Physics and Society
Strategic Coercion Within Alliances: The Greenland Sovereignty Game as an AI Stress Test
Rommin Adl and Peyton Williams
What happens when the strongest alliance member pressures a weaker member over territory and strategic control? We examine the Greenland sovereignty crisis as a stress test for LLM geopolitics, centered on the 2019-2026 U.S. push to acquire Greenland from the Kingdom of Denmark. The crisis nests two collective-action problems: Arctic strategic control and whether NATO can enforce alliance norms against the dominant member. We develop three games (asymmetric coercion; a NATO assurance game with a critical-mass tipping point; a triadic extensive-form game with social preferences) and test them with a multi-
agent simulation in which eight frontier LLMs play six geopolitical roles (United States, Denmark, Greenland, NATO, Russia, Canada) across 3,604 completed games and 108,120 action observations. Using inverse game theory, we recover each model's structural utility parameters (alpha, beta, gamma, delta, eta) for material self-interest, reciprocity, inequality aversion, norm respect, and commitment consistency. Three findings stand out. First, all eight models become more escalatory under coercion framing (four-action escalation rises from 10.7% to 28.6%). Second, Chinese-origin models show systematically different power-weight profiles from Western-origin models when playing the U.S. role. Third, peaceful US acquisition emerges in only 1.9% of clean games and only 3 of 8 frontier models ever achieve it, most prominently DeepSeek V3.2, which executes a stable five-round playbook through the metropole.
Prompts emphasizing jus cogens and self-determination reduce escalation back near baseline in the English-only confirmatory sample;
multilingual contrasts are reported as exploratory sensitivity checks. We position this as a structural
benchmark for LLM geopolitical behavior, complementing action-frequency
benchmarks.
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Physics and Society
The Cognitive Kardashev Scale: Quantifying the Material Envelope of Civilisational Computation
Sachin Sharma
How much thinking can a civilisation do? Kardashev ranked civilisations by the energy they command. This paper borrows his ladder and asks how much machine cognition each rung could support. The arithmetic is deliberately simple. A civilisation has some total power. Only a fraction of that can be spared for computing, and each joule spent buys computation at whatever efficiency the hardware of the day has reached. The product of the three sets a ceiling on machine thought. To keep the resulting quantities intelligible, I express them in units of the human
brain's own processing rate, as a rough yardstick rather than a claim about minds. Calibrating the ceiling against present-day supercomputers and AI accelerators led me to two conclusions I did not expect at the outset. Even today's energy supply could support far more machine cognition than humanity actually uses, so physical capacity is not what binds. And whether energy or hardware efficiency becomes the constraint over the coming decade turns on engineering choices that have not yet been made. On the question that may matter most, who gets access to the cognition it describes, the scale is silent. That is a matter of political economy, and the calibration is offered as an input to that debate.
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Optics
Propagation Maps, Maradona Exceptional Points, and Pele Singularities in Anisotropic, Tellegen, Chiral, Moving-Medium, Omega and Other Isotropy-Broken Materials
Maxim Durach
Anisotropic, Tellegen,
chiral, moving-medium-type, omega, gyrotropic,
hyperbolic, and multi-
hyperbolic materials form an important class of isotropy-broken photonic media in which wave propagation can no longer be characterized by the Fresnel wave surface alone. Here we show that Fresnel wave surfaces can be converted into propagation maps that organize positive- and negative-phase-velocity propagation together with attenuation and amplification. In Hermitian media, the boundary between forward and backward propagation forms the Michelangelo silhouette separatrix. This separatrix is also a continuous locus of Maradona exceptional points, where the index-of-refraction operator becomes defective even though the material medium remains Hermitian. In non-Hermitian media, the attenuation-amplification boundary forms the Caravaggio chiaroscuro separatrix. The associated Pele singularities occur where the handedness remains continuous while the gain-loss character changes sign. Their physical importance is revealed by the momentum-resolved density of states: at these points, the Lorentzian linewidth of the non-Hermitian momentum-resolved density of states (DOS) collapses, producing sharp DOS peaks whose sign reverses across the separatrix. Thus, Pele singularities are threshold-like gain-loss singularities of the Fresnel wave-surface propagation map, generated by non-Hermitian linewidth collapse. The result is a compact
geometric language for describing how handedness, degeneracy, loss, gain, and momentum-resolved DOS are organized in isotropy-broken electromagnetic materials.
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Physics and Society
Network-Based Interventions for HIV Prevention via Cascade-Aware Suppression of Transmission
Akseli Kangaslahti, Davin Choo, Milind Tambe et al. (+2 more)
Treating and preventing Human Immunodeficiency Virus (HIV) remains a critical global health challenge. While antiretroviral therapy provides a path toward viral suppression – effectively eliminating an individual's transmission risk – systemic resource constraints limit the reach of intervention efforts. This work addresses the strategic distribution of intensive resources among virally unsuppressed individuals to minimize the expected cascade of new infections within a transmission network. We formalize this challenge as a novel constrained optimization problem where we have resources to "treat" $k$ out of a set $\mathbf{P}$ of virally unsuppressed individuals, and establish its theoretical connections to existing computational literature. We then propose Cascade-Aware Suppression of Transmission (CAST), a
polynomial-time $(\delta, \epsilon)$-approximation
algorithm that achieves a $2\sqrt{|\mathbf{P}|}$ approximation ratio by leveraging connections to the Minimum-$k$-Union (MkU) problem and Hoeffding-style concentration bounds. Extensive evaluations on real-world HIV networks demonstrate that CAST outperforms standard public health and computer science baselines. Furthermore, we show that CAST is empirically robust across diverse infectious disease networks, varied edge probability initializations, and settings involving imperfect network data.
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All authors Akseli Kangaslahti, Davin Choo, Milind Tambe, Alastair van Heerden, Cheryl Johnson
Medical Physics
Voxel-aware oxygen kinetics resolves radiation-induced DNA damage retention across LET-oxygen conditions
Renato III Fernan Bolo and Ramon Jose C. Bagunu
Objective. Hypoxic tumor subvolumes resist radiation through elevated oxygen enhancement ratios (OER), yet no computational OER model is simultaneously particle-specific, mechanistically grounded, and fast enough for voxel-scale treatment planning. We present the VOxel-Aware Oxygen Model (VOxA) to address all three requirements. Approach. An Oxygen Model (OM) encodes particle-specific LET-OER dependence through dual sigmoidal transitions constrained to increase monotonically with atomic number Z, combined with Michaelis-Menten oxygen kinetics. A Voxel-Aware (VA) extension resolves per-DSB local energy heterogeneity via a calibrated particle-specific sensitivity parameter. Calibrated on 233 OER observations from 29 sources across 10 particle types (LET = 0.2-654 keV/um); DSB coordinates from TOPAS-nBio simulations. Main results. The OM achieves $R^2 = 0.719$ and MAE = 0.300 retention OER units; theoretical OER maximum 3.32 (2.4% from measurement), bootstrap median 3.37 [3.18, 4.09]. The composite $K_{\rm fix} + K_{\rm repair} = 2.82$ mmHg is tightly constrained despite high collinearity (r = 0.935). On the Furusawa heavy-ion subset, VOxA achieves 28.4% lower survival OER MAE than the clinical standard (63.1% on helium, 24.0% on carbon) and reproduces He < C < Ne Z-ordering that universal models cannot capture. The VA extension passes 18 tests confirming sample-size-invariant within-
nucleus coefficient of variation of the per-DSB retention probability. VOxA evaluates in under $10^{-3}$ ms per voxel, more than $10^6$ times faster than Monte Carlo chemistry. Significance. VOxA is the first particle-specific OER model to reproduce Z-ordering analytically at clinical planning speed, validated on the largest OER calibration
dataset for this model class. Committed-break coordinates at whole-
nuclear scale provide the input for inter-break topological analysis and hypoxic LET painting.
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Fluid Dynamics · Cross-listed from cond-mat.soft
Existent condition of partially wet state in capillary tubes
Chen Zhao, Jiajia Zhou and Masao Doi
We develop a theory that predicts the
equilibrium states of a fluid contained in a capillary which has corners. Each section of the tube can take three states: completely wet state where the tube section is completely occupied by the fluid, partially wet state where only the corners are occupied by the fluid known as corner film or finger, and completely dry state. We calculate the phase diagram of these states for a square tube with rounded corners. It is shown that the partially wet state can exist only in a certain region in the parameter space spanned by the
equilibrium contact angle and the corner
curvature.
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Plasma Physics
Capturing many-body effects in electrical conductivity of warm dense matter
Brian P. Robinson, Alina Kononov, Lucas J. Stanek et al. (+3 more)
Conductivity models for warm dense matter inform simulations of planetary structure and fusion experiments. State-of-the-art conductivity calculations based on density functional theory approximate many-body physics and neglect electron-electron scattering lifetimes. We introduce a many-body framework for electrical conductivity using the GW approximation of the electronic self-energy. For beryllium, improved transition energies yield a surprisingly large reduction in low-temperature DC conductivity, while electron-electron scattering primarily reduces high-temperature DC conductivity.
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All authors Brian P. Robinson, Alina Kononov, Lucas J. Stanek, Andrew D. Baczewski, André Schleife, Stephanie B. Hansen
Plasma Physics
Amir Jafari
Dynamic
alignment in MHD
turbulence is commonly interpreted as a tendency of Elsässer increments to align toward smaller inertial-range scales. This interpretation is based on the amplitude-weighted diagnostic \(\langle A_r\sin\theta_r\rangle/\langle A_r\rangle\), where \(A_r\) is the product of the two increment amplitudes and \(\theta_r\) is the unweighted folded angle. We show that a decrease of the weighted angle toward smaller scales does not require dynamical
alignment but can arise from a retention effect in measurements. At fixed scale, larger amplitudes correlate with smaller angles, making the weighted angle smaller than the unweighted angle without implying that the angular population evolves toward
alignment with scale. The same covariance-driven reweighting structure underlies the Price equation in evolutionary biology. Applied here in scale space, it separates angular
evolution from redistribution of amplitude weight: a lower measured weighted angle at smaller scales can reflect reweighting even when the unweighted angle remains nearly scale independent. In physical time, the picture predicts that, after matching initial amplitudes, high-amplitude large-angle fluctuations lose a larger amplitude fraction over finite lags than high-amplitude small-angle fluctuations, favoring intense small-angle events in weighted statistics. This retention picture allows perpendicular rms Elsässer increments to scale as \(\ell_\perp^{1/4}\), corresponding to an effective \(k_\perp^{-3/2}\) spectrum, without requiring dynamic
alignment of typical fluctuations. We test these results using the Johns Hopkins
Turbulence Database and NASA Wind measurements. Mean logarithmic increment amplitudes give steeper typical-amplitude slopes than rms-amplitude fits in both
datasets, showing stronger sensitivity of second-order statistics to intermittent intense events.
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Physics and Society
Cities of Knowledge and Big Science in Developing Countries: Luxury or Investment? The GCLSI Case
Víctor M. Castaño, Leonardo Lomelí-Vanegas, Giorgio Margaritondo et al. (+3 more)
This article analyzes the feasibility of having a second synchrotron in Latin America, to be located, in principle, in a city within the Greater Caribbean region but open to all the continent. It is shown that an initiative of this sort is compatible with the economies of the region and would require a marginal increase of the current regional investment in science, which is broadly below that of other regions of the world, with peaks of low financing precisely in the Greater Caribbean. The project is not only feasible, but, beyond its purely scientific interest. it would have an impact for the development of cities in the region. The article is mainly focused to analyze this impact from the social, economic, and political point of view. It is shown that the return of the investment would have its break-even point long before the end of the expected lifetime of the infrastructure, and that through a system of smaller accelerators, that would be part of the same project, the benefit would not concentrate on the country hosting the facility. These smaller facilities could contribute to the national development as possible
nuclei of cities of knowledge, project which belongs to the priority of some countries/cities of the region.
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All authors Víctor M. Castaño, Leonardo Lomelí-Vanegas, Giorgio Margaritondo, Vanessa Mejía-Casco, Claudio Pellegrini, Galileo Violini
Fluid Dynamics
Pressure reconstruction from error-embedded gradient measurements: a Gaussian-process generalization of Green's function integration
Zejian You, Mohamed Amine Abassi, Xiaofeng Liu et al. (+1 more)
Reconstructing scalar fields from error-embedded gradient measurements is a fundamental linear inverse problem with broad applications in computational physics. Conventional approaches, such as Poisson-based solvers and the Green's Function Integration (GFI) method, require explicit boundary conditions extracted from the same error-embedded observations. In this study we assess the accuracy of a Gaussian Process Regression (GPR) framework for reconstructing pressure fields in turbulent flows from error-embedded pressure-gradient data derived from kinematic measurements. The probabilistic nature of GPR inherently provides tunable denoising, eliminates the need for boundary conditions, and produces a pointwise posterior-variance error estimate. A central theoretical result of the present work is that GFI is the noiseless limit of GPR, which on the unbounded plane reduces to the well-known logarithmic kernel and in three dimensions to the inverse-distance kernel. The framework is validated on two-dimensional slices and three-dimensional subdomains of a forced homogeneous isotropic
turbulence from the Johns Hopkins
Turbulence Database. With an empirical mixture-of-Gaussians (MoG-$3$) kernel fitted directly to the pressure correlation function, GPR performs at least as well as GFI. In situations with under-resolved data or high noise, GPR outperforms GFI, while delivering a calibrated pointwise posterior uncertainty whose standardized residuals satisfy $|z|<2$ over $95\%$ of grid points. The framework extends to three dimensions through a tensor-product Kronecker solver coupled to conjugate gradients with close to $\mathcal{O}(N^3\log N)$ cost. A closed-form error lower bound on a periodic cube is derived for the GPR operator, with the residual gap attributable to boundary contamination on non-periodic finite domains.
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All authors Zejian You, Mohamed Amine Abassi, Xiaofeng Liu, Qi Wang
Chemical Physics
Size Extensive Auxiliary-Field Quantum Monte Carlo with Perturbative Coupled Cluster Trial Wavefunction
Yichi Zhang, Ankit Mahajan, Yann Damour et al. (+1 more)
In this work, we develop a size extensive Auxiliary-Field
Quantum Monte Carlo (AFQMC) approach that scales as $O(N^5)$ for local energy evaluation by treating the Coupled Cluster Singles and Doubles (CCSD) trial wavefunctions perturbatively. Comprehensive numerical examinations, spanning from main-group molecules to $3d$ transition metal complexes, demonstrate that this perturbative treatment introduces negligible bias. For small systems, our method achieves an accuracy and level of noise comparable to AFQMC with configuration interaction singles and doubles (CISD) trial wavefunctions while outperforming CCSD(T). This size extensivity offers a decisive advantage for large systems, as suggested by the ground state energies of non-interacting monomers and one-dimensional atomic chains. Finally, the numerical simulations of the uniform electron gas (UEG) provide evidence that, unlike the CCSD(T) method, our new approach does not suffer from infrared divergence in the thermodynamic limit (TDL).
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All authors Yichi Zhang, Ankit Mahajan, Yann Damour, Sandeep Sharma
Chemical Physics
Low-rank compression of two-electron reduced density matrices
Kemal Atalar, Hugh G. A. Burton, Andreas Grüneis et al. (+1 more)
Two-body reduced density
matrices (2RDMs) encode the essential two-electron physics of electronic states, but their quartic storage cost poses a major limitation in practical workflows. We investigate a simple protocol to compress both transition and non-transition 2RDMs into a lower-rank representation that preserves their wedge-product structure and physical
symmetries under truncation. The resulting decomposition couples Coulomb and exchange channels through a common set of low-rank factors, yielding a more compact rank-sparse representation than single-channel factorizations. For correlated states, the effective rank scales linearly with system size, achieving a $\sim99$% compression for the coupled-cluster 2RDM of octane while retaining chemical accuracy. We apply this to the recently introduced ab initio eigenvector continuation workflows, where many-body wave functions are interpolated across
nuclear geometries with mean-field cost. Here, 2RDMs between training states act as projectors into a subspace but their
memory scaling limits applications to larger systems. The compression scheme reduces the
memory cost from quartic to quadratic for a fixed error per electron. Metrics to systematically control the decomposition are investigated, enabling statistically resolved structural, dynamical and spectroscopic observables from nonadiabatic molecular dynamics simulations of photoexcited H$_{28}$ chains, interpolating from compressed near-exact DMRG training data. This establishes these structure-preserving compressed intermediates for practical correlated electronic structure workflows.
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All authors Kemal Atalar, Hugh G. A. Burton, Andreas Grüneis, George H. Booth
Geophysics
Metal Saturation and the Redistribution of Hydrogen in Earth's Mantle
Junjie Dong, Lars P Stixrude, Paul D Asimow et al. (+1 more)
Iron disproportionation reactions in mantle silicates can produce metallic iron that drives Earth's deep mantle toward metal saturation under reduced conditions. Subducting slabs transport hydrated silicates to these depths, where interactions with metallic iron can reduce structurally bound hydrogen in silicates to reduced hydrogen-bearing phases, such as molecular hydrogen or iron hydrides, leaving mantle rocks in effect dry. Using the thermodynamic code HeFESTo with its latest self-consistent treatment of iron-bearing mantle phases, we investigate the stability and distribution of metallic iron in Earth's pyrolitic mantle across a broad range of oxidation states, represented by whole-rock Fe3+/$\Sigma$Fe ratio from 1% to 10%. We find that metallic iron is present through much of the lower mantle across this range and, under very reduced compositions of whole-rock Fe3+/$\Sigma$Fe = 1-3%, extends into the upper mantle. Where subducted water meets metal-saturated regions, hydrous melts may form and migrate upward, rehydrating the overlying mantle or pooling near the transition zone. Metal saturation can thus redistribute hydrogen internally, creating a sharp contrast between a wet shallow mantle and a dry deep mantle. This redox-driven redistribution can decrease mantle silicate water storage capacity by 64-96% today, to only 0.1-0.8 modern ocean masses, and may explain the viscosity contrast near the upper-lower mantle boundary. Although quantitative estimates of metal abundance and distribution depend on thermodynamic assumptions and remain uncertain above 50 GPa, our results reveal the role of redox reactions between disproportionated iron and subducted water in governing the speciation and redistribution of hydrogen in Earth's mantle.
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All authors Junjie Dong, Lars P Stixrude, Paul D Asimow, Jie Li
Optics · Cross-listed from cond-mat.quant-gas
Giant critical response in a driven-dissipative quantum gas
Ross C. Schofield, Daniel Lim, Himadri S. Dhar et al. (+6 more)
Systems close to a phase transition turn weak perturbations into large responses. At
equilibrium, this amplification is closely linked to criticality: fluctuations grow, dynamics slow, and a common soft mode controls the response. Whether this correspondence survives in driven-dissipative
quantum systems, sustained by continuous pumping and loss away from thermal
equilibrium, remains an open question. Here we show experimentally that it does. In a room-temperature
semiconductor photon Bose-Einstein condensate, the critical slowing of spontaneous intensity fluctuations and the amplification of weak pump perturbations are measured independently. Both peak at the same condensate population, $\bar{n}_c = 1250$, where the dimensionless slowing factor and susceptibility reach the same value, $\bar{n}_c/2 = 625$. A single weakly damped collective
photon-reservoir mode governs both effects. This fluctuation-response correspondence in a finite open
quantum gas establishes critical susceptibility as a measurable dynamical signature of condensation, with peak gain set by system size.
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All authors Ross C. Schofield, Daniel Lim, Himadri S. Dhar, Robert A. Nyman, Akshay K. Verma, Edmund Clarke, Jon Heffernan, Florian Mintert, Rupert F. Oulton
Data Analysis and Statistics · Cross-listed from q-bio.QM
The Same Problem by Different Names: Unifying Regression Dilution and Regression to the Mean
José F. Fontanari and Mauro Santos
Regression to the Mean (RTM) and Regression Dilution are traditionally treated as unrelated issues in the clinical and ecological literatures. In this work, we demonstrate that within a linear errors-in-variables framework where baseline variables are subject to transient temporal or measurement noise, these two phenomena share an identical underlying mathematical signature. We unify these disparate traditions by comparing specialized clinical tools, such as the Berry shrinkage correction, with standard sign-agnostic structural
estimators like Major Axis (MA) and Reduced Major Axis (RMA) regression. Using an analytical framework, we evaluate the closed-form population limits and finite-sample performance of these methods across various noise-to-signal ratios and sample sizes. Our results show that the Berry method is a specialized tool designed for clinical scenarios where a 1:1 relationship is expected. However, applying it to ecological trade-offs with negative slopes can lead to severe errors. We provide maps of optimality to identify which
estimator most accurately recovers the true biological signal under different conditions. By reconciling these disparate methods, we offer a principled guide for researchers to choose the correct tool based on their data's noise profile rather than their disciplinary tradition.
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Optics
Plasmon exciton coupling enhances second order nonlinear response in borophene ZnO hybrid structures
Maximilian Black, Yaser Abdi, Prabhdeep Singh et al. (+7 more)
Nonlinear optical processes in low dimensional materials are often weak or
symmetry forbidden, limiting their use in nanoscale light sources and on chip frequency conversion. Here, we show that combining two weakly nonlinear systems, anisotropic borophene and excitonic zinc
oxide, yields an enhanced and resonant nonlinear response. In borophene ZnO
heterostructures, cathodoluminescence reveals a two orders of magnitude enhancement at 400 nm and 800 nm, due to an enhanced two
photon absorption process. Under tunable near infrared excitation, a clear second harmonic signal emerges with quadratic power dependence and strong resonance near 800 nm. We attribute this to nonlinear plasmon
exciton coupling, which reshapes the excitonic response and enables efficient hybrid pathways for frequency conversion. These results establish anisotropic plasmon
exciton hybridization as a route to controlling nonlinear optical responses in low dimensional
heterostructures.
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All authors Maximilian Black, Yaser Abdi, Prabhdeep Singh, Bharti Garg, Zahra Alavi, Mohammadreza Alikhanim, Mohammad Hossein Salemi Seresht, Fatemeh Chahshouri, Masoud Taleb, Nahid Talebi
Chemical Physics · Cross-listed from cond-mat.mes-hall
Bound States in Second-order Topological Graphitic Structures
Haiyue Huang, Prineha Narang and Ioannis Petrides
Quadrupole
insulators are a class of second-order topological
insulators (SOTIs) that host zero-dimensional corner states within a two-dimensional bulk. Despite their unique properties, their realization in electronic systems on realistic material platforms remains rare. In this work, we present a general design principle to obtain quadrupole
insulators based on two-dimensional graphitic structures. By engineering the positions and connections of zigzag edges, we identify four topological classes of graphitic structures. We show that topologically protected massless corner state emerge at the intersection of domains belonging to different topological classes. Crucially, by tuning the smoothness of the domain wall, we further demonstrate the appearance of additional massive localized states with non-zero angular momentum. Our results provide a practical framework for realizing experimentally accessible SOTIs and uncover the coexistence of both massless and massive bound states in two dimensions.
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Computational Physics · Cross-listed from quant-ph
Brendan K. Krueger, Stephan Eidenbenz, Shamminuj Aktar et al. (+8 more)
We present the
Quantum Hamiltonian Analysis Toolkit (QHAT), a newly developed application that provides a user-friendly interface for studying
Hamiltonians and performing
Hamiltonian simulation on fault-tolerant
quantum computers. QHAT enables the generation and analysis of
Hamiltonians through a powerful and feature-rich application, driven by simple inputs designed to reflect user needs rather than algorithmic details, so that productive research on your application of interest can be done without needing a deep understanding of
quantum computing
algorithms. QHAT enables a streamlined workflow to analyze
Hamiltonians and
Hamiltonian simulation, supporting multiple choices of
algorithms and analyses. It supports
Hamiltonians from multiple sources but can also generate
Hamiltonians based on a simple description of the system, saving intermediate data files for re-use when generating related
Hamiltonians. Deriving the parameters for
quantum computing
algorithms can be a challenge, so QHAT is built around user-facing concepts such as maximum allowable error, rather than being built around algorithmic details such as steps counts or order parameters. An emphasis on user-friendly interfaces and efficient analysis means that the barrier to entry is low while rapidly providing results useful for a broad scope of studies.
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All authors Brendan K. Krueger, Stephan Eidenbenz, Shamminuj Aktar, Rishabh Bhardwaj, John K. Golden, George Grattan, Abhijith Jayakumar, Anna Matsekh, Scott Pakin, Nandakishore Santhi, Reuben Tate
Space Physics
Secondary Electron-Only Reconnection Driven by Large Scale Ion-Coupled Reconnection and Electron Kelvin-Helmholtz Instabilities in Hybrid Simulations of Solar Wind Turbulence
Joaquín Espinoza-Troni, Giuseppe Arrò, Francesco Califano et al. (+2 more)
Electron-only reconnection (EREC) is a
magnetic reconnection regime occurring within subion-scale current sheets (CSs), exhibiting only electron jets, without any ion
outflows. EREC has been first observed in the Earth's magnetosheath, where its occurrence is linked to the small correlation length of
magnetic fluctuations, limiting the growth of CSs to very large scales. On the other hand, the development of EREC in open systems with large
magnetic correlation lengths, such as the
solar wind (SW), remains an open question. To address this problem, we employ a large-scale 2D hybrid simulation with finite electron inertia, investigating the development of EREC driven by
turbulence. By injecting energy at very large scales, we allow EREC to develop spontaneously due to the turbulent cascade, without any external small-scale forcing or imposed constraints on the
turbulence correlation length. We find that EREC develops in our simulation via two distinct
turbulence-driven mechanisms: (1) secondary EREC induced by the interaction of plasmoids in the
outflows of large-scale ion-coupled reconnection; (2) EREC directly driven at subion scales by the electron Kelvin-Helmholtz instability in small-scale velocity shears. Furthermore, we perform a statistical analysis of CSs using the machine-learning clustering
algorithm HDBSCAN, showing that subion-scale CSs capable of hosting EREC are dominant in our simulation. Our results suggest that EREC could occur even in large-scale space and astrophysical systems, like the SW, driven by secondary turbulent processes, potentially playing a key role in dissipating energy at kinetic scales.
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All authors Joaquín Espinoza-Troni, Giuseppe Arrò, Francesco Califano, Julia E. Stawarz, Pablo S. Moya
Geophysics
Deploying Self-Supervised Learning for Real Seismic Data Denoising
Giovanny A. M. Arboleda, Claudio D. T. de Souza, Carlos E. M. dos Anjos et al. (+6 more)
Self-supervised learning (SSL) has emerged as a promising approach to seismic data denoising as it does not require clean reference data. In this work, the deployment of the Noisy-as-Clean (NaC) method was evaluated for real seismic data denoising under controlled conditions. Two independent seismic acquisitions, each comprising noisy and filtered data, were organized into four real
datasets. The NaC SSL method was adapted to add real noise to the noisy input, controlled by a parameter. An experimental protocol with ten experiments was designed to compare different strategies for deploying the NaC SSL method with the supervised learning baseline, using identical network
topology and hyperparameters. The models were evaluated in terms of denoising performance, computational cost, and generalization capability. The results show that the synthetic additive white Gaussian noise (AWGN) is inadequate for the denoising of seismic data within the NaC method, and performance strongly depends on the compatibility between the injected and actual noise characteristics. Furthermore, both the characteristics of the seismic data and the noise level influence the performance of the model. Self-supervised fine-tuning on test data has improved SSL performance, whereas no such gain was observed for fine-tuning of supervised models. Finally, NaC has shown to be a simple, effective, and model-independent method that offers a feasible solution for the denoising of real seismic data.
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All authors Giovanny A. M. Arboleda, Claudio D. T. de Souza, Carlos E. M. dos Anjos, Lessandro de S. S. Valente, Roosevelt de L. Sardinha, Albino Aveleda, Pablo M. Barros, André Bulcão, Alexandre G. Evsukoff
Physics and Society
Big Mysteries Survey: Physicists' Views on Cosmology, Black Holes, Quantum Mechanics, and Quantum Gravity
Niayesh Afshordi, Phil Halper, Matteo Rini et al. (+1 more)
We present results from the Big Mysteries Survey, a large-scale survey conducted through the American Physical Society's Physics Magazine on foundational and controversial topics in contemporary physics. The survey provides a snapshot of physicists' views on issues in cosmology, black-hole physics,
quantum mechanics,
quantum gravity, and anthropic coincidences. A central finding is that several positions often described publicly as field-wide “consensus” views are, in practice, supported by much narrower majorities or by pluralities rather than majorities.
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All authors Niayesh Afshordi, Phil Halper, Matteo Rini, Michael Schirber
Atomic Physics · Cross-listed from quant-ph
Multi-Qubit Stabilizer Readout on a Dual-Species Rydberg Array
Yu Wang, Ryan Cimmino, Kenneth Wang et al. (+7 more)
The ability to locally control and measure subsets of ancilla
qubits in an efficient and crosstalk-free manner is a key ingredient in
quantum error correction (QEC). Dual-species neutral atom arrays offer an ideal implementation of these capabilities, enabling independent state preparation, manipulation, and detection on each species. In this work, we realize such a dual-species Rydberg array of Na and Cs atoms trapped in co-localized 2D optical tweezer arrays, using Na as an ancilla to measure stabilizers of surrounding Cs data
qubits. We identify the finite interspecies Rydberg-Rydberg interaction strength as a practical obstacle to high-fidelity multi-body
entanglement and show that, by tuning the Rabi frequency and the detuning of the Rydberg driving field, the resulting
geometric phase error can be compensated. This yields a protocol for simultaneous, non-destructive, in situ stabilizer readout of multiple data
qubits via global pulses alone. Using this protocol, we demonstrate non-destructive measurement of Pauli-Z stabilizers on four-
qubit Cs plaquettes via a single global Rydberg pulse sequence. Our results demonstrate dual-species tweezer arrays as a promising route towards scalable QEC and open the door to new
quantum control protocols leveraging both interspecies and intraspecies interactions.
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All authors Yu Wang, Ryan Cimmino, Kenneth Wang, Santiago Lopez, Jeffrey Li, Jin Ming Koh, Jonathan N. Hallén, Anne Matthies, Norman Y. Yao, Kang-Kuen Ni
Atomic and Molecular Clusters
Single-Photon Double Ionization of Ozone
Veronica Daver Ideböhn, Antoine Gloriod, Richard J. Squibb et al. (+13 more)
Ozone (O3) is a triatomic molecule of central importance in the chemistry and physics of the Earth's and other planetary atmospheres. Beyond its environmental significance, a detailed understanding of the electronic structure and ionization dynamics of ozone is essential for modeling atmospheric, ionospheric, and astrochemical processes. In the present work, we substantially extend the experimental and theoretical characterization of ozone into the regime of valence double photoionization. Using HeII-alpha, HeII-beta, and higher-energy
vacuum ultraviolet radiation in combination with a versatile multiple charged-particle correlation detection technique, we report the first single-
photon valence double ionization electron spectrum of O3. To interpret the experimental observations, we mapped the lowest potential energy surfaces of dicationic ozone employing post-Hartree-Fock multi-configurational-interaction methods, and computed with high accuracy the energetics of the relevant dissociation channels. Our results demonstrate that dissociative double ionization of ozone produces electronically excited cationic atomic oxygen fragments in addition to the ground-state dissociation pathway, revealing a richer fragmentation dynamics than hitherto recognized.
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All authors Veronica Daver Ideböhn, Antoine Gloriod, Richard J. Squibb, Andreas Hult Roos, Nihar Ranjan Behera, Ishita Kanungo, Elias Gustafsson, Simon Gällblad, Saga Berglund, Emelie Olsson, Gunnar Öhrwall, Gunnar Nyman, John M. Dyke, John H.D. Eland, Majdi Hochlaf, Raimund Feifel