Atmospheric and Oceanic Physics
Scaling Storm-Resolving Atmospheric AI Simulation to the Entire Planet
Zeyuan Hu, Akshay Subramaniam, Noel Keen et al. (+9 more)
Kilometer-scale convection shapes precipitation extremes, tropical organization, and cloud feedbacks, but most global atmospheric models approximate these processes at 25-100 km resolution. Global storm-resolving physics models resolve convective systems explicitly, but at a cost (roughly one MWh per simulated day on exascale supercomputers) that limits long-duration simulation. We introduce STRATA (Storm-resolving Tile-based autoRegressive Atmosphere
Transformer Architecture), the first autoregressive AI emulator for global storm-resolving atmospheric dynamics. STRATA is trained on the highest-resolution atmospheric
dataset yet used for global AI emulation: 17 days of SCREAM physics-model output at 4.9-km resolution (~25 million grid
cells) sampled every 10 minutes. Our central premise is that on 10-minute timescales atmospheric dynamics are predominantly local, so training on small spatial tiles trades scarce global temporal samples for abundant local spatial samples and enables global rollout via overlapping-tile blending. STRATA combines 3D patch
embedding and local 3D neighborhood
attention, a novel Stereographic Rotary Position
Embedding (StereoRoPE) for grid-invariant encoding, and a pixel-space de-aliasing decoder that suppresses patch-scale rollout artifacts. An iso-FLOP scaling study reveals that km-scale emulation requires ~10x more FLOPs per grid point than coarse-resolution AI weather models, consistent with the higher information density of convective-scale dynamics. Trained on only 17 days of data, STRATA produces stable 24-hour global rollouts with realistic km-scale dynamics across diverse regimes, though large-scale biases develop with lead time. It achieves 48 simulated days per megawatt-hour (more than 50 times better energy efficiency than the SCREAM physics model) and 741 simulated days per wall-clock day at 512 H100 GPUs.
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All authors Zeyuan Hu, Akshay Subramaniam, Noel Keen, Tao Ge, Jaideep Pathak, Mohammad Shoaib Abbas, Suman Ravuri, Karthik Kashinath, Naser Mahfouz, Peter Caldwell, Mike Pritchard, Noah Brenowitz
Solar and Stellar Astrophysics
Bolometric correction for cosmologically redshifted stars with dust: an update to the YBC database
Yang Chen, Xiaoting Fu, Léo Girardi et al. (+2 more)
Observations from HST & JWST continue to reveal gravitationally magnified high-
redshift star candidates, resulting in increasing demand for accurate
stellar bolometric corrections to compare
stellar models with observational data. We update YBC
stellar bolometric correction database by incorporating bolometric corrections for cosmologically redshifted
stars, called zYBC. The bolometric corrections are derived by redshifting
stellar spectra from libraries, attenuated by extinction curves for both the
dust in the host
galaxy and the Milky Way, and followed by convolution with the transmission curves of photometric filters. Our methodology incorporates the effects due to the cosmological K-correction and the
dust. Besides the spectral libraries in earlier YBC, we add NLTE-based spectral libraries for O, B
stars, which are better suited for hot massive
stars, particularly wind-included PoWR and CMFGEN models. The database supports key photometric systems for high-
redshift studies, such as HST/WFC3, JWST/NIRCam, and CSST's MSC and MCI, and maintains the flexibility to incorporate additional photometric systems upon request. As examples, we present colors as functions of Teff at various
redshifts for several photometric systems, which exhibit non-monotonic behaviors and demonstrate the necessity for a dedicated modelling. In particular, we find that the relations show larger dispersions at high
redshift than the zero
redshift case. This indicates that the
stellar parameters of high
redshift stars can be better determined than those of their local counterparts, given their
redshifts reliably determined through other methods and their photometric data are of high enough quality for physical parameter determination through spectral-fitting. We also show the difference in the effect brought by the different amount of extinctions. zYBC represents a valuable resource for high-
redshift star research.
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All authors Yang Chen, Xiaoting Fu, Léo Girardi, Helge Todt, Alessandro Bressan
Quantum Physics
Absorption capacity of separable noise: Bell-mixing thresholds on entanglement and teleportation
Xuan Du Trinh
We study Bell-mixing lines $\rho_\lambda=\lambda\Phi^+ +(1-\lambda)\sigma$, where $\Phi^+$ is a fixed Bell reference and $\sigma$ is a separable two-
qubit noise state. Along this line there are two operational crossings: the state becomes entangled, and it reaches
quantum teleportation advantage over classical strategies. We package these crossings as capacities of the noise state. The
entanglement absorption capacity $C_{\rm abs}(\sigma)$ is the largest amount of Bell reference that $\sigma$ can absorb while the partial transpose remains positive. The fidelity absorption capacity $C_F(\sigma)$ is the largest amount of Bell reference that $\sigma$ can absorb while keeping the maximal teleportation fidelity at or below the classical bound $2/3$. The thresholds corresponding to the two crossing points are obtained from the same Möbius map, $\lambda_* = C_{\rm abs}/(1+C_{\rm abs})$ and $\lambda_F = C_F/(1+C_F)$. We derive closed-form capacities and thresholds for product noise states and separable complex $X$ noise states. For product noise, $C_{\rm abs}$ depends only on local marginal purities, while $C_F$ also depends on orientation relative to the maximally entangled reference. For $X$ noise states, both capacities are explicit in all four Bell frames. We also study three extensions: arbitrary pure-state references, the
evolution of $X$ noise states and their capacities under local amplitude-damping and dephasing channels, and decomposition certificates that give lower bounds on the capacities, hence on the thresholds, for general separable noise.
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Materials Science
Symmetry-Enforced Ferroelectric Switching of Two-Dimensional Altermagnetism
Jiangyu Zhao, Yibo Liu, Guoli Wu et al. (+4 more)
Altermagnetism features strong momentum-dependent
spin splitting despite zero net magnetization, offering a transformative platform for next-generation spintronics. However, the nonvolatile and deterministic switching between its two equivalent
spin-splitting states remains a fundamental bottleneck. Here, we propose a universal layer-engineering paradigm to achieve
symmetry-enforced ferroelectric switching of two-dimensional altermagnetism. By sandwiching a conventional
antiferromagnetic monolayer between two identical ferroelectric layers, the out-of-plane polarization cleanly breaks the spatial
symmetry to induce robust altermagnetic splitting. Crucially, the global combined parity-time
symmetry dictates that reversing the ferroelectric polarization exactly inverts the altermagnetic
spin-splitting pattern. We rigorously validate this mechanism in the In2Se3/MnPTe3/In2Se3 trilayer using first-principles calculations. As a direct consequence, the ferroelectrically driven
spin-splitting reversal deterministically flips the anomalous
Hall effect signal, providing an unambiguous transport fingerprint to electrically distinguish the two altermagnetic states. Unconstrained by the stringent
symmetry requirements of intrinsic single-phase materials, our findings establish a versatile physical framework for electrically addressable altermagnetic spintronics.
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All authors Jiangyu Zhao, Yibo Liu, Guoli Wu, Xinru Li, Ying Dai, Baibiao Huang, Yandong Ma
Quantum Physics
Operational boundaries, threshold conditions, and self-quenching in single-emitter microcavity lasers
Alexandra Gospodinov, Celia Powers and Imran M. Mirza
We theoretically examine the emission dynamics of a three-level cascade single-emitter microcavity
laser using the open-system Lindblad master equation. In our numerical simulations, we expand the
Hilbert space dimensions to obtain converged observables free from truncation artifacts. We notice that the intracavity field builds up continuously to a peak value of $\langle n_p \rangle_{\rm max}$, bypassing the sharp thermodynamic thresholds of conventional ensemble
lasers. By tracking individual radiative rates and for the selected set of parameters, we isolate a physical threshold at a normalized pump rate of $\Gamma/\gamma_{12} \approx 2.45$, where net stimulated emission overcomes spontaneous noise. Crucially, comparing these numerical master equation solutions against factorized semiclassical models reveals that mean-field approximations omit a vital light-matter correlation drag force, leading to a substantial overestimation of the peak field intensity by more than 10%. We notice that the transient Wigner function undergoes complete phase
diffusion into a radially symmetric ring due to the absence of a phase-locking ensemble. Furthermore, steady-state noise calculations confirm that discrete incoherent pumping fluctuations restrict the field to strictly super-Poissonian statistics (with the Mandel parameter $Q > 0$ and the second-order coherence function with zero delay $g^{(2)}(0) > 1$), establishing the classical shot-noise limit as a strict lower bound. At high pumping rates, population trapping in the upper level creates an excitation bottleneck that suppresses the cavity field and causes self-quenching. Our results provide an essential baseline for optimizing solid-state
quantum dot and color-center nanophotonic architectures for lasing as well as for the generation of non-classical states of light.
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Astrophysics of Galaxies
Cosmic Rulers: Masers as Tools for Probing Structure in the Galaxy and Beyond, from AU to kpc
Kazi L. J. Rygl, Anna Bartkiewicz, Olga Bayandina et al. (+9 more)
Maser emission provides an unique window into astronomical sources across vast spatial scales - from tens to hundreds of astronomical units around protostars and evolved
stars up to kiloparsecs in distant
galaxies. These natural microwave amplifiers penetrate
dust shells in
star-forming regions, revealing the dynamics of
accretion disks and
outflows, trace envelopes and winds of evolved
stars, map
Galactic structure, while also allowing us to follow the
evolution of all these systems. Owing to their compactness and brightness masers provide precise astrometry as
cosmic rulers: measuring positions, structures and kinematics in dense regions, not easily accessible at other wavelengths. SKA-Mid will observe hydroxyl, methanol, and formaldehyde masers using bands 2, 5a and 5b, and later methylidyne radical masers in band 4. SKA-Mid's sensitivity and broad frequency coverage will support discoveries of new maser types and allow for simultaneous multi-transition and multi-species maser observations. In addition, bright masers can serve in the science verification of the SKA-Mid array during the deployment phase.
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All authors Kazi L. J. Rygl, Anna Bartkiewicz, Olga Bayandina, Andreas Brunthaler, Sandra Etoka, Simon Ellingsen, Dieter Engels, Tomoya Hirota, Arshia Maria Jacob, Jacco Th. van Loon, Alberto Sanna, Lucero Uscanga
Plasma Physics
Effect of externally applied resonant magnetic perturbations on resistive tearing modes
Qiming Hu, Q. Yu, Bo Rao et al. (+3 more)
Static resonant
magnetic perturbations (RMPs) generated by saddle coil current have been applied in J-TEXT tokamak experiments in order to study their effects on tearing mode instabilities. With increasing the RMP amplitude in time during the discharge, the mode stabilization is first observed, but a large locked mode follows if the RMP amplitude is increased to a too large value, indicating that the RMP amplitude is important in determining the
plasma response and the tearing mode behavior. By careful adjustment of the RMP amplitude, the (partial) stabilization of the m/n =2/1 tearing mode by RMPs of moderate amplitude has been achieved without causing mode locking (m and n are the poloidal and toroidal mode numbers). To compare with experimental results, nonlinear numerical modeling based on reduced MHD equations has been carried out. With experimental parameters as input, both the mode locking and mode stabilization by RMPs are also obtained from numerical modeling. Further calculations have been carried out to study the
plasma parameters affecting the mode stabilization by RMPs, including the
plasma rotation frequency, viscosity, Alfvén velocity, and the RMPs amplitude. It is found that the suppression of the tearing mode by RMPs of moderate amplitude is possible for a sufficiently high ratio of
plasma rotation velocity to the Alfvén speed. A larger
plasma viscosity enhances the mode stabilization.
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All authors Qiming Hu, Q. Yu, Bo Rao, Yonghua Ding, Xiwei Hu, Ge Zhuang
Statistical Mechanics
Quantitative description of cognitive fatigue in repetitive monotonous tasks
Shahar Hod
There is strong qualitative empirical evidence in the scientific literature that, due to cognitive fatigue, workers performing repetitive and monotonous tasks are characterized by a gradual deterioration in their performance abilities as the time-on-task increases, a phenomenon known as the vigilance decrement. Using a time-dependent Sisyphus random climb model, we provide a quantitative description of this intriguing phenomenon. In particular, we use analytical techniques in order to determine the success probability function $S(t;{\cal N})$ of Sisyphus workers, the time-dependent fraction of workers who succeed, after making $t$ repetitive operations or less, to complete their task by making ${\cal N}$ successful operations in a row without a single fault in between. It is explicitly shown that the functional behavior of the increasing-in-time one-operation tumble probability $1-s(t)$ of exhausted Sisyphus workers may have a dramatic effect on the probability of the workers to achieve their ultimate goal in repetitive monotonous processes. In particular, we prove that the Sisyphus random climb model with the inverse power law functional behavior $s(t)\sim t^{-1/{\cal N}}$ of the one-operation success probability marks the boundary between Sisyphus workers whose success functions $S[t;s(t),{\cal N}]$ approach $1$ asymptotically in time (implying that all the workers eventually complete their task) and Sisyphus workers whose success functions approach an asymptotic value which is less than $1$, in which case some of the exhausted Sisyphus workers never complete their task successfully.
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Mesoscale and Nanoscale Physics
Observation of Intrinsic Anderson Localization in Few-Layer ReS$_2$
Shreya Paul, Pritam Das, Devarshi Chakrabarty et al. (+2 more)
Electron localization phenomena are expected to play an important role in the transport properties of two-dimensional materials. Rhenium disulfide (ReS$_2$), with its narrow conduction bandwidth, is uniquely susceptible to this effect. However, extrinsic disorder caused by fabrication methods obscures inherent localization behavior arising from reduced dimensionality and degrades transport properties. We report intrinsic Anderson localization in few-layer ReS$_2$ by eliminating extrinsic fabrication-induced disorder through all-dry van der Waals assembly and suppressing interface charge trapping through a hexagonal boron nitride (hBN) gate dielectric. Temperature-dependent transport reveals a crossover from nearest-neighbor hopping to two-dimensional (2D) Mott variable-range hopping (VRH). The non-monotonic gate-voltage dependence of activation energy provides direct access to the energy-resolved band-tail density of states of the ReS$_2$ conduction band. 2D Mott VRH yields a localization length of (3.5 $\pm$ 0.1) nm, an order of magnitude larger than disorder-dominated devices, providing a quantitative characterization of intrinsic Anderson localization in ReS$_2$.
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All authors Shreya Paul, Pritam Das, Devarshi Chakrabarty, Shamashis Sengupta, Sajal Dhara
Applied Physics · Cross-listed from eess.SY
FPGA-based LQG controller and hardware-in-the-loop simulator implementation for nanomechanical systems
Vojtěch Mlynář, Johannes Berndorfer, Andreas Kugi et al. (+1 more)
We present an open-source framework for real-time Linear Quadratic Gaussian (LQG) control and hardware-in-the-loop (HIL) simulation on the affordable Red Pitaya STEMlab FPGA platform. The controller implements a discrete-time Kalman filter and Linear Quadratic Regulator (LQR) for systems with up to three coupled oscillatory degrees of freedom, targeting applications in levitated optomechanics, MEMS/NEMS, and related experimental platforms. Complementing the controller, the HIL simulator provides a~configurable second-order
stochastic plant with nonlinear input and output mappings, enabling realistic closed-loop testing under real-time and fixed-point constraints. A MATLAB-based workflow automates model configuration, controller synthesis, numerical scaling, and FPGA deployment without requiring specialized hardware expertise. As an end-to-end demonstration, we present the stabilization of a levitated nanoparticle in a two-dimensional double-well potential, illustrating the complete workflow from model definition and simulation to real-time feedback control.
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All authors Vojtěch Mlynář, Johannes Berndorfer, Andreas Kugi, Andreas Deutschmann-Olek
Astrophysics of Galaxies
The Sc, Ti, and V Abundance Discrepancy: Testing High-Mass IMF Variation and Massive-Star Rotation
Soonchul Choi, Eda Gjergo, Youngman Kim et al. (+1 more)
Scandium, titanium, and vanadium can be synthesized primarily in massive
stars. Yet many of the current
Galactic chemical
evolution models under-produce these elements at early epochs. Motivated by evidence that the initial mass function varied in the past on the
Galactic disc, we examine how assumptions about massive-
star rotation and the initial mass function affect the inferred
evolution of Sc, Ti, and V. We compute a grid of one-zone
Galactic chemical
evolution models that varies the initial rotational velocity of massive
stars and the high-mass slope of the initial mass function. We compare the resulting [X/Fe] vs [Fe/H] for X= Sc, Ti, and V tracks and cross-element correlations with
Galactic abundance data. We find that adopting rotating massive-
star yields with an initial rotational velocity of 300 km/s brings the model trends closer to metal-poor observations, especially for
halo stars ([Fe/H] $< -2$), and improves the joint behavior of Sc, Ti, and V. Variations of the high-mass slope of the initial mass function produce a secondary modulation. The remaining tensions, most apparent at
solar to super-
solar metallicities, motivate future work with a more complete treatment of the enrichment physics and model uncertainties.
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All authors Soonchul Choi, Eda Gjergo, Youngman Kim, Toshitaka Kajino
Materials Science
High-Mobility and High-Reliability Top-Gate Oxide Semiconductor Transistors by Oxygen Engineering
Kai Jiang, Zhiyu Lin, Ziheng Wang et al. (+2 more)
In this work, we investigate the role of oxygen (O) on the performance of top-gate (TG) atomic-layer-deposited (ALD)
oxide semiconductor transistors. The results reveal distinct defect characteristics and positive bias temperature instability (PBTI) degradation mechanisms between oxygen-rich (O-rich) and oxygen-deficient (O-poor) devices. It is found that an O-rich device fabrication process followed by O-free annealing can effectively achieve TG indium-rich (In-rich)
oxide semiconductor transistors with high mobility, high reliability and high stability in hydrogen environment because O-rich process can suppress oxygen vacancies and their interaction with hydrogen, while O-free annealing plays a critical role in minimizing the formation of O-rich defects such as oxygen dimers (O-O bonds). Consequently, TG In-rich transistors with high mobility, steep subthreshold slope, and high PBTI reliability at high temperature are demonstrated. The understanding of O-rich defects provides a new insight to overcome the mobility-stability trade-off.
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All authors Kai Jiang, Zhiyu Lin, Ziheng Wang, Chen Wang, Mengwei Si
High Energy Physics (Phenomenology)
EasyScan_HEP 2: LLM-Agent Parameter-Scan Workflows in High Energy Physics
Yang Xiao, Yuanfang Yue and Yang Zhang
Large-
language-model (LLM)
agents are beginning to reshape the preparation and steering of computational workflows in high-energy physics phenomenology. To accommodate this change, we upgrade EasyScan_HEP to make the construction of parameter-scan configuration files more accessible to LLM-
agent assistance. EasyScan_HEP 2 exposes command-line and machine-readable interfaces for LLM-
agent workflows, allowing an assistant to translate natural
language requests into an explicit .ini configuration that defines the scan method, external-program workflow, constraints, and outputs. The resulting configuration can be inspected through a local Web interface. The framework also supports LLM-
agent-guided extension to new scan methods, as illustrated by the integration of BESTFIT, EMCEE, and DYNESTY. In this way, EasyScan_HEP 2 adapts parameter-scan workflows to LLM-
agent use while preserving reproducibility, transparency, and user control.
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Optics
Unresolved-Sideband Optomechanics with Hexagonal Boron Nitride: Induced Transparency, Gain, and Frequency Combs
Francesco Fogliano, Thibaud Ruelle, David Jaeger et al. (+1 more)
Optomechanically induced transparency (OMIT) is usually modeled and studied in the resolved-sideband regime, but many compact microcavity platforms operate in the unresolved-sideband limit $(\kappa \gg \Omega_m)$. Here we investigate OMIT in this regime using a tunable fiber-based Fabry-Perot microcavity coupled to a suspended hexagonal boron nitride (hBN) drum resonator in a membrane-in-the-middle geometry. The system achieves a large single-
photon coupling rate of $g_0/2\pi \sim 180$ kHz and exhibits strong radiation-pressure backaction. By measuring OMIT spectra as a function of pump power and cavity detuning, we observe a crossover from a transparency-like dip to a gain feature in the reflected response. These maps are quantitatively reproduced by the full linearized optomechanical response, demonstrating the breakdown of the standard rotating-wave approximation used in the resolved-sideband limit. Finally, we drive the system into a nonlinear regime to generate optomechanical frequency combs. These results establish hBN fiber-cavities as a versatile architecture for unresolved-sideband optomechanics, nonlinear dynamics, and hybrid device integration.
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All authors Francesco Fogliano, Thibaud Ruelle, David Jaeger, Martino Poggio
Quantum Physics
Cumulant-based quantum relative Rényi functional
Atirat Meunson and Tanapat Deesuwan
We introduce a new cumulant-based
quantum relative Rényi functional as a candidate
quantum Rényi divergence, derived from the cumulant-generating function (CGF) of the
quantum relative surprisal operator and extending the classical connection between Rényi divergence and statistical cumulants to the
quantum setting. Unlike the Petz and sandwiched
quantum Rényi divergences, the proposed construction is motivated by statistical structure rather than operator-algebraic or operational principles. The functional naturally admits a path-integral-like representation through the Lie-Trotter product expansion, providing a trajectory-based interpretation of
quantum divergence in
Hilbert space. On its natural non-regularized domain for $\alpha>1$ under the support condition $\operatorname{supp}(\rho)\subseteq\operatorname{supp}(\sigma)$, we establish several fundamental properties, including positivity, reduction to the classical case, additivity,
unitary invariance, continuity, and monotonicity with respect to the Renyi parameter $\alpha$. Whether the functional satisfies the
quantum data-processing inequality (QDPI) under arbitrary CPTP maps remains open. To extend the analysis beyond the studied regime, we introduce a regularized version of the functional and study its behavior at $\alpha=0$. We show that the resulting relative quantumness quantity vanishes if and only if the underlying states commute, yielding a necessary and sufficient characterization of non-commutativity. For commutativity-preserving (CoP) channels, we further
conjecture a QDPI-type monotonicity relation for this quantity. Extensive numerical simulations provide strong evidence in support of this
conjecture, with no violations observed for the CoP channels considered in this work.
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Plasma Physics
Nonlinear modeling of the scaling law for the m/n=3/2 error field penetration threshold
Q. Hu, N.C. Logan, J.-K. Park et al. (+3 more)
The scaling law for the n=2 error field (EF) penetration threshold is predicted numerically based on nonlinear single-fluid and two-fluid modeling using the TM1 code. The simulated penetration threshold of radial
magnetic field br at the
plasma edge is scaled to the electron density ne, temperature Te, viscous time, toroidal field Bt and the natural frequency by scanning these parameters separately. Single fluid modeling shows that the EF threshold scaling is similar with the analytical scaling law in both the Rutherford and visco-resistive regimes. However, two-fluid modeling shows that the scaling law differs significantly in particular regarding the dependence on
plasma rotation. In detail, the scaling coefficient on density decreases from 0.67 to 0.56 and on temperature decreases from 0.67 to 0.32, while on viscous time is around -0.45 and on toroidal field decreases slightly from -1.15 to -1, when the ratio ExB over electron diamagnetic drift frequency varies from 0 to 10. Scans of the
plasma rotation reveals that the penetration threshold linearly depends on the perpendicular rotation frequency (or natural frequency), and there is a minimum in the required field amplitude when electron fluid frequency near 0. In addition, the enduring mystery of non-zero penetration threshold at zero
plasma natural frequency in EF experiments is resolved by two-fluid simulations. We find that the very small island and smooth bifurcation in EF penetration near zero frequency is hard to detect in the experiment, leading to a finite penetration threshold within the capability of the experimental measurements.
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All authors Q. Hu, N.C. Logan, J.-K. Park, C. Paz-Soldan, R. Nazikian, Q. Yu
Quantum Physics
Pauli Weight Hamiltonian Term Selection for Optimized Machine Learning Based Quantum Error Mitigation
Fadhil Fatih Shiddiq, Darell Timothy Tarigan, Hadyan Luthfan Prihadi et al. (+4 more)
Machine learning provides a scalable solution for
quantum error mitigation. However, the selection of appropriate Pauli strings for inclusion in training data remains a challenge. Current methods rely on heuristic or uniform random sampling, requiring data for every Pauli string in the
Hamiltonian, a process that scales linearly with measurements and grows with system size. To address this, we introduce
quantum error mitigation with prior knowledge of Pauli weights (Pauli weight
quantum error mitigation (Pi-QEM)), a systematic framework that selects training observables based on Pauli weight. By leveraging the relationship between variance and locality in parameterized
quantum circuits, Pi-QEM trains on a small subset of dominant, low-weight Pauli strings. In numerical simulations of molecular systems on a noisy IBM
quantum backend, Pi-QEM reduces ground-state energy estimation error by up to 34.01% using just a single dominant local observable, offering an efficient, scalable pathway for high-precision error mitigation on NISQ devices.
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All authors Fadhil Fatih Shiddiq, Darell Timothy Tarigan, Hadyan Luthfan Prihadi, Jusak S. Kosasih, Yanoar P. Sarwono, Leong-Chuan Kwek, Freddy Permana Zen
Solar and Stellar Astrophysics
Formation and Eruption of Filament Channel in Solar Active Region 12975: Insights from Observations and Simulations of Magnetic Field Evolution
Dinesh Mishra, P. Vemareddy and Brajesh Kumar
We studied the
magnetic field
evolution of active region (AR) 12975 using a time-dependent magnetofrictional (TMF) model. This AR produced two consecutive CMEs associated with M-class
flares on March 28, 2022. The AR exhibited a simple bipolar configuration, with new bipolar flux emerging from March 27. These emerging flux regions evolved through shear motions, forming a filament-channel that ultimately erupted on March 28 at 12:00 UT. The simulation, initialized at 12:00 UT on March 26, is driven by electric fields derived from a time-series of photospheric vector-magnetograms. It reproduces the observed coronal
evolution, including the gradual development of a sigmoidal, twisted flux rope (FR) over approximately 50 hours. The modeled temporal
evolution of
magnetic energy and helicity within the computational domain is consistent with the observed injection of both quantities. Furthermore, the ratio of current-carrying to total relative helicity reaches 0.23 at the time of observed eruption, however the
torus-unstable regime is attained when the helicity ratio reaches 0.32, approximately 7 hr after the observed eruption. Notably, the FR forms adjacent to pre-existing
magnetic fields, and a substantial portion of the coronal structure does not belong to the FR system. Consequently, the derived helicity thresholds vary and deviate from the proposed value of 0.29. While reproducing filament formation with high morphological accuracy, this study underscores the quantitative challenges involved in modeling and evaluating the eruptive behavior of different ARs.
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High Energy Physics (Theory)
Universal geometry as an organising principle for heterotic moduli
Jock McOrist
A family of heterotic compactifications carries more structure than a collection of solutions parametrised by
moduli. Once the compactification data are fibred over
moduli space, deformations become components of universal
curvatures. This note reviews that organisation and explains how it incorporates the $\alpha'^2$ supersymmetry corrections.
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Astrophysics of Galaxies
Probing IMF Variations in High-Redshift Early-Type Galaxies with SHARP
F. La Barbera, G. De Lucia, F. Ditrani et al. (+9 more)
The
stellar initial mass function (IMF), which describes the distribution of
stellar masses at birth, is a fundamental ingredient in shaping
galaxy evolution. Recent observations indicate that the IMF varies between
galaxies, depending on their mass, morphology, and
stellar content. In local early-type
galaxies (ETGs), spectroscopy, dynamics, and
lensing reveal bottom-heavy IMFs in dense central regions, with radial gradients toward a Milky Way-like distribution in the outskirts. Yet, the chemical enrichment of massive ETGs implies a dominant role of massive
stars during their early formation phases. These findings can be reconciled if the IMF evolves over
cosmic time – initially more top-heavy to enable rapid enrichment, and later dominated by long-lived, low-mass
stars. Directly measuring the IMF at z>1 is therefore essential to test such time-dependent IMF scenarios, including variations in the
dwarf-to-
giant and
stellar mass-to-light ratios. To date, no direct observational confirmation of these IMF variations – or of their physical origin – has been obtained. The SHARP spectrograph on the E-ELT, with unprecedented spatial resolution and sensitivity compared to facilities such as JWST, and broader spectral coverage than other E-ELT instruments, will enable spatially resolved spectroscopy of IMF-sensitive features in high-
redshift ETGs up to z~3, providing unique insights into the origin of the non-universal IMF in massive
galaxies.
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All authors F. La Barbera, G. De Lucia, F. Ditrani, F. Fontanot, P. Franzetti, A. Gallazzi, A. Gargiulo, M. Longhetti, P. Saracco, C. Tortora, A. Vazdekis, S. Zibetti
Physics and Society
Social Statements: A Proposal for a Social-Value Balance Sheet and Profit-Loss Statement
Takeshi Kato, Yoshinori Hiroi, Sae Horiguchi et al. (+2 more)
This study proposes a new set of a firm's "social statements" that represent social value, in contrast to conventional financial statements that represent economic value. Financial statements externalize social and environmental costs, and this externalization is one of the primary causes of contemporary social problems. Insights from anthropology, philosophy, and sociology suggest that social value is grounded in social relationships, joint actions, and communication. Building on this understanding, we assign numerical indicators of a firm's social relationships with external stakeholders to the items of a balance sheet and a profit-loss statement as social statements. This approach enables unified measurement units and simplified calculation compared with existing methods for evaluating social impact or social value. Moreover, similar to financial statements, social statements allow firms to be assessed using managerial indicators such as equity ratios and profit margins. The significance of social statements lies in incorporating social value–alongside financial value–into corporate decision-making, and in encouraging social transformation as firms publicly articulate their social value.
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All authors Takeshi Kato, Yoshinori Hiroi, Sae Horiguchi, Tetsushi Koike, Shingo Hashimoto
Biological Physics
Fock-Space Formulation of the Lifetime of a Unicellular Organism
Yehuda Roth
What is life? In this work, we take life to mean a dynamical tendency to conserve identity for as long as possible. For a single bacterium, identity is carried by its chromosomal DNA code, so the bacterium is alive precisely insofar as it actively maintains a well-defined chromosomal configuration over time and can, in principle, replicate this configuration into progeny. For a multicellular organism, many
cells share essentially the same DNA code and behave as a single coherent entity; in that case, life corresponds to the persistence of a common genetic identity across the cellular ensemble, rather than to the survival of any particular
cell.
Cell duplication in multicellular organisms likewise serves to maintain this dynamical tendency to conserve identity over time. In previous studies we implemented this idea at the multicellular and colonial scale using a classical notion of coherence, in which an organism is represented by a single nonseparable state over the DNA codes of its constituent
cells, while a colony is describable as a separable ensemble. Here we apply the same principle to the simplest possible case, a single bacterium, and show that its biological identity can be identified with the coherence of its chromosomal DNA code within an abstract state space. We then introduce a Fock-space representation in which bacteria carrying given codes occupy fermionic modes, and replication, repair, and death are realized as elementary operators acting on these modes. Within this framework we define the lifetime of a unicellular organism as the integral coherence time of a code-occupation autocorrelation function and, in a minimal Markovian model, obtain a compact expression in which the lifetime coincides with the inverse decay rate of the corresponding identity mode.
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Quantum Physics
Atom diffraction in the strong-coupling regime
Carina Kanitz, Jakob Bühler, François Aguillon et al. (+6 more)
Analytic methods based on matter-wave diffraction are a cornerstone in condensed-matter research, providing access to static and dynamic materials properties down to the atomic level. In these experiments, the shape of the diffraction pattern is largely determined by the
lattice at
equilibrium whereas vibrationally-induced distortions are treated perturbatively. Here, we show that the perturbative approach does not hold for helium diffracted at kiloelectronvolt energy through freestanding single-layer
graphene. In this case, we enter a new regime of strong coupling where the projectile strongly interacts with the electron density of several
lattice atoms simultaneously, leading to phase shifts of several radians. In consequence,
lattice distortions introduce a significant phase spread that cannot be described by the typically employed Debye-Waller factor. We show that the weak-coupling regime is retained for atomic hydrogen diffraction. The experimental results are supported by simulations, providing a regime-independent approach to describe the influence of
phonons on atom diffraction phenomena.
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All authors Carina Kanitz, Jakob Bühler, François Aguillon, Vladimír Zobač, Jaime Glerum, Toma Susi, Maxime Debiossac, Philippe Roncin, Christian Brand
General Relativity and Quantum Cosmology
Cosmological Stealth fields and Non-Equilibrium thermodynamics
Gilberto Aguilar-Pérez, Cuauhtemoc Campuzano, Víctor H. Cárdenas et al. (+2 more)
We investigate the connection between cosmological stealth scalar fields and non-
equilibrium thermodynamics in a spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) background. We consider a non-minimally coupled scalar field whose energy-momentum tensor vanishes identically, allowing the field to evolve on a dissipative cosmological background without producing gravitational backreaction. We show that the stealth condition leads to a generalized Riccati equation for the scalar-field kinematics, where the dissipative pressure acts as a thermodynamic driving term. In terms of the variable $y=\dot{\phi}/(H\phi)$, the system admits two thermodynamic branches: a stable attractor selected by
entropy production and an unstable repeller. We also construct the corresponding phase-space structure in the $(y,\omega_{\rm eff})$ plane and identify a near-critical regime associated with $\zeta=1/4$. Finally, we reconstruct the stealth potential and present a bulk viscous realization in which irreversible
entropy production drives the universe toward an asymptotic de Sitter state while the stealth field tracks the dissipative background. We further develop the linear scalar perturbations of the model and show that, although the stealth field is gravitationally invisible at the background level, its perturbation couples directly to the dissipative-pressure perturbation. This coupling provides a mechanism for distinguishing dissipative and non-dissipative sources that share the same background expansion history. Our results suggest that stealth fields can be interpreted as dynamically non-trivial thermodynamic trackers of non-
equilibrium cosmological
evolution.
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All authors Gilberto Aguilar-Pérez, Cuauhtemoc Campuzano, Víctor H. Cárdenas, Miguel Cruz, Joel Saavedra
High Energy Astrophysical Phenomena
JWST Medium-Resolution Infrared Spectroscopy of SN 2022acko: Tracing Molecule Formation in the Nebular Phase
K. Medler, T. Mera, C. Ashall et al. (+28 more)
The Type II
supernova (SN II) SN 2022acko was the first to be spectroscopically observed by the James Webb Space
Telescope ($\textit{JWST}$). Here, we analyze SN 2022acko's second and third $\textit{JWST}$ spectra obtained at $+259$ and $+368$ d. We identify strong features associated with hydrogen along with Intermediate-Mass and Iron-Group Elements (IM/IGEs). The medium-resolution mode of $\textit{JWST}$/MIRI uniquely enables the isolation of emission features, allowing us to determine the structure of SN 2022acko, directly coupling the spectroscopic features and the explosion mechanism. We find that IMEs display peak velocities of $~ 300$ km s$^{-1}$, significantly larger than the $~ 100$ km s$^{-1}$ measured for H, He, and IGEs. We suggest a bipolar
outflow best explains this ejecta distribution, although Rayleigh-Taylor instabilities may also contribute. Additionally, we find a bulk velocity offset of $~ 97.4^{+86.3}_{-42.3}$ km s$^{-1}$ in the ejecta which we associate with the natal kick of a
neutron star. CO emission is also detected while no SiO or
dust signatures are observed. We fit the CO first-overtone and fundamental bands with MOFAT and find a clumped distribution is required with a CO mass increasing from $1.55\times10^{-4}$ M$_{\odot}$ at $+259$ to $2.47\times10^{-4}$ M$_{\odot}$ at $+368$ d. This CO mass is approximately an order of magnitude lower than that of SN 2024ggi. As the first $\textit{JWST}$ nebular-phase study of a low-mass SN II, this work shows that such events form substantially less molecules than more massive SNe II, with
dust formation likely occurring on longer timescales, if at all.
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All authors K. Medler, T. Mera, C. Ashall, P. Hoeflich, E. Baron, M. Shahbandeh, J. M. DerKacy, E. Fereidouni, C. M. Pfeffer, S. Shiber, P. Brown, C. Burns, A. Cikota, T. de Jaeger, A. Do, D. O. Jones, L. Galbany, W. B. Hoogendam, E. Hsiao, K. Krisciunas, S. Kumar, J. Lu, P. Mazzali, N. Morrell, M. Phillips, B. Shappee, M. D. Stritzinger, N. Suntzeff, M. Tucker, L. Wang, Y. Yang
High Energy Physics (Phenomenology)
Evidence for differential kinetic freeze-out of the $\phi(1020)$ meson in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV
Neeraj and Amal Sarkar
In heavy-ion collisions, hadronic species with small interaction cross sections may decouple from the evolving fireball earlier than the bulk, yet quantitative evidence for this differential freeze-out has remained elusive. We report that the $\phi(1020)$
meson does not kinetically freeze out with the bulk
hadrons in 0–5% central Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV: a Boltzmann-Gibbs blast-wave contour analysis of ALICE $\phi(1020)$ $p_{\rm T}$ transverse-momentum spectra shows that the bulk $\pi/K/p$ freeze-out point is excluded at $4.1\sigma$ ($\Delta\chi^2 = 21.7$). Despite its
proton-like mass, the $\phi$ exhibits freeze-out parameters incompatible with those of the bulk
hadrons, implying that the observed spectral hardening cannot be attributed solely to mass-dependent collective expansion. Instead, it is naturally explained by the OZI-suppressed $\phi$-
hadron interaction cross section which causes $\phi$ to decouple earlier and probe a distinct freeze-out surface. The exclusion is robust under all systematic variations tested and is qualitatively reproduced by SMASH hadronic transport simulations. These findings establish the $\phi$
meson as a clean probe of species-dependent hadronization, and provide quantitative evidence for a kinetic freeze-out hierarchy in ultra-relativistic heavy-ion collisions.
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Quantum Physics
Entanglement Structure Across $\mathbb{Z}_n$ Phase Transitions in 1D Rydberg Atom Arrays
Hyeonjun Yeo, Kabgyun Jeong and Hyunchul Nha
Multipartite
quantum entanglement plays a crucial role in the emergence of different
quantum phases and their transitions in
quantum many-body systems. It is of general interest to know what sort of analysis on
quantum entanglement can bring us a profound insight to understand the rich dynamics of
quantum many-body systems. In this work we study the characteristics of
quantum entanglement in relation to $\mathbb{Z}_n$-ordered phases emerging under a varied strength of 1-dim Rydberg interaction. We propose an approach based on the structure of pair-wise
entanglement across the Rydberg chain using two-
qubit concurrence as an
entanglement measure. We define an
entanglement-structure factor via
Fourier analysis of total concurrence at each site and address $\mathbb{Z}_n$ phase transitions in comparison with the conventional order-parameter based on local density, i.e. magnetization. We also discuss how the required two-
qubit concurrence can be measured in analog Rydberg atom arrays using site-selective erasure and parametrized
laser pulses. Our investigation suggests that an
entanglement-structure-based approach can provide a powerful tool in analyzing
symmetry-breaking in
quantum phase transitions.
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Nuclear Theory
Zhi-Ying Qin, Jia Zhou and Jun Xu
Based on the relativistic mean-field model and assuming $G$-parity invariance, we have studied the equation of state of
baryon- and
neutron-rich matter produced in low-energy relativistic heavy-ion collisions. Similar to the traditional isospin
symmetry energy, we define the
baryon-antibaryon
symmetry energy characterizing the energy difference due to the
baryon-antibaryon asymmetry. The potential difference between nucleons and antinucleons is correlated with the potential contribution of the
baryon-antibaryon
symmetry energy mainly from the vector interaction in
baryon-rich matter. The isospin
symmetry energy is considerably reduced even with a small fraction of antinucleons compared to the traditional case with only nucleons. A more attractive antineutron potential than antiproton potential is observed, and the isospin splitting of the mean-field potential for antinucleons is found to be intrinsically larger than that for nucleons in
baryon- and
neutron-rich matter.
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Astrophysics of Galaxies
Chemical evolution of the Milky Way disc with radial gas flows: a Lagrangian approach
Fiorenzo Vincenzo
Chemical abundance patterns result from the interplay between gas
accretion,
star formation, and radial mixing of gas and
stars. Disentangling these processes is crucial to recover the mechanisms shaping the formation and
evolution of
galaxies. We model the chemical
evolution of the
Galactic disc in the presence of radial gas flows, to assess their impact on the [O/Fe]-[Fe/H] abundance patterns and on the radial gradients of [Fe/H] and [O/H]. We develop fast, semi-analytic solutions for the gas surface mass density and the abundances of alpha-elements and iron, accounting for radial gas flows and chemical enrichment from core-collapse and Type Ia
supernovae. The model follows a Lagrangian approach, using the method of characteristics, reducing the solutions to one-dimensional integrals. We apply our model to the Milky Way disc assuming a two-infall scenario. When radial gas flows are present, the chemical abundances of the gas at a given radius result from its whole inward journey in the disc, reflecting the
star formation and
accretion experienced at every radius it crossed. The integrated
stellar mass along the characteristic is lower than the local value by up to an order of magnitude at v = 1.5 km/s. Models with mild flows of v = 1.5 km/s reproduce simultaneously the observed [O/Fe]-[Fe/H] distribution across the disc, the present-day
stellar surface-density profile, and the [Fe/H] and [O/H] gradients, improving also the agreement with the observed age-abundance relations. The
stellar mass formed per Type Ia
supernova sets the [O/Fe] ratio and departs from its in-situ value by up to ~50 per cent, making the alpha-enhancement the quantity on which radial flows leave their strongest signature. Following the gas along its trajectory is essential to recover the correct enrichment history even for models with mild radial gas inflows. The code is made publicly available.
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Quantum Physics
Topological phase transition in chaotic optomechanical systems
Xiao-Jun Zhang
Hidden structures with well-defined predictability are uncovered in the
evolution of a chaotic optomechanical system from the perspective of the $\epsilon$-machine. Tuning the frequency of the driving
laser can switch off this predictability, and such behaviour corresponds to a phase transition that is deeply related to topological changes in phase space. The transition probabilities between causal states allow us to define an
entropy (uncertainty) that serves as an effective order parameter. This phase transition can be readily demonstrated in currently available experiments by monitoring the quadrature of the optical mode. We hope that this work could fundamentally broaden the regimes of cavity micromechanics and nonlinear optics.
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