Physics and Society
The dynamics of early transoceanic voyages: A resource-coupled model of crew health and survival
Nuno Crokidakis
The great transoceanic voyages of the Age of Discovery imposed severe human costs on their crews. Long travel durations, deteriorating sanitary conditions, and finite food and water supplies made disease, exhaustion, and mortality central features of maritime expansion. We propose a minimal compartmental model describing the voyage itself as a dynamical system coupling crew health and resource depletion. The population is divided into healthy, ill, and dead individuals, while an additional variable represents the effective level of provisions on board. Illness incidence depends nonlinearly on resource availability, capturing the increasing health risk associated with deteriorating food, water, and sanitary conditions. The coupled ordinary differential equations are analyzed in the transient regime relevant to finite-duration voyages. Rather than reconstructing specific historical expeditions, the model identifies generic mechanisms linking provisioning, health deterioration, mortality, and voyage duration. Numerical results show that resource limitations can substantially reduce the healthy and operational fraction of the crew even when overall survival remains relatively high, revealing a distinction between demographic survival and operational viability. Increasing initial provisioning delays the crossover at which ill individuals become as numerous as healthy individuals and extends the period over which the crew remains predominantly operational. We also introduce a critical provisioning time, defined as the time required for resources to reach a prescribed stress threshold, and find an approximately linear dependence on the initial resource buffer. The framework provides a quantitative perspective on the internal dynamics of early transoceanic
navigation and illustrates how dynamical-systems approaches can contribute to the study of historical processes.
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Quantum Physics
State-Selective Floquet Memory in Degenerate Manifolds
Ayan Sahoo, Argha Debnath and Debraj Rakshit
In order to understand which initial states retain
memory under periodic driving, it is necessary to depart from the ideal limit giving rise to invariant structures and work inside near-degenerate
manifolds. We show that degeneracy itself is not conclusive and what actually matters is how perturbations, such as structural and driving imperfections, acts on the projected multiplet. For systems decoupling into the local clusters in the ideal limit, the projections can be computed within degenerate perturbation theory. There the stability is decided by two criteria: the coupling can not connect the state with other degenerate partners in the
manifold, either by kinetic blocking, or more generally, by diagonalizing the projected coupling, and the drive's local selection rule must admit only transfer energies detuned from Floquet sidebands, in which case the projected drive generator exactly vanishes. We formalize these understandings in a periodically driven clean, short-ranged alternating XXZ chain and demonstrate a set of results that include, long-lived states, both of product form and entangled across the clusters, a periodic family of sideband resonances, and an explicit example showing opposite fates for states with identical energy and charges.
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Mesoscale and Nanoscale Physics
Coplanar Lateral Gating MoS2 on SrTiO3: A Unified Platform for Classical and Quantum Devices
Prasad Muragesh, Manav Murali, Venkatesha Modur Ramachandra et al. (+1 more)
Atomically thin transition-metal dichalcogenides, such as MoS2, offer a promising route to surpass the scaling limits of silicon owing to their excellent electrostatic control and resilience to short-channel effects. Realizing this potential depends critically on gate-stack engineering, where strong gate coupling must be achieved without compromising the pristine two-dimensional interface. Here, we demonstrate a coplanar lateral-gating architecture for MoS2 field-effect transistors fabricated directly on single-
crystal SrTiO3. The exceptionally high permittivity of SrTiO3 enhances gate-channel coupling. The coplanar geometry eliminates the need for a separate gate
insulator, reducing interface disorder. Owing to the
quantum paraelectric nature, the SrTiO3 dielectric constant increases upon cooling, enhancing the gate coupling, leading to a decrease in threshold voltage and subthreshold swing an effect that contrasts with conventional FET architectures. The dielectric-free MoS2 surface, combined with enhanced electrostatic control, makes this architecture a promising platform for low-power two-dimensional electronics and cryogenic
quantum devices.
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All authors Prasad Muragesh, Manav Murali, Venkatesha Modur Ramachandra, Madhu Thalakulam
Astrophysics of Galaxies
Water maser detections toward 70 ${\mu}$m infrared dark clumps at early star formation stage
Chao Ou, Shanghuo Li, Junzhi Wang et al. (+2 more)
Water masers provided powerful probes of shocked gas and protostellar activity during the early stages of
star formation. Using VLA K-band observations of the 22 GHz water line, we report the first detections of water masers toward dense cores in five 70 ${\mu}$m infrared dark clumps, providing evidence for active
star formation at an early evolutionary stage. We detected ten unresolved maser spots comprising thirteen velocity components, with peak flux densities of 13–499 mJy and deconvolved full widths at half maximum (FWHMs) of 0.51–3.54 km s-1. Eleven components had FWHMs below 1 km s-1, while their velocity offsets from the systemic velocities traced by the NH3(1,1) main line ranged from 0.83 to 50.73 km s-1. Four water maser spots were associated with 1.3 mm continuum emission, three of which were also associated with molecular
outflows traced by CO 2-1 emission. No CO
outflow signature was detected toward the remaining spots within the observed field of view, suggesting that water masers could trace deeply embedded protostellar activity whose
outflows were not yet detectable in CO emission. For AGAL031, the non-detection of StokesV emission toward the strongest maser component yields an upper limit on the line of sight
magnetic field strength on the order of a few hundred mG. Our results showed that
star formation was already active in 70 ${\mu}$m infrared dark clumps and that 22 GHz water masers provided insights into early protostellar environments that remained difficult to probe with common
star formation tracers.
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All authors Chao Ou, Shanghuo Li, Junzhi Wang, Ian W. Stephens, Yuqiang Li
Solar and Stellar Astrophysics
Gaia method paper: an algorithm to detect flare events in Gaia time-series
E. Distefano, A. C. Lanzafame, A. F. Lanza et al. (+14 more)
The third
Gaia data release (GDR3) includes the gdr3_rotmod catalogue of 474026
stars with variability that is attributed to
magnetic activity analogous to that observed in the Sun, arising from rotational modulation induced by spots and faculae. These
stars are therefore expected to exhibit flaring activity driven by
magnetic reconnection processes. We aim to demonstrate that
stellar flares can be reliably identified and characterised in the sparsely sampled \gaia\ photometric time series. We developed and validated a dedicated
flare-detection pipeline that exploits the simultaneous multi-band photometry in the $G$, $G_{\rm BP}$, and $G_{\rm RP}$ bands. The
algorithm identifies outliers associated with a concurrent increase in brightness and blueing of the
stellar colour, and applies consistency criteria to distinguish genuine
flare events from instrumental or calibration artefacts. Applying this method to the gdr3_rotmod catalogue, we detect 3217
flares occurring on 2818
stars out of 474026 analysed sources. All events are provided in a dedicated catalogue together with their photometric amplitudes. For a subset of 348
flares, we estimate an effective temperature using a black-body approximation, and we identify 29 hyper-
flares with amplitudes $A(G)\ge0.75$ mag, which occur preferentially in M
dwarfs. Despite the sparse temporal sampling of
Gaia, our results demonstrate that its multi-band photometry and spectrophotometric information enable the robust detection of
flares and the basic characterisation of their properties across an all-sky
stellar sample. This work establishes the methodological foundation for future
Gaia flare catalogues and provides a homogeneous, complementary view of
stellar flaring activity alongside high-cadence missions such as Kepler and TESS.
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All authors E. Distefano, A. C. Lanzafame, A. F. Lanza, S. Messina, I. Pagano, M. Audard, G. Jevardat de Fombelle, B. Holl, I. Lecoeur-Taibi, N. Mowlavi, K. Nienartowicz, L. Rimoldini, D. W. Evans, M. Riello, P. García-Lario, P. Gavra, L. Eyer
Quantum Physics
The effects of shot noise on the quantum computation of NMR spectra
Sebastian Walch, Keith R. Fratus, Jan-Michael Reiner et al. (+1 more)
Recent advances in the field of
quantum computing hardware motivate the search for applications which demonstrate so-called
quantum advantage. One promising use case that has been identified is the simulation of
quantum many-body systems. The computational resources required for performing such a simulation on a classical computer generally grow exponentially with the size of the system being modeled, which is ultimately due to the exponential growth of the
Hilbert space in which the dynamics of such a system take place. While digital
quantum computers natively evolve
quantum states directly in such a
Hilbert space, thus naively avoiding this problem, the result of such a computation is typically not obtained as a deterministic output. Rather, it requires projective measurements which are fundamentally affected by shot noise. Any desired expectation values must therefore be reconstructed from repeated measurements, making the number of those measurements a relevant computational resource, and thus an important consideration for any potential claims of
quantum advantage. In this work, we study how this resource scales with system size (a scaling which itself depends on the desired accuracy of the final result), using the simulation of
nuclear magnetic resonance (NMR) spectra as a test case. We study this scaling for both real-world molecules, as well as a class of model NMR
Hamiltonians which allow for efficient large-scale simulations with one-dimensional, two-dimensional, and all-to-all interactions. We find that the required resources increase only weakly with molecular size, far below the exponential growth of the underlying
Hilbert space. This result suggests that shot noise should not pose a fundamental barrier to achieving
quantum advantage in the simulation of NMR systems, and perhaps for many-body systems more broadly.
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All authors Sebastian Walch, Keith R. Fratus, Jan-Michael Reiner, Igor Lesanovsky
High Energy Physics (Phenomenology)
Investigation of low-lying $\Omega_b(1P)$ states in an unquenched coupled-channel framework
Zi-Le Zhang, Si-Qiang Luo, Shuai-Wei Wang et al. (+1 more)
In this work, we study the unquenched effects on the low-lying $\Omega_b(1P)$ states with a coupled-channel equations. We reveal how the unquenched effects affect the $\Omega_b(1P)$ spectroscopy and component mixing. The numerical results indicate that the $J^P=1/2^-$ $\Omega_b(1P)$ state dominated by the $j_\ell=0$ configuration exhibits significant coupled-channel effects due to its $S$-wave coupling to the $\Xi_b\bar{K}$ channel, where $j_\ell$ denotes the total angular momentum of the light
flavor degrees-of-freedom. In this scenario, the mass of this state may be shifted close to or below the $\Xi_b\bar{K}$ threshold, making the radiative and isospin-breaking channels kinematically allowed decay processes. The present analysis provides a coupled-channel perspective on the low-lying $\Omega_b(1P)$ spectrum and offers guidance for future experimental studies of excited bottom
baryons.
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All authors Zi-Le Zhang, Si-Qiang Luo, Shuai-Wei Wang, Qin Chang
Statistical Mechanics
Universal 1/f Noise in the Power Spectra of Energy Time-series in Solvated DNA Dynamics
Harsh Sahu, Deepika Sardana, Pramod Kumar et al. (+3 more)
We investigate energy fluctuations of solvated DNA in three conformations: G-quadruplex, Hairpin, and Duplex. Our comprehensive molecular dynamics (MD) simulations demonstrate that the time-series of interaction energies for DNA self, DNA-water and DNA-ion show 1/f noise with a universal decay exponent $\beta \simeq 0.90$. We show that DNA
topology and structural
rigidity modulate its dynamic coupling with the surrounding hydration shell and mobile counter-ions. This coupling critically shapes the 1/f noise profile: DNA self energies in flexible structures (G-quadruplex, Hairpin) display pronounced low-frequency modes absent in the rigid Duplex. These findings reveal how the interplay between DNA
topology and environmental coupling governs different
stochastic behavior in biologically relevant forms of DNA.
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All authors Harsh Sahu, Deepika Sardana, Pramod Kumar, Ajay Kumar Chand, Sobhan Sen, Sanjay Puri
Quantum Physics
Entanglement Dynamics in Katz-Weighted Graph States
Lucio De Simone, Lorenzo Capra and Roberto Franzosi
We investigate the
entanglement dynamics of
quantum states defined on graphs with non-local Ising interactions governed by the Katz kernel of the underlying network. The interaction pattern is physically motivated by a gapped fermionic mediator propagating on the same graph, whose perturbative elimination yields an effective Katz-weighted Ising
Hamiltonian. Using the
Entanglement Distance, we derive an exact analytical expression for the
entanglement generated from an initially separable state and apply it to representative deterministic graph families. We then characterize the dynamics in different propagation regimes. In the weak-Katz regime, the dynamics admits a systematic motif expansion with triangles entering at first order order and four-cycles, local degree structure, and overlappin triangles appearing at second order. In the strong-propagation regime, the interaction is instead dominated by the principal adjacency mode and by the localization properties of its eigenvector. For Erdős–Rényi graphs, the weak-propagation expansion can be averaged analytically, revealing a locally tree-like contribution in the sparse regime and saturation of the
Entanglement Distance density in the dense regime. Our results connect
entanglement dynamics with both the walk-based and spectral structure of complex networks.
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Materials Science
Ultralow-Tensile Strain Enables Exciton Funneling and Energy Transfer to Boost MoSe2 Photoluminescence Quantum Yield
Gayatri, Mehdi Arfaoui, Debashish Das et al. (+14 more)
Strain engineering is a powerful route for controlling the
exciton dynamics in van der Waals (vdW)
heterostructures (HSs). The interlayer energy transfer (ET) process is another key factor in controlling the photocarrier relaxation pathways in vdW HSs. In this work, we combine these two processes to achieve an 8-fold enhancement to the relative photoluminescence (PL)
quantum yield (QY) in a HS formed from monolayers of ReS2 and MoSe2, separated by a thin hBN interlayer, placed onto an hBN bubble. We achieve this enhancement by applying only 0.1% biaxial tensile strain, which results in efficient
exciton funneling and an increased transition dipole moment. Our experimental data are supported by first-principles density-functional theory and coherent transfer-
matrix method calculations, ruling out optical interference as the dominant origin of the enhancement. This work provides an innovative route for enhancing the PL QY of vdW materials via interplay between the tensile strain and the ET process.
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All authors Gayatri, Mehdi Arfaoui, Debashish Das, Mateusz Raczyński, Marta Bilska, Piotr Tatarczak, Aleksandra Krystyna Dąbrowska, Tomasz Kazimierczuk, Takashi Taniguchi, Kenji Watanabe, Piotr Kossacki, Andrzej Wysmołek, Saroj Kumar Nayak, Adam Babiński, Johannes Binder, Maciej R. Molas, Arka Karmakar
Chemical Physics
FOSY: Segmental Backbone Assignment in Intrinsically Disordered Proteins
Dmitry M. Lesovoy, Tatiana Agback, Panagiota S. Georgoulia et al. (+3 more)
Backbone resonance assignment is a prerequisite for most biomolecular NMR applications, yet conventional multidimensional strategies frequently fail for intrinsically disordered
proteins (IDPs) and regions (IDRs) because of severe spectral overlap, rapid amide
proton exchange with water, and missing sequential correlations. In many biological applications, however, complete
protein assignment is unnecessary, as only a limited sequence segment surrounding a functional site is required. Here we introduce segmental backbone assignment, an assignment strategy implemented by FOcused SpectroscopY (FOSY), which concentrates experimental effort on relatively short regions while retaining the high-dimensional sequential connectivity needed for unambiguous assignments. We present a self-consistent suite of selective two-dimensional FOSY experiments that enables bidirectional assignment walks along the
protein sequence through complementary forward and backward transfer schemes. The methodology employs frequency-selective polarisation transfer to replace high-dimensional experiments with sensitive and readily interpretable 2D spectra while preserving the information content of multidimensional correlation experiments. The approach is demonstrated by completing the assignment of G302-K311 segment, which is missing in the published assignment of the 441-residue human Tau
protein. The approach complements conventional multidimensional or residue type-selective assignment strategies by providing an efficient means of traversing assignment interruptions and rapidly characterising functionally important segments in intrinsically disordered
proteins.
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All authors Dmitry M. Lesovoy, Tatiana Agback, Panagiota S. Georgoulia, Irena Matecko-Burmann, Bjorn M. Burmann, Vladislav Y. Orekhov
General Relativity and Quantum Cosmology
Quasinormal modes of Schwarzschild–AdS black holes with a near-horizon reflective surface
Libo Xie, Liang-Bi Wu, Yu-Sen Zhou et al. (+3 more)
We investigate the scalar quasinormal mode (QNM) spectrum of Schwarzschild-AdS black holes with a partially reflective surface placed near the event horizon. The corresponding QNM problem is solved numerically using Chebyshev spectral collocation. The resulting spectra exhibit a characteristic cavity structure at sufficiently large real part, where the modes form approximately equally spaced sequences whose spacing and damping are controlled mainly by the cavity length and the surface reflectivity. For large AdS radius, an additional weakly damped quasibound-state branch appears due to trapping between the centrifugal barrier and the AdS potential wall. We show that these spectral features can be understood within a finite radial cavity picture. A WKB analysis provides a quantitative asymptotic description of the spectra which have high real parts. We find that changes in the near-horizon boundary condition can lead to substantial changes in the QNM spectrum, indicating the strong sensitivity of Schwarzschild–AdS QNMs to the effect of horizon correction.
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All authors Libo Xie, Liang-Bi Wu, Yu-Sen Zhou, Xi-Ning Dong, Zong-Kuan Guo, Rong-Gen Cai
Atomic Physics
Small-Angle Differential Cross Sections for Symmetrical Resonant Charge Exchange in Molecular Hydrogen
Jibak Mukherjee, Kamal Kumar, Harpreet Singh et al. (+2 more)
We measured state selective scattering angle distributions in non-dissociative-state single electron capture in $\lbrace 5, 7.5, 10\rbrace$ keV/u, $\left[\mathrm{H^+ + H_2}\right]$ and $\left[\mathrm{H_2^+ + H_2}\right]$ collisions, using Cold Target
Recoil Ion Momentum Spectroscopy (COLTRIMS). In our measurements, range of the scattering angle was small where diffraction effect is expected to take place, and, the ground state electron capture - symmetrical resonant channel for the $\mathrm{H_2^+}$ projectile and near resonant channel for the $\mathrm{H^+}$ projectile - was fully resolved from other channels. We analyzed the data considering $\mathrm{H_2^+}$ and $\mathrm{H_2}$ possess two independent-identical scattering centers and exhibit multi center interference effect. By comparing these equal-velocity collisions, we investigated the atomic nature of the individual scattering centers. We observed Fraunhofer diffraction from a circular aperture like patterns with equal fringe widths, for both the projectiles, in ground state channel. We applied a simple toy model to reconstruct the circular apertures.
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All authors Jibak Mukherjee, Kamal Kumar, Harpreet Singh, Manojit Das, Deepankar Misra
Mesoscale and Nanoscale Physics
Predictive Structure to Thermal Conductivity Modeling Framework for BEOL Interconnect Stacks in Advanced Technology Nodes Enabled by Extensive Layer Resolved Thermal Measurements
Zifeng Huang, Yiyang Sun, Tianyu Jia et al. (+2 more)
The increasing structural complexity of BEOL interconnect stacks in advanced integrated
circuits demands a structure-aware thermal conductivity (ąppa}) modeling framework. However, generalizable models derived from layer-resolved thermal measurements that quantitatively capture the dependence of ąppa} on interconnect structures remain lacking, limiting predictive thermal analysis. Here, we establish an experimentally derived, structure-aware ąppa} modeling framework enabled by time-domain thermoreflectance measurements with ~100 nm depth resolution. Statistical analysis of a compiled
dataset comprising over 40 experimentally measured layer-resolved ąppa} values across diverse BEOL layers reveals a generalizable empirical structure-to-ąppa} relationship, enabling predictive modeling based on interconnect structure. An intra-layer three-dimensional ąppa} distribution model based on effective medium theory and realistic layouts further resolves spatial ąppa} variations within practical interconnect layers. Together, these models establish an experimentally derived, structure-aware ąppa} modeling framework for predictive and generalizable thermal analysis of advanced interconnect stacks and 3D ICs.
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All authors Zifeng Huang, Yiyang Sun, Tianyu Jia, Runsheng Wang, Zhe Cheng
Strongly Correlated Electrons
Pressure-induced electronic and structural evolution of EuIrGe3
N.S.Dhami, V. Baledent, I. Batistic et al. (+10 more)
We investigated the pressure-induced
evolution of the electronic and
crystal structure of the noncentrosymmetric BaNiSn3-type antiferromagnet EuIrGe3 using x-ray absorption spectroscopy, synchrotron x-ray diffraction complemented by density functional theory calculations, and electrical resistivity measurements. The Eu L3-edge spectra reveal a continuous increase in the mean Eu valence under compression, accompanied by modifications of the Ge and Ir electronic states. High- pressure x-ray diffraction shows anisotropic
lattice compression in the tetragonal (I4mm) phase and provides evidence for a structural phase transition above 38 GPa. The experimentally deter- mined
lattice and equation-of-state parameters are in good agreement with the DFT calculations. Electrical resistivity measurements reveal a monotonic increase in the
antiferromagnetic ordering temperatures up to 18 GPa, indicating that the
antiferromagnetic ground state remains robust despite the increasing contribution of the nonmagnetic Eu3+ configuration to the intermediate va- lence state. These results demonstrate that EuIrGe3 exhibits a pressure response distinct from EuCoGe3 and EuRhGe3, highlighting the important role of the transition metal d-electron states in the pressure-induced electronic and structural
evolution of the EuT Ge3 family
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All authors N.S.Dhami, V. Baledent, I. Batistic, C. M. N. Kumar, D. Kaczorowski, L. Nataf, J. M. Ablett, J.-P. Rueff, J. P. Itie, P. Fertey, S. R. Shieh, P. Popcevic, Y. Utsumi Boucher
Astrophysics of Galaxies
Revisiting the interpretation of HI Zeeman measurements in the diffuse interstellar medium
Adrien Barthas and Andrea Bracco
The HI Zeeman effect provides one of the few direct probes of
magnetic field strengths in the diffuse atomic interstellar medium (ISM), yet the physical quantity recovered by the standard weak-field
estimator remains uncertain in multiphase gas. This is especially relevant to the low-column-density branch of the observed
magnetic field–column density relation, which is nearly flat below NH~1E22 cm-2 and remains difficult to explain theoretically. We investigate this issue using synthetic HI Zeeman observations of multiphase magneto-hydrodynamic simulations of the atomic ISM performed with RAMSES, complemented by analytical two-phase models of the thermally bistable atomic medium. We find that both emission and absorption Zeeman measurements recover the
magnetic field weighted by optical depth along the line of sight, rather than the density-weighted field. The two converge only in limiting cases, such as isothermal gas or homogeneous
magnetic fields across phases. In realistic multiphase media, the Zeeman-derived field statistically exceeds the density-weighted field by factors of a few, with the strongest departures when cold and warm atomic gas both contribute significantly to the column density. Our analytical models reproduce this behavior and show that thermal bistability generates both an excess and a large dispersion between Zeeman-derived and density-weighted fields, even when the intrinsic
magnetic field increases monotonically with density. The effect is strongest below NH~1E22 cm-2, where the temperature contrast between cold and warm HI causes optical-depth and density weighting to diverge. We conclude that HI Zeeman observations primarily trace the optical-depth-weighted
magnetic field. This intrinsic thermal weighting may contribute to the broad distribution, and possibly part of the apparent flattening, of the observed
magnetic field-column density relation.
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Materials Science
A Computational Method to Simulate Electrostatic Actuation in Polycatenated Architected Materials
Mateus Maciel Vivaldi and Alexandre F. Fonseca
A novel class of polycatenated architected materials (PAMs) has recently emerged, exhibiting distinctive mechanical properties such as stress-strain hysteresis and a geometry-driven transition between solid-like and fluid-like behavior. Although finite element models exist for conventional PAMs, none currently account for electrostatic effects. Here, we propose and qualitatively validate a computational framework to simulate the structure, dynamics, and mechanical response of electrostatically charged PAMs. Our approach successfully reproduces electrostatic actuation in close agreement with experiments, and reveals that electrostatic charges enable a reversible fluid-to-solid transition while also providing a means to estimate electrostatic stiffness. Notably, stiffness enhancements of up to sevenfold are achieved upon charging. This work expands the design space of PAMs and offers a predictive tool for actively controllable mechanical metamaterials.
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Soft Condensed Matter
Inferring interactions between active particles using harmonic traps
Arnaud Compagnie, Joscha Mecke, Ivo Buttinoni et al. (+1 more)
Quantifying the interactions between active Janus particles remains a challenge that needs to be addressed to describe their collective behaviour. Inspired by a photonic force microscopy setup where two active Janus particles are confined in separate optical tweezers, we derive the steady-state probability distribution of each particle bearing signatures of the pair phoretic interaction, which can be generalised to a broader range of interactions. This approach allows us to infer interaction forces and torques from positional configurations without any knowledge of the particle orientations. Unraveling the distance-dependent interaction between active particles is essential to harnessing them as building blocks for advanced materials with dynamic properties.
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All authors Arnaud Compagnie, Joscha Mecke, Ivo Buttinoni, Hartmut Löwen
Earth and Planetary Astrophysics
Prospects for Mercury Observations with the BepiColombo Laser Altimeter (BELA): Implications for Estimating Surface Roughness from Laser Altimetry
Gaku Nishiyama, Alexander Stark, Christian Hüttig et al. (+12 more)
Surface reflectance and roughness are key to understanding Mercury's geologic
evolution. The BepiColombo
Laser Altimeter (BELA) will measure these properties alongside topography, but predicting its performance requires realistic modeling of
laser return pulse shapes, unlike a simplified Gaussian approximation in earlier models. We develop a comprehensive return-pulse simulation framework for BELA that includes non-Gaussian transmitted pulses, analog filtering in the receiver chain, and pulse-shape modification by footprint-scale topography. Using high-resolution lunar digital terrain models and synthesized fractal topography as Mercury analogs, we develop calibration and correction methods and estimate measurement errors expected in future BELA observations. Range errors average 1.5 m or less below 1000 km altitude, and energy errors are small enough to distinguish dark deposits, regolith, and exposed ice below 900 km. Pulse width proves unreliable as a roughness proxy under realistic conditions; we instead constrain roughness from digitized pulse shapes, underscoring the value of time-resolved data for future planetary altimeters.
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All authors Gaku Nishiyama, Alexander Stark, Christian Hüttig, Kai Wickhusen, Christian Althaus, Thomas Behnke, Ernst Hauber, Klaus Gwinner, Konrad Willner, Noriyuki Namiki, Frederic Schmidt, Jean Barron, Hugo Lancery, Azar Arghavanian, Hauke Hussmann
Superconductivity
Superconductivity in Pb2-xBixPd Single Crystals
S. Srivastava and R. P. Singh
Chemical substitution provides an effective route to tune the structural and superconducting properties and to explore the
evolution of superconductivity across related materials. In this work, we investigate the effect of Pb/Bi mixing on superconductivity in possible topological
superconductors \ch{Pb2Pd} and $\beta$-\ch{Bi2Pd}, by synthesizing and characterizing single
crystals of \ch{Pb_{2-x}Bi_{x}Pd} ($0.2\le x\le1.8$). Increasing Bi content triggers a structural phase transition from non-symmorphic ($I4/mcm$, $x<1$) to layered ($I4/mmm$, $x\ge1$) and induces a monotonic expansion of the
lattice parameters. Across the doped range, all superconducting samples behave as weakly-coupled type-II
superconductors exhibiting isotropic s-wave superconducting gaps.
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High Energy Physics (Phenomenology)
Comparing theoretical descriptions of Drell-Yan angular coefficients
Nikita Gramotkov and Oleg Teryaev
A quantitative comparison of the predictions of three theoretical descriptions (TMD, pQCD and geometrical) of the angular coefficients in Drell-Yan Z-
boson production with new experimental data on angular coefficients obtained by the ATLAS, CMS and LHCb collaborations has been performed. In the central rapidity region at low-$Q_T$, the TMD calculation provides a better description of the $A_0$ and $A_2$ coefficients among the descriptions considered. The differences between the approaches are less pronounced for $A_1$,$A_3$ and $A_4$ coefficients. The results identify $A_0$,$A_2$ and the Lam–Tung relation as the most sensitive observables at low-QT and illustrate the domains of applicability of the three descriptions.
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Applied Physics
Three-dimensional vector waves in time-variant materials, with applications in time-reversed focusing and Green's function retrieval
Kees Wapenaar and Dirk-Jan van Manen
The behavior of wave propagation and scattering in time-variant materials has been studied by many authors, for electromagnetic as well as for mechanical waves. Most studies consider two-dimensional waves, governed by scalar wave equations. Here we introduce a unified wave equation for three-dimensional electromagnetic and elastodynamic vector-wave propagation and scattering in homogeneous, time-variant materials. Using the
symmetry properties of this equation, we establish the conservation of net field-momentum density, and a reciprocity relation between causal and acausal Green's functions. The latter relation is exploited in the derivation of the counterparts of classical time-reversed focusing and Green's function
retrieval for time-variant materials.
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Earth and Planetary Astrophysics
Exoplanet detection through photometric orbital phase modulations
J. Lillo-Box and O. Balsalobre-Ruza
Since the detection of the first extrasolar
planets thirty-five years ago, the dawn in detected signals has been driven primarily by radial velocity and transit techniques. However, other methodologies have gained significant interest due to their ability to explore specific niches that are challenging to access with traditional approaches. In this article, we focus on the photometric orbital phase modulations induced by
planets, describe the methodologies and equations and highlight their developments and prospects for the future.
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Atmospheric and Oceanic Physics
Unreported large errors from two PAMGuard three-dimensional localizers of whale calls
Maya Mathur, Luke Stoner-Eby, Devin Pascoe et al. (+1 more)
Confidence intervals of location (CIL) of calling marine mammals, derived from time-differences-of-arrival (TDOA) between receivers, depend on errors of TDOAs, receiver location, clocks, sound speeds, and location method. When these errors are minuscule, simulations yield small errors of PAMGuard's 3D simplex localizer when click sounds of beaked and sperm whales originate in a 1000 x 1000 x 1000 $\mbox{m}^3$ region using five receivers having horizontal and vertical separations of 1000 m and 150 m respectively. Realistic uncertainties of sound speed up to $\pm 10$ m/s lead to errors up to $10^{14}$ m. With clocks maintained by atomic standards and common practice of correcting TDOA from synchronization measurements at the start and end of an experiment, errors of location are up to $10^{4}$ m. Errors up to $10^2$ and $10^3$ m are found when the receiver's locations are uncertain within 10 and 40 m respectively. Errors of PAMGuard's 3D
hyperbolic localizer are almost independent of the above uncertainties, yielding errors of location up to about $10^4$ m even when simulated errors are minuscule. Causes of PAMGuard's 3D location errors are unknown. These
algorithms are briefly compared to another method designed to yield a reliable CIL.
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All authors Maya Mathur, Luke Stoner-Eby, Devin Pascoe, John L. Spiesberger
Quantum Physics
Dissipative phase transitions in quantum reservoir computing
Da Zhang and Zhang-Qi Yin
Enhanced performance of
quantum reservoir computing has been associated with dynamical phase transitions, but whether this connection extends to dissipative systems and which relaxation mechanisms underlie it remain insufficiently understood. We systematically compare driven-dissipative Kerr reservoirs across first-order and continuous dissipative phase transitions and find enhanced
memory and nonlinear processing near both phase boundaries. Although the closure of the Liouvillian gap marks the transitions in the thermodynamic limit, computational performance does not generally follow gap suppression. An exact post-training Liouvillian-mode decomposition quantitatively attributes the trained
memory to intrinsic relaxation channels. It shows that the gap mode contributes only weakly, while finite-rate modes and their cross-contributions dominate the enhanced capacity. These results go beyond phenomenological correlations by directly linking
memory capacity to the intrinsic Liouvillian relaxation spectrum. Moreover, these findings provide a physical basis for designing dissipative
quantum reservoirs and testing
memory-enhancement mechanisms in experimentally accessible Kerr platforms.
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High Energy Astrophysical Phenomena
Evolution and mergers of eccentric white dwarf binaries encountering intermediate-mass black holes
Adarsh Pandey, Aryabrat Mahapatra and Tapobrata Sarkar
We study how a close passage past an intermediate-mass black hole (IMBH) changes the
evolution of an eccentric white
dwarf (WD) binary that has nominal Roche lobe overflow at internal pericenter. Using three-dimensional smoothed particle hydrodynamics, we follow binaries with eccentricity $e_{\rm in}=0.6$ and mass ratios $q=0.2$ – $0.7$ on
parabolic, retrograde orbits around a Schwarzschild IMBH at two encounter strengths, $\beta^b=0.5$ and $1.5$. We compare them with the same binaries evolved in isolation. The IMBH greatly speeds up the merger. Every IMBH-perturbed binary that merges does so during or shortly after its second internal pericenter passage, which is always less than the time taken to merge in isolation. The merger outcome is not monotonic with encounter strength. The $q=0.2$ binary retains two bound cores for $\beta^b=1.5$ but merges at $\beta^b=0.5$. In the deeper encounter it settles onto a less eccentric post-encounter orbit, showing that the timing of the encounter relative to the inner orbit plays an important role. Deep encounters also produce transient reversals of the internal orbital angular momentum for $q=0.2$ – $0.4$, while the material bound to the accretor gains more
spin angular momentum than that bound to the donor. The specific orbital angular momentum of the binary CM around the IMBH changes by only a few $\times10^{-4}$ of its initial value. We also identify He-origin material that can burn helium on a dynamical timescale, amounting to $\sim15$ – $17\%$ of the He-origin mass for $q=0.7$. IMBH encounters can therefore quantitatively change the
evolution of eccentric WD binaries.
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Mathematical Physics · Cross-listed from math.RT
Unitary Branching for $\mathfrak{sl}(m\vert n), \mathfrak{osp}(m\vert 2n)$ and $F(4)$
Steffen Schmidt
We determine the branching of irreducible
unitary representations of the basic classical Lie superalgebras $\mathfrak{sl}(m|n)$, $\mathfrak{osp}(m|2n)$, and $F(4)$ under restriction to their even subalgebras. The proof combines Dirac inequalities for the Huang-Pandžić-Dirac operator $\operatorname{D}_{\mathfrak{g},\mathfrak{g}_{\bar{0}}}$ with a super analogue of Freudenthal's recursion derived from the Dirac formalism. We extend the Dirac method to positive systems that are not adapted to the relevant real form by transporting the Dirac inequality through odd reflections and determining the resulting correction terms. This yields finite recursive procedures that determine the occurring even constituents and their branching multiplicities, together with closed formulas for the latter, uniformly in the degree of atypicality. For $\mathfrak{sl}(m|n)$, the corrected Dirac inequalities also give a characterization of unitarity for all positive systems relevant to
unitary representations.
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Quantum Physics · Cross-listed from eess.AS
State-Space-Based FIR Filtering on a Quantum Computer
Roope Salmi, Davide Rocchesso and Vesa Välimäki
Many signal processing tasks require intensive computations.
Quantum computing promises to accelerate certain tasks, but
algorithms must be designed around the limitations of
quantum mechanics. This paper provides a
quantum implementation of finite impulse response (FIR) filters, which are a widely used tool in classical signal processing. The filter can be parallelized and composed as part of larger
quantum algorithms, with potential for speedups using
quantum amplitude estimation and future fault-tolerant
quantum hardware. To accomplish these properties, we introduce a state-space framework wherein sample-based signal processing is performed with
unitary quantum circuits. We present the
quantum delay gate as the
quantum analog of the delay line in discrete-time signal processing.
Unitary circuits intrinsically describe lossless systems, but we also implement lowpass and other bounded filters by emulating a projection operator. The FIR filter implementation is tested and demonstrated with a
quantum circuit simulator.
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Cosmology and Nongalactic Astrophysics
Predictions on the abundance of primordial black holes: results from the SMILE VLBI milli-lensing sample
Xinyue Jiang, Shuo Cao, Marek Biesiada et al. (+4 more)
Primordial black holes (PBHs) formed in the early universe represent a well-motivated dark matter candidate. However, their abundance in the intermediate-to-high mass range ($10^6$-$10^9\,M_\odot$) remains relatively less constrained. In this mass regime, the corresponding Einstein radii on the milliarcsecond scale make Very Long Baseline Interferometry (VLBI) the most direct observational probe via milli-
lensing of compact
radio sources. In this paper, we present predictions for the abundance of PBH dark matter ($f_{\rm PBH}$) using the large SMILE sample of $\sim 5000$ flat-spectrum compact
radio sources. Under the optimistic observational conditions (with an angular resolution of $1.5\,\mathrm{mas}$, a maximum image separation of $100\,\mathrm{mas}$, and a maximum detectable flux ratio of $40$), assuming that no milli-
lensing events are confirmed, we obtain the projected 95% upper limit of $f_{\rm PBH}\lesssim0.12%$ in the intermediate-to-high mass range, which would be approximately an order of magnitude tighter than previous VLBI milli-
lensing limits. Broader lognormal mass functions yield correspondingly weaker projected limits. Generalising the optical depth to account for magnification bias and finite-core resolvability changes these projected limits by only about $5$%. Moreover, we show that the predicted limits are highly sensitive to a small number of confirmed events, i.e., even one confirmed milli-
lensing event would relax the projected upper limit to $0.20$%, highlighting the critical importance of robust candidate confirmation in the SMILE sample. Finally, under the optimistic baryonic
accretion scenario, the PBH mass growth changes the projected limits by $\lesssim 1$% within the VLBI-sensitive mass range, confirming the robustness of our results.
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All authors Xinyue Jiang, Shuo Cao, Marek Biesiada, Xuanni Chen, Yalong Nan, Xinyang Jin, Xuchen Tai
Plasma Physics
Experimental setup for testing nanocalorimeter sensors as a plasma diagnostics tool
Carles Corbella, Feng Yi and Andrei Kolmakov
The application of microfabricated nanocalorimeters for real-time, highly sensitive, and selective monitoring of the energy fluxes from low-pressure
plasma discharges has been reported recently. Here, we describe the experimental setup for complementary characterization of nanocalorimeters performance using
plasma diagnostics techniques. Langmuir probe, retarding field energy analyzer (RFEA), optical emission spectroscopy (OES), quadrupole mass spectrometry (QMS), and thermocouple-based thermometry constitute the
plasma monitor suite. We discuss two application examples of the
plasma monitor suite: (1) discrimination between electron- and ion-induced heat fluxes via sensor direct current (DC) biasing, and (2) detection of fast temperature transients in pulsed discharges. The main goal of this work is to demonstrate a nanocalorimetry platform as a real-time metrology for
plasma processing and process control.
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