Instrumentation and Methods for Astrophysics
Multi-night photometric repeatability of STDWeb: an empirical error budget from a 14-night campaign on a single field
Pierre-Yves Lechapelain
Web-based photometric pipelines such as STDWeb are routinely used by small observatories and professional-amateur networks across the full range of photometric science: variable
stars,
supernovae,
exoplanet transits, transient follow-up. The formal magnitude uncertainty they report describes a single reduction of a single frame; campaign science instead requires the scatter of the same
star, same field, night after night. We measure this empirically on the field of the Einstein Probe trigger EP-WXT 01709274151, observed on 14 nights in 2026 July: 157
Gaia-like G exposures reduced homogeneously with STDWeb, analysed through 101 constant field
stars (10.5<G<14.5). The median formal error is 8.1 mmag (6.7 mmag for the bright half), and within a single night the empirical differential scatter matches it ($\chi_{\rm within}\simeq1$). Used naively - taking the pipeline's mag_calib, which lives in the instrumental pseudo-band - each
star acquires a night-level offset of 7-9 mmag, the campaign scatter grows to 11-12 mmag, and the formal error is roughly half of the true one ($\chi_{\rm camp}=1.5$-$1.7$). We show that this entire excess is the epoch-dependent colour term: analysing the catalogue-system magnitude $m_{\rm sys}$ = mag_calib + colour term x (BP-RP) collapses the night term to 3.4 mmag, restores $\chi_{\rm camp}=1.0$-$1.1$, and improves the absolute
Gaia-anchored per-
star repeatability from 43 to 9.5 mmag, with the nightly zero-point peak-to-peak shrinking from 130 to 11 mmag and the airmass and colour correlations of the residuals vanishing.
Stellar colours fitted from the light curves themselves reproduce
Gaia BP-RP to 0.027 mag (r=0.98) and yield an identical budget: the correction needs no external colour catalogue. We provide the closed variance decomposition, practical recommendations, and a cautionary note on re-deriving zero points outside the pipeline.
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Quantum Physics
RF-Budgeted Frame Compilation for Frequency-Multiplexed Superconducting-Qubit Control Using Qubit-Control Identity Records and a Circuit-Informed RFSoC Model
Mingqi Ge and Anne-Marie Valente-Feliciano
Frequency-multiplexed superconducting-
qubit control requires more than carrier assignment: the RF budget of a shared source can perturb multi-
qubit rotations through finite bandwidth, crest factor, clipping, quantization, jitter, spurs, compression, crosstalk, and leakage. We present an RF-budgeted frame-compilation and validation workflow that combines
qubit-control identity (QID) records, a MATLAB/Simulink-based
circuit-informed RFSoC source-chain model, QuTiP qutrit dynamics, and Qiskit-derived
algorithm workloads. QID records encode
qubit-specific computational and leakage transition frequencies, pulse parameters, and drive-scale calibration, while the RF-chain profile and effective crosstalk-coupling
matrix are provided as separate compiler inputs. Candidate multitone RF frames are scheduled under RF-budget constraints, propagated through the RFSoC model, decoded into computational and leakage transition frames, and evaluated in QuTiP for rotation error, leakage-aware fidelity, computational-subspace survival, and transient leakage. The studies progress from single-qutrit pulse closure to pairwise coexistence, multitone RF-frame capacity, and Bernstein-Vazirani (BV) and QAOA microwave layers extracted from Qiskit
circuits. The simulations show that longer pulses improve per-frame aggregation but do not necessarily minimize time-normalized layer cost; clustered frequency maps, larger rotations, and multitone leakage stacking tighten closure. Under the nominal RF budget, a Qiskit-derived 12-
qubit BV -Y90 layer closes in three validated four-tone frames at 240 ns, while QAOA mixer partitions vary with rotation angle and pulse duration. All reported results are model-based, decoherence-free simulation diagnostics rather than measured hardware fidelities or wiring-reduction claims.
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Astrophysics of Galaxies
GATOS: Distinct Feedback Modes in AGN Central Regions Revealed by Spatially Resolved JWST Spectroscopy
Lulu Zhang, Chris Packham, Erin K. S. Hicks et al. (+25 more)
This manuscript presents JWST MIRI/MRS observations of the central $r \approx 40-240$ pc regions of five active
galactic nuclei (AGN) spanning a wide range of luminosities (${\rm log}\,L_{\rm bol}/{\rm erg\,s^{-1}} \approx 39.8-43.8$). Combining multiphase diagnostics from polycyclic aromatic hydrocarbons (PAHs), molecular hydrogen (H$_2$), and ionized gas at spatial scales of $\sim 4-24$ pc, this study presents a spatially resolved investigation into the effects of the two distinct AGN feedback modes–radiative and kinetic–on the surrounding medium. The results indicate that these two feedback modes, associated with AGN irradiation and shock processing, respectively, collectively drive the relative suppression of PAH emission in the
nuclear regions of the targets studied here. Moreover, the coexistence of these two AGN feedback modes, especially the shock processing associated with either jets or
outflows, in the central regions of AGN naturally explains both the bimodal distribution of PAH band ratios observed in the targets studied here and the seemingly disparate results reported in the literature. Although based on a limited sample, these findings provide new insights into calibrating
star-formation rates (SFRs) from PAH emission in AGN, and more importantly, lay the groundwork for a practical framework to diagnose and quantify AGN feedback in the JWST era.
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All authors Lulu Zhang, Chris Packham, Erin K. S. Hicks, Ismael García-Bernete, Almudena Alonso-Herrero, Ric I. Davies, Martin J. Ward, Daniel E. Delaney, Takuma Izumi, Dimitra Rigopoulou, Cristina Ramos Almeida, Omaira González-Martín, Rogemar A. Riffel, Claudio Ricci, Montserrat Villar-Martín, Francoise Combes, Miguel Pereira-Santaella, Sebastian F. Hoenig, Andrew J. Bunker, Peter G. Boorman, Enrica Bellocchi, Nancy A. Levenson, Santiago García-Burillo, Fergus R. Donnan, Anelise Audibert, Lindsay Fuller, Tanio Díaz-Santos, David J. Rosario
Statistical Mechanics
A Shared Observation Shields Collective Fluctuations while Preserving Local Independence
Hu Cang
As a
liquid approaches its glass transition, its dynamics turns heterogeneous: mobile and immobile regions coexist, and the four-point susceptibility $\chi_4$ that quantifies this heterogeneity grows sharply. Interpreting that growth is subtle, because the collective signals experiments record, such as a tagged particle's trajectory, an overlap function, or a mean field, are generated by the same particles they describe. Here we compute exactly what conditioning on such a shared record does to the population that produced it, for a broad class of stochastically observed systems; the guiding example is a tagged particle and the cage of $z$ neighbors that drives its force history. Using a Girsanov path transformation, we prove that the conditioning multiplies the independent joint law of the $z$ trajectories by exactly one term: a centered-square penalty along the single collective direction the record can see. Any fixed pair of particles stays nearly independent, with covariance falling as $O(z^{-1})$ and mutual information as $O(z^{-2})$, the property known as propagation of chaos, yet the $z(z-1)$ weak pair correlations add coherently into a finite suppression of collective fluctuations, the Schur shield $D - C = -C^2(aI + C)^{-1} \preceq 0$. An exactly solvable Brownian model calibrates the construction. The physical consequence is a calculable baseline for dynamical heterogeneity: conditioning itself contributes a computable, nonpositive amount to the susceptibility of a conditioned ensemble, so the genuine cooperative signal is the excess of the measured $\chi_4$ over this baseline rather than over zero, a comparison that existing simulation data can already perform.
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Chemical Physics
Chemical potentials from structure factors: I. Neutral multi-component mixtures
Roya Savoj, Xiaoyu Wang, Musahid Ahmed et al. (+1 more)
The chemical potentials of multi-component mixtures underlie many physical and chemical phenomena, but remain challenging to compute. The S0 method enables the computation of chemical potentials from
equilibrium molecular dynamics simulations, by leveraging the thermodynamic relationship between particle number fluctuations and derivatives of chemical potentials, followed by numerical integration along different compositions. Here we generalize the S0 method from two-component mixtures to neutral multi-component mixtures. We first extend the statistical mechanical formalism to high-dimensional compositional space, and then introduce a Gaussian process integration scheme combined with active learning to efficiently integrate chemical potentials and sample diverse compositions. We use this method to compute the mixing free energies of a molten metal
alloy, and the solubilities of two paracetamol polymorphs in water-ethanol solvents. The extended S0 method provides a practical and scalable route for computing chemical potentials in neutral bulk multi-component mixtures from atomistic simulations.
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All authors Roya Savoj, Xiaoyu Wang, Musahid Ahmed, Bingqing Cheng
Mesoscale and Nanoscale Physics
Magnetoelastic coupling in stripe-domain states of yttrium iron garnet
Nimisha Arora, Daniel Prestwood, Takashi Kikkawa et al. (+4 more)
We study magnetoelastic coupling in stripe-domain
magnetic states of $3\,\mathrm{\mu m}$-thick YIG thin films grown on a GGG substrate. Broadband
ferromagnetic resonance reveals low-frequency stripe-domain
magnon branches modulated by a field-independent
phonon comb with a frequency spacing of $3.5\,\mathrm{MHz}$, matching the value predicted for confined thickness-shear modes of the GGG substrate. Analytical fitting yields coupling rates that vary between $0.33$–$0.54\,\mathrm{MHz}$ and cooperativities of order $10^{-1}$, indicating that the system is in the weak-coupling regime without resolvable avoided-crossing gaps.
Magnon-
phonon mode-overlap calculations using finite-element simulations show that the weak coupling arises from phase and domain-sign cancellation: the local magnetoelastic coupling is sizable, but more than $99\%$ of the coherent overlap cancels across the stripe texture. Fully coupled simulations further demonstrate
phonon-mediated excitation of a remote YIG layer and show that efficient propagating-
phonon generation requires spatially asymmetric
magnon modes, establishing
magnetic texture as a control parameter for
magnon–
phonon coupling.
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All authors Nimisha Arora, Daniel Prestwood, Takashi Kikkawa, Eiji Saitoh, Jack Gartside, Will Branford, Hidekazu Kurebayashi
Materials Science
Pressure-Induced Stacking Disorder and Suppression of Long-Range Sm-type Order in Medium-Entropy Rare-Earth Alloys
Raimundas Sereika, Matthew P. Clay, Kallol Chakrabarty et al. (+1 more)
Rare-earth medium-
entropy alloys provide a platform for investigating how chemical disorder modifies the well-established pressure-induced structural
evolution of close-packed $4f$ lanthanides. Here, we study TbHoEr and TbHoDy using synchrotron X-ray diffraction in diamond anvil
cells. Both
alloys transform from the ambient hexagonal close-packed (hcp) structure to a double hexagonal close-packed (dhcp) phase, while no well-resolved bulk Sm-type intermediate phase is observed. For TbHoEr, compression to 70 GPa further reveals a high-pressure rhombohedral hR24 phase. Unlike the constituent heavy lanthanides, however, both
alloys bypass the intermediate Sm-type phase. Two-dimensional diffraction images further reveal streak-like diffuse scattering in the transition region, indicating stacking disorder and limited stacking coherence along the close-packed direction. These observations indicate that the transformation proceeds through a stacking-disordered close-packed state rather than through a well-ordered bulk Sm-type phase. We propose that configurational disorder, local
lattice distortion, stacking-fault energetics, and transformation kinetics collectively suppress the development of long-range Sm-type order. The results demonstrate that medium-
entropy alloying can fundamentally modify pressure-induced stacking pathways in rare-earth materials under extreme conditions.
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All authors Raimundas Sereika, Matthew P. Clay, Kallol Chakrabarty, Yogesh K. Vohra
Disordered Systems and Neural Networks · Cross-listed from cs.LG
Correlation flow governs learning at criticality
Andrea Combette, Nelly Pustelnik and Antoine Venaille
The initialization of deep neural networks determines whether information and gradients can propagate across depth, yet a unified theory connecting these properties to learning dynamics remains elusive. Combining mean-field theory and random
matrix theory, we establish a direct link between correlation propagation and the Neural Tangent Kernel (NTK) that governs learning in the sequential limit of infinitely wide, infinitely deep networks. Correlation propagation to infinite depth is possible only at a single, critical point in the weight-bias variance plane. At this point, we leverage the algebraic decay of the end-to-end Jacobian with depth to prove that the NTK becomes exactly proportional to the output correlation at infinite depth, tying together information propagation and learning dynamics. We further show that orthogonal initialization suppresses the leading finite-size corrections present under Gaussian initialization, clarifying the respective roles of the two initialization ensembles in this limit. These theoretical predictions are validated quantitatively on finite-width, finite-depth networks. Together, these results demonstrate that orthogonal initialization and criticality are required to control the asymptotic dynamics of deep learning.
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Quantum Physics
Entanglement and non-local magic in a non-unitarily deformed non-Hermitian bipartite system
Chen-Huan Wu
Non-Hermitian degeneracies are usually discussed through spectral coalescence, whereas
entanglement is a property of eigenvectors and need not be fixed by the
eigenvalues alone. We formulate a compact bipartite model that separates these two notions. A Hermitian operator with a degenerate eigenspace is transformed by an invertible non-
unitary similarity map. The resulting
Hamiltonian is non-Hermitian and retains a non-defective degeneracy at every finite value of the non-Hermiticity parameter. For an exactly solvable two-
qubit realization, the right eigenstates evolve continuously from product states to maximally entangled states although the spectrum is unchanged. We distinguish the positive right-state reduced density
matrix from the generally non-positive biorthogonal reduction, for which
entropy may become complex. The same two-
qubit solution gives a closed partial-transpose negativity and a Schmidt-gauged non-local magic.
Entanglement grows monotonically with the non-Hermiticity parameter, whereas the non-local magic vanishes for both the product and maximally entangled limits and is largest at an intermediate coupling. In larger bipartite spaces, the Page
entropy and Haar-averaged purity provide reference values for eigenstate typicality. These diagnostics separate non-defective degeneracy, exceptional-point sensitivity, Haar-typical
entanglement, and non-stabilizer correlations without relying on a proliferation of basis-dependent spectral quantities.
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High Energy Physics (Phenomenology)
Perturbative Dissipation in Minimal Warm Inflation
Daniel J. H. Chung, Nidhi Sudhir and Lian-Tao Wang
We present an analysis of the perturbative modes of dissipation in the minimal warm inflation model where an
axion-inflaton is coupled to a
gluon thermal bath through the
axion-gauge coupling. The corresponding friction coefficient, which generically is governed by IR physics, for the processes we consider is dominated by Landau damping of soft space-like
gluons and the plasmon decay of hard on shell
gluons. Since both of these processes are IR dominated, the friction coefficient becomes sensitive to the non-perturbative
magnetic mass scale $m_{g}^{-1} \sim (\alpha T)^{-1}$ which in turn leads to the friction coefficient's overall linear proportionality to $\alpha$, which is much less suppressed in $\alpha$ powers compared to the well understood term from Chern-Simons (CS)
diffusion $(\propto \alpha^5)$. On the other hand, this contribution to the friction coefficient is suppressed due to slow roll. We show that this can be viewed as a suppression of local spontaneous CPT violation for derivative couplings in general and that time correlations of nonlocal variables which do not fall off at large time separations are what allow an unsuppressed friction coefficient.
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Physics and Society
Space–time message passing for endemic diseases
Peter Mann and Simon Dobson
Message passing is exact for progressive epidemics on trees: infection is unidirectional, and a node's neighbours are uncorrelated in the cavity graph. A recurrent disease breaks this even on a tree due to backtracking. A node infects a neighbour, recovers, and is reinfected by it, so infection traverses an edge in both directions. Unrolled along a time axis, the outward and return transmissions together with the node's own persistence in time form a closed cycle in the space–time graph, correlating the states that ordinary message passing assumes independent. We treat these correlations by solving the dynamics exactly inside a ball of radius d about an edge and closing the ball's boundary with a single conditional per-edge message. For fixed-period susceptible–infected–susceptible dynamics this generates a hierarchy of closures on the endemic state indexed by d, in which the ball of radius d treats exactly every space–time cycle of spatial reach at most d and retains the remainder only through the mean rate supplied by its boundary. Linearising the resulting message map gives the endemic threshold, with an accuracy that increases with d. We compare the hierarchy against Monte Carlo simulation on random and empirical networks, finding excellent agreement.
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Solar and Stellar Astrophysics · Cross-listed from math.AP
On the nonlinear instability of nonrotating Stars
Zhiwu Lin and Xinlin Wu
We study radial nonlinear instability of compactly supported nonrotating
equilibria of the three-dimensional Euler–Poisson system with a physical-
vacuum boundary. Let $n^u(\mu)$ denote the radial instability index furnished by the turning-point theory of Lin and Zeng. Under general structural assumptions on the pressure law, suppose that $n^u(\mu)>0$ and that the
equilibrium is not a mass extremum, $M'(\mu)\neq0$. Conditional on the existence of a sufficiently regular radial solution on the relevant time interval, we establish two nonlinear escape criteria. First, every perturbation with
Hamiltonian strictly below that of the
equilibrium exits a fixed neighborhood on a logarithmic time scale controlled by the least unstable linear growth rate. For the subclass of data for which the associated Lyapunov functional is initially nonnegative, we also obtain an explicit exponential lower bound in the weighted displacement norm. Second, sufficiently small perturbations whose Riesz projection onto the finite-dimensional unstable subspace is not too small escape on a logarithmic time scale. The second argument uses the exponential trichotomy of the linearized
Hamiltonian flow and an invariant-cone estimate. In the polytropic class, the conditional estimates combine with the radial physical-
vacuum local theory to yield unconditional nonlinear instability in the corresponding classical-solution
topology. The results complement Jang's nonlinear instability
theorem for Lane–Emden
stars by treating mechanisms that do not require initial
alignment with a leading growing eigenmode and by applying, conditionally, to unstable branches for general equations of state.
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Astrophysics of Galaxies
KCWI Discovery of a Spatially Resolved Kpc-Scale Ionized Outflow in NGC 1275
Kylie Yui Dan, Hanae Inami, Thomas Bohn et al. (+5 more)
We present new Keck
Cosmic Web Imager observations of the central few kiloparsecs of NGC 1275, the brightest cluster
galaxy of the Perseus Cluster. These integral field spectroscopic data reveal a warm-ionized
outflow traced by H$\beta$ and the [O III] doublet extending out to $\sim2.5$ kpc from the
nucleus. The warm-ionized
outflow has an [O III]-derived $v_{50}$ of up to $\sim570$ km/s, $w_{80}$ of up to $3780$ km/s, and H$\beta$-derived outflowing mass of $(2.7 \pm 0.3)\times 10^6$ M$_\odot$. Our H$\beta$-derived warm-ionized outflowing mass rate of 2.7$\pm$0.7 M$_\odot$ yr$^{-1}$ is comparable to the estimated cold molecular disk
accretion rate of 1$-$10 M$_\odot$ yr$^{-1}$, which could be a sign of self-regulation between the pc-scale cold gas feeding the active
galactic nucleus (AGN) and the warm wind accelerated out to kpc scales. In the host
galaxy, we detect an enhancement in the [O III] / H$\beta$ ratio in the direction of the receding jet, which may imply jet interaction with the host interstellar medium. The
outflow component also shows a clear enhancement of [O III] / H$\beta$ that positively correlates with $w_{80}$ and $v_{50}$, indicative of AGN influence and/or fast shocks. Both the
outflow and host
galaxy [O III] / H$\beta$ ratio decrease with increasing distance from the center, showing that the influence of the AGN is confined to the central $\sim2$ kpc. These results are the first resolved measurements of a kpc-scale ionized wind in NGC 1275 and provide a view into how both jets and winds contribute to the feedback cycles in complex cool core cluster systems.
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All authors Kylie Yui Dan, Hanae Inami, Thomas Bohn, Sylvain Veilleux, Vivian U, Tianmu Gao, Justin Kader, Rosalie McGurk
Quantum Physics
Randomness Certification and Trade-offs in the Prepare-and-Broadcast Scenario
Tailan S. Sarubi, Moisés Alves, Vinícius F. Alves et al. (+4 more)
We investigate the prepare-and-broadcast scenario, a multipartite extension of dimension-constrained prepare-and-measure experiments in which a
quantum system is distributed to multiple receivers. We derive fundamental trade-offs between prepare-and-measure witnesses, Bell nonlocality, and
quantum random access code performance. We further develop a semi-device-independent randomness certification framework based on prepare-and-broadcast witnesses, showing that the maximal
quantum violation certifies two bits of joint randomness, exceeding the limit achievable from the CHSH inequality while remaining robust to noise. Finally, we show that the prepare-and-broadcast scenario naturally accommodates stronger
adversarial models in which the eavesdropper retains a
quantum system correlated with the measurement device, providing a natural framework for semi-device-independent randomness certification against
quantum side information.
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All authors Tailan S. Sarubi, Moisés Alves, Vinícius F. Alves, Santiago Zamora, Diogo H. G. Duarte, A. de Oliveira Junior, Rafael Chaves
Statistical Mechanics
Persistence probability based dynamics and phase diagrams in biased q-voter models
Amit Pradhan, Pratik Mullick and Parongama Sen
Persistence probability in opinion dynamics models estimates the tendency of the
agents not to change their initial opinion till the present time. Here we consider two nonlinear q-voter models with binary opinions, where the dynamics are governed by a biased choice when the q panel is not unanimous. The models are studied for different parameter ranges corresponding to the known stationary states. Mean field theory and numerical simulations are used to compute the persistence probability for the two types of opinion separately. The long time behavior in general is either a saturation or a decay that can be approximated by an exponential form, depending on the chosen parameters. Based on this, phase diagrams in the parameter space are presented for both the models. The regions in the phase diagrams indicate a strong correlation with the behavior of fixed points in the corresponding models, which is non-trivial as far as the persistence probability is concerned.
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Fluid Dynamics
SDF-Aware Weighting: Adaptive Eikonal Regularisation for Three-Dimensional Level-Set Physics-Informed Neural Networks
Muhammad Akbar Khan
Adaptive loss-balancing schemes for physics-informed neural networks rest on a premise that every residual should be driven to zero. For level-set advection with an eikonal regulariser that premise fails: the eikonal term penalises deviation of $\lVert\nabla\phi\rVert$ from unity, a property transport preserves only under rigid motion; where the exact solution departs from a signed-distance function the eikonal residual of the correct answer is nonzero, and driving it to zero moves the network away from that answer. We show that standard gradient-norm balancing fails in exactly this way, its weight remaining near its initial value throughout training on
benchmarks where the property is violated, and we introduce SDF-Aware Weighting (SAW), which combines a residual-
quantile gate with a gradient-norm ratio so that points exhibiting legitimate departure are excluded before the surviving term is scaled. Across four three-dimensional
benchmarks SAW selects an eikonal weight within an order of magnitude of the value located by an eighteen-run manual sweep, spanning four decades from $10^{-1}$ to $10^{-5}$ with a single fixed configuration. On the slotted sphere, where the initial field is non-differentiable at reentrant edges, SAW attains a lower error than any weight in that sweep. Two smooth rigid
benchmarks serve as controls: SAW is worse there, as expected when its premise does not hold. An ablation with the gate disabled shows the slot is nearly entirely filled while the relative $L_2$ error reads $1.06\%$, indistinguishable from a field that never represented the slot. We give a feature-restricted measure that separates the two cases.
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Instrumentation and Methods for Astrophysics
Design and simulation of a photonic lantern-inspired astrophotonic chip for spectral sensing
Avi Patel, Kevin A. Bundy, Aditya Sengupta et al. (+10 more)
Compact astrophotonic sensors can trade general-purpose spectral coverage for task-specific wavelength discrimination in a small integrated footprint. Developed with the Mazin Lab at UC Santa Barbara, this chip couples a single-mode input into a multimode interference region and seven-port fanout, producing wavelength-dependent output power fingerprints for spectral
retrieval. Using ANSYS Lumerical FDTD simulations in silicon nitride, we compare symmetric and staggered-release geometries and quantify throughput, wavelength-dependent changes in the seven-port output distribution, and sensitivity near a 745 nm design point. We optimize over the tested
geometric parameter space and identify designs with improved throughput and wavelength discrimination, including increased throughput-weighted Fisher information relative to the baseline. These results suggest that lantern-inspired integrated photonics can enable compact, task-specific spectral sensors for astrophotonic applications.
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All authors Avi Patel, Kevin A. Bundy, Aditya Sengupta, Matthew C. DeMartino, Anna Gagnebin, Emiel Por, Majid Mohammad, Michael Arena, Aled Cuda, Kiana Ejercito, Stephen Eikenberry, Ben Mazin, Holger Schmidt
Optics
Fisher-Information Design of Ridge-Loaded Subwavelength Slits
J. Sumaya-Martinez and O. Olmos-Lopez
We present an information theoretic framework for extraordinary optical transmission through a subwavelength slit containing symmetric internal ridges. Full wave finite element spectra are interpreted with a reduced Fabry Perot model in which the ridge interfaces introduce a reactive discontinuity phase associated with modal impedance mismatch and evanescent field loading. Fisher information is used to quantify how reliably resonance positions and
geometric parameters can be inferred from transmission measurements. For an isolated Lorentzian resonance under white Gaussian noise, the Fisher information for the resonance center scales linearly with the quality factor when amplitude, sampling, and noise are fixed. We also extend the formulation to correlated Gaussian noise and Poisson shot noise, showing why the resonance with the highest Q is not necessarily the most informative under realistic experimental conditions. The framework clarifies the interpretation of ridge induced effective cavity corrections and provides a reduced order route toward Fisher information driven inverse design of subwavelength resonators.
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General Relativity and Quantum Cosmology
Apparent horizon thermodynamics in an exponential $f(Q)$ gravity model
A. Oliveros and Ivan R. Vasquez
We investigate the thermodynamics of the apparent horizon in an exponential $f(Q)$
gravity model characterized by the two parameters $b$ and $n$, within a spatially flat Friedmann–Lemaître–Robertson–Walker background and the coincident gauge. Focusing on the $n=1$ solution, we use the approximate cosmological solution for the Hubble parameter up to second order in the exponential parameter $b$ to study the
redshift evolution of the apparent-horizon radius and the Kodama–Hayward temperature. We formulate Hayward's unified first law in terms of the Misner–Sharp–Hernandez mass, the work density, and the energy-supply vector, and show that the horizon dynamics admits an
equilibrium thermodynamic description. The associated
entropy differential is proportional to $f_Q+2Qf_{QQ}$, yielding exponentially suppressed corrections to the Bekenstein–Hawking area law and recovering $S=A/4$ in the limit $b\to0$. We then examine the generalized second law (GSL) by including the
entropy of matter inside the apparent horizon. When the matter and horizon temperatures are identified, we adopt the GSL viability criterion $f_Q+2Qf_{QQ}\geq0$ previously derived in the literature. The observationally motivated best-fit values of $b$ satisfy this condition over the
redshift interval studied and produce departures from $\Lambda$CDM mainly at late times. In contrast, sufficiently large positive values, approximately $b>0.26$, can violate the GSL in the future region $z<0$. These results show that apparent-horizon thermodynamics provides a complementary constraint on the parameter space of exponential $f(Q)$ cosmology.
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Instrumentation and Methods for Astrophysics
Design evolution for the Wide-field Spectroscopic Telescope
Will Saunders, Corentin Cudennec, Roland Bacon et al. (+4 more)
WST is proposed as the next large ESO project to follow ELT, combining Multi-Object Spectroscopy and Integral Field Spectroscopy. Each mode offers order-of-magnitude gains over current systems, and each also presents unprecedented design challenges, both separately and in combination. For large MOS systems, both science performance and spectrograph costs vary steeply with the delivered image quality, so exceptional delivered image quality is paramount. But the 12m aperture and 2 degree field give WST an etendue larger than Rubin, larger that LAMOST, and larger than all other existing MOS
telescopes combined; while the IFS, segmented primary and windy site all add additional constraints. Hence finding designs with good image quality is challenging. Eventually, 3-lens Forward Cassegrain designs with loss-less ADC were developed in variants mostly differentiated by M2 diameter. The lowest technical risk design, with the smallest M2, was selected as the baseline, with wind-shake control a primary driver. However, other designs have better as-designed image quality, and their perceived risks may diminish as the system design and underlying technologies mature. For IFS mode, delivered image quality is just as crucial, but this is achieved through additional optics and NGS GLAO over the 3'x3' field. The challenges come from (a) transferring the F/3.4 Forward Cassegrain focus to a fixed focus under the
telescope; (b) a requirement that the 3'x3' field be selectable from a 13' diameter FoV without repointing the
telescope; (c) including a suitably conjugated mirror for GLAO correction; (d) doing all this with minimised vignetting and surface count. Various designs were explored; the baseline design has a field-selecting pick-off at
telescope focus, combined with large reimaging optics at Nasmyth, giving an F/28.5 fixed IFS focus.
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All authors Will Saunders, Corentin Cudennec, Roland Bacon, Philippe Dierickx, Roelof de Jong, David Lee, Gaston Gausachs
Materials Science
An Interfacial Balance Rule Governs Binder-Electrolyte Coupling in Lead-Free Perovskite Energy Storage
Arun Kumar, Ayush Kumar Pandey, Ankur Yadav et al. (+4 more)
Electrode binders are conventionally regarded as inert structural components. Here, we show that in lead-free perovskite supercapacitors, the binder defines the optimal electrolyte composition. Across a factorial
matrix of poly(vinylidene fluoride) (PVDF) loadings and LiTFSI concentrations in CsSnCl$_3$ electrodes, the capacitance optimum shifts systematically with binder content along a single linear relationship, described by the Interfacial Balance Rule ($\lambda+\theta=1$), where $\lambda$ and $\theta$ are the normalized lithium-supply and
polymer contributions at the optimized interfacial state. The same relationship holds for hybrid MASnCl$_3$, showing that the optimum is governed by the
polymer-electrolyte interface rather than the perovskite
lattice chemistry. Simulations using a pre-trained MACE machine-learned interatomic potential show that PVDF adopts a planar configuration on CsSnCl$_3$ and simultaneously interacts with cationic and anionic sites. This configuration homogenizes lithium adsorption energetics, introduces fluorine-mediated coordination, and confines lithium to a two-dimensional interfacial region while preserving lateral mobility. Tuning
polymer coverage through surface density and chain length reveals a finite interfacial lithium accommodation capacity that marks the onset of out-of-plane aggregation. The Interfacial Balance Rule provides a macroscopic descriptor of this finite interfacial resource, balancing
polymer-mediated lithium stabilization against limited accommodation space. Binder loading is therefore an active design parameter for
polymer-regulated energy-storage interfaces.
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All authors Arun Kumar, Ayush Kumar Pandey, Ankur Yadav, Vishnu Saraswat, Shiladitya Sengupta, Abhishek Tewari, Monojit Bag
High Energy Physics (Theory)
Complex CFTs: Holography and Interfaces
Luis Camargo-Carlos and Michael Gutperle
We investigate complex conformal field theories and interfaces between such theories, using methods of holography and two dimensional CFT. We use holography to prove the Im-flip property of complex conjugate CFTs. We construct a complex Janus solution and calculate some
holographic observables. Complex RG-flow interfaces are obtained numerically. On the CFT side, complex interfaces are constructed for free
boson CFTs with and without background charge. Boundary states are constructed, and transmission and reflection coefficients are calculated in both cases.
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Quantum Physics
Machine Learning for Specialized QKD Aspects: A Survey of Adaptive Protocols, Free-Space Links, 6G Integration, and Steerability-Aware Security
Hasan Abbas Al-Mohammed and Afnan S. Al-Ali
Quantum Key Distribution (QKD) provides information-theoretic security grounded in the laws of
quantum mechanics, yet practical deployment increasingly extends beyond conventional point-to-point fiber links. Several rapidly emerging QKD directions are often studied separately, including adaptive protocol and parameter support; free-space, satellite,
UAV, and high-altitude platform (HAP) channels; integration with IoT and 6G networks;
quantum-secured
federated learning;
Quantum Machine Learning (QML) assisted decision support; and steerability-aware estimation for one-sided device-independent QKD. This survey examines how Machine Learning (ML), Reinforcement Learning (RL), and QML address these specialized scenarios and organizes the literature into five thematic pillars: (I) adaptive protocol and parameter support; (II) free-space, satellite,
UAV, and HAP-assisted QKD; (III) QKD for IoT, 6G, and
quantum-secured
federated learning; (IV) QML-assisted QKD functions; and (V) steerability-aware and one-sided device-independent QKD security estimation. For each theme, we follow a consistent problem, conventional solution, and ML/RL/QML solution structure and summarize reported gains using metrics such as accuracy, mean absolute percentage error, QBER reduction, and secret key rate improvement. We further provide thematic and cross-theme comparison tables and identify open challenges, including
dataset scarcity, transferability across weather and mobility conditions, interpretability, trustworthy QML, and the boundary between ML-based decision support and security certification. This survey serves as a focused reference for adaptive, non-terrestrial, and application-integrated QKD systems.
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Quantum Physics
Energetic Cost of Temporal Information Processing in Quantum Reservoirs
Gabriele Cenedese, Gonzalo Manzano, Gian Luca Giorgi et al. (+1 more)
Quantum reservoir computing offers a promising route toward energy-efficient machine learning by processing temporal information with minimal training overhead. Yet, the physical principles linking its energetic cost to computational performance remain largely unexplored. Here we show that, in an interacting
spin reservoir, information encoding and information processing are governed by distinct physical mechanisms. In the weak interacting regime, we derive an analytical expression for the average (switching) work, showing that the energetic cost of encoding new inputs is determined by the local response of the reservoir units. In contrast, interactions primarily redistribute the encoded information, generating
memory and nonlinear features while only weakly affecting the work. This separation produces opposite correlations between energetic cost and performance for representative linear and nonlinear
benchmark tasks. Our results identify the switching work as the energetic signature of information encoding and clarify when energetic efficiency and computational performance are compatible.
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All authors Gabriele Cenedese, Gonzalo Manzano, Gian Luca Giorgi, Roberta Zambrini
Astrophysics of Galaxies
The Quasar Feedback Survey: Ionised Outflows in type 2 QSOs with MUSE data
M. Bianchin, C. M. Harrison, T. Costa et al. (+13 more)
We study ionised gas properties in a sample of 18 luminous (log L$_{\rm bol}\geq45$ erg/s) obscured QSOs at 0.085<z<0.2 observed with VLT/MUSE as part of the multi-wavelength
Quasar Feedback Survey (QFeedS) and with VLA at low- and high-resolution data. We compare the
outflow-related quantities with values reported in the literature and investigate possible correlations between the
outflows and other properties of the ionised gas such as the electron density. We adopt a non-parametric approach to characterise the ionised gas kinematics, traced by the [O III]5007 emission line, and use $W_{80}$ measured from the unresolved
nuclear spectra as a threshold to identify
outflow-dominated spaxels. A qualitative comparison between the
radio and the $W_{80}$ maps shows that, in general, the peak of the
radio coincides with the peak of the $W_{80}$. The [O III]5007 is used as a proxy for the ionised gas mass, and the
outflow-related properties are obtained in two different ways: the global, which uses flux-weighted velocities and radii; and the peak, relying on radial profiles. We correct the [O III]5007 flux for extinction using the Balmer decrement. We take advantage of the MUSE sensitivity and use the [Ar IV]4711,4740 doublet, only observable in the integrated r=1.5” spectra, to measure the electron density in each
galaxy. We obtain $500<n_{e}{\rm[ cm^{-3}]}<27700$, leading to 0.03$<\dot{M}_{\rm out}/{\rm (M_{\odot} yr^{-1})}<$4.17 and $39<\dot{E}_{\rm kin}/{\rm [erg/s]}<42$. Our results emphasise the importance of accurate n$_e$ determination, leading to a difference of ~1 dex in the
outflow rates and kinetic powers. We observe a positive correlation between $n_e$ and $V_{\rm out}$, interpreted as compression of the gas at higher velocities. This correlation should be further investigated at other luminosity and
redshift ranges, but it can inform future
outflow simulation studies.
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All authors M. Bianchin, C. M. Harrison, T. Costa, V. Mainieri, R. A. Riffel, G. Venturi, D. Kakkad, C. Ramos Almeida, P. H. Cezar, S. Ward, A. Girdhar, S. Molyneux, L. Ulivi, E. P. Farina, J. Mullaney, F. Arrigoni Battaia
Quantum Physics
Toward Standardized Quantum Provenance: A Cross-Provider Analysis, Unified API, and Reference Prototype
Jouni Peltonen, Vlad Stirbu, Tommi Mikkonen et al. (+1 more)
Quantum software development requires provenance describing programs, compilation, execution, hardware characterization, results, and software environments, but providers expose this information through heterogeneous software development kits, application programming interfaces, and resource models. We analyze publicly documented provenance access across 15
quantum platforms spanning five hardware technologies and find fragmented, incomplete coverage, with compilation provenance weakest. We propose an evidence-aware OpenAPI 3.1 provenance contract and provider-adapter architecture, evaluated through a fixture-backed reference prototype at QMill covering Amazon Braket, IBM
Quantum, and IonQ. All records validate against one common contract while preserving provider-specific semantics, explicit evidence origins, and graceful handling of incomplete data.
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All authors Jouni Peltonen, Vlad Stirbu, Tommi Mikkonen, Cesare Pautasso
Quantum Physics
Yanli Shi, Xiwen Zhang, Yuri Shvyd'ko et al. (+1 more)
Nuclear quantum memories in the hard X-ray regime offer some key advantages over their optical counterparts, such as broader bandwidth and lower background noise. A Doppler frequency comb protocol has been theoretically proposed [X. Zhang et al., Phys. Rev. Lett. 123, 250504 (2019)] and recently demonstrated experimentally [S. Velten et al., Sci. Adv. 10, eadn9825 (2024)] for the storage and
retrieval of X-ray
photons. However, achieving on-demand
retrieval remains challenging because of the requirement for precise and synchronous mechanical motion of multiple absorbers. We propose a hybrid,
magnetic-Doppler
nuclear frequency comb composed of Doppler-shifted resonant absorbers with lifted
nuclear spin degeneracy, which expands the Doppler comb structure. By synchronously reversing the directions of both the
magnetic fields and absorber velocities, the system achieves time-reversed phase
evolution dynamics that allows for efficient on-demand
photon retrieval with significantly reduced mechanical complexity.
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All authors Yanli Shi, Xiwen Zhang, Yuri Shvyd'ko, Olga Kocharovskaya
Strongly Correlated Electrons
Quantum Formulation of Chiral Vortical Effect in Weyl Semi-metals
B. Q. Song
The
chiral vortical effect (CVE) is the generation of an axial current in a rotating Weyl
fermion; its description is presently based on semiclassical frameworks. In this work, we develop a fully
quantum formulation for CVE, solving the exact
evolution of microscopic spinful wavefunctions, which enables a bottom-up quantitative test of semi-classical theories and postulated distributions $f_{\text{CVE}}$ in different reference frames. Notably, it shows that $f_{\text{CVE}}$ is over a ground-state-free Floquet spectrum, qualitatively distinct from a thermal
equilibrium distribution (i.e.,
fermi form $f_F$), underscoring CVE as a non-
equilibrium phenomenon, distinguished from other
chiral transports. The $f_F$ only approximately holds when three conditions are simultaneously fulfilled: (1) slow rotation $\omega R/v_F\ll 1$, (2) high chemical potential $\mu/(\hbar v_F R)\gg 1$, (3) isotropic
symmetry, where $R$ is the size, $v_F$ is
fermi velocity. In these conditions, the theory recovers established semiclassical results, including the current-response coefficients and the magnetization contribution; otherwise, it uncovers
quantum phenomena such as “void states", deviation from the semiclassical formula $j_{\text{CVE}} \sim \mu^2$, a $v_F$-independent charge pumping. The theory is based on semimetals, providing more experimentally accessible detection than fundamental Weyl particles.
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Quantum Physics
Quantum-classical crossover in noisy monitored oscillators
Joseph M. Ryan, Simon Gorbaty, Stephen W. Teitsworth et al. (+1 more)
The
quantum first-passage problem involves
stochastic trajectories conditioned on measurement outcomes. The timing statistics of such trajectories remain largely unexplored in open
quantum systems. Here, we investigate the first-passage time to an energy threshold for a ubiquitous model: a harmonic oscillator driven by classical additive noise. We find that projective measurements and energy quantization lead to substantial differences between the
quantum and classical first-passage-time distributions at low thresholds, while these differences gradually diminish as the threshold energy increases. We treat the problem using both ensemble-averaged conditioned density-
matrix dynamics and trajectory-resolved
stochastic pure-state dynamics. The two descriptions yield indistinguishable timing statistics. Quantization effects appear in the ensemble-level phase-space distributions of the surviving states and vanish at larger threshold energies. Individual trajectories reveal emergent
quantum signatures from the repeated measurements, such as persistent Wigner negativity. Our results provide a framework for using first-passage processes to create measurement-induced nonclassical resource states and to study the
quantum-classical crossover of monitored systems.
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All authors Joseph M. Ryan, Simon Gorbaty, Stephen W. Teitsworth, Crystal Noel
High Energy Physics (Phenomenology)
Topological analysis of scale-invariant spatial fluctuations in ultrarelativistic heavy-ion collisions
Salman Khurshid Malik, Ramni Gupta, Fakhar Ul Haider et al. (+1 more)
The QGP-to-hadronic matter phase transition and QCD critical point in heavy-ion collisions can be identified by studying spatial fluctuations among final-state particles using intermittency analysis. First CMC-based intermittency analysis in the two-dimensional angular ($\eta$, $\varphi$) phase space, using EPOS as the background model is presented. Critical fluctuation signals are extremely weak, constituting only a few percent of the total event sample and are severely diluted by the overwhelming non-critical background, rendering traditional intermittency analyses insufficient for reliable signal extraction. To extract the weak critical signal, we employ a two-stage topological machine learning framework combining Topological Data Analysis (TDA) with deep learning. In the first stage, particle events are represented as two-dimensional point clouds and a Delaunay-based sub-level set filtration is constructed to extract Betti curves as multiscale topological invariants, corrected for multiplicity bias via azimuthal randomisation and classified by two complementary architectures, a TopoPointNet (TPN) and Boosted Decision Trees (BDT). Since event-level classification alone is insufficient to restore the critical scaling, a second stage applies a particle-level density filter, explicitly stripping away the diffuse thermal background and isolating the densely packed critical clusters. The two stage pipeline successfully restores the power-law scaling of the normalized factorial moments, enabling accurate recovery of the intermittency index in ($\eta$, $\varphi$) space and establishing topological machine learning as a robust data driven tool for probing the QCD critical point and the phase structure of strongly interacting matter in heavy-ion collisions at LHC energies.
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All authors Salman Khurshid Malik, Ramni Gupta, Fakhar Ul Haider, Balwan Singh