Strongly Correlated Electrons
Thermal Hall Resistivity as a Unifying Description of Phonon Thermal Hall Effect in Various Insulators
Dirui Wu, Ying Kit Tsui, Xavier Loh et al. (+8 more)
A considerable
phonon thermal
Hall effect was recently discovered across a diverse collection of materials. To clarify this enigmatic thermal
Hall response in various
insulators, we investigate the doped Mott
insulator La$_{5/3}$Sr$_{1/3}$NiO$_4$ as an example material system and reveal a characteristic
phonon-dominated thermal
Hall effect. As a sensitive probe of the transverse thermal response, the thermal
Hall resistivity $w_{xy}$ exhibits an insulating-like temperature dependence $w_{xy}(T)$, a linear
magnetic-field dependence $w_{xy}(H)$ near $H=0$, and a $T$-linear thermal
Hall angle at low temperatures. The presence of similar phenomena across a series of
insulators suggests that $w_{xy}$ serves as a unifying description of
phonon thermal
Hall effect, corroborated by an apparent correlation between the insulating-like $w_{xy}(T)$ and material's localized electronic state.
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All authors Dirui Wu, Ying Kit Tsui, Xavier Loh, Minseong Lee, Eun Sang Choi, Takao Sasagawa, Toshimitsu Ito, Xiao Renshaw Wang, Pinaki Sengupta, Xinyang Zhang, Christos Panagopoulos
Instrumentation and Methods for Astrophysics
Infrasound Newtonian Noise Estimation at the Einstein Telescope Candidate Site Sos Enattos
Wathela Alhassan, D. Rosinska, M. Suchenek et al. (+2 more)
We investigate the seasonal variability of atmospheric infrasound and its contribution to Newtonian noise (NN) at the Sos Enattos site, a leading candidate location for the Einstein
Telescope (ET). Infrasound data recorded at three stations, SOE0 (surface), SOE1 ($-84$ m) and SOE3 ($-160$ m), are analysed over multiple seasons to characterise both the temporal variability and the depth dependence of the acoustic field. At the surface, the median amplitude spectral density (ASD) at 1 Hz shows no consistent seasonal modulation, and its variability is driven primarily by wind; the apparent dependence on sea state largely reflects its correlation with wind speed. Underground, where local wind noise is suppressed, a winter maximum of 4–7 dB above the quietest season is observed in both years of data. Using the measured sound-pressure spectra, we estimate the corresponding NN contribution for an underground cavern with the dimensions foreseen for ET, assuming an isotropic field of acoustic plane waves. The surface pressure field, acting through the atmosphere above a test mass at 200 m depth, exceeds the ET-D design sensitivity in median conditions between 1.6 and 7.1 Hz, by up to a factor of 4.7. Inside the cavern, the median NN remains a factor of 1.4 below ET-D with the pressure measured at SOE1, but exceeds it between 2.5 and 8.7 Hz, by up to a factor of 3.5, with the pressure measured at SOE3. The attenuation is not monotonic with depth: the deeper station SOE3 shows higher levels than SOE1 above a few hertz, pointing to local, anthropogenic sources in the underground infrastructure. These results show that underground placement is essential but not sufficient on its own, and that the acoustic emission of the underground infrastructure and future laboratory equipment will require careful evaluation and mitigation to keep atmospheric NN below the ET design sensitivity.
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All authors Wathela Alhassan, D. Rosinska, M. Suchenek, E. Fenyvesi, T. Bulik
Fluid Dynamics
A physics-assisted deep neural network-based closure framework for velocity gradient dynamics in compressible flows with vibrational non-equilibrium
Deep Shikha and Sawan S Sinha
In this study, we propose a dynamical model for the
evolution of velocity gradients in compressible turbulent flows with vibrational non-
equilibrium effects, using physics-assisted deep neural networks. Such models provide a powerful framework for understanding the nonlinear physics associated with small-scale structures. In compressible flows, the influence of thermodynamic fields on velocity-gradient dynamics is represented through thermodynamic gradient field (TGF) tensor. The TGF tensor is one of the primary unclosed terms in velocity-gradient
evolution equations. The TGF tensor comprises contributions from the pressure-Hessian tensor, $\rho\boldsymbol{H}$, and the baroclinic tensor, $\boldsymbol{B}$. Accordingly, the proposed framework incorporates closures for both $\boldsymbol{H}$ and $\boldsymbol{B}$ tensor dynamics. Building upon existing phenomenological closures for the $\boldsymbol{H}$ tensor governing mechanisms, we develop a neural-network-based closure for the inviscid mechanism responsible for generating the $\boldsymbol{B}$ tensor. Unlike the other recently used tensor bases, the presented work employs a novel tensor basis allowing for the inclusion of non-symmetric features in the model. The framework also incorporates a data-driven closure for vibrational non-
equilibrium effects.The resulting framework combines phenomenological and data-driven representations of various $\boldsymbol{H}$ and $\boldsymbol{B}$ tensors governing mechanisms, termed as the hybrid enhanced homogenized Euler equation (H-EHEE) model. Model predictions are evaluated across a range of turbulent Mach numbers and compared against direct numerical simulation (DNS) data and existing compressible velocity-gradient models. The H-EHEE model exhibits close agreement with DNS statistics and provides significant improvements over existing models, particularly in highly compressible flow regimes.
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Computational Physics
Matrix-free phase-field modeling of fracture in micromechanical testing simulations of inelastic materials
Fabio Di Gioacchino, Rezgar Shakeri, Zachary Atkins et al. (+4 more)
Resolving steep damage gradients across diffuse cracks in the phase-field modeling of fracture favors the use of high-order finite elements, for which
matrix-free methods can provide superior performance and scalability. Here, we implement the Peric & Dettmer constitutive framework for visco-elastoplastic materials in an open source solid mechanics library supporting
matrix-free operators for high-order finite elements with p-multigrid preconditioning on GPUs. We introduce a rheological fracture element assembled in series with the Peric & Dettmer block, keeping fracture and inelastic material properties mutually independent. We conduct numerical simulations of tensile and compressive quasistatic tests on synthetic particle-
matrix microstructures using an El Capitan high-performance computing prototype. The results reproduce representative inelastic responses and fracture patterns, including X-shaped cracking observed in
polymer-bonded explosives and cup-and-cone fracture in ductile metals.
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All authors Fabio Di Gioacchino, Rezgar Shakeri, Zachary Atkins, Karen Stengel, Layla Ghaffari, Jeremy Thompson, Jed Brown
Mesoscale and Nanoscale Physics
Exceptional-Point Geometry of Weak Topological Boundary States
Rafael A. Molina, Kevin González and Pedro A. Orellana
In this article, we demonstrate that weak
topology can be formulated geometrically in terms of exceptional singularities of an analytically continued Bloch
Hamiltonian. A general plaquette
chiral model in two dimensions serves as a minimal realization of dual weak
topology, possessing two independent families of weak topological invariants, one for each spatial direction. The weak-topological edge states correspond to exceptional points in complex momentum space, while corner zero modes emerge from exceptional curves obtained by complexifying both momenta. Compact localized states arise when the exceptional roots collapse to the origin. This framework provides a unified complex-momentum description of edge, corner, and compact localization.
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Superconductivity
Magnetically memorable inductance in superconducting multilayer resonators
R. Tyumenev, D. S. Kalashnikov, B. V. Fradkin et al. (+10 more)
Superconductor-ferromagnet hybrid structures with tunable kinetic inductance are promising elements for neuromorphic and
quantum computing
circuits. We report the fabrication and microwave characterization of split-ring resonators based on Nb/Co/Nb/Co/Nb/Al
spin-trigger multilayers and demonstrate a non-volatile
spin-valve effect on their resonant properties. Reversal of the relative magnetization orientation of the cobalt layers produces a reproducible shift of the resonant frequency up to 4 MHz at zero applied
magnetic field, corresponding to a change in the kinetic inductance of the structure. The incorporation of a proximitized aluminum overlayer is shown to enhance the inductance contrast between the parallel and antiparallel
magnetic states by a factor of approximately three relative to structures without this layer. The experimental results are in quantitative agreement with a microscopic model based on the Usadel equations. The demonstrated
magnetic memory of the resonant frequency at zero field establishes
spin-trigger multilayers as viable field-programmable inductive elements for superconducting digital and neuromorphic
circuits.
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All authors R. Tyumenev, D. S. Kalashnikov, B. V. Fradkin, A. A. Neilo, A. G. Shishkin, N. V. Klenov, I. I. Soloviev, A. A. Golubov, M. Yu. Kupriyanov, I. A. Golovchanskiy, V. S. Stolyarov, A. S. Sidorenko, S. V. Bakurskiy
Nuclear Theory
Impact of Baryon anti-Baryon annihilation on hyperon ($\Lambda$, $\bar\Lambda$) production and apparent strangeness enhancement in $\bar\Lambda/\bar{p}$ in heavy ion collisions at SPS energy
Ekata Nandy and Subhasis Chattopadhyay
A deconfined medium of
quarks and
gluon, called the
Quark-
Gluon Plasma (QGP) is produced when heavy-
nuclei are collided at relativistic energies. The QGP formation is often characterized by a phenomenon called strangeness enhancement where, the relative production of strange-to-non-strange particles are enhanced in central collisions compared to peripheral or
proton-
proton interactions. Besides the enhancement in K/$\pi$ ratios, a non-monotonic energy dependence was also reported for $\bar{\Lambda}$ to $\bar{p}$ ratios at CERN SPS, attributed to a signature for the strangeness enhancement as well. As anti-particles are produced directly from the reaction, the $\bar{\Lambda}$/$\bar{p}$ ratios are considered as a cleaner probe for the strangeness enhancement. However, at this energy range hadronic interactions have a dominant role to play and, importantly for $\bar{\Lambda}$ and $\bar{p}$, processes like
baryon-anti-
baryon ($\mathrm{B\bar{B}}$) annihilation can have a significant impact. In this work, we use a hadronic transport model UrQMD, to investigate the role of
baryon-anti-
baryon ($\mathrm{B\bar{B}}$) annihilation on $\Lambda$, $\bar{\Lambda}$ hyperon production and its effect on $\bar{\Lambda}$/$\bar{p}$ ratios. The UrQMD calculations that include $\mathrm{B\bar{B}}$ annihilation can produce the trend of average transverse mass spectra for $\Lambda$ and $\bar{\Lambda}$, as well as, the characteristic enhancement in $\bar{\Lambda}$/$\bar{p}$ ratios in data as a function of centrality and collision energy. Furthermore, $\bar{\Lambda}$/$\bar{p}$ ratios extracted from the feed-down corrected SPS data are seen to be in good agreement with UrQMD model calculations with $\mathrm{B\bar{B}}$ annihilation. This suggests that $\bar{\Lambda}$/$\bar{p}$ enhancement is not necessarily because of strangeness enhancement and $\mathrm{B\bar{B}}$ annihilation has a significant role to play.
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Mesoscale and Nanoscale Physics
End-State-Controlled Quantum Transport in Armchair Graphene Nanoribbon Artificial Quantum Materials
David M T Kuo
Artificial
quantum materials based on atomically precise
graphene nanostructures provide an ideal platform for exploring
quantum phenomena arising from localized electronic states. Here, we develop a real-space theoretical framework to elucidate the microscopic origin of interface states in
graphene architectures composed of $n$-triangulenes and armchair
graphene nanoribbons (AGNRs). By continuously tuning the coupling between
graphene building blocks, we reveal the
evolution of triangulene zero-energy modes and AGNR end states into compact localized node orbitals at three-arm junctions. For the
chiral bipartite junctions considered here, the number and sublattice character of these node orbitals follow a general counting relation, $N_{node,\delta}=|N_{es,t,A(B)}-N_{tri,0,B(A)}|$, where $N_{es,t}$ is the total number of AGNR end states contributed by the three AGNR arms and $N_{tri,0}$ is the number of triangulene zero-energy modes. The resulting node-orbital chirality is determined by the dominant constituent: when $N_{es,t}>N_{tri,0}$, they inherit the sublattice chirality of the AGNR end states ($\delta=A(B)$), whereas for $N_{tri,0}>N_{es,t}$ they inherit that of the triangulene zero-energy modes ($\delta=B(A)$). Using experimentally synthesized triangulene nanographenes as representative examples, we further identify their low-energy zero-mode structure and investigate its manifestation in tunneling transport within an extended Anderson framework. Finally, we demonstrate that these node orbitals can serve as elementary building blocks for constructing artificial
graphene nanoribbons with highly tunable flat subbands near the
Fermi energy. The resulting compact localized states exhibit controllable degeneracy and strongly anisotropic
quantum transport.
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Astrophysics of Galaxies
What's Missing in AGN Feedback? Lessons learnt from Magneticum, IllustrisTNG and Simba
D. T. Mazengo, P. Popesso, I. Marini et al. (+20 more)
Accurately balancing gas reservoirs,
star formation, and feedback across
cosmic time remains a central challenge for
galaxy formation models in modern hydrodynamical simulations. While different feedback prescriptions reproduce selected local
galaxy properties with varying success, the most pronounced discrepancies emerge in predictions for the hot gas content of dark matter
halos. We examine three state-of-the-art cosmological simulations: Magneticum, IllustrisTNG, and SIMBA, which struggle to simultaneously reproduce observed
galaxy and
halo gas properties in the local Universe. We confront their predictions with spatially resolved
galaxy data from MaNGA and recent constraints on the hot gas mass fraction-
halo mass (fgas-Mh) relation from eROSITA and Sunyaev-Zel'dovich (SZ) measurements. Reproducing the observed fgas-Mh relation requires strong active
galactic nucleus (AGN) feedback. However, such feedback often leads to excessive quenching in simulated
galaxy populations. Magneticum and SIMBA match the observed gas fraction relation but predict an overabundance of quenched
galaxies. In contrast, IllustrisTNG implements weaker AGN feedback, yielding more realistic
star-forming fractions but systematically overpredicting hot gas masses in massive groups and poor clusters. Overall, these tensions indicate current feedback models remain incomplete, not only in the total energy injected but also in the timing, location, and coupling of this energy to the surrounding gas. Our results therefore highlight the need to revisit subgrid feedback prescriptions and develop more self-consistent models capable of simultaneously regulating
galaxy growth and the thermodynamic properties of
halo gas. Motivated by this discrepancy, a companion study will explore whether the feedback strengths required to match
halo gas constraints inevitably lead to overquenching and distorted
galaxy demographics.
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All authors D. T. Mazengo, P. Popesso, I. Marini, L. M. Valenzuela, N. de Isídio, V. Toptun, Mirjana Pović, Petri Väisänen, J. M. Sunzu, R.-S. Remus, V. Biffi, K. Dolag, R. Davé, A. Fraser-McKelvie, A. Dev, S. Vladutescu-Zopp, A. Merloni, G. Ponti, C. Aydar, S. Shreeram, L. A. Kahinga, J. O. Chibueze, P. Privatus
High Energy Physics (Theory)
Energy-Energy Correlators at Strong Coupling
Max Jackson, Lecheng Ren, Bo Wang et al. (+1 more)
We study energy-energy correlators (EEC) in planar $\mathcal{N}=4$ super Yang-Mills theory at strong 't Hooft coupling $\lambda$. We consider the EEC in states created by half-BPS operators of arbitrary dimension $p$, and determine the corresponding event-shape function up to order $\lambda^{-3/2}$ from the worldsheet representation of the AdS Virasoro-Shapiro amplitude with Kaluza-Klein external states. For $p=2$ we compute the second
curvature correction, which completes the EEC through order $\lambda^{-2}$; the new contribution improves the agreement with recently derived non-perturbative bounds at intermediate coupling. We further develop a complementary method in which the strong-coupling expansion coefficients of the EEC are extracted directly from the Wilson coefficients of low-energy expansion of the AdS Virasoro-Shapiro amplitude, and find the two approaches in perfect agreement.
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All authors Max Jackson, Lecheng Ren, Bo Wang, Congkao Wen
Instrumentation and Methods for Astrophysics
Fast Inference on Astronomical Time Series with Trans-Dimensional Flow Matching Posterior Estimation
Nina van der Meulen, Tin Hadži Veljković, Daniela Huppenkothen et al. (+2 more)
The analysis of time series plays an important part in the study of (fast) transient events, including gamma-ray bursts, magnetar bursts, fast
radio bursts, and
solar flares. A common approach is to decompose the time series into pulses and study the pulse characteristics, such as location and amplitude, in order to constrain physical models of the source and its environment. However, estimating both the number and characteristics of these pulses presents a trans-dimensional inference problem that traditional sampling methods such as Markov Chain Monte Carlo (MCMC) and Nested Sampling struggle to solve efficiently. Simulation-based inference methods, often incorporating machine learning techniques, provide an alternative approach when traditional approaches are insufficient. Here, we introduce trans-dimensional Flow Matching Posterior Estimation (t-FMPE) implemented on a
transformer architecture capable of efficient, amortized trans-dimensional inference on uniformly sampled univariate time series data. In this initial study, we apply the method to three test cases: simulated time series with known ground-truth parameters, observational data of Fast
Radio Bursts and observations of X-ray bursts from magnetars. We show that t-FMPE achieves qualitative agreement with MCMC reference posteriors, successfully reproducing parameter correlations, as quantified through classifier two-sample tests. The trained network performs inference several orders of magnitude faster than MCMC and nested sampling, reaching sampling rates of 100 posterior samples per second for an 80-dimensional parameter space. The results demonstrate potential of t-FMPE for large-scale analysis of time series
datasets when traditional sampling methods become infeasible, and also enable inferring unbiased posteriors in the presence of observational biases such as dead time.
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All authors Nina van der Meulen, Tin Hadži Veljković, Daniela Huppenkothen, Benjamin Kurt Miller, Christoph Weniger
Soft Condensed Matter
Helical stability of double-stranded semiflexible chains with interstrand interactions
Farisan Dary, Donn Liew, Haiyi Liang et al. (+1 more)
The mechanical and structural properties of dsDNA have been successfully described by models with varying levels of complexity and coarse-graining schemes. Prior work has characterized local stacking/twist effects and force-torque phase diagrams under external constraints. However, the role of base-pairing and torsional elasticity in global morphological transitions remain poorly characterized in the absence of external constraints. Here we investigate the delicate balance required for the strength of base-pairing interactions and the twisting energy to preserve the double-helix structure in a model made up of two semiflexible chains. We found that the model exhibits several distinct morphological phases: flat, random coil, double-helix, and the unwound double-helix. We calculate the Gauss linking number to characterize transitions between these phases.
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All authors Farisan Dary, Donn Liew, Haiyi Liang, Ee Hou Yong
Cosmology and Nongalactic Astrophysics
Inferences for f(R) Models from Late-Time Megamaser Observational Data
Umang, Abha Dev Habib and Nisha Rani
In this work, we study three widely used models of f(R)
gravity, namely HuSawicki, Starobinsky and ArcTanh along with the standard cosmology model ($\Lambda$CDM). For this, we employ the megamaser angular diameter distance and velocity measurements from the Megamaser Cosmology Project, which provide a purely
geometric determination of the Hubble constant. We constrain the parameters using the Markov Chain Monte Carlo method. Our results show that values of the Hubble Constant, $H_{0}$, obtained for all four models are in concordance with its value obtained from other late-time observational data such as SNe Ia. The constraints on $H_{0}$ in all the models under study are restrictive and the marginalized estimates lie close to 73 $\mathrm {km s^{-1} Mpc^{-1}}$. The marginalized estimates of the deviation parameter, b, for the three f(R)
gravity models lie close to zero. This late-time
dataset, thus predicts that f(R) models mimic $\Lambda$CDM. However, the matter density, $\Omega_m$, remains weakly constrained for all the models with its marginalized estimate close to 0.5. Further, comparison of the four models (f(R) models and $\Lambda$CDM) using information criteria such as Akaike Information Criterion and
Bayesian Information Criterion shows that within current uncertainties, the
dataset finds f(R) models statistically indistinguishable from $\Lambda$CDM. This is consistent with the fact that the favoured value of b for each of the f(R) models lies close to zero.
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High Energy Physics (Theory)
Andrea Campoleoni and Lea Mele
Electric and
magnetic Carrollian actions for
fermions of arbitrary
spin in any spacetime dimension are defined as inequivalent $c \to 0$ limits of the relativistic Fang-Fronsdal actions.
Astrophysics of Galaxies
MIGHTEE: The Host-Galaxy Associated Catalogue of the Radio Sources in MIGHTEE Continuum Data Release 1
C. L. Hale, J. Hamlett, I. H. Whittam et al. (+34 more)
Radio continuum surveys provide samples of active
galactic nuclei (AGN) and
star forming
galaxies (SFGs) to high
redshifts, free of biases due to
dust obscuration. However,
radio detected sources require multi-wavelength counterparts to understand their intrinsic properties (e.g.
redshift,
stellar mass) and to study the
evolution of
star formation and AGN activity. In this work we present host
galaxy counterparts for the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) survey continuum Data Release 1 in regions with the best ancillary data (totalling 7.5 sq. deg). We combine statistical cross-matching and visual inspection to identify Ks-band selected host
galaxies, and additionally combine multiple
radio components into single physical objects, where needed. This results in a combined
radio catalogue of ~66 000 sources, with host counterparts and
redshifts identified for ~95 per cent of sources in the COSMOS field, ~91 per cent in XMM-LSS and ~90 per cent in CDFS-DEEP. This includes a significant fraction of sources with spectroscopic
redshifts within the COSMOS field (~50 per cent), with ~30 and ~20 per cent in the XMM-LSS and CDFS-DEEP fields respectively. Using the cross-matched catalogue, we make an initial identification of
radio-excess and
star forming
galaxies based on comparisons of the
radio luminosities to host
star formation rates. Using this split as a proxy for
radio loud AGN or SFGs, we present expectations for the
redshift distributions of these sources, finding broad agreement with those from deep
radio luminosity functions and simulated catalogues.
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All authors C. L. Hale, J. Hamlett, I. H. Whittam, M. J. Jarvis, M. J. Hardcastle, S. L. Jung, N. Stylianou, R. G. Varadaraj, M. Vaccari, L. Barchiesi, P. N. Best, K. K. L. Charlton, E. Malefahlo, E. Moravec, J. P. Moss, M. Rakototafika, T. F. Rarivoarinoro, F. Sinigaglia, M. N. Tudorache, S. I. Loubser, L. Heino, A. Saintonge, A. Mazumder, N. Netshiavha, D. J. B. Smith, L. Verdes-Montenegro, J. Delhaize, H. Pan, F. Pozzi, Z. Randriamanakoto, L. Stockenstroom, A. A. Vărăşteanu, E. Vardoulaki, W. L. Williams, R. A. A. Bowler, L. Marchetti, A. Matthews
Quantum Physics
Approximate Quantum State Preparation Through Proximal Policy Optimization
Marco Mordacci and Michele Amoretti
In this work, a
quantum architecture search framework for approximate
quantum state preparation (QSP) is proposed. QSP is a challenging task, since the search space grows exponentially with the number of
qubits, making the identification of the optimal
circuit non-trivial. To address this problem, deep reinforcement learning is employed through an
agent based on proximal policy optimization. The objective of the
agent is to identify the best possible approximation of the target state while simultaneously minimizing the number of gates used. At each step, the
agent appends a new gate to the
circuit and recomputes the fidelity between the approximated state and the target states. Various experiments have been performed from 2 to 5
qubits. Both predefined states, such as Bell, GHZ, W, and Dicke states, and completely random states are considered. The proposed framework is able to achieve approximation errors of $10^{-14}$.
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Instrumentation and Detectors
Single event effects in the HCCStar ASICs for ITk strip upgrade
Shaogang Peng, Jeff Dandoy, Bruce Gallop et al. (+12 more)
Triple Modular Redundancy (TMR) technology has been implemented in the design of the HCCStar to reduce digital state changes and ensure reliable operation. We tested the effectiveness of the protection by placing HCCStar chips in a
proton beam. We studied corrected bit flips in registers and actual single event effects in the LCB and LP paths under different
proton energies. Our estimate is that the LP data-loss fraction relative to the 400 kHz readout is $O(10^{-10})$ during normal operation and there will be $O(10)$ corrected bit flips per HCCStar bit per year at the HL-LHC.
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All authors Shaogang Peng, Jeff Dandoy, Bruce Gallop, Hantao Jing, Jaya John John, Paul Keener, Pedro Leitao, Qiang Li, Weiguo Lu, Godwin Mayers, Mitch Newcomer, Peter Phillips, Zhixin Tan, Matt Warren, Yan Zhou
High Energy Physics (Theory)
One-point holographic correlator in the expanding universe
Souvik Paul, Gopinath Guin and Sunandan Gangopadhyay
In this article, we have calculated the time-dependent thermal one-point function of massive operators within an expanding universe. We employ the Randall-Sundrum II braneworld model combined with a $p$-brane gas in the bulk, enabling us to represent various matter-dominated cosmological scenarios localised on the brane. Applying the geodesic formula introduced by Grinberg and Maldacena in \cite{Grinberg:2020fdj}, we have calculated the thermal one-point functions of massive operators within the universe. The time-dependent one-point functions for different matter-dominated universes, both single-component and multi-component, are derived from the brane's evolving radial position. The time-dependent positions of the branes have been obtained using the second Israel junction condition. Additionally, we have analyzed the early and late-time behaviors of the thermal one-point function across various matter-dominated universes.
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Optics
Phase singularity enabled polarization switchable analog spatial differentiation in an atomic MoS$_2$ planar Fabry-Pérot cavity
Zhonglin Li, Yingying Wang, Jiawei Kang et al. (+3 more)
Reconfigurable analog optical computing requires rapid and efficient switching between core mathematical operations, such as first- and second-order spatial differentiation. Here, we demonstrate a monolayer MoS$_2$ integrated a planar Fabry-Pérot (F-P) cavity that performs polarization switchable analog spatial differentiation under oblique incidence. By exploiting polarization dependent phase singularities, the device satisfies distinct optical transfer functions for different-order differentiation at the same operating condition. As a result, first-order and second-order derivatives of input images are experimentally realized by simply switching the incident polarization. These results establish the planar cavity as a compact reconfigurable spatial differentiator, whose computational order is controlled solely by light polarization. This approach provides a fast, convenient, and integration friendly strategy for tunable optical computing, and enables polarization switchable edge detection for image processing, with potential applications in real-time object recognition, feature extraction, and optical data compression.
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All authors Zhonglin Li, Yingying Wang, Jiawei Kang, Yangyang Zhang, Wenjun Liu, Zexiang Shen
Quantum Physics
Evolutionary stability and payoff equivalence in an Eisert-Wilkens-Lewenstein quantum game
Azhar Iqbal and Derek Abbott
An evolutionarily stable strategy (ESS) is a strategy that, once adopted by a population, cannot be invaded by any sufficiently rare alternative (mutant) strategy. We analyse evolutionary stability in an Eisert–Wilkens–Lewenstein (EWL) quantization of a symmetric $2\times2$ coordination game, whose classical mixed
equilibrium $p^*=1/2$ is not an ESS. In the restricted two-parameter EWL strategy space, the corresponding
quantum strategy is a strict symmetric Nash
equilibrium and an ESS for every
entanglement strength $\gamma>0$. In the full $SU(2)$ strategy space it remains a Nash
equilibrium, but in the unreduced game, in which every
unitary is a distinct strategy, exact payoff duplicates preclude strictness and ESS for every pure strategy. For the agreement-payoff class, the payoff factors through a Bloch map; identifying payoff-equivalent
unitaries gives the reduced space $U(1)\backslash SU(2)\cong S^2$, where strictness and ESS are restored for $\gamma>0$. An arbitrarily small perturbation outside this class that preserves $p^*=1/2$ yields a profitable deviation, so the reduced-space result is not generic.
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Fluid Dynamics
A One-Dimensional Integral Equation for a Porous Horizontal Disc under Water Waves
Luiz Fernando de Moraes Campos Filho, Leandro Farina and Juliana Sartori Ziebell
Wave scattering by a thin, porous circular plate submerged in deep water is investigated. The problem is formulated as a second-kind hypersingular Fredholm integral equation over the unit disk, solved numerically using the Boundary Element Method. The analysis focuses on calculating hydrodynamic forces, specifically added mass (real part) and damping coefficient (imaginary part). Results demonstrate the influence of the porosity parameter G: less porous plates (G real) increase added mass and hydrodynamic force, while more porous plates (G imaginary) reduce these effects but increase the damping coefficient. The proposed formulation is validated, showing excellent agreement with established literature.
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Quantum Physics
Conditional probabilities in quantum-optical settings
Alfredo Luis
We examine conditional probabilities derived from the joint noisy measurement of two complementary observables. We show that conditioning on one variable can lead to reduction of uncertainty in the other one, even completely eliminating uncertainty. We show that the conditional distribution cannot, in general, be represented in Born form using the marginal positive operator valued measure and any physical system state, nor can it be derived from typical rules of state reduction. We examine these issues in two basic
quantum-optical schemes. These are double homodyne detection and a
qubit measurement.
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Atomic Physics
Reassessment of line profile asymmetry in measurements of the 1s-2s energy interval in hydrogen
D. Solovyev, A. Anikin, T. Zalialiutdinov et al. (+1 more)
Experiments to determine transition frequencies in the hydrogen atom represent some of the most precise spectroscopic measurements and are at a higher level among simple atomic systems. The most persistent measured value in hydrogen is the energy interval corresponding to the $1s-2s$ two-
photon transition. The achieved experimental precision is several parts of $10^{-15}$ and has not changed over the last two decades. Although repeated experiments in 2011 and 2013 have improved the accuracy by several times, the frequency value has not changed significantly. On this basis, the frequency of the $1s-2s$ transition holds pivotal for determining physical quantities such as the Rydberg constant and the
proton charge radius. Theoretical efforts to study in detail the effects that might influence such precise measurements have not revealed significant contributions. The present work revises the theoretical analysis of the line contour asymmetry and its influence on the determination of the two-
photon absorption transition frequency, taking into account the theoretical achievements of recent years in this direction. It is shown that the asymmetry of the observed profile can lead to a $1s-2s$ transition frequency shift at the level of modern experimental accuracy. The found frequency shift is consistent with the line shape model contribution that forms the error budget of the experimental measurements. Adjustment can be carried out on the basis of the asymmetric profile that has become standard in recent years.
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All authors D. Solovyev, A. Anikin, T. Zalialiutdinov, L. Labzowsky
Quantum Physics
Picosecond-resolved entanglement distribution over an urban free-space channel
Alessandro Laneve, Fabrizio Cienzo, Santiago Gomez et al. (+18 more)
Time-evolving entangled states describe
quantum particles whose correlations evolve in time according to a well-defined dynamics. Such states can be generated in a variety of physical systems and are promising resources for several
quantum technologies, ranging from
quantum clock synchronization to
quantum communication. However, their full potential is currently limited by the fact that the
entanglement dynamics often occur on timescales comparable to the achievable synchronization precision, especially in experiments aimed at distributing
entanglement through noisy urban channels. In this context, accurate timing is not merely a technical detail, but a fundamental requirement for faithfully observing and exploiting the underlying
quantum correlations. Here, we demonstrate the faithful distribution of a fast-evolving entangled state over a 270 m free-space channel connecting two buildings in the center of Rome. The developed system incorporates a synchronization device capable of achieving sub-50 ps timing accuracy between the two ends of the link while simultaneously supporting channel stabilization. Our results demonstrate that time-evolving
entanglement can be reliably transmitted through a noisy urban free-space channel, representing an important
benchmark toward long-distance free-space
quantum communication and the future implementation of time-correlated entangled states in demanding scenarios such as satellite-based
quantum networks.
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All authors Alessandro Laneve, Fabrizio Cienzo, Santiago Gomez, Paolo Barigelli, Philip Menz, Mattia Beccaceci, Giuseppe Ronco, Giorgia Grossi, Ievgen Brytavskyi, Thomas Oberleitner, Markus Wiener, Christian Weidinger, Tobias M. Krieger, Ailton Garcia Jr., Saimon Filipe Covre da Silva, Michele B. Rota, Nicolò Spagnolo, Henning Weier, Fabio Sciarrino, Armando Rastelli, Rinaldo Trotta
Materials Science
Tunnel magnetoresistance effect with a Cr-doped $\mathrm{RuO_{2}}(110)$ altermagnet
Katsuhiro Tanaka, Takuya Nomoto and Ryotaro Arita
Antiferromagnets can have a finite
spin-polarization in the momentum space when their
magnetic structure breaks the macroscopic time-reversal
symmetry. This
spin-polarization can produce a
spin-polarized electric current even in antiferromagnets with vanishingly small net magnetizaton, which supports the antiferromagentic tunnel magnetoresistance (TMR) effect. In this paper, using first-principles calculations, we study the TMR effect with a doped altermagnet $\mathrm{Ru}_{1-x}\mathrm{Cr}_{x}\mathrm{O}_{2}$ with $(110)$ orientation, whose collinear
antiferromagnetic structure breaks the time-reversal
symmetry macroscopically. The momentum-dependent
spin-polarization combined with the $(110)$
crystal orientation makes the electric current
spin-polarized through bulk $\mathrm{Ru}_{1-x}\mathrm{Cr}_{x}\mathrm{O}_{2}(110)$. We further calculate the TMR effect in the $\mathrm{Ru}_{1-x}\mathrm{Cr}_{x}\mathrm{O}_{2}(110)/\mathrm{TiO_{2}}(110)/\mathrm{Ru}_{1-x}\mathrm{Cr}_{x}\mathrm{O}_{2}(110)$ tunnel junction and show that a finite TMR effect emerges. Based on the analysis of the tunneling transport, the TMR effect is attributed to the
spin polarized tunneling transport with momentum dependence and the interfacial
magnetic structures, as well as the
spin-polarized electric current in a bulk form of $\mathrm{Ru}_{1-x}\mathrm{Cr}_{x}\mathrm{O}_{2}(110)$.
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Optics
Design and Optimization of Metasurfaces for Silicon Photonics: PhD Thesis
Mathys Le Grand
Metasurfaces, two-dimensional arrangements of subwavelength nanopillars, provide local control over the phase of light, enabling flat optical functions beyond conventional refractive components. Their inverse design, finding the pillar distribution producing a target response, faces two obstacles: the immense dimensionality of the design space and the prohibitive cost of rigorous electromagnetic simulations, precluding exhaustive exploration at device scale. This thesis addresses the challenge in three stages. The first assesses the reliability of rigorous Maxwell solvers: comparing three implementations of Li's factorization rules for RCWA shows that spectral convergence does not guarantee physical fidelity, as these rules implicitly distort the simulated permittivity, most severely in the plasmonic regime. FDTD, immune to such artifacts, is retained as ground truth throughout. The second stage removes the computational bottleneck: a local phase-approximation model, then fully convolutional surrogates trained on FDTD simulations of large pillar metasurfaces, predict the near field almost instantaneously. Exploiting problem
symmetries quadruples the training database, and the surrogates generalize to much larger apertures while remaining differentiable. The third stage
benchmarks three strategies under a common FDTD protocol ($R^2$ between realized and target far fields): Gerchberg-Saxton
retrieval and Local Model ($R^2\approx0.925$), surrogate-based and heuristic-initialized gradient descent ($R^2\approx0.975$), and a generative framework based on
diffusion models and Schrödinger bridges. Hybrid posterior sampling and amplitude constraints restore scale-invariant fidelity on surfaces over 230 times larger than training, with diverse, fabrication-tolerant designs. Database enhancement lifts every approach to $R^2\approx0.97$.
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Quantum Physics
Vacuum-induced interference in light scattering by multilevel atomic chains
Aleksei Konovalov, Giovanna Morigi and Nicola Piovella
We investigate cooperative light scattering by an ordered chain of multilevel atoms, which possess two quasi-resonant transitions with parallel dipole moments. Interference between dipole transitions induced by coupling with the
vacuum gives rise to so called cross-damping and cross-shifts, that modify the incoherent and coherent dynamics and can be manifest in the spectroscopic properties of the emitted light. We determine the excitation spectrum when the atomic chain is driven by an external
laser in the limit in which the dipolar transitions can be described by harmonic oscillators and the scattering is coherent. We show that the interplay of multilevel interference and superradiance can give rise to measurable effects in chains of alkali-metal atoms.
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General Relativity and Quantum Cosmology
The leading-soft cubic graviton self-interaction on the black-hole horizon
Ayanendu Dutta
We expand the Einstein–
Hilbert action to cubic order about the Schwarzschild horizon, in the even Regge–Wheeler gauge of the Gaddam–Groenenboom–'t~Hooft near-horizon framework, and derive the cubic graviton self-interaction. Our central result is a vanishing
theorem: at leading soft order the self-coupling of the purely traceless longitudinal polarizations is identically zero. This is a framework-specific statement: even RW gauge, GGV sector, leading soft order. The surviving interaction lives in the trace sector; its on-shell equal-$\ell$ weight $W(\lambda,\lambda,\lambda)=-3\lambda(2\lambda^2+\lambda+3)/(\lambda+1)^2$, follows from two independent derivations agreeing to machine precision. We simulate the resulting
Hamiltonian at two complementary scales. On IBM Qiskit/Aer, with exact cross-checks, the hardware-format
circuits confirm quantitatively what two structural facts already predict, a conserved charge that only the cubic vertex violates (opening $\phi\phi\to hh\to4\phi$) and a resonance-free boost spectrum (gap $\to1/2$): the longitudinal channel is perturbatively rigid, and the simulation measures the residual dressing ($d_{\rm eff}=1.06$; multiplicity far from thermal, Poisson, and Haar). A
symmetry-graded
matrix-product-state
evolution then climbs the multipole ladder to sixty modes, the $120$-
qubit register, and settles the one question the multiplet cannot: on a late-time measure common to both engines the inelasticity converges to $\bar\eta_\infty\simeq0.16$ (understated by the single multiplet), the dressing stays area-law with peak
entanglement $\simeq0.45$ nats far below the Page value, and the result is cutoff-converged and robust to $96$
qubits at larger occupation. The
rigidity therefore persists rather than scrambling as the register grows.
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General Relativity and Quantum Cosmology
New generalization of the Barboza-Alcaniz parametrization of Dark energy
Shahab Shahidi
A generalization of the Barboza-Alcaniz parametrization of dark energy is proposed. This is a three-parameter model which can resolve the shortcomings of the Barboza-Alcaniz behavior at future times. We show that cosmological data favor the new parametrization over both the Barboza-Alcaniz model and $\Lambda$CDM. We also consider the cosmological implications of the model and show that the qualitative behavior mimics to the original Barboza-Alcaniz model, with a slightly smaller acceleration rate.
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Solar and Stellar Astrophysics
Transport of angular momentum and chemical elements by the MRI dynamo in stellar radiative zones
Laurène Jouve, François Lignières, Jérôme Guilet et al. (+1 more)
The question of angular momentum transport by
magnetic fields has recently been revived by the detection of
magnetic fields in the deep interior of red
giant stars. We aim at characterizing the efficiency of the transport of angular momentum and chemical elements in a
stellar radiative zone subject to the magneto-rotational instability, in situations where hydrodynamical instabilities are not triggered. We use a large set of zero-net flux shearing-box simulations modelling a portion of a
stellar radiative zone located close to the equatorial region. The shear is imposed in the direction of
gravity, mimicking a radial differential rotation and rotation is perpendicular to
gravity. We aim at establishing scaling laws between the transport efficiency and key parameters such as stratification and rotation. We obtain simulations where the MRI is triggered on the self-consistently built longitudinal field and then produces a state of self-sustained
turbulence that we associate with dynamo action. We find that in the parameter range explored, both rotation and stable stratification strongly affect the vertical transport of angular momentum which is always dominated by the Maxwell stress component. In a similar way, we find that the transport of chemical composition is even more strongly affected by the stratification but less severely by rotation. Scaling laws are established and tentative extrapolations to
stellar values are discussed. Transport by the stratified MRI dynamo is very promising to reconcile
stellar evolution models and asteroseismic inversions of internal rotation rates of
stars.
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All authors Laurène Jouve, François Lignières, Jérôme Guilet, Alexis Vanbesien