Fluid Dynamics
Visualizing Lagrangian Heat Transport Paths and Density Structures in Unsteady Heat Transfer
Besm Osman, Andrei Jalba, Michel Speetjens et al. (+1 more)
Convective heat transfer is traditionally visualized from a Eulerian perspective using scalar temperature fields, offering limited insight into the underlying transport mechanisms. A Lagrangian view, analogous to mass transport along fluid paths, can reveal coherent structures and transport routes invisible from a Eulerian view of temperature. However, heat transport is aperiodic and non-conservative, hampering the application of fluid mixing and transport visualization techniques, developed primarily for time-periodic, conservative transport. We present a particle-based visualization technique that addresses these challenges by advecting massless particles along a time-reparameterized spacetime formulation of thermal transport, accumulating path contributions to reveal coherent transport routes and finite-time attracting and repelling structures that conventional methods cannot show.
Read the full abstract ▾
All authors Besm Osman, Andrei Jalba, Michel Speetjens, Anna Vilanova
Materials Science
Strengthening and interface-mediated plastic co-deformation in an ultrafine Cr-Ni eutectic: A nanomechanical investigation
Arkajit Ghosh, Mustafa Tobah, Jianing Zhou et al. (+2 more)
Ultrafine eutectic
heterostructures provide a stringent test of plasticity in high-strength materials, where deformation must be accommodated through interfaces and strain gradients. Room temperature ductility is typically limited by premature fracture of the hard phase, leaving open the fundamental questions regarding the interface spacing, atomic structure and local chemistry that enable plastic co-deformation. Here we address this question using a model system of Cr-Ni binary
alloy, processed via electron-beam powder bed fusion that produces a lamellar eutectic microstructure of Cr-rich BCC and Ni-rich FCC phases, with an average interlamellar spacing of ~450 nm. Atomic-resolution STEM revealed a stepped semi-coherent FCC/BCC interface with the Kurdjumov-Sachs orientation relationship and Ni-enrichment confined to a few atomic planes on the BCC side. In situ micro-scale compression and tension tests in SEM demonstrate high flow stresses coupled with large plastic strains without cracking, indicating stable accommodation of plastic incompatibility. Correlative TEM/HR-STEM establishes a deformation sequence: initial plasticity is dominated by strain-gradient driven dislocation accumulation in the FCC lamellae adjacent to interfaces, followed by deformation twinning in FCC and local interfacial shear and reorientation. The BCC phase subsequently develops a high density of mobile dislocations. Atomistic modeling has been employed to understand the influence of the FCC/BCC interface atomic structure and chemistry on the slip activation in the hard phase. These findings show that nanoscale confinement, stepped K-S interfacial structure, and interfacial chemistry collectively promote dislocation glide in a hard phase below its monolithic brittle to ductile transition temperature, and plastic codeformation at high flow strengths.
Read the full abstract ▾
All authors Arkajit Ghosh, Mustafa Tobah, Jianing Zhou, Jian Wang, Amit Misra
Chaotic Dynamics · Cross-listed from q-bio.PE
Immune history shapes recurrent epidemics of antigenically related variants
Ryuichi Kumata, Yuma Fujimoto, Hisashi Ohtsuki et al. (+1 more)
Population immunity carried over from past epidemics of an antigenically variable pathogen influences the epidemic of new variants based on their antigenic similarity to the previous ones. We develop a recurrent SIR model where a population faces sequential, antigenically related variants. The model yields a recurrence map for the population susceptibility to successive variants under the assumption of status-based population immunity. The model reveals that stable, equal-sized recurrent epidemics occur across broad parameter ranges, but can be destabilized when transmission is strong and antigenic escape is limited, leading to period-2 or more, or even more complex epidemic dynamics. Epidemic size is maximized at an intermediate basic reproduction number: higher transmissibility boosts immediate infection but also enhances cross-immunity, reducing future susceptibility of the population. Our results clarify how immune history shapes recurrent epidemics and why success in one wave does not ensure larger future epidemics.
Read the full abstract ▾
All authors Ryuichi Kumata, Yuma Fujimoto, Hisashi Ohtsuki, Akira Sasaki
Instrumentation and Detectors
TD-Link: A Daisy-Chain Optical Architecture for Integrated Data Readout and Deterministic Timing Distribution in Large-Scale Detector Systems
Andrea Abba, Gianluca Becuzzi, Matteo Bianchini et al. (+8 more)
TD-Link is an optical communication architecture that combines high-throughput data readout and sub-nanosecond timing synchronization over a single fiber for large-scale detector systems. It adopts a multidrop daisy-chain ring
topology connecting a Data Concentrator to up to sixteen FERS front-end boards per link, with up to eight links per concentrator. Operating at 3.125 Gb/s, TD-Link carries data, synchronization, and control traffic in the same serial stream through a
token-based streaming protocol that minimizes per-hop latency and supports on-the-fly payload fragmentation. Deterministic latency is enforced at two levels. On the concentrator, transmitter lanes are aligned by using the half-full flag of the multi-gigabit transceiver (MGT) elastic buffer as a one-bit phase detector: a firmware state machine steps the transmit phase interpolator (PI) until the buffer pointer difference crosses half-depth, locking every lane to the same phase condition. On each front-end board, where the synchronization pulse must also cross from the recovered-clock to the transmit domain, the residual three-to-five-cycle ambiguity of the synchronizer is removed by a calibration-free multiphase oversampling time-to-digital converter (TDC) with 0.8 ns bins, which time-stamps the incoming edge on the transmit time base so that a scheduler regenerates it at a fixed, programmable latency. A Digital Dual Mixer Time Difference (DDMTD)
circuit measures the inter-concentrator phase. Tests with CERN PicoTDC-equipped FERS boards show a board-to-board synchronization $\sigma$ of 24 ps on the same ring, 27 ps across transceiver quads, and 28 ps across two cascaded concentrators, against an intrinsic front-end floor of 7 ps. Over more than one thousand cold boots without re-calibration, the boot-to-boot spread of the board-to-board skew stayed below 20 ps, consistent with the 18.6 ps phase-interpolator step.
Read the full abstract ▾
All authors Andrea Abba, Gianluca Becuzzi, Matteo Bianchini, Francesco Caponio, Stefano Carsi, Alberto Cusimano, Camilla Maggio, Annalisa Mati, Daniele Ninci, Andrea Picchi, Carlo Tintori
Superconductivity
Characterization of Hydroxyls in Surface Oxide of Superconducting Tantalum and Their Mitigation in Quantum Circuits
Ekta Bhatia, Nicholas Pieniazek, Aleksandra Biedron et al. (+7 more)
Recently, tantalum (Ta) has gained
attention in superconducting
quantum circuits due to the longer coherence times achieved when replacing niobium (Nb) in capacitor pads. Previous literature shows that surface
oxides that form upon ambient exposure on superconducting metals such as Ta, Al, and Nb host two-level system (TLS) defects, which are a leading source of microwave loss and decoherence. While the surface
oxides of Nb and Al have been extensively studied, Ta
oxides remain less well understood. Using secondary ion mass spectrometry of alpha-Ta films deposited at 300 mm wafer scale, we show for the first time that hydroxyls accumulate in the Ta suboxide region above the underlying Ta. Angle-resolved X-ray photoelectron spectroscopy shows that the surface region is dominated by Ta2O5, with sub-stoichiometric TaOx present in between the Ta2O5 and underlying Ta. The thickness of the tantalum
oxide is confirmed by transmission electron microscopy. We demonstrate that [OH] incorporation can be suppressed by replacing the native
oxide with an
oxide formed during chemical mechanical planarization of alpha-Ta films. Our findings support the hypothesis that TLS defects are non-uniform within the
oxide thickness and suggest hydroxyls as a probable molecular origin of these loss channels. Furthermore, we show the feasibility of
plasma nitridization as a method to decrease hydroxyl loading on alpha-Ta surfaces. The modulation of hydroxyl content through surface engineering of alpha-Ta can enable the fabrication of more robust, high-coherence superconducting
quantum circuits by addressing a potential TLS source.
Read the full abstract ▾
All authors Ekta Bhatia, Nicholas Pieniazek, Aleksandra Biedron, Sandra Schujman, Hunter Frost, Zhihao Xiao, Jakub Nalaskowski, Kevin Musick, Thomas Murray, Satyavolu Papa Rao
Materials Science
Two-dimensional vertically polarized Hg3AsSe4I monolayer for efficient photocatalytic water-splitting: promoting carrier separation by intrinsic electric field and Rashba effect
Xinfeng Chen, Wenchao Shan, Fengfeng Ye et al. (+1 more)
Efficient separation of photo-excited electron-hole pairs is essential for developing the high performance photocatalysts towards light-driven water-splitting applications. To this end, pho tocatalytic performances of two-dimensional (2D) semiconducting ferroelectric (FE) materials with out-of-plane polarizations have been extensively explored. However, out-of-plane polarizations in 2D FE materials are susceptible to the critical thickness limitation and can be easily compensated by surface adsorbates. On the other hand, 2D vertically polarized materials with stable and ir reversible out-of-plane polarizations may overcome the critical thickness limitation, enabling the practical advantage for spatial separation of photo-excited electron-hole pairs during the photo catalytic reactions. In the current work, 2D vertically polarized Hg3AsSe4I, an experimentally synthesized van der Waals (vdW) layered material, has been systematically investigated as a high performance 2D photocatalyst. Owing to its semiconducting band gap suitable for visible-light absorption, high carrier mobility, and desirable band edge
alignment ideally matching water reduc tion and oxidation potentials, Hg3AsSe4I monolayer fulfills both optical and electronic prerequisites for photocatalytic water-splitting reactions. Besides the stable vertical polarization able to persist in Hg3AsSe4I monolayer, the dual mechanism for efficient separation of photo-excited carriers has also been demonstrated. Rashba
spin-orbit coupling (SOC) of large strength emerges within 2D Hg3AsSe4I, splitting the band edges into
spin-resolved band branches with unique
spin-momentum locking characters.........
Read the full abstract ▾
All authors Xinfeng Chen, Wenchao Shan, Fengfeng Ye, Gaoyang Gou
Nuclear Experiment
Nuclear electromagnetic moments by spin-precession methods
Georgi Georgiev, Dimiter L. Balabanski, Andrew E.Stuchbery et al. (+1 more)
Nuclear moment studies carried out with
spin-precession methods at and after the turn of the millennium are critically assessed. A period of about 30 years is covered, during which much of} the focus of
nuclear structure research shifted from high-
spin physics to studies of
neutron-rich exotic
nuclei. The formalism for the extraction of
nuclear moments is described. The $\beta$-
nuclear magnetic resonance/
nuclear quadrupole resonance ($\beta$-NMR/NQR), the time-dependent perturbed angular distribution (TDPAD), the transient field, the
recoil-in-
vacuum (RIV), and the tilted-foils methods for measurements of
nuclear magnetic dipole and electric quadrupole moments are described in detail, as well as the requirements for their application in studies of exotic
nuclei. The impact of
nuclear-moment measurements on the understanding of key topics of
nuclear structure research is discussed. {Key results on short-lived states, mainly from transient-field measurements, are reviewed. Included are comparisons with large-basis shell model calculations, discussions on the nature of weakly-collective
nuclei, insights into emerging collectivity away from closed shells, and electromagnetic properties of odd-$A$ rotors.} In the field of high-
spin physics, research related to high-
spin yrast and $\mathrm{K}$ isomers, superdeformation,
magnetic, anti-
magnetic, and
chiral rotation is covered. In
neutron-rich exotic
nuclei, studies related to the $\mathrm{N=20}$, $\mathrm{N=28}$ and $\mathrm{N=40}$ “islands of inversion”, the structure of
nuclei around $^{68-78}$Ni and $^{132}$Sn, and in the $A \sim 100$ mass region are discussed.
Read the full abstract ▾
All authors Georgi Georgiev, Dimiter L. Balabanski, Andrew E.Stuchbery, Hideki Ueno
Chemical Physics
Real-time simulation of charge migration within the time-dependent Kohn-Sham DFT
Rajarshi Sinha-Roy, Clément Guiot du Doignon, Evan Munaro-Langloÿs et al. (+2 more)
Attosecond technologies provide unique opportunities to study electron dynamics and electron correlation on their intrinsic timescales. From a theoretical perspective, this places strong constraints as an accurate treatment of electron correlation is required. Recently, it was demonstrated that time-dependent density-functional theory (TDDFT) is capable of correctly predicting correlation-driven charge migration arising from hole mixing following ionization of the highest occupied molecular orbital (HOMO). Given the ability of TDDFT to treat large-scale systems, this approach offers promising perspectives for investigating electron-correlation-driven mechanisms in complex molecules. In this work, we assessed the constraints and limitations associated with using TDDFT to study this mechanism. We found that the charge-migration dynamics are already correctly reproduced using local-density approximation for the exchange-correlation functional, provided the states involved in the coherent superposition are well described within the TDDFT. However, for dynamics triggered by the ionization of orbitals below the HOMO, artificial ultrafast dynamics may appear on top of the charge-migration dynamics. These artifacts indicate that careful analysis of the simulated dynamics is required in order to reliably predict phenomena that could be observed experimentally.
Read the full abstract ▾
All authors Rajarshi Sinha-Roy, Clément Guiot du Doignon, Evan Munaro-Langloÿs, Franck Rabilloud, Victor Despré
Geophysics
The effect of 20th century industrialization: Power station, acid rains, over-pumping, on an erstwhile uniform freshwater dune aquifer in Haifa Bay, Israel
Vasily Rogojin and Joel Kronfeld
A small phreatic sand dune aquifer lies along the shore of Haifa Bay. It has been exploited for its freshwater resources since the 1930s. During this time the salinity has increased continuously, partly by seawater intrusion due to overpumping. The chemistry of the young aquifer water is laterally variable and is characterized by excess SO$_4^{2-}$, high $Sr^{2+}$ concentrations above that of modern seawater, high alkalinity, and markedly enriched $\delta^{13}C_{DIC}$ values. Acidic winter rains, formed from $SO_x$ and $NO_x$ gaseous emissions from a nearby power station, leach the dry deposition that accumulated across the dune surface during the dry summers. The acidity also partially dissolves the aragonite sea shells in the dune sands, remnants of a previous marine transgression. As a consequence, this adds $Sr^{2+}$, $Ca^{2+}$ excess, and alkalinity, while leading to enriched $\delta^{13}C_{DIC}$ values, particularly during the winter, at which time the radiocarbon activity in the DIC is observed to decrease.
Read the full abstract ▾
Disordered Systems and Neural Networks
Non-self-averaging topological Anderson insulator
Zheng-Wei Zuo and Jun-Chong Liu
Current research on the disordered topological
quantum phases primarily focuses on the uncorrelated and short-range correlated disorder regime. These topological Anderson
insulators are typically self-averaging. However, topological
quantum systems with long-range correlated disorder have received limited
attention due to the absence of tractable analytical methods. In fact, the long-range correlated disorder introduces more complex effects on topological
quantum states. Here, we demonstrate that the long-range correlated disorder could induce anomalously statistical feature where the topological Anderson states become non-self-averaging, and the phase diagram is strongly dependent on individual disorder configurations. We term this statistical phase the non-self-averaging topological Anderson
insulator. The non-self-averaging property is identified by the non-vanishing finite values of the relative variance of the Lyapunov exponent in the thermodynamic limit, alongside the non-Gaussian distributions of the Lyapunov exponent. Consequently, the topological properties of a single disordered sample deviate from the ensemble average, causing a breakdown of the central limit
theorem. The non-self-averaging topological Anderson
insulator provides insights into the interplay between correlated disorder and
topology.
Read the full abstract ▾
High Energy Astrophysical Phenomena
A self-consistent single-fluid framework for neutron stars admixed with mirror dark matter
Adamu Issifu, Constança Providência, Franciele M. da Silva et al. (+2 more)
We develop a self-consistent dark matter admix
neutron star framework based on a contact vector current–current interaction that couples the chemical potentials of both sectors through mutual mean-field shifts, with the dark matter (DM) fraction $F_D = N_D/N_B$ fixed as a global input parameter. This formulation provides a physically motivated alternative to fixed-density prescriptions, allowing the local DM density to follow the baryonic matter (BM) density throughout the
stellar interior. As an application, we consider a mirror-DM scenario with exact
symmetry between the dark and visible sectors and investigate NS matter using the NL3$\omega\rho$, FSU2R, NL3, and DDME2 equations of state (EOSs). We find that the amount of DM introduced through $F_D$ weakens the binding of dense matter, reduces its incompressibility, and softens the EOS, while the DM–BM interaction governs the microscopic behavior of the DM in the dense BM medium. Consequently, DM increases the central density and compactness of NSs, lowers their maximum masses, and shifts the onset of the direct Urca process to higher
stellar densities. As a consequence, the onset of rapid cooling is shifted to more massive
stars for models with a stiff
symmetry energy and to less massive
stars for models with a soft
symmetry energy, depending on the extra compactness that results from the DM admixture. These results demonstrate that mirror-DM admixtures modify both the microscopic composition and macroscopic structure of NSs, with potential implications for their thermal
evolution and multimessenger observational signatures.
Read the full abstract ▾
All authors Adamu Issifu, Constança Providência, Franciele M. da Silva, Débora P. Menezes, Tobias Frederico
High Energy Physics (Experiment)
Modeling Falling Backgrounds with Exponential Mixtures
Austin Townsend, Marc Osherson, Mike Hildreth et al. (+1 more)
Searches for new physics at the LHC often look for localized excesses on smoothly falling background distributions. Several classes of background models have been considered, including
polynomials and other parametric families; however, these approaches can require extensive analysis-specific development as
datasets grow. In this work, we motivate the finite exponential mixture as a flexible semi-parametric class of functions for approximating falling distributions, drawing on results from extreme value theory. Using two published
datasets ($n=28,619,185$ and $n=5,036$), we show that the exponential mixture performance is comparable to existing methods for both small and large
datasets. Finally, in simulation studies ($n = 5,036$), we find that the finite exponential mixture exhibits small bias relative to the true statistical uncertainty while maintaining consistent nominal coverage in the bulk.
Read the full abstract ▾
All authors Austin Townsend, Marc Osherson, Mike Hildreth, Stefano Castruccio
High Energy Physics (Theory)
Modularity of resurgent topological string
Gengbei Guo, Jiashen Chen and Jie Gu
Topological string free energy has a rich collection of non-perturbative contributions which are labeled by D-brane charge vectors, and the associated Stokes constants are conjectured to coincide with BPS or DT invariants, i.e. D-brane multiplicities. In this paper, we provide additional evidence to this
conjecture by studying modular properties of non-perturbative contributions. We argue using resurgence theory that non-perturbative contributions form orbits of local monodromy group induced by singular points inside a stability chamber, and that the associated Stokes constants must be the same across the orbits. In some examples, this allows generation of infinitely many Stokes constants, which reproduce the entire BPS spectrum. In addition, following [DK26], we also show that generators of Stokes transformations of non-holomorphic partition function satisfy Lie brackets of the Kontsevich-Soibelman Lie
algebra, making it possible to identify the global Stokes transformation with the Kontsevich-Soibelman wall-crossing invariant.
Read the full abstract ▾
Plasma Physics
Reexamination of collisional ionization cross sections including double photoionization processes
Lucas Ansia, Pedro Velarde, Marta Fajardo et al. (+1 more)
Collisional ionization (CI) cross sections in dense
plasmas remain difficult to constrain due to uncertainties in
plasma conditions and the overlapping spectral signatures of competing atomic processes. The use of x-ray free electron
lasers (XFELs) to both heat and probe solid-density targets has significantly advanced the field by eliminating assumptions about ion density. However, questions remain regarding collisional cross sections, suprathermal electron
evolution and competing atomic processes. In this work, we revisit experimental data from XFEL-heated aluminum, previously analyzed using collisional radiative models that did not treat the degenerate electron distribution and atomic processes self consistently. We present a new analysis using BibBarT which dynamically evolves non-thermal electron populations and explicitly includes degeneracy effects. Furthermore, we incorporate an important atomic process recently observed in
plasma state that mimic signatures of CI, shake-off. Our results show that including shake-off processes improves agreement with observed emission features, and lowering recombination rates further improves the agreement with data – indicating a possible overestimate of three-body recombination in these conditions.
Read the full abstract ▾
All authors Lucas Ansia, Pedro Velarde, Marta Fajardo, Gareth Williams
Astrophysics of Galaxies
Kolmogorov turbulence across multi-fractal gas in Polaris Flare
Xunchuan Liu, Pak-Shing Li and Yihuan Di
We reveal a pristine, scale-invariant 3D Kolmogorov velocity cascade ($\alpha_V^{\mathrm{3D}} \sim 2/3$) spanning $0.05$–$20$~pc in the Polaris
Flare using PPCOS $^{12}\text{CO}$ data. A transition scale at $\sim 0.5$~pc marks a bifurcation in the structure functions' exponents, below which the degree of intermittency is also saturated. By deriving an analytical mapping relation ($\alpha_V^{\mathrm{3D}}=\alpha_V-\frac{1}{3}\alpha_I$), we obtain the scale-invariant value of $\alpha_V^{\mathrm{3D}}$, proving that the apparent transition stems from
geometric projection and a changing density fractal dimension rather than a turbulent mode shift. Kolmogorov
turbulence is smoothly inherited from the large-scale cold neutral medium, remaining uninterrupted by compression or
gravity below 0.1 pc.
Read the full abstract ▾
High Energy Physics (Theory)
Dissipative hydrodynamic actions and horizon symmetries in gravity
Mike Blake, Arpit Das and Richard A. Davison
We give a prescription to compute a dissipative action describing the large-scale thermal stress tensor dynamics of a
holographic quantum field theory dual to AdS$_4$
gravity, in the context of the Schwinger-Keldysh formalism. Our prescription is valid to quadratic order in perturbations about the thermal
equilibrium state. The hydrodynamical degrees of freedom of this action are realised in
gravity as relative diffeomorphisms between the black hole horizon and the two asymptotic boundaries of the Crossley-Glorioso-Liu contour. We explicitly compute the action to first order in derivatives, and confirm it correctly reproduces the known hydrodynamic Green's functions. Our prescription requires a choice of horizon boundary conditions for the metric. We study the horizon
symmetries that preserve these, and their relation to conjectured hydrodynamic
symmetries responsible for many-body
quantum chaos.
Read the full abstract ▾
High Energy Physics (Theory)
Soft Algebras via Bulk Double Soft Limits
Sruthi A. Narayanan
Soft and collinear limits of "celestial amplitudes" give rise to infinite dimensional
symmetry algebras for two-dimensional (2D) "celestial" conformal field theories (CFTs). A small subset of these operators generates the action of the entire set recursively via the commutation relations. Insertion of this subset into celestial CFT correlators gives the boundary version of the first three terms in a soft expansion of the corresponding 4D bulk gravitational scattering amplitude. In this paper, we find that a bulk analog of this, which would allow the entire soft expansion of a gravitational amplitude to be determined via just the first three terms, does not follow trivially from the celestial
algebras. We show how the interplay of soft and collinear limits results in subtleties for bulk amplitudes that do not show up in the boundary description. We also briefly comment on this construction in gauge theory.
Read the full abstract ▾
Mathematical Physics
On the spherical symmetry and finite-range assumptions of the interaction potential in the low energy study of dilute Bose gases
Lukas Reichmann and Arnaud Triay
We consider a Bose gas on the three-dimensional
torus in the Gross–Pitaevskii regime and explain how to remove the assumptions of radiality and compact support on the interaction potential in the proof of Bose–Einstein condensation and convergence of the excitation spectrum to Bogoliubov's prediction. In particular, we sketch the proof of [55].
Read the full abstract ▾
General Relativity and Quantum Cosmology
Environmental effects vs. modified gravity in the LISA massive black hole binary population
Lorenzo Copparoni and Enrico Barausse
Gravitational-wave signals from massive black hole binaries observed by LISA can carry imprints of both the astrophysical environment of the source and possible deviations from general relativity. We investigate whether environmental effects leave a detectable imprint on the LISA binary population, and whether they can mimic modified-
gravity effects with the same frequency dependence. As representative channels we adopt
accretion and viscous migration in a circumbinary disk for the environmental sector, and a time-varying Newton constant $\dot G$ for the modified-
gravity sector. All three effects enter the waveform at the same negative post-Newtonian order and are described, at leading order, by a common phase-deformation parameter, which makes them formally degenerate at the single-event level. Combining Fisher-
matrix forecasts with a hierarchical nested-sampling analysis of synthetic catalogs from astrophysically motivated population models, we find that, even under extreme astrophysical assumptions – an active fraction of $50\%$, together with a super-Eddington
accretion tail – the population-level posteriors remain fully compatible with
vacuum. However, a hierarchical population-wide analysis may yield a non-trivial upper limit on the active fraction and a mild lower bound on the slope of the Eddington-ratio distribution. Environmental effects are therefore unlikely to bias LISA's tests of general relativity with massive black hole binaries in astrophysically realistic scenarios.
Read the full abstract ▾
Instrumentation and Detectors
Real-Time FPGA-Based SiPM Detector Emulation Using a Temporally Quantized Model
Stefano Carsi, Edoardo Proserpio, Andrea Abba et al. (+2 more)
We present a real-time hardware implementation of a versatile detector emulator capable of reproducing realistic silicon photomultiplier signals. Our approach builds upon the open-source SimSiPM framework, originally developed to simulate the microscopic response of silicon photomultipliers, including
photon detection efficiency, optical crosstalk, afterpulsing, and dark counts. SimSiPM provides idealized
photon-level data with arbitrary temporal and amplitude resolution. In contrast, our emulator, built on a field-programmable gate array, translates this fine-grained simulation into physically realizable analog signals, maintaining real-time operation and finite hardware resolution. The system receives simulated
photon events either via a 10-gigabit Ethernet stream or directly from the processing system of a system-on-chip, and performs on-chip temporal quantization, dividing time into bins equal to one clock cycle. All
photon hits within a bin are accumulated, and their contribution is combined through a weighted temporal averaging scheme that preserves sub-bin precision. Signal shaping is executed entirely in hardware, using parallel one-pole recursive filters that synthesize the rise and the two decay components of the response. The resulting waveform is converted to analog through dual 16-bit digital-to-analog converters operating at 2.5 gigasamples per second. This architecture generates physically accurate detector signals in real time, rather than replaying precomputed waveforms. It also generalizes beyond silicon photomultipliers, providing a flexible framework for hardware-in-the-loop testing of front-end electronics. The proposed implementation demonstrates high throughput, low latency, and minimal processor overhead.
Read the full abstract ▾
All authors Stefano Carsi, Edoardo Proserpio, Andrea Abba, Francesco Caponio, Valentina Arosio
High Energy Physics (Phenomenology)
Dark matter energy exchange in stars orbiting supermassive black holes
Stephan A. Meighen-Berger, R. Andrew Gustafson, Nicole F. Bell et al. (+3 more)
Stars on tight orbits around the supermassive black hole at the
Galactic Center pass through regions where the dark matter~(DM) density may be strongly enhanced. We compute the orbit-averaged DM-induced energy exchange for S4714 as an example. It is a
star on an exceptionally close and relativistic orbit around Sagittarius~A*. For a spiked dark matter profile, the exchange reaches the
stellar luminosity at $\sigma_{\chi p} \sim 10^{-36}~\mathrm{cm}^2$ for MeV-GeV masses and $\sigma_{\chi e} \sim 5\times10^{-38}~\mathrm{cm}^2$ for sub-MeV masses, opening a new annihilation-free route toward dark-
star phases. These cross sections lie within the range predicted by freeze-in scenarios and are consistent with
cosmic-ray–boosted and
solar-reflection dark matter constraints.
Read the full abstract ▾
All authors Stephan A. Meighen-Berger, R. Andrew Gustafson, Nicole F. Bell, Jayden L. Newstead, Sandra Robles, Ian M. Shoemaker
Quantum Physics
Twisted Gaussian Schell States in Quantum Optics: Twist-Assisted Nonclassicality and Entanglement
Fabricio Toscano, G. Cañas, A. Z. Khoury et al. (+2 more)
We introduce the Twisted Gaussian Schell (TGS) state, a two-mode mixed Gaussian state defined as the
quantum-optical analog of the Twisted Gaussian Schell-model beam of classical paraxial optics, characterized by the so-called twist phase. In the TGS state, the twist parameter arises when an asymmetric two-mode thermal state is subject to local squeezing after the action of phase shifters and a beam splitter. Its defining
quantum feature is nonclassicality: although the state is separable in its natural bipartition, when the twist parameter is nonzero there are global quadratures that can be squeezed below the shot-noise limit. The nonclassicality has also a direct signature in the joint
photon-number distribution, which we obtain in closed form. Moreover, coupling each mode to an ancillary
vacuum at a balanced beam splitter yields a four-mode state with
entanglement in select $2\times2$ bipartitions, with local description given by two TGS states, and all $1\times3$ bipartitions. For fixed input squeezing, increasing the twist parameter activates
entanglement where the state is otherwise separable and deepens it where already present. The classical physicality bound on the twist parameter coincides with the
quantum physicality condition. These results advance the two-way bridge between classical beam engineering and
quantum information.
Read the full abstract ▾
All authors Fabricio Toscano, G. Cañas, A. Z. Khoury, P. H. Souto Ribeiro, S. P. Walborn
Quantum Physics
Simulating generic single-qubit open-dynamics via polarization-frequency coupling in a photonic interferometer
Kalle Raikisto, Alberto Ferrara, Tom Kuusela et al. (+2 more)
We propose a photonic platform for simulating arbitrary single-
qubit open-system dynamics using a single
photon in an open Mach-Zehnder interferometer. A birefringent quartz plate induces a coupling between the polarization and frequency degrees of freedom. By treating the latter as an effective environment, we analytically derive the reduced polarization dynamics. We show that the resulting
evolution is characterized by a controllable interplay between populations and coherence, instead of the usual dephasing caused by quartz plates. By adjusting the
photon frequency distribution and interferometric parameters, we demonstrate that target single-
qubit states can be efficiently reproduced through a tunable optical protocol expected to work under accessible experimental conditions. The simulator is benchmarked against paradigmatic open-system evolutions, including depolarization and non-Markovian dynamics, achieving high accuracy. Our results establish polarization-frequency engineered photonic interferometers as a versatile protocol for simulation of open
quantum systems.
Read the full abstract ▾
All authors Kalle Raikisto, Alberto Ferrara, Tom Kuusela, Rosario Lo Franco, Jyrki Piilo
Cosmology and Nongalactic Astrophysics
Cosmology from HI galaxy surveys with the SKA
Ainulnabilah Nasirudin, Philip Bull, Ziad Sakr et al. (+8 more)
The 21cm line from neutral hydrogen is expected to be a ubiquitous (albeit faint) tracer of
galaxies in the late Universe. With SKAO-MID, large wide-field surveys of several million HI-containing
galaxies will become feasible, resulting in catalogues of sufficient size to measure large-scale structure observables such as
baryon acoustic oscillations and
redshift-space distortions. While optical
galaxy surveys over comparable areas are generally deeper,
radio surveys of this kind have a number of other advantages, such as broader sampling of the
halo mass function and the possibility of measuring luminosity distances via the Tully-Fisher relation. In this chapter, we provide predictions for the
galaxy number counts versus
redshift that will be achievable with a wide-field HI
galaxy survey on SKAO-MID, along with corresponding forecasts for cosmological observables. Given the substantial uncertainty in the HI mass function with
redshift, we bracket our predictions using a handful of different modelling methods.
Read the full abstract ▾
All authors Ainulnabilah Nasirudin, Philip Bull, Ziad Sakr, Joël Mayor, Benedict Bahr-Kalus, Hengxing Pan, Stefano Camera, José Fonseca, Liantsoa F. Randrianjanahary, Gabriella De Lucia, Marta Spinelli
Quantum Physics
Synthesizing Compound Pulse Gadgets for Hamiltonian Simulation on Trapped-Ion Platforms
Ria Patel, Masoud Hakimi Heris, Yuan Liu et al. (+1 more)
Standard gate-level transpilation introduces significant physical noise and overhead for high-precision
quantum algorithms, such as the
Quantum Singular Value Transformation (QSVT), on near-term trapped-ion hardware. Current compilers treat
quantum operations as discrete units, forcing the physical control layer to execute highly fragmented
laser pulses. To address this hardware-software disconnect, this work introduces a holistic pulse synthesis strategy that bypasses discrete gate-stitching to compile
algorithms directly into continuous compound pulse gadgets. As a proof-of-concept, we target
Hamiltonian simulation of the $H_2$ molecule, block-encoding the problem into a QSVT
circuit to approximate the time-
evolution operator $U = e^{-i H t}$ across 3 computational ions (2 system, 1 ancilla). We utilize the Gradient Ascent Pulse Engineering (GRAPE)
algorithm to generate these compound gadgets and evaluate our methodology using noisy Lindblad master equation simulations. Preliminary observations indicate that the proposed strategy achieves significant temporal compression, reducing the total pulse schedule duration compared to standard compilers. Furthermore, synthesizing operations holistically eliminates the control-layer latency associated with discrete pulse lookup overhead. By streamlining the physical control schedule, this methodology offers a promising pathway to execute operations faster, highlighting the potential for compound gadgets to increase the computational depth achievable within fundamental $T_2$ decoherence limits.
Read the full abstract ▾
All authors Ria Patel, Masoud Hakimi Heris, Yuan Liu, Frank Mueller
Biological Physics
Dynamical noisy canalization in morphogenesis: lessons from Hydra regeneration
Oded Agam and Erez Braun
Developmental robustness is framed as progress through a fixed Waddington-type landscape. We argue that in morphogenesis this landscape evolves through coupled bio-signaling, mechanical, and physiological processes, while fluctuations aid exploration. In Hydra regeneration,
stochastic Ca activity plays a major role in reshaping the landscape of accessible morphologies as regeneration unfolds, including the early progressive confinement of tissue fluctuations. We propose testing this framework of dynamical noisy canalization in developmental systems.
Read the full abstract ▾
Optics
Axion Polarimetric Experiment (APE)
Qazal Rokn, Ryan Netrval, Aldo Ejlli et al. (+1 more)
We present the
Axion Polarimetric Experiment (APE), a cavity-enhanced polarimeter designed to search for ultralight
axion and
axion-like-particle dark matter through a time-dependent rotation of the linear polarization of
laser light. In cavity-based schemes, intracavity quarter-wave plates can restore coherent buildup of the
axion-induced orthogonal polarization, but their transmissive loss limits the achievable finesse. To avoid transmissive intracavity optics, we propose a folded Fabry-Perot cavity that employs dielectric phase-shifting mirrors. At an incidence angle near $45^\circ$, these mirrors provide a reflection-phase difference $\Delta\phi \equiv \phi_s-\phi_p \simeq \pi/2$ between $s$ and $p$ polarizations and therefore act as reflective quarter-wave plates. We present the coating design, thickness optimization, and measurements of the phase shift and optical loss of the phase-shifting mirrors. Using a heterodyne polarimetric readout and an explicitly stated noise model, we derive design-level sensitivity projections for the
axion-
photon coupling $g_{a\gamma\gamma}$. These projections should be interpreted as target sensitivities for the proposed cavity configuration, since the full-system birefringence noise and angular-jitter coupling remain to be measured.
Read the full abstract ▾
All authors Qazal Rokn, Ryan Netrval, Aldo Ejlli, Guido Mueller
Fluid Dynamics
Visualization of Inertial and Kelvin Waves on the Quantum Vortex Lattice in Superfluid Helium
Florian Lorin, Charles Peretti, Corentin Bourjaillat et al. (+3 more)
Superfluid $^4$He subjected to steady rotation develops a regular
lattice of
quantum vortices aligned with the rotation axis. We prepare this
lattice in a rotating cryostat, perturb it with a constant heat flux, and visualize
vortex deformation waves that propagate in the
lattice and grow in energy with the forcing. Below twice the rotation rate, we show that these waves feature a continuous frequency spectrum whose structure corresponds to inertial waves. At larger frequencies, we report several observations suggesting the presence of Kelvin waves over a continuous range of frequency. These results, obtained through space- and time-resolved velocity measurements of
quantum vortex lines, appear as quantitative constraints for modern two-way coupled
vortex filament models. They further offer new insights into perturbed
quantum vortex systems in three-dimensional
quantum fluids.
Read the full abstract ▾
All authors Florian Lorin, Charles Peretti, Corentin Bourjaillat, Patrik Švančara, Pierre-Philippe Cortet, Mathieu Gibert
Soft Condensed Matter
The Role of Compressibility in Modified Quasi-Linear Viscoelasticity: A Comparison of Simple Shear and Torsion
Valentina Balbi and Griffen Small
We investigate the role of compressibility in the modified quasi-linear viscoelastic (MQLV) constitutive framework for soft solids at finite strain, where shear and bulk responses are governed by distinct relaxation functions. Analytical and semi-analytical results are derived for simple shear and torsion, under incompressible and slightly compressible assumptions. We show that compressibility affects the response only when volume changes occur: under isochoric deformations, the bulk contribution vanishes, while even small deviations from isochoricity significantly alter the normal response. Shear stress and torque are largely insensitive to compressibility, whereas normal stress and axial force exhibit pronounced sensitivity due to the coupling between shear and bulk relaxation. We further demonstrate that volumetric effects interact with the Poynting effect: in simple shear they oppose each other, reducing relaxation, while in torsion they reinforce each other, enhancing it. These trends agree with
brain tissue experiments but reveal limitations of the slightly compressible model for highly compressible materials, such as agarose gels. Overall, the results emphasise the importance of accounting for compressibility in modelling normal stress responses and motivate the development of fully compressible formulations and numerical implementations.
Read the full abstract ▾
General Relativity and Quantum Cosmology
Gravitational Wave Signatures of Schwarzschild Black Hole in a Generalized Dehnen-Type $(1,4,\gamma)$ Dark Matter Halo
Bahromjon Shokirov, Arabboy Mirzakulov, Tursunali Xamidov et al. (+1 more)
In this paper, we investigate timelike geodesic motion, periodic orbits, and the associated gravitational-wave signals around a Schwarzschild-like black hole (BH) embedded in a generalized Dehnen-type dark matter (DM)
halo. We show that the Dehnen-type $(1,4,\gamma)$ DM
halo profile modifies test-particle dynamics, with increasing the parameter of density profile, $\gamma$, leading to larger marginally bound orbit (MBO) and innermost stable circular orbit (ISCO) radii and angular momenta, together with a higher ISCO energy. These findings provide further insight into the role of the DM distribution in modifying the orbital dynamics, energy, and angular momentum of timelike test particles near the BH. Furthermore, we investigate the gravitational-wave signals produced by a
stellar-mass compact object moving along periodic orbits around a supermassive BH embedded in a generalized Dehnen-type DM
halo. Using the numerical kludge approach, we calculate the orbital trajectories and the corresponding gravitational-wave polarizations. We find that increasing the
halo parameters $\gamma$, $\rho_s$, and $r_s$ produces larger periodic orbits, longer orbital periods, and lower waveform amplitudes. The resulting spectra lie mainly in the millihertz frequency range, while several characteristic-strain peaks lie above the sensitivity curves of future space-based gravitational-wave detectors such as LISA, Taiji, and TianQin. These results suggest that the surrounding DM
halo may leave observable imprints on extreme mass-ratio inspiral (EMRI) gravitational-wave signals.
Read the full abstract ▾
All authors Bahromjon Shokirov, Arabboy Mirzakulov, Tursunali Xamidov, Sanjar Shaymatov