Instrumentation and Detectors
Overview and design optimization of a custom hybrid X-ray telescope for the International Axion Observatory (IAXO)
Yue Yu, Jooyun Woo, Ipek Altunyurt et al. (+34 more)
We present the design optimization for maximizing the effective area of a custom X-ray optic for the International
Axion Observatory (IAXO) and BabyIAXO, including its novel hybrid configuration that enables full coverage of the 700-mm-diameter
magnetic bore with minimal stress imposed on the mirrors; shell layout optimized for
axion spectra and spatial distribution; and the coating recipes that enhance reflectivity in the energy range of interest. We evaluate how these design choices improve the observation signal-to-noise ratio (SNR) of BabyIAXO and IAXO by calculating the broad-band effective area and simulating the point spread function (PSF) and focal spot at the detector plane. The cost-effective and scalable optic offers an energy response from 0.03–15 keV, achieving an effective area that exceeds 2400 cm$^2$ near 1 keV - the peak of the ABC
axion spectrum - and remains above 1700 cm$^2$ around 3 keV - the peak of the Primakoff
axion spectrum. It yields a half-power diameter (HPD) of $\sim 46^{\prime\prime}$ for an on-axis point source at infinity, and a focal-spot HPD of $\sim 120^{\prime\prime}$ for the radial distribution expected for
axion signals within the approximately $3^{\prime}$-radius
solar core. A relatively generous fabrication-error budget is also summarized. The custom optic, accounting for fabrication errors, is anticipated to deliver a more than $55$-fold enhancement in the SNR.
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All authors Yue Yu, Jooyun Woo, Ipek Altunyurt, Stefano Basso, Vadim Burwitz, Francisco R. Candón, Juan Francisco Castel Pablo, Marta M. Civitani, Todd Decker, Klaus Desch, Desiree Della Monica Ferreira, Javier Galan, Maurizio Giannotti, Louis Helary, Peter L. Henriksen, Alba María Huerva, Igor G. Irastorza, Eftychia Kotsiou, Axel Lindner, Frank Marutzky, Sonny Massahi, Sam Moseley, Takashi Okajima, Johanna von Oy, Diego Paredes-Sanz, Giancarlo Parodi, Kerstin Perez, Michael J. Pivovaroff, David Reuther, Anacorina Romero, Jaime Ruz, Vyshnavi Sabbi, Tobias Schiffer, Uwe Schneekloth, Daniele Spiga, Marcela Stern, Julia K. Vogel
Quantum Physics
Arnold–Nielsen Geometry for Complexity-Deformed Noncommutative Transport
Alberto Acevedo and Antonio Falcó
We deform the Carlen–Maas–Wirth framework for noncommutative dynamical optimal transport by an Arnold–Nielsen type complexity operator. A positive state-independent operator $G$ compatible with the
Hilbert bimodule structure of a noncommutative differential calculus $\partial\colon\M\to\Hcal$ can be absorbed into the calculus itself, \[ \partial_G:=G^{1/2}\partial. \] The corresponding complexity-weighted transport problem is exactly the unweighted transport problem generated by $\partial_G$, whenever the deformed quadratic form remains Dirichlet. In finite dimensions we prove existence of minimizers for density-dependent Petz-class metrics and for fixed physical complexity weights, the latter without commutation between $G$ and the state-dependent mobility. On
unitary orbits we identify the induced distance with a quotient metric coming from a right-invariant complexity geometry. This yields an exact Bell-state preparation result via Clairaut's relation and an exactly computed restricted-path upper bound for GHZ preparation; the Lindblad detailed-balance case is included only as
entropy-gradient-flow background.
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Medical Physics · Cross-listed from cs.HC
FMRP-LEAN: A HIPAA-Compliant AI-Augmented LIMS Architecture for End-to-End Clinical Assay Workflow Optimization
Eva McCord, Ernest Pedapati and Zag ElSayed
Clinical biomarker workflows in translational research settings often rely on spreadsheet-driven tracking, manual quality control (QC) reconciliation, and loosely integrated systems, resulting in limited state visibility, delayed reporting, and increased operational risk. These challenges are particularly pronounced in multi-day assays such as Luminex-based quantification of Fragile X Messenger Ribonucleoprotein (FMRP), where HIPAA-compliant data governance, deterministic workflow progression, and coordinated communication across laboratory and clinical teams are required. This paper presents FMRP-LEAN, a HIPAA-compliant, AI-augmented Laboratory Information Management System (LIMS) architecture that formalizes biospecimen lifecycle management through a finite-state workflow model with explicit transition guards and dwell-time observability. The system integrates a self-hosted Supabase/PostgreSQL stack deployed within hospital-controlled infrastructure, hybrid edge-internal isolation with encrypted tunneling and loopback-only services, and bi-directional REDCap synchronization. A unified MRN-UUIDv7 identifier framework with QR-based tracking ensures traceable clinical-research linkage under PHI residency constraints. FMRP-LEAN incorporates automated statistical QC pre-screening and a governance-constrained AI operations module that operates exclusively on aggregate projections, with deterministic fallback guarantees. Deployment demonstrates improved workflow observability, reduced QC latency, and enhanced cross-role transparency between laboratory technicians, research coordinators, and patient-facing teams. The architecture provides a reproducible model for secure, state-explicit, and AI-augmented clinical research workflows in regulated healthcare environments.
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General Relativity and Quantum Cosmology
Critical analysis of some weak-field Weyl conformal gravity solutions
Miguel Yulo Asuncion and Reinosuke Kusano
The field equations of Conformal
Gravity (CG) are constructed from fourth-order derivatives of the metric. While the second-order field equations of General Relativity (GR) reduce to a second-order Poisson equation in the weak-field limit, those of CG yield a fourth-order one. Despite this, works by Tanhayi, Fathi, and Takook [Mod. Phys. Lett. A 26, 2403 (2011)], Payandeh and Fathi [Int. J. Th. Phys. 51, 2227 (2012)], and Fathi, Olivares, and Villanueva [
Galaxies 9, 43 (2021)] use second-order Poisson equations to generate purported solutions to CG in a weak-field limit. We demonstrate that these solutions are erroneous due to the use of second-order Poisson equations instead of appropriate fourth-order ones. We also point out other inconsistencies in the derivations of these metrics, such as the assertion that known CG (electro)
vacuum solutions describe the interiors of matter distributions.
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Instrumentation and Methods for Astrophysics
The High-Speed FPGA Readout System for the Advanced X-ray Imaging Satellite (AXIS)
Declan O'Neill, Jill Juneau, Peter Orel et al. (+17 more)
The Advanced X-ray Imaging Satellite (AXIS) is a Probe-class mission concept designed to deliver arcsecond spatial resolution, high-sensitivity spectral imaging across the 0.3-10 keV band. The X-ray Astronomy and Observational Cosmology (XOC) Group at Stanford, in collaboration with the MIT Kavli Institute (MKI) and MIT Lincoln Laboratory (MIT-LL), is developing the AXIS X-ray camera, including both the detector and the front-end readout electronics required to meet the mission's demanding performance goals. The
telescope's focal plane detector consists of four 1440x1440 pixel charge-coupled devices (CCDs) developed by MIT-LL, each featuring 16 parallel output channels. These outputs are amplified by a high-speed, low-power, low-noise application-specific integrated
circuit (ASIC) - the Multi-Channel Readout Chip (MCRC) - developed at Stanford. Following amplification, the analog signals are digitized and processed to construct a pixel array, prior to event detection. Here, we present the field-programmable gate array (FPGA) architecture developed to enable high-speed, parallelized readout of these CCD channels. The FPGA samples 16 analog-to-digital converter (ADC) channels at 50 MHz, performs preprocessing of pixel data, which is then streamed via User Datagram Protocol (UDP) over a 1 Gb Ethernet link to the back-end system for event reconstruction. Our design demonstrates the goal readout performance for AXIS (20 frames per second) and provides a framework for future high-throughput X-ray observatories.
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All authors Declan O'Neill, Jill Juneau, Peter Orel, Sven Herrmann, Gregory Prigozhin, Eric D. Miller, Steven W. Allen, Marshall W. Bautz, Tanmoy Chattopadhyay, Kevan Donlon, Robert Goeke, Catherine E. Grant, Beverly LaMarr, Christopher Leitz, R. Glenn Morris, Abigail Y. Pan, Tonya L. Peshel, Artem Poliszczuk, Haley R. Stueber, Keith Warner
Quantum Physics
Statevector-to-Hardware Reconstruction of a Four-Qubit ZZ Quantum Kernel: A Single-Backend Case Study of Three Execution Jobs
Rostyslav Sipakov
Hardware noise and finite sampling perturb the fidelity estimates forming a
quantum-kernel Gram
matrix. We measured how far three hardware-reconstructed Gram
matrices depart from an exact statevector reference for one frozen four-
qubit ZZ feature map on N=24 indoor air-quality windows, executed on ibm_fez at 1024 shots per
circuit in three single, non-interleaved jobs: baseline, dynamical decoupling alone, and gate twirling alone. All were complete, finite, and positive-semidefinite. Off-diagonal root-mean-squared error (RMSE) against the reference was 0.0878, 0.0864, and 0.0427; full-
matrix centered kernel
alignment (CKA) ranged 0.933-0.989 and the post hoc diagonal-excluded (U-centered) CKA 0.816-0.986. The gate-twirled job deviated least on every reported geometry axis; its baseline contrasts are deletion-stable for the Spearman, mean-absolute-error, RMSE, and full-
matrix CKA diagnostics, while the Pearson and diagonal-excluded contrasts fall just below that convention. Dynamical decoupling was not separated from the baseline. The observed error exceeded both finite-shot reference scales, so, under those sampling-only models, sampling does not explain it. Centered kernel-target
alignment did not track reconstruction fidelity and stayed at or below each label-permutation reference: implementation fidelity and task relevance are distinct diagnostic axes. All configuration-level statements describe three realized jobs on one backend; no mitigation-efficacy, classifier-superiority,
forecasting, or
quantum-advantage claim is made.
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High Energy Astrophysical Phenomena
Probing the High-Energy Emission of the VHE-emitting Changing-Look Blazar B2 1420+32
Anjum Peer, Zahir Shah, Sikandar Akbar et al. (+2 more)
We present a multi-wavelength temporal and spectral study of the changing-look blazar B2~1420+32 using
Fermi-LAT, Swift-XRT, and Swift-UVOT data from MJD~58818–60721. The source reached a peak 0.1–300~GeV
photon flux of $(4.62 \pm 0.29) \times 10^{-6}\,\mathrm{ph\,cm^{-2}\,s^{-1}}$ around MJD~60488, about 60 times the 4FGL-DR4 average, during which the
photon index hardened to $2.19 \pm 0.14$; the flux–index
evolution shows only weak evidence for global harder-when-brighter behaviour. The fractional variability is strongly energy dependent, largest in $\gamma$-rays, substantial in the optical/UV, and low in X-rays. Strong $\gamma$-ray–optical/UV correlations and a moderate $\gamma$-ray–X-ray correlation indicate that the X-ray emission tracks the $\gamma$-ray variability less closely than the optical/UV emission. The X-ray spectra are best described by a log-parabola, and the negative
curvature measured in four of the five states suggests that the X-ray band samples the transition between the high-energy tail of the synchrotron component and the onset of the inverse-Compton component. We identified five activity states and modelled the high-energy (X-ray and $\gamma$-ray) component of their broadband spectral energy distributions (SEDs) using synchrotron self-Compton (SSC), external Compton (EC), and SSC+EC scenarios. The SSC-only and EC-only models either require physically disfavoured parameters or fail to reproduce the VHE emission, whereas SSC+EC provides the most self-consistent description, with a seed-
photon temperature of $\sim 10^{3}$~K favouring an infrared
torus origin. The brighter states require larger bulk Lorentz factors and higher jet powers, while the
magnetic field varies only modestly, indicating that the flux
evolution is governed by a combination of Doppler boosting and jet energetics.
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All authors Anjum Peer, Zahir Shah, Sikandar Akbar, Bari Maqbool, Ranjeev Misra
Cosmology and Nongalactic Astrophysics
The burgeoning rise of the 21-cm forest I: constraints on the optical depth of the intergalactic medium at $5.38 < z < 5.84$
Chanasorn Kongprachaya, Gianni Bernardi, Emilio Ceccotti et al. (+3 more)
The redshifted 21-cm line is a promising probe of the Epoch of Reionization, during which the first generation of
stars ionized the InterGalactic Medium (IGM). We aimed to constrain the IGM neutral Hydrogen fraction and
spin temperature via redshifted 21-cm absorption against high-
redshift radio sources. We analysed an 18-hour observation of the
radio-loud
quasar PSO J352.4034-15.3373 ($z = 5.84$) in the 203-222.5 MHz band. We obtained a continuum image with a $0.66$ mJy/beam rms noise and a spectrum with $3.6$ mJy/beam rms noise per 390 kHz-wide channel. We fit the
quasar spectrum with a power-law continuum modified by an intervening 21-cm absorption, testing two scenarios: an island model, a residual cold neutral Hydrogen patch surviving at the end of reionization, and a global model, approximating the overall decline of the IGM HI fraction and
spin temperature with
redshift. Combining archival data spanning 150 MHz to 3.0 GHz with our measurements, we determined a
quasar flux density of $86.8 \pm 1.1$ mJy at 200 MHz and a spectral index of $-0.88 \pm 0.02$ across the full frequency range. We found no evidence for the 21-cm absorption from intervening neutral Hydrogen at $5.38<z<5.84$. Assuming the island model, we set a 95% confidence lower limit on the IGM
spin temperature of $1.73$ K in residual HI regions. Assuming the global model, we constrained the 21-cm optical depth to $\tau_{21}< 0.02$ (95% C.L.). These results provide constraints on the 21-cm optical depth near the end of reionization, over the $5.38 < z < 5.84$ range, and confirm that the IGM was heated above the adiabatic cooling limit ($\sim 0.8$ K at $z = 5.68$), consistent with theoretical predictions and with 21-cm power spectrum measurements at higher
redshifts. Our results also disfavour the presence of extremely cold HI regions at $z < 5.84$ and open the way to future 21-cm absorption from high-
redshift sources.
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All authors Chanasorn Kongprachaya, Gianni Bernardi, Emilio Ceccotti, Andrei Mesinger, Benedetta Ciardi, Oleg M. Smirnov
Instrumentation and Detectors
Detector Performance and Dark Matter Sensitivity of CYGNO with HFO-1234ze Gas Admixtures
F.D. Amaro, R. Antonietti, E. Baracchini et al. (+42 more)
The CYGNO project develops optical time projection chambers for directional dark matter searches, using a He:CF4 (60:40) gas mixture at atmospheric pressure and a triple-GEM amplification stage. We investigate the addition of 1-10% HFO-1234ze as a hydrogen-containing additive with low global warming potential. The charge response and scintillation light yield are studied with the MANGO prototype, complemented by secondary-scintillation spectroscopy of the baseline mixture and mixtures containing 1% and 2.5% HFO. Increasing the HFO concentration shifts the charge-response curves towards higher GEM voltages and strongly suppresses the scintillation emission in both the ultraviolet and visible bands. We use the measured optical response to estimate the impact on projected
spin-independent WIMP-nucleon and
spin-dependent WIMP-
proton exclusion limits for a CYGNO-like directional detector. Under the assumed detector-response model, the higher optical energy threshold largely outweighs the benefit of the additional light target, although a 1% HFO admixture retains a limited advantage for low-mass
spin-dependent interactions. An idealized fixed-threshold
benchmark is also considered to illustrate the potential of the modified target composition without the optical threshold penalty.
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All authors F.D. Amaro, R. Antonietti, E. Baracchini, L. Benussi, F.M. Brunbauer, C. Capoccia, M. Caponero, L.G.M. de Carvalho, G. Cavoto, I.A. Costa, A. Croce, M. D'Astolfo, G. D'Imperio, E. Dane', G. Dho, E. Di Marco, J.M.F. dos Santos, D. Fiorina, F. Iacoangeli, Z. Islam, E. Kemp, H.P. Lima Jr, G. Maccarrone, R.D.P. Mano, D.J.G. Marques, G. Mazzitelli, P. Meloni, A. Messina, C.M.B. Monteiro, R.A. Nobrega, E. Olivieri, I.F. Pains, E. Paoletti, F. Petrucci, S. Piacentini, D. Pierluigi, D. Pinci, F. Renga, A. Russo, G. Saviano, P.A.O.C. Silva, N.J. Spooner, R. Tesauro, S. Tomassini, D. Tozzi
High Energy Physics (Experiment)
Lightest $0^{-+}$ Glueball as Dominant Constituent of $X(2370)$
BESIII Collaboration
With 10 billion $J/\psi$ events collected at \mbox{BESIII}, the decay of $X(2370)\rightarrow K^{*}(892)^{0}\bar{K}^{0}+\mathrm{c.c.}$ is searched for via the $J/\psi\rightarrow\gamma K_{S}^{0}K_{S}^{0}\pi^{0}$ process. No evidence of this decay mode is found, with $\mathcal{B}[J/\psi\rightarrow\gamma X(2370)] \times \mathcal{B}[ X(2370) \rightarrow K^{*}(892)^{0}\bar{K}^{0}+\mathrm{c.c.} \rightarrow K^{0}_{S}K^{0}_{S}\pi^{0}] < 2.7\times 10^{-6}$ at the $90\%$ confidence level. The suppression of the $K^{*}(892)\bar{K}$ mode indicates the $X(2370)$ as a
flavor-singlet state. It is the first
flavor-singlet light
hadron observed above $1~\textrm{GeV}/c^{2}$. All \mbox{BESIII} measurements on the $X(2370)$ are summarized. A dominant component of the lightest $0^{-+}$ glueball is essential for a natural and complete explanation of the properties of the $X(2370)$~\textemdash~the mass,
spin-parity, high production rate in $J/\psi$ radiative decays, decay pattern similarities to that of $\eta_{c}$,
flavor-singlet property, narrow partial decay width, and suppression of radiative decays to $\omega$ and $\phi$, since these properties are all consistent with the features of the lightest $0^{-+}$ glueball while other interpretations at present are disfavored. This supports that the lightest $0^{-+}$ glueball is the dominant constituent of the $X(2370)$.
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Instrumentation and Methods for Astrophysics
Fast, low-noise CCD systems for future strategic X-ray missions
Haley R. Stueber, Tanmoy Chattopadhyay, Tonya L. Peshel et al. (+12 more)
Future strategic X-ray missions, such as those targeted by the Great Observatories Maturation Program (GOMaP), require fast, low-noise X-ray imaging spectrometers. To achieve the speed and noise capabilities required by such programs, our Stanford team, in collaboration with the MIT Kavli Institute (MKI) and MIT Lincoln Laboratory (MIT-LL), is developing enhanced X-ray charge-coupled devices (CCDs) and readout systems that leverage tailored application-specific integrated
circuits (ASICs). Here, we report the energy resolution and noise performance achieved using some of the latest MIT-LL CCDs in conjunction with Stanford-developed Multi-Channel Readout Chip (MCRC) ASICs. Additionally, we present a new sampling method for simultaneous optimization of the output gate (OG), reset gate (RG), and reset drain (RD) biases which, in combination with new integrated fast summing well (SW) and RG clock operation modes, enables the data rates and noise required for future X-ray
telescopes. Finally, we present noise power spectral density (PSD) and waveform analysis methods and posit a physical model for characterizing and understanding output stage noise behavior.
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All authors Haley R. Stueber, Tanmoy Chattopadhyay, Tonya L. Peshel, Abigail Y. Pan, Steven W. Allen, Marshall W. Bautz, Kevan Donlon, Catherine E. Grant, Sven Herrmann, Beverly J. LaMarr, Eric D. Miller, R. Glenn Morris, Peter Orel, Artem Poliszczuk, Gregory Y. Prigozhin
Instrumentation and Detectors
High-accuracy ultrasonic positioning of calibration sources in the Jiangmen Underground Neutrino Observatory
Ziqian Xiang, Rongcheng Chen, Zhangmin Chen et al. (+20 more)
Precise source positioning is essential for detector calibration in large
liquid scintillator detectors such as JUNO, particularly in regions where purely mechanical control is insufficient. An ultrasonic positioning system has been developed to reconstruct the three-dimensional coordinates of a calibration source without interfering with
photon collection or contaminating the
liquid scintillator. The method combines a sound-speed modeling based on dedicated laboratory measurements and in-detector temperature profiles, waveform-based arrival-time reconstruction, and an in-situ calibration of the effective receiver geometry using central-axis deployments. With six active receivers, central-axis positioning yields a mean error of 1.23 cm relative to the known deployment reference. For off-axis operation in the Cable Loop System calibration plane, a detector-realistic simulation that includes timing resolution, sound-speed variation, and receiver-coordinate smearing predicts a positioning uncertainty of 2.40 cm. These results demonstrate that ultrasonic positioning can provide centimetre-level source accuracy for large
liquid scintillator detectors and can support off-axis calibration in JUNO-like experiments.
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All authors Ziqian Xiang, Rongcheng Chen, Zhangmin Chen, Qian Chen, Diwash Ghimire, Jiaqi Hui, Junting Huang, Junjie Jiang, Daijin Li, Haojing Lai, Kai Luo, Rui Li, Yilin Liao, Jianglai Liu, Yue Meng, Yazhen Shi, Duo Teng, Linwei Tao, Qi Wang, Changsheng Ye, Guolei Zhu, Ping Zhang, Tao Zhang
Cosmology and Nongalactic Astrophysics
Beyond $j=1$: Observational Constraints on Almost-$\Lambda$CDM Cosmologies
Jess Worsley, Saikat Chakraborty and Peter Dunsby
The cosmographic condition $j(z)=1$ provides the kinematical signature of the spatially flat $\Lambda$CDM model independently of any specific dark-energy or modified-
gravity theory. We investigate the extent to which current observations permit departures from this condition by considering three phenomenological “almost-$\Lambda$CDM” cosmographic closures, in which the
cosmic jerk differs slightly from unity through a small deformation parameter $\epsilon$. The models are constrained using Markov Chain Monte Carlo analyses of recent DESI
baryon acoustic oscillation measurements together with compressed Planck
cosmic microwave background likelihoods and the Union3, Pantheon+, and DESY5 Type Ia
supernova compilations. Rather than assuming a parameterized dark-energy equation of state, our cosmographic framework reconstructs the expansion history directly from observations, with the effective dark-energy equation of state emerging as a derived quantity. We find that all three closures are tightly constrained to the vicinity of the $\Lambda$CDM cosmographic fixed point, with Planck data driving the preferred
evolution toward $j_0\simeq1$ and $w_{\rm DE,0}\simeq-1$. Despite their distinct kinematical constructions, the reconstructed dark-energy
evolution consistently exhibits smooth freezing behaviour close to $w=-1$, without crossing the phantom divide. Model comparison using the Akaike and
Bayesian information criteria shows that the almost-$\Lambda$CDM models remain statistically competitive with standard dark-energy parameterizations while requiring fewer assumptions about the functional form of $w(z)$. These results demonstrate the power of model-independent cosmography for constraining the
cosmic expansion history and provide a natural framework for future studies of cosmological perturbations and structure formation.
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Fluid Dynamics
Revisiting Rotary Blade Aerodynamics and Wake Behavior of a Vertical-Axis Wind Turbine via a High-Order Actuator-Line Framework
Abdullah Al Imran and Meilin Yu
Vertical-axis wind turbines (VAWTs) experience highly unsteady blade loading and
vortex shedding during operation, and the relationship between blade-wake interaction and useful power extraction remains unclear. The present study addresses this gap by relating phase-dependent blade loading and instantaneous wake activity to the mean velocity deficit and net power extraction across distinct operating regimes. Specifically, we show that deep dynamic stall produces large-scale
vortex shedding and an energetic instantaneous wake, yet yields only a shallow mean velocity deficit and little net power. Near-optimal operation, by contrast, produces a more organized wake and substantially greater momentum extraction. To study the VAWT dynamics in a cost-effective way, we extended our previously developed steady source term formulation to a time-accurate, high-order numerical framework that couples flux reconstruction and actuator line model on fixed Cartesian grids, incorporating Gaussian force projection, a modified Boeing–Vertol dynamic stall model, and a double multiple streamtube based induction closure. The framework reproduces experimental near-wake profiles and predicts power coefficients comparable to those obtained from a three-dimensional large eddy simulation based actuator line model, with a peak power coefficient approximately 6% lower than the reference value. An upwind-downwind force decomposition shows that dynamic stall acts predominantly during the upwind passage, temporarily increasing power under deep stall conditions while providing little net power overall. Light stall, by limiting large-scale flow separation and the subsequent loss of lift, maintains more consistent power-producing blade loading and therefore yields substantially greater mean power extraction.
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Fluid Dynamics · Cross-listed from cs.CE
IteraSim RAG: A Multi-Stage Retrieval-Augmented Agentic Back-End for OpenFOAM-Based Computational Fluid Dynamics
Pratyush Kumar
Configuring a computational fluid dynamics (CFD) case in OpenFOAM requires assembling a multi-directory input deck of mutually consistent solver, discretisation and boundary-condition dictionaries – a task that remains a substantial barrier to non-specialist use of open-source CFD software. Large
language models (LLMs) coupled with
retrieval-augmented generation (RAG) can lower this barrier, but existing systems retrieve with a single flat query, apply one
retrieval strategy to operationally distinct requests, and let a single
agent both draft and review its own output. We present IteraSim RAG, a
retrieval-augmented software back-end for automated OpenFOAM case generation built around these three limitations. An LLM first expands the query into physics, solver-keyword and troubleshooting variants, Reciprocal Rank Fusion then merges the resulting ranked lists, and Maximal Marginal Relevance re-ranks the fused candidates against an HNSW-indexed dense vector store. A deterministic keyword router dispatches tool-conditioned workflow queries and corpus-wide physics queries down separate
retrieval paths, and generation is split across an Architect, an InputWriter and a Reviewer
agent, backed by a static canonical-knowledge layer covering solver selection,
turbulence closures, boundary conditions and finite-volume defaults. On an openly released 28-case
benchmark spanning zero-shot setup, few-shot generalisation, single-parameter modifications and
turbulence-model swaps, the pipeline attains a mean
retrieval coverage of 77.9% (median 79.1%), with the parameter-modification category exceeding 90%. All six reference configurations run to completion on OpenFOAM v2506, and two synthetically corrupted cases are diagnosed and repaired within the bounded Reviewer loop using only the solver log and the canonical layer. The
benchmark, scoring rubric and figure scripts are released for reproducibility.
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Optics
Probing the temperature dependence of dielectric function of ternary transition metal dichalcogenides: towards thermo-driven ultrathin photonic components
Artsruni Margaryan, Maria Levonyan, Maksim Sargsyan et al. (+4 more)
Transition metal dichalcogenides (TMDs), along with their ternary derivatives, have attracted considerable
attention mostly due to pronounced excitonic resonances emerging in visible (Vis) and near-infrared (NIR) spectral regions, enabling strong light-matter interaction. Nevertheless, a comprehensive insight of the temperature-dependent optical dispersions for the most of representatives of the family remains yet unrevealed. Here, we report on systematic studies of dielectric permittivity functions of uniaxial ternary MoSSe and WSSe across 430-1000 nm spectral region over a broad temperature window of 80-670 K. We show that the temperature
evolution of their dielectric responses is governed by Varshni's formalism in Vis spectral region further affecting their high refractive index properties at the lossless NIR spectral tails. Furthermore, we exploit the measured optical dispersion of ternary WSSe designing ultrathin plano-convex NIR photonic lenses that demonstrate continuous modulation of performance with temperature variation. Our work provides critical insights for the creation of next-generation thermo-driven nanophotonic and optoelectronic devices.
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All authors Artsruni Margaryan, Maria Levonyan, Maksim Sargsyan, David Karakhanyan, Meri Hayrapetyan, Kostya S. Novoselov, Davit A. Ghazaryan
High Energy Physics (Phenomenology)
Monopoles, Strings, Walls and Gravitational waves
Rinku Maji and Qaisar Shafi
The gauge
symmetry breaking $SU(2) \to U(1) \to Z_2 \to 1$ successively produces monopoles, strings and domain walls bounded by strings (WBS), with the elementary monopole carrying a $U(1)$
magnetic flux twice as large as the elementary string. The elementary strings and subsequently WBS emit gravitational waves, and during their decay, the WBS yield a network of composite strings that carry the same $U(1)$ flux as the monopoles. Depending on the cosmological
evolution, we provide the gravitational wave spectra generated by the elementary strings and WBS, in combination with the composite strings which are either effectively stable, quasistable, or metastable. These three scenarios are also realized in the
symmetry breaking chain $SU(3) \to SO(3) \to Z_2 \to 1$. Both $SU(2)$ and $SU(3)$ have appeared in the literature as
flavor gauge
symmetries.
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Computational Physics · Cross-listed from cs.LG
Interval and fuzzy physics-augmented neural networks (iPANN and fPANN) for uncertainty quantification and propagation in constitutive modeling
Somesh Pratap Singh, Govinda Anantha Padmanabha, Jingye Tan et al. (+4 more)
Constitutive modeling under uncertainty remains a central challenge for reliable mechanics simulations, particularly when the available stress-deformation data are sparse, noisy, or heterogeneous. We propose interval and fuzzy physics-augmented neural networks (iPANNs and fPANNs) for uncertainty-aware hyperelastic constitutive modeling. iPANNs learn sparse lower, mean, and upper free energy density branches whose stresses, obtained by automatic differentiation, ultimately enclose noisy stress observations. In contrast to this deterministic interval description, fPANNs embed the learned iPANN branches into a fuzzy-set representation through membership-level (alpha-cut) interpolation, yielding a nested family of admissible responses. iPANNs and fPANNs encode mechanistic constraints by preserving objectivity, consistency and promoting polyconvexity and, smoothed L0 regularization promoting interpretable energy representations. The bound models are trained through a two-stage transfer-learning procedure in which a sparse mean constitutive response is learned first and then fine-tuned into lower and upper energy branches. We evaluate the framework on synthetic isotropic hyperelastic data with heteroscedastic noise, varying random realizations, shifted noise means, and varying noise magnitudes. The results show that the learned bounds enclose noisy stress observations while generalizing to the test set. Further, we examine the propagation of uncertainty through the mean, upper and lower bound predictions of the learned iPANN models in a finite element setting. The proposed framework provides a compact, physics-consistent route for distribution-free aleatoric uncertainty quantification in hyperelastic constitutive modeling, and propagation in downstream finite element simulations.
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All authors Somesh Pratap Singh, Govinda Anantha Padmanabha, Jingye Tan, Steven Yang, Reese E. Jones, D. Thomas Seidl, Nikolaos Bouklas
Computational Physics
Reconstructing local environments from concise atomistic representations
Jigyasa Nigam, Tuong Phung, Ameya Daigavane et al. (+2 more)
Symmetry-based representations of local atomic structure, such as the power spectrum or bispectrum, are routinely used to characterize the structural diversity of
datasets and as input features for atomistic machine learning. Although these descriptors systematically incorporate increasingly complex
geometric correlations, it remains unclear if a given feature can be mapped back to a discrete point cloud, whether such a reconstruction is unique, and how changes in the descriptor are reflected in the underlying atomic geometry. The choice and discretization of the radial and angular bases, as well as the high dimensionality of the resulting feature vectors – which may contain hundreds or thousands of components – make this interpretation even more challenging. In this work, we investigate the inverse problem of recovering atomic structures from local invariant descriptors. We show that accurate reconstructions can be obtained from remarkably compact descriptors of different correlation orders, each comprising only a few tens of features. Even representations that are formally incomplete or locally ill-conditioned can be inverted to accurate
geometric reconstructions of atomic environments across molecular and material
datasets. Our reconstruction framework provides a general algorithmic means of identifying approximate degeneracies of invariant descriptors and recovering distinct atomic environments that cannot be distinguished by a given representation. Finally, by reconstructing atomic configurations from descriptors, we examine how perturbations in invariant descriptors of different correlation orders translate into structural distortions.
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All authors Jigyasa Nigam, Tuong Phung, Ameya Daigavane, Aria Mansouri Tehrani, Tess Smidt
Lattice Field Theory
Nucleon unpolarized second Mellin moments using lattice QCD ensembles with physical quark masses and in the continuum limit
Constantia Alexandrou, Simone Bacchio, Jacob Finkenrath et al. (+6 more)
We compute the
matrix elements of the energy-momentum tensor of the nucleon using four ensembles of twisted mass clover-improved
fermions with the up, down, strange and charm
quark masses tuned to approximately their physical values. The four ensembles have similar physical volume and
lattice spacings $a=0.080$~fm, $0.068$~fm, $0.057$~fm, and $0.049$ fm, allowing us to take the continuum limit directly at the physical pion mass point. We compute both connected and disconnected
quark contributions as well as
gluon contributions. All renormalization functions, including the mixing of the
quark singlet with the
gluon, are determined non-perturbatively. We extract the gravitational form factors in the continuum limit at $Q^2=0$ and evaluate the contribution of
quarks and
gluons to the momentum and angular momentum of the
proton. Using the values of the intrinsic
quark spin computed using the same gauge ensembles we also determine the orbital angular momentum for each
quark flavor.
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All authors Constantia Alexandrou, Simone Bacchio, Jacob Finkenrath, Christos Iona, Giannis Koutsou, Christian Kummer, Yan Li, Bhavna Prasad, Gregoris Spanoudes
Superconductivity
Stacking-tuned superconductivity and competing charge-density-wave states in NbSe$_2$
Sandra Sajan, Xinze Yang, Haojie Guo et al. (+9 more)
Layer stacking provides a powerful yet underexplored route for reshaping collective
quantum order in van der Waals materials. Here we use high-resolution scanning tunneling microscopy and spectroscopy to show that the stacking sequence alone can qualitatively transform the charge density and superconducting orders in NbSe$_2$, while preserving the same in-plane atomic structure. Comparing the 4Ha and 2H polytypes, we find that, unlike the ubiquitous triangular incommensurate $3Q^\mathrm{I}$ order of 2H-NbSe$_2$, 4Ha-NbSe$_2$ hosts two competing CDW states with no measurable correlation with local strain: a unidirectional commensurate $1Q^\mathrm{C}$ phase and a triangular incommensurate $3Q^\mathrm{I}$ phase, with $Q^\mathrm{I}=Q^\mathrm{C}+\delta$. We introduce a phase-resolved analysis that directly maps the gradient of the CDW phases and reveals
vortices bound to the $1Q^\mathrm{C}$ - $3Q^\mathrm{I}$ phase boundaries. These
vortices accommodate the momentum mismatch $\delta$ through abrupt $2\pi$ phase slips, providing a mechanism by which distinct charge orders coexist. Superconductivity is also reshaped by stacking, while both polytypes exhibit multiband pairing.
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All authors Sandra Sajan, Xinze Yang, Haojie Guo, Tarushi Agarwal, Samuel Mañas-Valero, Carla Boix-Constant, Eugenio Coronado, Fernando de Juan, Eduardo H. da Silva Neto, Ravi P. Singh, Maria N. Gastiasoro, Miguel M. Ugeda
Quantum Physics
Collective Electronic Entanglement via Infrared Cavity-Induced Vibronic Transduction
Vivek Yadav, Bar Cohn, Shmuel Sufrin et al. (+2 more)
Polaritonic architectures seek to engineer molecular properties by hybridizing localized degrees of freedom with delocalized optical cavity fields. However, scaling laws impose a severe bottleneck on N-molecule collective strong coupling: because each molecule contributes only a fractional share to the collective state, localized responses undergo O(1/N) ensemble dilution. We demonstrate a violation of this scaling using fluorescence-encoded infrared spectroscopy of molecular ensembles under vibrational strong coupling, where macroscopically synchronized electronic responses scale as O(1). This scale-invariance reveals a regime of vibronic
quantum transduction, where non-local vibrational
entanglement is translated into collective electronic
entanglement. By demonstrating the generation of macroscopically entangled electronic states from vibro-polaritons without an O(1/N) penalty, these results provide a scalable framework for room-temperature
quantum technologies and coherent steering of non-adiabatic chemical pathways.
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All authors Vivek Yadav, Bar Cohn, Shmuel Sufrin, Uri Peskin, Lev Chuntonov
Instrumentation and Methods for Astrophysics
HARMONI at ELT: Reoptimization of the NGSS natural guide star sensors system for MCAO compatibility
Kjetil Dohlen, David Le Mignant, Anne Bonnefoi et al. (+16 more)
HARMONI is the first-light, adaptive optics assisted, near-IR integral field spectrograph for the ELT. It covers a spectral range from below 800nm to 2400nm with resolving powers from 3000 to 7000 and spatial sampling of 25mas and 6mas. It can operate in three adaptive optics (AO) modes: single conjugate AO (SCAO), high-contrast AO (HCAO), and multi-conjugate AO (MCAO). The project is resuming its final design phase after a rescope design phase that has lasted two years. This paper describes the impact of the rescope on the natural guide
star sensors (NGSS) system, imposing wide-ranging changes in particular to the low-order wavefront sensors (LOWFS) previously optimized for LTAO operation as well as on the external support and enclosure (ESE) whose external interfaces have changed. The high-contrast module (HCM) is also deeply affected due to the modified plate scale of the instrument, and the single-conjugate AO sensor (SCAOS) benefits from a reduced patrol field requirement. Description of the changes will be given together with the associated system analysis involving requirements flow-down, revisited functional analysis, and updated product breakdown structure. Elements of the new system management structure and work breakdown will also be included.
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All authors Kjetil Dohlen, David Le Mignant, Anne Bonnefoi, Marc Dubbeldam, Johan Floriot, Iago Funes Vecino, Laurent Jocou, Yoann Richaud, Alexis Carlotti, Zalpha Challita, Anne Costille, Andrew Dunn, David King, Deborah Malone, Guillermo Mercant Rubio, Timothy Morris, Jean-Francois Sauvage, Lazar Staykov, Teodora Aleida Viera Curbelo
Mathematical Physics · Cross-listed from math.PR
Anticoncentration of the Permanent in Ginibre Ensembles
Frederic Koehler and Pui Kuen Leung
Let $\mathbb{K}\in\{\mathbb{R},\mathbb{C},\mathbb{H}\}$, put $\beta=\dim_{\mathbb{R}}\mathbb{K}$, and let $G_n^{\mathbb{K}}$ be an $n\times n$
matrix with i.i.d. standard $\mathbb{K}$-Gaussian entries, namely a standard $\mathbb{K}$-Ginibre
matrix. We prove that the normalized row-ordered permanent $W_n^{\mathbb{K}}=\operatorname{per}_{\mathbb{K}}G_n^{\mathbb{K}}/\sqrt{n!}$ has a radial density $p_n^{\mathbb{K}}$ satisfying $\|p_n^{\mathbb{K}}\|_\infty=p_n^{\mathbb{K}}(0)\lesssim_\beta n^{(\beta+2)/4}$ and $\sup_{z\in\mathbb{K}}\mathbb{P}(|W_n^{\mathbb{K}}-z|\leq\varepsilon)\lesssim_\beta n^{(\beta+2)/4}\varepsilon^\beta$. In particular, for $\mathbb{K}=\mathbb{C}$, this resolves the Permanent Anticoncentration
Conjecture of Aaronson and Arkhipov. The proof compares the squared Gaussian permanent with the squared (Study) determinant in Laplace-transform order.
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Instrumentation and Detectors
Demonstration of a cryogenic, switchable electron source for low-temperature detector calibration
D.A. Bennett, M. Borghesi, P. Campana et al. (+17 more)
We present the realization of a prototype of a compact, switchable electron source operating at cryogenic temperatures, demonstrated at energies ranging from 100 eV to 300 eV, and conceptually extendable to an arbitrary energy range. The electrons are produced via photoelectric emission, induced by a LED illuminating two 400~nm-thick commercial aluminum layers inside a cryostat, and are subsequently accelerated by a voltage of up to 300~V. Detection is carried out with an array of transition-edge sensor (TES) microcalorimeters designed for X-ray detectors, where we successfully observe signals consistent with electrons produced at the source at rates of $\gtrsim$1~Hz and with an efficiency of $\gtrsim 10^{-14}\ e^-/\gamma$. One of the potential applications of this prototype is the development of a calibration method for cryogenic detectors, based on the generation, acceleration, and multiplication of electrons, followed by their conversion into high-energy
photons.
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All authors D.A. Bennett, M. Borghesi, P. Campana, R. Carobene, A. Cattaneo, M. De Gerone, M. Faverzani, L. Ferrari Barusso, E. Ferri, S. Gamba, A. Giachero, M. Gobbo, D. Labranca, J. Mates, R. Moretti, A. Nucciotti, L. Origo, D.R. Schmidt, D.S. Swetz, J.N. Ullom
Computational Physics · Cross-listed from cs.LG
Multi-modal transformer for signal classification in nanopore blockade experiments
Sandro Kuppel, Julian Hoßbach, Samuel Tovey et al. (+1 more)
Nanopore devices have emerged as powerful tools for single-molecule sensing, with potential for rapid, portable diagnostics. They detect changes in ionic current as analytes enter nanometer-scale pores, providing a means of identifying diverse biomarkers from their characteristic signal patterns. However, these signals are highly complex, and reliably assigning them to specific molecules remains a major challenge. Here, we address this by introducing a multi-modal deep learning architecture that jointly processes multiple signal representations, including raw time-series data, wavelet-based images, and static feature vectors. Our approach surpasses existing methods by more than 10 percentage points on a 42-peptide
benchmark and transfers to a 20-amino-acid
dataset with near-perfect accuracy. The model integrates complementary information from these representations, with
attention analysis showing that the time-series and wavelet-image inputs emphasize different features of the same event. Together, these results demonstrate the potential of machine learning to enable robust, high-accuracy molecular identification with nanopore sensors.
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All authors Sandro Kuppel, Julian Hoßbach, Samuel Tovey, Christian Holm
Computational Physics
Bayesian Inference: Kernel-Based Model for Surface Temperature Reconstruction in Ice Borehole Thermometry
Kshema Shaju, Thomas Laepple and Peter Zaspel
Reconstructing past surface temperature from shallow ice borehole temperature profiles requires solving an ill-posed inverse problem while quantifying uncertainties arising from measurements and prior assumptions.
Bayesian formulations enable probabilistic reconstruction of surface temperature histories and uncertainty quantification. Existing reversible jump-Markov chain Monte Carlo approach based on adaptive piecewise-linear surface temperature models can, however, be computationally demanding. Here, we introduce a kernel-based surface temperature model that enables the use of a parallel ensemble Markov chain Monte Carlo sampler for efficient exploration of the solution space and quantification of the posterior. Using synthetic experiments, we investigate the effects of kernel configuration, measurement uncertainty, measurement density, and temporal smearing on reconstruction performance. We find that reconstruction quality is largely insensitive to the number of kernels once the kernel basis is sufficiently dense. Reducing measurement uncertainty substantially improves reconstructions, whereas increasing the number of borehole temperature measurements provides only marginal benefit. Finally, we evaluate the method using realistic surrogate
climate histories that combine long-term temperature changes with
stochastic climate variability. The kernel-based surface temperature model cannot represent short-term variability and therefore cannot fully explain the realistic measurements, highlighting the need to account for this approximation uncertainty. The likelihood is adapted to include the approximation uncertainty of the surface temperature model, yielding robust reconstructions with reliable posterior uncertainties. Overall, our results demonstrate that kernel-based
Bayesian inversion provides an efficient framework for shallow ice borehole based
climate reconstructions.
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Fluid Dynamics
Label-Free Finite-Volume-Residual Training of Attention Graph Neural Networks for Coupled Thermo-Fluid Fields
Tianyu Li, Zhiwei Cao, Qingang Zhang et al. (+3 more)
Neural surrogates are widely used in scientific machine learning for fast prediction of three-dimensional (3D) thermo-fluid fields. However, generating training data using conventional numerical solvers often incurs substantial computational and storage costs. We propose to train an
attention graph neural network by minimizing the finite-volume method (FVM) residuals of the governing equations. These residuals are evaluated directly on the mesh, requiring no labeled data. We evaluate the trained surrogates against computational fluid dynamics (CFD) references and a data-supervised baseline across four scenarios. On the two steady-state
benchmarks, each solved on the same mesh as its CFD reference, the FVM-loss model reproduces the reference flow and temperature fields with mean field-averaged normalized root-mean-square errors (nRMSEs) near 3%, including the buoyancy-energy coupling. On the two parametric transient cases, the FVM-loss model attains lower rollout errors than the supervised baseline in almost every field, while avoiding the data-generation cost entirely. These results indicate that the FVM loss can provide a practical training signal for neural surrogates and reduce the model development cost.
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All authors Tianyu Li, Zhiwei Cao, Qingang Zhang, Ruihang Wang, Binyang Song, Yonggang Wen
Cosmology and Nongalactic Astrophysics
Interacting Dark Energy and Dark Matter in O(3) No-Scale Gravity
Lincoln da S. Pereira, Muzi Hong, Elisa G. M. Ferreira et al. (+1 more)
Dark Energy (DE) and Dark Matter (DM) are among the greatest mysteries in particle physics and cosmology, since their origins remain unclear. It is intriguing to consider whether both may originate from a purely gravitational sector. We propose that they arise from degrees of freedom associated with the partners of the Brans-Dicke
boson in No-Scale
Gravity, a fundamental scale-invariant gravitational theory in which the Planck scale is illusional. We consider the Brans-Dicke
boson, together with two scalar fields, to form a vector multiplet under an $O(3)$
symmetry, whose angular directions in the Einstein frame are identified with DM and DE. Small explicit breaking of $O(3)$ generates their masses and interaction, and we show that the resulting model reproduces the required background cosmological
evolution and present-day abundances, with the lighter field providing a dynamical DE component at late times. Although the DE field remains canonical, the interacting cosmology exhibits an effective phantom-like
evolution at late times, of the type suggested by DESI in combination with other cosmological probes, without introducing a fundamental phantom degree of freedom. The model provides a first-principles realization of interacting DE, in which DM, DE, and their coupling emerge from the
symmetry structure of the underlying gravitational theory.
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All authors Lincoln da S. Pereira, Muzi Hong, Elisa G. M. Ferreira, Tsutomu T. Yanagida
General Relativity and Quantum Cosmology
Parity-violating spatially covariant gravity at total derivative order $d=5$
Jin-Jian Song and Xian Gao
We extend the
polynomial construction of parity-violating spatially covariant
gravity (SCG) to total derivative order $d=5$, where $d=d_{\mathrm{t}}+d_{\mathrm{s}}$ counts the total number of temporal and spatial derivatives. After organizing the monomials by $(d_{\mathrm{t}},d_{\mathrm{s}})$ and reducing them using integrations by parts, tensor
symmetries, three-dimensional
curvature identities, the Schouten identity, and the Cayley-Hamilton relation, we obtain a $59$-element basis: $2$, $40$, and $17$ monomials in the sectors $(0,5)$, $(2,3)$, and $(4,1)$, respectively. A direct inspection separates $35$ monomials containing neither the lapse velocity $\mathcal{L}_{\bm{u}}\ln N$ nor $\mathcal{L}_{\bm{u}}K_{ij}$ from $11$ lapse-velocity monomials and $13$ monomials containing higher normal derivatives of the spatial metric. The latter two sectors require a dedicated degeneracy analysis. For tensor perturbations about a spatially flat cosmological background, the acceleration-free part of the manifestly first-order-in-time sector contains $16$ basis elements, whose quadratic action depends on only four combinations of coefficients. These combinations generate helicity-odd corrections proportional to $k/a$ and $(k/a)^3$ in the kinetic and gradient functions. We derive two relations that enforce luminal phase velocity for both circular polarizations while still allowing helicity-dependent kinetic normalization and damping.
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