes non-perturbatively, directly from detector operators acting on asymptotic hadronic states, and encode it in an event generator source functional. This distribution contains every measurement a detector can make, and is therefore what a generator must compute with precision, including the effects of hadronisation. Restricting the functional to the energy flow yields the parton shower source functional, which is infrared and collinear safe and contains every calorimetric observable, making it a natural object against which to assess parton-shower accuracy. We compute its logarithmic structure at one loop in $e^+e^-$ annihilation, finding it directly sensitive to kinematic recoil and hence to the recoil scheme of a parton shower. The parton shower functional depends on a continuum of low scales, one for each resolved direction, and in a toy model its logarithms cannot be entirely resummed within a factorisation whose
evolution derives only from the high-scale physics. Our operator-based formulation opens the door to the study of event-generator-like systems in theories beyond QCD, including conformal theories such as $N=4$ super-Yang-Mills theory, and thereby offers a new route to non-perturbative insight into event generation.
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High Energy Astrophysical Phenomena
MRI Turbulence versus $\alpha$-Viscosity in Circumbinary Disks: Implications for Gravitational-Wave Dephasing and Accretion Variability
Mudit Garg and Yan-Fei Jiang
Our understanding of gas torques on massive black hole binaries (MBHBs) relies on hydrodynamical (HD) simulations of circumbinary disks (CBDs) in which an $\alpha$-viscosity models angular momentum transport. However, CBDs around MBHBs near merger are hot, magnetized
plasmas where transport is driven by magnetohydrodynamical (MHD)
turbulence sustained by the magnetorotational instability (MRI). We test how well an $\alpha$-viscosity captures MRI
turbulence with 3D global Athena++ simulations of a locally isothermal CBD around an equal-mass, circular MBHB, run in HD and MHD from the same initial
torus on identical grids, so that only the transport mechanism differs. Excising the region within twice the binary separation, $r<2~a_{\rm bin}$, allows $1000$ orbits of
evolution, several times longer than previous MHD simulations. Both disks deliver the same
accretion rate, and the gas beyond $2~a_{\rm bin}$ exerts a positive torque in both, yet the MHD torque is $3.5$ times larger and $3$ times more variable. Near the midplane, transport is similar in the disk body but three times weaker in MHD at the cavity edge, where $2$-$3$ times more mass piles up in a more eccentric cavity, raising the torque. The
accretion rate is modulated mainly at twice the binary frequency in HD, but by a persistent lump at the cavity edge and its beat with the binary in MHD. The outer-disk torque therefore implies a contribution to the gas-induced phase shift in the gravitational-wave signal of LISA binaries $3.5$ times larger than in $\alpha$-disk models, and a different variability signature for LSST and Roman.
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High Energy Physics (Phenomenology)
Revisiting Critical Higgs Inflation: Electroweak Couplings, CMB Observables, and Perturbative Unitarity
Sarah R. Geller, Sol Gutierrez-Lara, David I. Kaiser et al. (+1 more)
We revisit the scenario of critical
Higgs inflation, in which inflation is driven by the Standard Model
Higgs boson with parameters chosen close to a critical point, giving rise to an inflection point in its potential. After reviewing this model, we perform a systematic study of its viability centered around three criteria: (1) consistency with electroweak-scale measurements, (2) ability to reproduce the
cosmic microwave background (CMB) observables, and (3) sensitivity of the model predictions to unknown UV physics, based on a breakdown of perturbative unitarity. We first show that compliance with electroweak-scale measurements is controlled by the parameters in the
Higgs potential at inflationary scales, also updating the literature values. We then demonstrate how for any choice of potential parameters, agreement with the CMB observables can be achieved through the choice of the nonminimal coupling, in both metric and Palatini formulations of
gravity. However, we also find that there exist no regions of parameter space, in either the metric or Palatini formulations, in which compliance with all three physical criteria is possible. While this does not exclude the possibility of the
Higgs field driving inflation, it means that predictions for any observable are in principle sensitive to the details of the model's UV completion.
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All authors Sarah R. Geller, Sol Gutierrez-Lara, David I. Kaiser, Thomas Steingasser
High Energy Physics (Phenomenology)
Dark Matter Stability from residual flavour symmetries
Giacomo Landini, Simone Marciano and Federico Mescia
We propose a model-independent framework in which Dark Matter stability emerges naturally from residual discrete $\mathbb{Z}_N$
symmetries left unbroken by the spontaneous breaking of continuous flavour
symmetries, both Abelian and non-Abelian. No ad hoc stabilizing
symmetry is required, as Dark Matter stability is an inherent consequence of the underlying flavour dynamics. As an explicit example, we construct a prototype model based on a $\text{SU}(2)_\text{F} \otimes \text{U}(1)_\text{F}$ Froggatt-Nielsen
symmetry, which successfully reproduces the observed charged lepton mass spectrum and the PMNS mixing
matrix, while identifying the lightest sterile
neutrino as a stable Dark Matter candidate. Furthermore, we study the Dark Matter phenomenology within our model in the freeze-in regime, including production channels mediated by higher-dimensional operators suppressed by the cutoff scale $\Lambda$. Our analysis shows that continuous flavour
symmetries can provide a unified, self-consistent framework addressing both the flavour puzzle and the origin, stability, and production of Dark Matter.
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Strongly Correlated Electrons
Berry curvature from plane-wave mixing: A three-band model with emergent symmetries
Avi Vadali and Tomohiro Soejima
Two-dimensional materials can host topological phases stabilized either by an intrinsic moiré potential or topological crystallization. Crucial to the
topology of these phases is the interplay between the (self-consistently generated) potential and the spinor structure, which imbues the band-projected potential with momentum-dependence. Truncating this potential at linear-order in momentum, we obtain a three-band model that captures the low-energy band structure and Berry
curvature of such topological bands. We analytically find that the Berry
curvature strongly depends on momentum-dependence of the potential. Furthermore, we identify that the model can be tuned to have emergent
symmetries, including $U(1)$ and anti-
unitary symmetries. Emergent-
symmetry breaking perturbations drive the system to regimes hosting topological flat bands, quadratic band touchings, and multiple Dirac cones. We recover many of these features when studying an un-truncated model of a $\lambda$-jellium spinor inside of a periodic potential. Our results reveal a rich interplay of spinor structure and a potential in determining the
topology of the ground state.
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High Energy Physics (Phenomenology)
Implications for new physics solutions to the LSND and MiniBooNE anomalies after MicroBooNE results
Waleed Abdallah, Raj Gandhi and Samiran Roy
Over the past couple of decades, the
Liquid Scintillator
Neutrino Detector (LSND) and MiniBooNE (MB)
neutrino experiments have provided statistically significant evidence of persistent and as yet unexplained electron-like event excesses. The MicroBooNE experiment, with sensitive particle identification capabilities designed to shed light on these anomalous results, has conducted a number of analyses to test whether the excess is due to
photons, electrons or $e^+e^-$ pair productions, all of which give almost identical signals in LSND and MB. Recent MicroBooNE searches, in addition to checking Standard Model (SM) processes, have focused on proposed new physics scenarios involving new mediators and dark portals beyond the SM. We study the consequences and effects of these analyses for the many theoretical proposals put forth to generate the three types of signals above in order to understand the observed excesses. We discuss which classes of solutions are allowed, disallowed or require further scrutiny involving theoretical and experimental efforts. We give an example of a new solution that survives the restrictions imposed by MicroBooNE results and other existing bounds. We point out that a light ($m\leq 30$ MeV) dark neutral
spin zero mediator with dominantly pseudoscalar couplings, decaying to an $e^+e^-$ pair, can account for the observations. We indicate that if such a model is realised, it may point to the possibility that
neutrinos are Dirac particles, and that there are dark Heavy Neutral Leptons (HNLs) of mass ${\cal O}(100)$ MeV. We discuss issues related to CP violation and ultra-violet completion of these models. Finally we stress that a search for the excess in incoherent scattering channels in MicroBooNE and SBND could help clarify the physics behind these persistent anomalies.
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Cosmology and Nongalactic Astrophysics
Interpreting the stacked kinetic SZ signal II: the degeneracy between satellite galaxies and baryonic feedback
Lurdes Ondaro-Mallea, Boryana Hadzhiyska and Raul E. Angulo
The kinetic Sunyaev-Zel'dovich (kSZ) signal stacked around a
galaxy sample traces the gas around
halos and is a powerful probe of baryonic feedback. Its interpretation, however, depends on the satellite
galaxies in the sample. Using the FLAMINGO hydrodynamical simulations and DESI-like samples of luminous red
galaxies (LRGs), bright
galaxies survey (BGS), and emission-line
galaxies (ELGs), we show that satellites and feedback have similar effects: both suppress the small-scale signal. This degeneracy arises because stacking on satellites, which are offset from the centre of their host
haloes, mimics the extended gas distribution produced by feedback. Although satellites make up only 20-30% of each sample, they account for 50-80% of the signal because they occupy more massive
halos than centrals; thus their imprint on the stacked profiles can be as large as that of feedback. At the precision of current DESI$\times$ACT data, neglecting satellites in the modelling biases the inferred gas fractions low, by up to a factor of two, and overestimates the feedback strength, particularly for the LRG and BGS samples. Remaining agnostic about the satellite population avoids this bias but reduces the constraining power, so robust constraints would require knowing the satellite fraction to better than 10%, for instance from
lensing and clustering data of the same
galaxy samples. Finally, a further contribution from satellites will become statistically significant with upcoming surveys: satellites trace the anisotropic gas distribution around their host
haloes, an effect that contributes 10% of the signal, and will likely require simulation-based models to capture.
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Mesoscale and Nanoscale Physics
Revealing topological protection through unprotected operations in a Majorana parity qubit
Sebastian Miles, Juan Daniel Torres Luna, Francesco Zatelli et al. (+7 more)
A recent experiment reported coherent parity oscillations between minimal Kitaev chains, demonstrating a Majorana parity
qubit (arXiv:2607.09511). Operations on this
qubit are controlled by coupling two Kitaev chains and are intrinsically unprotected against noise in the coupling strength. Here we show how the exponential protection in the underlying chains can nevertheless be revealed through unprotected
qubit operations. To this end, we develop an analytical theory of quasistatic dephasing for two coupled $N$-site Kitaev chains at the sweet spot. In Rabi experiments, protection can be resolved by adapting the operating point with chain length: depending on the coupling architecture, it appears as an exponentially increasing optimized number of coherent oscillations or as a longer coherence time. Ramsey experiments show an exponentially increasing coherence time, provided the chains can be sufficiently decoupled. Our analytical theory takes into account the non-Gaussian splitting statistics of the Kitaev chains, allowing us to quantitatively predict the scaling with chain length. Moreover, we determine how residual noise and imperfections limit the range of chain lengths over which this scaling can be observed. Our results show how
qubit dynamics can be used to probe Majorana protection in experimentally realistic devices.
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All authors Sebastian Miles, Juan Daniel Torres Luna, Francesco Zatelli, Nick van Loo, Antonio Lombardi, Vincent P. M. Sietses, Florian J. Bennebroek Evertsz', Bart Roovers, Leo P. Kouwenhoven, Michael Wimmer
Computational Physics
Principles and Techniques for Agentic Research in Experimental Physics
Niko R. Reed, Declan M. Daly, Andrew J. Beling et al. (+4 more)
The use of artificial intelligence (AI) in physics research is increasingly common, yet few guidelines exist for its effective use. Starting with a principles-based approach, we outline a set of ten requirements for collaborative AI
agents in experimental physics, spanning scientific norms, effective
agent use, and domain expertise. We take a human-centered approach in which
agents act as collaborators that amplify rather than replace the expertise of a human researcher (user) who directs the work and is responsible for its results. We then present a framework designed to enforce these requirements, detailing methods for improving off-the-shelf behavior of large
language models (LLMs) with custom scaffolding and describing general-purpose scientific workflows and skills. In particular, we highlight the power of closed-loop campaigns where
agents work iteratively toward a well-defined goal. We demonstrate the potential of this mode of research through six case studies in experimental physics, covering device design, hardware control, neural network optimization, physical model identification, and data analysis. All six case studies result in useful work products that add utility to our research, including a neural network architecture and solid-state
quantum defect photodynamic model that substantially outperform our published work; a microwave waveguide design that extends a published design concept to a fabrication-ready device meeting our experimental constraints; a
quantum control pulse sequence candidate that improves simulated performance by more than an order of magnitude; commissioning of an NMR spectrometer to $\sim$1~Hz frequency precision on live hardware; and finally a data-fitting pipeline that achieves, to our knowledge, the first reconstruction of the Ising microstate of an artificial
spin-ice array from diffraction-limited
magnetic imaging.
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All authors Niko R. Reed, Declan M. Daly, Andrew J. Beling, Jordan D. Giandrea, Ronald L. Walsworth, John W. Blanchard, Daniel Ang
Geophysics · Cross-listed from cs.LG
CartoVec: General-Purpose Location Embeddings from Open Map Data
Furkan Gursoy
Geographic coordinates are common inputs in applied machine learning, but latitude and longitude describe position rather than the surrounding environment. Image-grounded location encoders learn this context from satellite or ground-level imagery; structured open map data offers another source of supervision whose utility for continuous coordinate encoders remains less explored. We introduce CartoVec, a coordinate encoder trained to predict Overture-derived land cover, land use, transportation, place and connectivity targets at multiple spatial scales, without image inputs or downstream-task labels. We evaluate frozen
embeddings on Census outcomes, Airbnb prices and Philadelphia crime in the US Northeast using spatial block cross-validation. CartoVec has the highest mean performance on most Census outcomes and the highest average across the full suite, with several comparisons close across folds. The findings support open map data as a practical source of reusable location representations with a coordinate-to-vector interface that requires no map lookup at inference. The open-weight model is available at https://huggingface.co/gursoyfurkan/CartoVec.
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Cosmology and Nongalactic Astrophysics
Beyond the Kullback–Leibler divergence: the likelihood-ratio distribution as a detectability measure
Amirhossein Samandar, Mikel Martin Barandiaran, Linn Htat Lu et al. (+13 more)
The Kullback–Leibler (KL) divergence is the expectation value of the log-likelihood ratio between two specified models, evaluated with respect to one of the two models. It provides an average measure of the distinguishability of the models. We examine its connection to discovery potential and the accuracy of parameter estimates when one model represents a null hypothesis, and the alternative is a family of models characterized by one or more continuous parameters. For data drawn from a multivariate Gaussian distribution, we derive the log-likelihood-ratio distribution and its cumulants under two such hypotheses. We then search over the alternative model's parameter space and use peak prominence, the height of a likelihood-profile peak above its surrounding baseline, as an operational detection statistic. Repeating this search on simulated data drawn from the null model allows us to calibrate the prominence threshold for a specified false-positive rate. We study a toy Gaussian model as well as three cosmological examples involving
cosmic topology, the tensor-to-scalar ratio, and dark energy. In all these cases, detectability of a particular model depends not only on KL divergence, but also on the size of the model parameter space, the likelihood-ratio distributions, and the distance of the model from any parameter space boundaries. The relationship between KL divergence, discovery potential, and parameter estimation must therefore be calibrated for each family of models and detection statistic under consideration.
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All authors Amirhossein Samandar, Mikel Martin Barandiaran, Linn Htat Lu, Andrew H. Jaffe, Deyan P. Mihaylov, Glenn D. Starkman, Cynthia Trendafilova, Yashar Akrami, Stefano Anselmi, Javier Carrón Duque, Craig J. Copi, Fernando Cornet-Gomez, Arthur Kosowsky, Anna Negro, Ricardo G. Rodrigues, Andrius Tamosiunas
Quantum Physics
Error-Corrected QRAM Queries with One-Fault-Tolerant CSWAP Gates
Shifan Xu, Connor T. Hann, Nathan Wiebe et al. (+2 more)
Quantum random-access
memory (QRAM) enables coherent queries to classical data. However, the \(O(N)\)
qubits required for a
memory with \(N=2^n\) addresses make QRAM appear vulnerable to noise. Though bucket-brigade routing provides intrinsic noise resilience to reduce the error in QRAM, improving the fidelity of QRAM queries is still an important and challenging problem. We introduce a low-overhead protection framework for bucket-brigade QRAM with two complementary components. First, we propose a one-fault-tolerant repeat-until-success logical controlled-SWAP gate using the \([[4,2,2]]\) code under erasure noise channel. Interleaved erasure checks and local recovery correct every single erasure, so the leading logical failure probability is second order in the physical erasure error rates. Second, we exploit validity constraints of bucket-brigade routing to define local parity checks directly on the router states, without adding extra data
qubits to create code redundancy. Under bit-flip noise, minimum-weight perfect matching with noiseless syndrome measurements corrects single interior faults, while open spatial boundaries retain a first-order contribution in the residual bit-flip rate. Monte Carlo simulations confirm quadratic suppression for the protected controlled-SWAP and improved depth scaling for decoded QRAM router-state snapshots. The two codes admit a concatenated realization in which the inner code supplies erasure protection and the outer code optionally corrects interior logical bit flips. Together, these results show how routing constraints and a protected non-Clifford routing gate can improve QRAM reliability under biased and erasure-dominant noise.
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All authors Shifan Xu, Connor T. Hann, Nathan Wiebe, Steven M. Girvin, Yongshan Ding
Mesoscale and Nanoscale Physics
Spatial Engineering of Topological Quantum Matter with Structured Light
Matias Mustonen, Ali G. Moghaddam, Teemu Ojanen et al. (+1 more)
Structured light provides a powerful means of controlling matter while itself exhibiting nontrivial spatial
topology. Here, we show that these spatial structures can be harnessed to locally engineer the topological properties of matter. In a paradigmatic example of a topological
insulator with Dirac surface states driven by an optical skyrmion beam, we show that structured light spatially tailors the effective
Hamiltonian, yielding position-dependent topological gaps and Dirac velocities. The resulting gap modulation can create topological and trivial regions separated by optically defined interfaces, without introducing material boundaries or chemical modifications. We further show that the geometry of these interfaces can be controlled through the spatial structure of the light, in particular its orbital angular momentum. Our results establish structured light as a route to dynamically pattern topological phases and open a broader perspective on the interplay between
topology in light and matter, including the possibility of transferring topological characteristics between the two.
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All authors Matias Mustonen, Ali G. Moghaddam, Teemu Ojanen, Marco Ornigotti
General Relativity and Quantum Cosmology
Vanishing Love Numbers of Kerr-Newman Black Holes
Sumanta Chakraborty, Takuya Katagiri, Paolo Pani et al. (+1 more)
Tidal Love numbers characterize the conservative response of compact objects to external perturbations and provide a powerful probe of their nature. While the static Love numbers of Schwarzschild, Kerr, and Reissner–Nordström black holes remarkably vanish, the tidal response of a generic Kerr–Newman black hole has remained unexplored due to the intrinsic coupling between gravitational and electromagnetic perturbations. Exploiting a recent breakthrough in the separability of these perturbations, we analytically determine the static tidal response of the most general stationary black hole in four-dimensional Einstein–Maxwell theory. For arbitrary multipole order, charge, and
spin, we show that the entire
matrix of conservative Love numbers vanishes, including the mixed gravito-electromagnetic couplings. We also compute the nonvanishing static dissipative response induced by frame dragging.
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All authors Sumanta Chakraborty, Takuya Katagiri, Paolo Pani, Jun-Xi Shi