Geophysics
Dispersion-Guided Physics-Aware Deep Inverse Operator for Surface Wave Mode Separation
Yang Cui, Sujith Swaminadhan, Yangkang Chen et al. (+2 more)
Surface-wave (SW) dispersion analysis is widely used in near-surface geophysics and seismology to determine shear-wave velocity structures by measuring SW
geometric dispersion in seismic data. Among the available approaches, multichannel analysis of surface waves (MASW) and two-station methods are commonly employed to extract dispersion information for SW inversion. However, the coexistence of fundamental and higher modes in seismic data poses challenges for these methods, particularly for two-station analysis. To separate the different mode components, we propose a physics-aware unsupervised deep-learning framework. The method acts as a deep inverse operator that directly separates fundamental- and higher-mode components in the time-space domain using an adaptive Gaussian mask constructed in the frequency-phase-velocity (f-v) domain. Physical constraints are incorporated into the loss function by maximizing energy concentration within the target mask while suppressing leakage outside it. Through backpropagation, the network learns the inverse mapping from physical constraints in the f-v domain to wavefield separation in the time-space domain without requiring labeled training data. Numerical experiments on both synthetic and field data show that the framework provides a robust and automated solution for SW mode separation, facilitating more reliable dispersion-curve picking and improving the accuracy of subsequent SW inversion.
Read the full abstract ▾
All authors Yang Cui, Sujith Swaminadhan, Yangkang Chen, Christian Schiffer, Myrto Papadopoulou
Materials Science
Single-orbital tight-binding model for chiral one-dimensional hybrid organic-inorganic lead halide perovskites
Yuya Ominato, Tetsuya Furukawa, Ayumi Ishii et al. (+1 more)
We present a single-orbital tight-binding model for the low-energy electronic states of the
chiral one-dimensional hybrid organic-inorganic lead halide perovskite $\mathrm{(}R/S\mathrm{-PEA)PbI}_3$. The model is constructed from a single effective orbital on each of the four
symmetry-related sites in the primitive unit
cell and incorporates layer, in-plane sublattice, and
spin degrees of freedom. With separate parameter sets for the conduction and valence bands, the effective
Hamiltonian reproduces the overall band dispersions obtained from density-functional-theory calculations and quantitatively captures the
spin splittings near the band edges. It also captures the leading
spin-polarization patterns of the Bloch states, showing that the band-edge
spin splitting and
spin polarization are encoded in a small number of
symmetry-adapted
spin-dependent hopping terms. We further analyze the accidental degeneracies of the effective
Hamiltonian using screw
eigenvalues and antiunitary operators. This analysis separates accidental degeneracies originating from the restricted term content of the effective
Hamiltonian from degeneracies enforced by nonsymmorphic screw
symmetries and time-reversal
symmetry. The present model provides a
symmetry-transparent starting point for understanding the band-edge electronic structure of
chiral lead halide perovskites and for analyzing optical,
spin, and transport responses in this class of materials.
Read the full abstract ▾
All authors Yuya Ominato, Tetsuya Furukawa, Ayumi Ishii, Tetsuaki Itou
Instrumentation and Methods for Astrophysics
Enhanced wavefront sensing for the Roman Coronagraph Instrument: Gaussian probes and compact model validation
Lukas Delaye, Iva Laginja, Pierre Baudoz et al. (+10 more)
The Coronagraph Instrument on the Roman Space
Telescope will be the first space-based system to demonstrate closed-loop focal-plane wavefront sensing and control, a key step towards the Habitable Worlds Observatory. Beyond the baseline Hybrid Lyot Coronagraph, "enhanced modes" are being developed to improve efficiency and science yield. One such mode uses Gaussian probes for electric field estimation, extending the linear regime and allowing higher probe amplitudes. This may increase signal-to-noise, reduce exposure time, accelerate dark hole convergence, and extend operation to
stars as faint as $V\sim5$. For those reasons, it was selected by the Coronagraph Community Participation Program's Hardware Working Group as the first technology demonstration carried out on Roman in early 2027. We present numerical simulations using a noise-free compact software model, which demonstrate the benefits of replacing the nominal probes with Gaussian probes.
Read the full abstract ▾
All authors Lukas Delaye, Iva Laginja, Pierre Baudoz, Axel Potier, Johan Mazoyer, Raphaël Galicher, Susan F. Redmond, Alexis Lau, A. J. Riggs, Dan Sirbu, Emiel H. Por, Rémi Soummer, Laurent Pueyo
Quantum Physics
A Variational Surrogate Approach to Finite-Horizon Quantum Control via Hardware-Efficient Ansatz
Nahid Binandeh Dehaghani, Rafal Wisniewski and A. Pedro Aguiar
We present a variational
quantum framework for finite-horizon
quantum control based on hardware-efficient ansätze. The objective is to steer a
quantum system from a given initial state to a desired target state over a fixed time horizon by minimizing a terminal cost defined in terms of state fidelity. Instead of explicitly synthesizing time-dependent control fields or enforcing
Hamiltonian reachability constraints, the proposed method reformulates the control objective as a variational optimization problem in which a hardware-efficient parameterized
quantum circuit provides a surrogate parameterization of the terminal
evolution. The
circuit consists of alternating layers of single-
qubit rotations and entangling gates, whose parameters are optimized using classical routines to minimize the terminal infidelity. This formulation avoids reliance on problem-specific or physics-inspired ansätze, providing a flexible and implementation-friendly approach compatible with near-term
quantum devices. Numerical experiments on multi-
qubit state-transfer
benchmarks demonstrate high-fidelity state transfer while highlighting the trade-off between ansatz expressivity, optimization complexity, and scalability with respect to system size and
circuit depth.
Read the full abstract ▾
Materials Science
Strain-Tunable Shift Current and Magneto-Optical Kerr Effect in Multiferroic Altermagnet Fe2Mo3O8
Shengqiao Wang, Bo Zhao, Harish K. Singh et al. (+6 more)
Altermagnetism has recently emerged as a compelling frontier in spintronics, seamlessly merging the agile tunability of ferromagnets with the hallmark merits of antiferromagnets. As a prototypical polar multiferroic featuring distinctive altermagnetism, Fe2Mo3O8 hosts an ideal playground for exploring the intricate interplay among ferroelectric polarization, altermagnetic order, and
spin-dependent responses. Here, employing first-principles calculations, we systematically investigate the coupling among polarization,
spin splitting, shift current, and magneto-optical responses in Fe2Mo3O8. Our findings reveal that switching the ferroelectric polarization not only inverts the sign of the shift current but also comprehensively reshapes the momentum-space
spin-splitting texture. Furthermore, the shift current and magneto-optical spectrum exhibits strong tunability under mechanical strain. Remarkably, the application of a-axis uniaxial strain breaks the crystalline
symmetry, thereby activating a finite magneto-optical Kerr effect that is otherwise forbidden in the pristine phase.
Read the full abstract ▾
All authors Shengqiao Wang, Bo Zhao, Harish K. Singh, Jiahao Xie, Fu Li, Hongbin Zhang, Yang Su, Chen Shen, Lijun Zhang
High Energy Physics (Theory)
On interacting non-Abelian antisymmetric tensor field models
I. Buchbinder and N. Kozyrev
We study the gauge structure of interacting antisymmetric tensor field models obtained by the dimensional reduction on a group
manifold. In such models a dimensionful parameter related to the size of the compact
manifold plays the role of a coupling constant. We focus on open issues of reducibility of the gauge transformations in these theories and show that stages of reducibility of the interacting models coincide with ones of corresponding free counterparts.
Read the full abstract ▾
Statistical Mechanics · Cross-listed from math.PR
Semi-open boundary for random walking shocks
Márton Balázs
Non-stationary time
evolution of interacting particle systems is in general a rather difficult topic however, exceptional examples are known where hidden processes within the model make the description manageable. These hidden processes often take the form of a finite number of interacting random walks and in some cases, rather than being hidden, were very explicitly revealed as second class particles associated with the model. The examples of asymmetric exclusion and exponential bricklayers model are known in this context, where such distributional structure was demonstrated in infinite volume. Here we find boundary mechanisms that save this remarkable structure in finite volume of the model with semi-open boundaries that let ordinary particles, but not the shocks, through. This finding also allows to characterise nontrivial two-species, non-reversible stationary distributions subject to our special boundary rates.
Read the full abstract ▾
General Relativity and Quantum Cosmology
The entropy of dynamical black holes deviating from electrovacuum in second order
Wen-Tao Fu, Ming-Fei Ji, Yu-Sen Zhou et al. (+1 more)
We study the
entropy of dynamical black holes in Einstein–Maxwell theory. Starting from a stationary electrovacuum background with a bifurcate Killing horizon, the apparent horizon is constructed perturbatively in Gaussian null coordinates, and the area of its cross section is derived to second order. Within the covariant phase space formalism, we introduce a modified canonical energy that incorporates contributions from external matter and is naturally related to the second-order variation of the
entropy through the balance law. Under the null energy condition and the asymptotic stationary condition, the
entropy is proportional to the area of the apparent horizon up to second-order and satisfies the second law. Without the null energy condition, establishing this area law requires additional assumptions.
Read the full abstract ▾
All authors Wen-Tao Fu, Ming-Fei Ji, Yu-Sen Zhou, Li-Ming Cao
General Relativity and Quantum Cosmology
Qualitative Analysis of Cosmological Models Using Dynamical System Perspective
Sayantan Ghosh
This thesis investigates theoretical and observational aspects of
cosmic acceleration, focusing on dark energy models and modified
gravity frameworks. The goal is to analyse their viability, dynamical behaviour, and perturbative stability to identify models capable of describing the accelerated expansion of the Universe. Chapter 1 reviews the essential background General Relativity, and mathematics of teleparallel and symmetric teleparallel geometries, basic cosmological models, matter components, and the key observational probes. The chapter concludes with a summary of modified
gravity theories, including f(R), f(T) and f(Q). Chapter 2 studies a dissipative Chaplygin gas cosmology in f(Q)
gravity. The model is constrained using the CC and Pantheon+SH0ES
dataset, and its performance is assessed through information criteria and diagnostic tools such as Om and statefinder analysis. Chapter 3 reconstructs the dynamics of Dirac-Born-Infeld (DBI) dark energy using Hubble and DESI observations via Gaussian Processes. The reconstructed potential is fitted to theoretical models using chi-square and MCMC techniques, giving constrains on DBI scalar field. Chapter 4 analyses canonical scalar-field cosmology in coincident f(Q)
gravity using dynamical systems. Chapter 5 extends the dynamical analysis to the DBI scalar field in f(Q)
gravity. Chapter 6 examines scalar-field
evolution at both background and perturbation levels. Perturbation equations for key gauge invariant variables are derived, and an extended phase space combining background and perturbation dynamics is constructed. Finally, chapter 7 summarizes the main results along with scope for future research. Further mathematical details including derivation of field equation and cosmology equations and foundational issues related to f(Q)
gravity are compiled in the following four sections: Appendix A, Appendix B, Appendix C and Appendix D.
Read the full abstract ▾
Materials Science
Photogeneration and signatures of coherent phonons in time-resolved photoemission spectroscopy: First-principles time-dependent adiabatic GW approach
Yang-hao Chan, Zhenglu Li and Steven G. Louie
Coherent
lattice dynamics can be observed in pump-probe time-resolved and angle-resolved photoemission spectroscopy (TR-ARPES) as a periodic modulation of intensity and energy of photoelectrons over probe time. We present an ab initio time-dependent GW approach including electron-
phonon (e-ph) couplings to simulate the photogeneration of coherent
phonons and their effects on the TR-ARPES of monolayer MoS2. We demonstrate that state-resolved e-ph coupling strength can be obtained from analyzing coherent
phonon modulations on TR-ARPES. Features of both the impulsive stimulated Raman scattering mechanism and the displacive excitation mechanism of coherent
phonon generation are identified in our simulations. We clarify their origins and the coincident selection rule of coherent
phonon generation and Raman scattering intensity. This method provides supports to analyze coherent
phonon dynamics and e-ph couplings in TR-ARPES and enables quantitative engineering of band structure through coherent
phonons.
Read the full abstract ▾
Materials Science
The self-organized vacancy order in Pr$_9$Ge$_{16}$
Jayashani S. T. Wickramasinghe, Melissa G. Anderson, Kelci Graville et al. (+11 more)
In this work, we report the discovery of a new
crystal structure on the Ge-rich side of the Pr-Ge binary phase diagram. Using a high-temperature flux technique, we grew single
crystals of $Pr_9Ge_{16}$, which adopt a previously unreported orthorhombic $Fdd$2 structure type featuring ordered Ge vacancies. We present the anisotropic
magnetic properties and identify the crystallographic $b$ axis perpendicular to the
crystal plane as the
magnetic easy axis. Temperature-dependent resistivity measurements reveal metallic behavior with a distinct anomaly at $T_{\mathrm{C}}$ = 14.3 K.
Hall resistivity data indicate that electron-like carriers dominate, with a carrier concentration on the order of $10^{27}~\mathrm{m}^{-3}$. The
magnetic order is readily suppressed by a
magnetic field of approximately 0.4 T applied along the easy $b$ axis.
Read the full abstract ▾
All authors Jayashani S. T. Wickramasinghe, Melissa G. Anderson, Kelci Graville, Gregory T. McCandless, Zachary J. Morgan, Brianna R. Billingsley, Tai Kong, Hyunsoo Kim, Aleksandr V. Chernatynskiy, Simon G. Mitchell, Liang Wu, Julia Y. Chan, Feng Ye, Halyna Hodovanets
Quantum Physics
When Close Enough Is Not Enough: Autoregressive Drift in Quantum Circuit Synthesis
Mehdi Saeedi, Eddie Richter and Paul Hartke
Quantum circuit optimization for fault-tolerant computing requires exact functional equivalence while minimizing expensive non-Clifford resources such as T gates. We study this problem using a compact 44.8M-parameter encoder-decoder
transformer with structured
circuit tokenization, evaluating on parameterized
circuits (2-6
qubits) and Clifford+T
circuits (3-6
qubits). On parameterized
circuits, a hybrid approach – structure from the
transformer, angles from classical optimization – achieves median fidelity 1.000 on 3-6
qubit circuits. On Clifford+T
circuits, where all gates are discrete and no post-processing is possible, the model learns valid syntax and accurate T-Count statistics, yet exact equivalence degrades sharply with target length – from 88% on
circuits with <=9 gates to near zero beyond 26 gates. We trace this failure to autoregressive drift: early-
token divergence cascading irrecoverably through left-to-right decoding. Two levers partially mitigate the drift: inference-time strategies that generate multiple candidates and select via equivalence verification raise exact-match rates from 7% to 22.5%, while scaling training data by 2.5x pushes them to 39.5%. Yet the degradation with target length persists – even with more data, exact equivalence drops from 94% on short
circuits to under 4% beyond 26 gates. The contrast between settings is our central finding: when approximate outputs can be rescued by post-processing, the
transformer succeeds; when exact discrete correctness is required, autoregressive drift limits reliability, with both inference-time search and data scaling as effective levers while training-side fine-tuning and model-level diversification are not.
Read the full abstract ▾
Earth and Planetary Astrophysics
Plasma chemistry and electron-moderated pathways in substellar atmospheres: a new perspective on the L/T transition
Matthew I. Swayne, Declan A. Diver and Craig R. Stark
The long-standing puzzle of the CO/CH$_{4}$ transition in brown
dwarfs endures. Although the bulk spectral
evolution across an atmosphere can be accounted for through thermal
equilibrium cloud models, the behaviour in the NIR remains unaccounted for, indicating that additional, non-thermal processes may influence atmospheric chemistry alongside conventional pathways. We explore cloud-driven electrical activation, where low-energy sparks to full lightning discharges, unlocks non-
equilibrium reaction pathways inaccessible under thermal conditions alone. To quantify this, the aim of this paper is to model the electron-moderated atmospheric chemistry with SPARCKS, a bespoke zero-dimensional code that solves the coupled set of particle balance equations for substellar
plasma activation and reaction kinetics, focusing on the key CO-CH$_{4}$ electron-moderated chemistry across the parameter ranges $T_{\rm gas} \in [700, 1600]$ K} and $T_{e} \in [2, 5]$ eV. We simulate a 1 microsecond pulse, representing a short dart-stepped leader; and, two pulsed systems with $(t_{\rm on}, t_{\rm off})$ = ($10^{-8}$ s, $10^{-6}$ s) and $(10^{-9}$ s, $10^{-9}$ s), representing small-scale inter-grain discharges, consistent with a typical characteristic substellar atmosphere. Our results show that even modest, physically plausible energies can strongly perturb atmospheric composition: an electron energy of 3.0 eV is sufficient to halve the CH$_{4}$/CO ratio in our sample atmosphere within one microsecond. Beyond the CO-CH$_{4}$ system, electron-moderated
plasma chemistry exerts a far-reaching influence on substellar atmospheric composition.
Read the full abstract ▾
High Energy Astrophysical Phenomena
Identifying potentially missed extended sources in the Fermi-LAT 4FGL Catalog using clustering analysis
Giovanni Cozzolongo, Alison M. W. Mitchell, Samuel T. Spencer et al. (+2 more)
Many
Fermi Large Area
Telescope (LAT) sources remain unassociated. Some may be extended sources represented by multiple catalog entries, as found for HESS J1813-178. We search for clusters of unassociated
Fermi-LAT sources and test whether single extended-source models describe them better than multiple catalog sources. We applied DBSCAN to 4FGL sources with a linking scale of $0.3^\circ$ over 5 GeV-1 TeV. Each cluster contains at least one unassociated source and up to one extended or point-like associated source from selected categories, including
pulsars,
pulsar wind nebulae and
supernova remnants. Using Fermipy, we compared extended- and multiple-source models and characterized each candidate spectrally and morphologically, focusing on the
Galactic plane. We identified 48 clusters containing 124 sources, each with at least one unassociated source. For all 8 clusters passing our quality selection, an extended-source model is statistically preferred. At linking scales of $0.4^\circ$ and $0.5^\circ$, all 8 clusters retain their core sources. Cross-matches with the Second
Fermi Galactic Extended Sources Catalog (2FGES) and the HESS
Galactic Plane Survey (HGPS) showed that 5 clusters overlap known extended sources. The other 3 clusters, including one cluster with a morphology dependent on the interstellar emission model, have no counterpart in either catalog and are new extended-source candidates. Spatial clustering combined with likelihood-based model comparison can uncover extended sources missed in the
Fermi-LAT catalog and complements existing searches.
Read the full abstract ▾
All authors Giovanni Cozzolongo, Alison M. W. Mitchell, Samuel T. Spencer, Dmitry V. Malyshev, Tim Unbehaun
Strongly Correlated Electrons
Emergent $s+id$ Superconductivity from the Interplay between Electronic Correlations and Electron-Phonon Coupling in $\mathrm{R}_{1-x}\mathrm{Sr}_x\mathrm{NiO}_2$
Zi Yuan, Jun Zhan, Xianxin Wu et al. (+1 more)
Recent tunneling measurements on infinite-layer nickelates have revealed spatially varying superconducting
symmetries, whose microscopic origin remains unclear. Motivated by this observation, we investigate the interplay between electron correlations and electron-
phonon interactions in infinite-layer nickelates by combining first-principles calculations with the fluctuation-exchange-Migdal-Eliashberg theory. Our calculations show that
spin fluctuations yield robust $d$-wave superconductivity on the Ni $d_{x^2-y^2}$ orbital, whereas electron-
phonon coupling induces $s$-wave pairing on an interstitial orbital, leading to an $s+id$ superconducting state. The emergence of the $s$-wave component is strongly carrier-density dependent: an intermediate electron-
phonon coupling of $\lambda=0.4$ stabilizes the $s+id$ state at $n=0.9$ but not at $n=0.8$. These results imply that local oxygen defects tune the local electron density and form finite-size domains with distinct pairing
symmetries, offering a compelling explanation for the spatially inhomogeneous superconducting
symmetries observed in experiments.
Read the full abstract ▾
All authors Zi Yuan, Jun Zhan, Xianxin Wu, Shaozhi Li
High Energy Physics (Theory)
Quantum States Prepared by Wormholes: Long-Wavelength Deviations from Bunch-Davies
George Lavrelashvili and Jean-Luc Lehners
Wineglass wormholes mediate the nucleation of baby universes out of an asymptotically Anti-de Sitter or flat spacetime. Upon materialization, the new universe naturally undergoes an inflationary phase. Here we study the
quantum state of tensor and probe scalar field fluctuations that these wormhole geometries prepare, finding that they reproduce the Bunch-Davies
vacuum for short-wavelength modes but lead to deviations from Bunch-Davies on large scales. These deviations, which depend on the charge of the wormhole, cause a small shift as well as oscillations in the angular power spectrum generated by an ensuing inflationary phase, and thus provide a distinctive cosmological observable. The wormholes are supported by either axionic or
magnetic charges. In the limit of vanishing charge, they undergo a topological transition after which they contain no-boundary instantons. We find that the small-charge limit suppresses deviations from the Bunch-Davies state for both scalar and tensor fluctuations, indicating that the topological transition is smooth.
Read the full abstract ▾
General Relativity and Quantum Cosmology
Evaluating KAGRA upgrade scenarios for multimessenger observations of binary neutron stars
Yuta Michimura, Soichiro Morisaki, Kenta Hotokezaka et al. (+1 more)
Binary
neutron star mergers are key targets for multimessenger astronomy, motivating future upgrades of gravitational-wave detectors. For KAGRA, both broadband sensitivity improvements that increase the binary
neutron star detection range, and high-frequency optimizations targeting
neutron-
star physics are under consideration. We present a computationally efficient framework to evaluate the multimessenger performance of detector upgrades by combining Fisher-
matrix estimates of localization area and localization volume with detector duty factors and binary
neutron star merger rates. We apply this framework to proposed KAGRA upgrade scenarios within the LIGO-Virgo-KAGRA network. For identical sources, the high-frequency upgrade improves sky localization by about 20% compared with the broadband option. However, when detection rates are taken into account, the broadband upgrade yields a larger number of well-localized events. Despite its shorter binary
neutron star range than the other detectors, the inclusion of KAGRA increases the number of events localized within $10^3$ Mpc$^3$ volume by about 60%. These results provide a quantitative framework for evaluating future detector upgrades from the perspective of multimessenger observations.
Read the full abstract ▾
All authors Yuta Michimura, Soichiro Morisaki, Kenta Hotokezaka, Masaomi Tanaka
Soft Condensed Matter
Depletion Capture and Rayleigh–Onsager Dynamics in Receptor-Mediated Endocytosis
Jinjie Liu, Zhongcan Ouyang and Hao Wu
Receptor-mediated endocytosis requires a particle to approach a membrane in a crowded extracellular environment, form ligand-receptor bonds, and wrap the membrane against bending, tension, and cytoskeletal viscoelastic resistance. We develop a two-stage theory. The capture stage uses the exact ideal hard-sphere Asakura–Oosawa sphere-plane excluded-volume geometry. The wrapping stage combines a spherical-cap coordinate, a quadratic single-mode free energy, a standard linear solid with one internal strain variable, and a two-variable Rayleigh–Onsager (RO) gradient flow. The creep compliance is mapped exactly onto a long-time spring in parallel with a Maxwell branch, preserving both the creep retardation and stress relaxation times. The free energy is strictly convex by its Hessian convexity, and the linear wrapping system has two real negative
eigenvalues and an explicit double-exponential solution. Two independent arguments establish strict monotonicity for positive initial drive: the irreducible Metzler structure with its positive
semigroup and the interlacing of Laplace poles with positive velocity residues. The first-passage equation has a unique finite root below the unconstrained long-time limit. Normal-cone conditions specify the projected dynamics on $0\le x\le2$, and the projected system retains the Lyapunov inequality of the unconstrained gradient flow. From the same free energy we derive long-time adhesion thresholds, the threshold-minimizing radius, the finite-size window, and the critical
cell modulus. The $95\%$ spherical-area criterion is treated as an operational near-complete threshold, with $90\%$, $95\%$, and $99\%$ compared. The capture analysis includes the exact overlap volume, depletion force, Carnahan–Starling pressure rescaling, Stokes approach time, and Brenner wall-drag correction.
Read the full abstract ▾
Biological Physics
On seasonal trunk thermal buffering and its electrical signature in mature trees
Jean-Baptiste Boulé, Vincent Courtillot, Dominique Gibert et al. (+4 more)
Tree trunks contain living tissues whose functioning depends on their thermal environment, yet the processes governing trunk temperature under field conditions remain poorly understood. In particular, it is unclear whether hydraulic transport contributes to buffering trunk temperature against atmospheric variability. We investigated this question by continuously monitoring sapwood temperature, local air temperature, soil temperature at 1~m depth, and spontaneous electrical potential (SP) in six mature trees, comprising three oaks and three hornbeams, over multiple years in a temperate urban forest garden. trunk temperature exhibited a smoother seasonal cycle than air temperature and remained consistently closer to deep-soil temperature, indicating substantial thermal buffering. Seasonal components extracted from the time series revealed a coherent delayed relationship between SP and the trunk-soil temperature difference. Phase-space analysis showed reproducible hysteresis across individuals, and instantaneous phase estimates indicated a lag of approximately 100~days in five of the six trees. A minimal energy-balance model further showed that trunk heat storage alone was insufficient to reproduce the observed seasonal dynamics. Positive effective soil-coupling coefficients were obtained for most individuals, although their magnitude varied markedly among trees. These results are consistent with a contribution of vertically mediated, hydraulically linked heat transfer to seasonal trunk thermal regulation. They further suggest that spontaneous electrical potentials may provide a non-invasive, integrative indicator of slow hydraulic and thermal processes within trees. Such thermo-hydraulic coupling may influence the thermal environment of the cambium and phloem and could therefore contribute to tree responses to seasonal heat and climatic variability.
Read the full abstract ▾
All authors Jean-Baptiste Boulé, Vincent Courtillot, Dominique Gibert, Fernando Lopes, Alexis Maineult, Pierpaolo Zuddas, Jean de Bremond d'Ars
Instrumentation and Methods for Astrophysics
A genetic algorithm for peer-review panel composition
Ferdinando Patat
The composition of scientific review panels is a constrained optimization problem in which a finite pool of experts must be distributed among multiple panels while balancing scientific expertise and demographic diversity. As the number of possible panel configurations grows very rapidly with the number of reviewers, exhaustive searches rapidly become computationally impractical. In this paper I present a genetic
algorithm designed to optimize panel composition for the European Southern Observatory (ESO) proposal evaluation process. Panel assignments are represented through a chromosome-based encoding. Candidate solutions are evaluated using a fitness function based on four imbalance indicators: scientific expertise, gender, country affiliation, and professional seniority. The method is tested using real reviewer data from the ESO proposal handling system. The results show that the genetic
algorithm rapidly identifies panel configurations with substantially lower imbalance than those obtained from random assignments and progressively improves the quality of the overall population. Beyond producing a single optimized configuration, the approach generates a set of high-quality panel realizations that can subsequently be filtered according to additional operational constraints not explicitly included in the fitness function. Although developed for ESO, the methodology is general and applicable to a wide range of panel-based peer-review systems.
Read the full abstract ▾
Optics
Twist Engineering for Reconfigurable Optical and Optoelectronic Devices
Gang Huang, Annan Helian, Mengting Jiang et al. (+12 more)
Reconfigurable optical and optoelectronic devices require compact tuning mechanisms capable of reshaping electronic, excitonic, polaritonic, and photonic responses without rebuilding the underlying nanostructure. Against this backdrop, twist has emerged as a powerful
geometric degree of freedom that reconfigures interlayer coupling, momentum matching,
symmetry, radiation channels, and
chiral response by simply rotating adjacent two-dimensional layers or photonic
lattices. In this Review, we survey twist-engineered optical and optoelectronic devices spanning van der Waals materials and photonic platforms. We first review the current landscape of twist-angle metrology, classifying existing characterization approaches into three complementary categories: direct structural imaging, methods based on moiré periodicity and morphological features, and techniques that infer the twist angle from spectroscopic or electronic responses. We then survey the principal technological routes for twist-angle control, including deterministic transfer and growth strategies, atomic force microscopy (AFM)-assisted manipulation,
quantum twisting microscopy (QTM), microelectromechanical systems (MEMS), and emerging non-contact approaches, highlighting their respective capabilities, limitations, and prospects for programmable and scalable moiré photonic platforms. Finally, we discuss the future
evolution of twist engineering from the fabrication of individual twisted structures toward dynamically reconfigurable, feedback-controlled, and manufacturable photonic systems. We further highlight MEMS-based rotation, piezoelectric actuation, and micro-
LiDAR as representative enabling technologies and emerging applications within this broader landscape.
Read the full abstract ▾
All authors Gang Huang, Annan Helian, Mengting Jiang, Chi Wang, Yu Xing, Mayank Joshi, Jae Yeong Lee, Jiang Wang, Syed M Assad, Ping Koy Lam, Qiushi Liu, Lin Wu, Young-Wook Cho, Yuan Ma, Xuezhi Ma
Instrumentation and Detectors
Traceable In Situ Microwave Power Measurement at the Cryogenic Device Plane in a Dilution Refrigerator
Paolo Panetta, Andrea Celotto, Alessandro Alocco et al. (+7 more)
Accurate knowledge of the microwave power delivered to a cryogenic device under test (DUT) is essential for the characterization and operation of superconducting
quantum circuits. However, this information is difficult to obtain inside dilution refrigerators because of distributed attenuation, impedance mismatch, switch-path repeatability, and temperature-dependent microwave components. This paper presents an in situ measurement method for RF power at the cryogenic device plane. The method uses a custom variable temperature stage (VTS) as a cryogenic thermal-transfer element. The TVS is alternately heated by a four-wire DC heater and by microwave power dissipated in a 20 dB pass-through attenuator. By fitting the thermal transients and comparing the corresponding steady-state temperatures, the absorbed microwave power is inferred from a directly measured DC electrical power through an AC/DC substitution procedure. The finite reflection and transmission of the attenuator are then accounted for by cryogenic two-port scattering-parameter measurements based on a switch-assisted Short–Open–Load–Reciprocal calibration, so that the result is referred to the DUT reference plane. The system is demonstrated in a dilution refrigerator with powers between -43 and -58 dBm at the DUT input plane. The demonstrated relative standard uncertainty ranges from about 2% at -43.9 dBm to about 40% at -57.6 dBm. The proposed approach combines thermal RF power transfer, cryogenic S-parameter correction, and uncertainty evaluation in a measurement architecture compatible with
quantum-device experiments, providing a practical route toward traceable microwave-power calibration at millikelvin stages.
Read the full abstract ▾
All authors Paolo Panetta, Andrea Celotto, Alessandro Alocco, Bernardo Galvano, Luca Fasolo, Emanuele Palumbo, Luca Callegaro, Luca Oberto, Patrizia Livreri, Emanuele Enrico
Cosmology and Nongalactic Astrophysics
Exploring Hu-Sawicki-like modified gravity with Genetic Algorithms
Chiara De Leo, Elisa Fazzari, Matteo Martinelli et al. (+1 more)
We investigate whether viable Hu-Sawicki-like $f(R)$ models can produce deviations from $\Lambda\mathrm{CDM}$ that can be tested against current background cosmological data. We adopt a machine-learning approach based on Genetic
Algorithms (GA) to reconstruct analytical perturbations around the Hu-Sawicki class of models. We develop a pipeline that interfaces the GATO GA code with the CANDI cosmology code. Each $f(R)$ function generated by the GA is first tested against theoretical viability conditions, including stability, the recovery of a standard matter-dominated epoch, the General Relativity limit, and chameleon screening mechanism. Viable candidates are then passed to CANDI to reconstruct the corresponding background cosmology and are tested against DESI DR2 BAO measurements and the Pantheon+ Type Ia
supernova catalogue. %\newline The deviations we find are largest at late times, where the lower
curvature makes modified-
gravity effects more relevant, and are rapidly suppressed at higher
redshift, in agreement with the imposed matching to the matter-dominated era. To further quantify deviations from the standard cosmological model, we compute the $Om(z)$ diagnostic. It shows only a very small departure from the constant $\Lambda\mathrm{CDM}$ behaviour. The effective dark energy equation of state associated with the reconstructed $f(R)$ function also evolves only weakly, showing a mild transition from an effective quintessence-like nature to an effective phantom-like regime. Overall, our results indicate that, within perturbations around the Hu-Sawicki class of models, current background data allow only limited deviations from $\Lambda\mathrm{CDM}$.
Read the full abstract ▾
All authors Chiara De Leo, Elisa Fazzari, Matteo Martinelli, Savvas Nesseris
Geophysics
An Extension to the Procedure for Developing Uncertainty-Consistent Shear Wave Velocity Profiles from Inversion of Experimental Surface Wave Dispersion Data
Joseph P. Vantassel and Brady R. Cox
Measurements of shear wave velocity (Vs) with uncertainty are critical for site-specific probabilistic seismic hazard studies. However, rigorously quantifying the uncertainty in Vs over large enough areas and great enough depths remains challenging. In 2021, Vantassel and Cox (i.e., VC21) proposed a procedure for developing suites of Vs profiles from surface wave testing whose uncertainty were consistent with the experimental dispersion data's uncertainty. The VC21 procedure was a significant step forward, however, it requires a full dispersion data
matrix to compute inter-wavelength phase velocity correlations. While applicable to many practical cases, VC21 could not be applied to the case where multiple surface wave arrays of different sizes were deployed at a site as a means of developing broadband dispersion data and deeper Vs profiles. In response, this work extends the VC21 procedure using two possible approaches for estimating a full dispersion data
matrix. Approach 1 uses a selection of theoretical dispersion curves from an initial, traditional surface wave inversion. Approach 2 estimates the full data
matrix by combining pieces of the data
matrix obtained from the experimental dispersion measurements. Both approaches are evaluated using two synthetic
datasets; one relatively-simple, three-layered model and one more-complex, five-layered model. Approach 1 and Approach 2 were able to reasonably estimate the true correlation
matrix and recover uncertainty-consistent Vs profiles similar to the true distribution of Vs. While the uncertainty of the recovered Vs profiles were higher than is often assumed, the engineering proxies computed from those Vs profiles, namely the time averaged shear wave velocity in upper 30 m and the fundamental site period, showed substantially less uncertainty indicating the Vs profiles, while uncertain, are effective at capturing a site's ...
Read the full abstract ▾
Mesoscale and Nanoscale Physics
Dynamical Generation of Rectified Electric Current
Jin-Xin Hu and Congjun Wu
Rectification is a fundamental nonlinear transport process that converts an alternating drive into a direct current. In this work, we propose a general theoretical framework for electric current rectification triggered by a dynamical external drive that couples to an arbitrary well-defined operator of a periodic system, and which in the static limit forbids any steady current. In the dynamical regime, the finite frequency $\Omega$ of the time-varying drive breaks time-translation invariance and injects energy into the system, enabling a second-order nonlinear rectified current that has no static counterpart. This rectification process has two distinct origins: (i) an
impurity-scattering-modified distribution function at finite frequency, and (ii) a time-domain anomalous velocity stemming from a dynamical mixed Berry
curvature. Both contributions persist when the driving frequency lies well below the optical transition gap. Applying our general theory to a buckled
magnetic system subject to an out-of-plane oscillating electric field, we characterize the generated current as a nonlinear magnetoelectric gyrotropic effect and predict that the induced rectified current is sensitive to the
magnetic order, thereby offering a feasible electrical probe of Néel order in non-coplanar antiferromagnets.
Read the full abstract ▾
Materials Science
Antiphase boundary-driven large exchange bias and negative magnetoresistance in NiCo2O4
Biswanath Pramanik, Pushpesh Pathak and Binoy K. Hazra
Nickel-based spinel
oxide has recently attracted significant
attention due to its remarkable magneto-transport properties, promising various spintronic applications. In this study, we observe an exchange bias effect, where the
magnetic hysteresis loop shifts both horizontally and vertically when single-phase nanocrystalline NiCo2O4 is cooled in the presence of an external
magnetic field. The magnitude of the exchange bias field is approximately 375 Oe at 5 K, and this effect disappears around 300 K. Furthermore, NiCo2O4 shows semiconducting behaviour in longitudinal resistivity and demonstrates a substantial negative magnetoresistance of ~31.5% at 10 K. The magnetoresistance exhibits a butterfly-shaped behaviour at low
magnetic fields and becomes almost linear at high
magnetic fields. A detailed analysis of the negative magnetoresistance and exchange bias reveals that both phenomena originate from the formation of antiphase boundaries in the as-synthesized NiCo2O4 sample, as confirmed by the high-resolution transmission electron micrograph.
Read the full abstract ▾
Strongly Correlated Electrons
Magnetic field-driven phase switching in the antiferromagnetic Mott insulator Ca$_3$(Ru$_{0.99}$Ti$_{0.01}$)$_2$O$_7$
Ksenia S. Rabinovich, Tim Priessnitz, Nils Gross et al. (+7 more)
A bandwidth-controlled
antiferromagnetic Mott-insulating phase in Ca$_3$(Ru$_{1-x}$Ti$_x$)$_2$O$_7$ is realized through isovalent substitution at the Ru site. For a dilute substitution with only 1% Ti, the Mott
insulator ground state remains nearly degenerate with the ground state of pristine Ca$_3$Ru$_2$O$_7$, where the Ru moments are ferromagnetically aligned within the metallic RuO$_2$
bilayers stacked in an
antiferromagnetic fashion. The exceptionally shallow free energy landscape of this doped compound arises from intertwined electron-electron and electron-
lattice interactions. This makes its
magnetic and transport properties highly sensitive to external perturbations. We systematically investigated
magnetic-field-induced phase switching in Ca$_3$(Ru$_{0.99}$Ti$_{0.01}$)$_2$O$_7$ to explore its
magnetic $H$-$T$ phase diagram. With the field applied along the easy $b$-axis, parallel to the
antiferromagnetic moments, the magnetization exhibits a first-order
spin-flop transition at $\approx $ 6 T, indicating reorientation of the Ru moments perpendicular to the field. The transition is accompanied by a decrease in the electrical resistance, but the
spin-flop phase remains insulating. Above 10.5 T, all Ru moments align with the $b$-axis, resulting in a forced
ferromagnetic metallic phase. In contrast, neither
spin-flop nor forced-
ferromagnetic phases are observed up to 14 T, when the field is applied along the $a$-axis. While the electronic kinetic energy and the electron-
lattice coupling contribute to the free-energy balance of this system, the resulting $H$-$T$ phase diagram is remarkably simple and closely resembles that of a canonical anisotropic antiferromagnet, albeit with substantially renormalized critical fields.
Read the full abstract ▾
All authors Ksenia S. Rabinovich, Tim Priessnitz, Nils Gross, George Jackeli, Maximilian J. Krautloher, Pascal Reiss, Eberhard J. Goering, Jurgen H. Smet, Bernhard Keimer, Alexander V. Boris
High Energy Astrophysical Phenomena
An internal shock model calibrated with real gamma-ray burst light curves using a genetic algorithm
Manuele Maistrello, Cristiano Guidorzi, Shiho Kobayashi et al. (+1 more)
The origin of gamma-ray burst (GRB)
prompt emission remains an open question. The internal shock (IS) model is a leading scenario for converting relativistic ejecta kinetic energy into gamma rays, but its parameters have not yet been fully calibrated against observed GRB light curves (LCs) to reproduce their diversity. We adopt a machine-learning framework to optimise the IS model by comparing simulated and observed LC properties from three GRB catalogues (Swift/BAT,
Fermi/GBM, CGRO/BATSE). Assuming a
redshift-dependent GRB formation rate, we employ a genetic
algorithm to minimise a loss function based on six independent metrics capturing both average behaviours and statistical distributions. The optimised model reproduces several key observational properties, including the average post-peak temporal profile, autocorrelation function, and the distributions of duration, signal-to-noise ratio, number of peaks, peak flux, and fluence. We also derive constraints on the central engine activity: (i) the number of emitted shells is well described by a generalised Zipf distribution, analogous to the Gutenberg-Richter law for earthquakes, and (ii) the rest-frame shell-emission times follow a negative exponential distribution, indicating a
stochastic process with a constant ejection probability. This calibrated IS model provides a physically grounded framework for interpreting GRB variability and predicting GRB populations detectable by future missions.
Read the full abstract ▾
All authors Manuele Maistrello, Cristiano Guidorzi, Shiho Kobayashi, Romain Maccary
Statistical Mechanics
Emergence of drifted diffusion in quantum walks with subspace restart
Liwei Qiao, Ruoyu Yin and Wei Zhang
Restart of a
quantum process is typically modeled as a global reinitialization that erases the system's entire history. Here we introduce subspace restart, a protocol that periodically resets only the internal degrees of freedom while preserving the spatial distribution, as a tunable knob for the
quantum-to-classical crossover. Using the discrete-time
quantum walk as an example, we show that this selective reset drives the walker into an engineered drifted-
diffusion regime. This phenomenon can be understood by a Huygens-Fresnel mechanism, where each restart fragments the wave function into a set of independent secondary sources to screen long-range correlations and isolate a robust classical backbone, whose drift and diffusivity are set by the
geometric orientation of the initial coin and the restart period. Residual
quantum interference, confined to effective light cones, survives only as a short-range correction that renormalizes these coefficients and imprints periodic modulations on the cumulants. Our results establish subspace restart as a route to controlling the
quantum-to-classical crossover in synthetic
lattices.
Read the full abstract ▾
High Energy Physics (Phenomenology)
Physically Consistent Parameter Inference: Transparent Machine Learning Emulation in High Energy Physics and Cosmology
Jorge Alda, Jacobo Asorey, Alejandro Mir et al. (+1 more)
Global fits in high energy physics and cosmology often face the challenge of exploring high-dimensional parameter spaces with computationally expensive or topologically complex likelihood functions. In this work, we present a Machine Learning framework designed to emulate complex, often non-Gaussian likelihood landscapes using gradient-boosted regression trees (XGBoost). We discuss the advantages of the Machine Learning approach in terms of computational efficiency and the resolution of confidence regions, particularly in scenarios with complex correlations or "curved" degeneracies. We validate this methodology by applying it to a recent analysis on flavour anomalies in semileptonic $B$
meson decays and discussing the adaptability of this framework to other phenomenological systems, such as
axion-like particles or cosmology global fits. Finally, we utilise SHAP (Shapley Additive exPlanations) values to provide a transparent analysis of feature importance, ensuring that the Machine Learning predictions remain physically interpretable and consistent with the underlying physics.
Read the full abstract ▾
All authors Jorge Alda, Jacobo Asorey, Alejandro Mir, Siannah Peñaranda