Tootfinder

Numerous Bidirectionally Propagating Plasma Blobs near the Reconnection Site of a Solar Eruption
Zhenyong Hou, Hui Tian, Maria S. Madjarska, Hechao Chen, Tanmoy Samanta, Xianyong Bai, Zhentong Li, Yang Su, Wei Chen, Yuanyong Deng
https://arxiv.org/abs/2404.18092

Numerous Bidirectionally Propagating Plasma Blobs near the Reconnection Site of a Solar Eruption
Current sheet is a common structure involved in solar eruptions. However, it is observed in minority of the events and the physical properties of its fine structures during a solar eruption are rarely investigated. Here, we report an on-disk observation that displays 108 compact, circular or elliptic bright structures, presumably plasma blobs, propagating bidirectionally along a flare current sheet during a period of $\sim$24 minutes. From extreme ultraviolet images, we have investigated the te…

Excitation of Quasiperiodic Fast-propagating Waves in the Early Stage of the Solar Eruption: #CoronalMassEjection: https://english.cas.cn/newsroom/research_news/phys/202402/t20240222_657581.shtml

Broad and Bi-directional narrow quasi-periodic fast-propagating wave trains associated with a filament-driven halo CME on 2023 April 21
Xinping Zhou, Yuandeng Shen, Yihua Yan, Ke Yu, Zhining Qu, Ahmed Ahmed Ibrahim, Zehao Tang, Chengrui Zhou, Song Tan, Ye Qiu, Hongfei Liang
https://arxiv.org/abs/2404.18391

Broad and Bi-directional narrow quasi-periodic fast-propagating wave trains associated with a filament-driven halo CME on 2023 April 21
This paper presents three distinct wave trains that occurred on 2023 April 21: a broad quasi-periodic fast-propagating (QFP) wave train and a bi-directional narrow QFP wave train. The broad QFP wave train expands outward in a circular wavefront, while bi-directional narrow QFP wave trains propagate in the northward and southward directions, respectively. The concurrent presence of the wave trains offers a remarkable opportunity to investigate their respective triggering mechanisms. Measurement …

This https://arxiv.org/abs/2401.12054 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_grqc_…

Twisting asymptotic symmetries and algebraically special vacuum solutions
In this paper, we study asymptotic symmetries and algebraically special exact solutions in the Newman-Penrose formalism. Removing the hypersurface orthogonal condition in the well studied Newman-Unti gauge, we obtain a generic asymptotic solution space which includes all possible origins of propagating degree of freedom. The asymptotic symmetry of the generalized system extends the Weyl-BMS symmetry by two independent local Lorentz transformations with non-trivial boundary charges, which reveal…

PRP: Propagating Universal Perturbations to Attack Large Language Model Guard-Rails
Neal Mangaokar, Ashish Hooda, Jihye Choi, Shreyas Chandrashekaran, Kassem Fawaz, Somesh Jha, Atul Prakash
https://arxiv.org/abs/2402.15911

PRP: Propagating Universal Perturbations to Attack Large Language Model Guard-Rails
Large language models (LLMs) are typically aligned to be harmless to humans. Unfortunately, recent work has shown that such models are susceptible to automated jailbreak attacks that induce them to generate harmful content. More recent LLMs often incorporate an additional layer of defense, a Guard Model, which is a second LLM that is designed to check and moderate the output response of the primary LLM. Our key contribution is to show a novel attack strategy, PRP, that is successful against sev…

This https://arxiv.org/abs/2403.10975 has been replaced.
link: https://scholar.google.com/scholar?q=a

Nonequilibrium tricritical behaviour in anisotropic XY ferromagnet driven by elliptically polarised propagating magnetic field wave
Three dimensional anisotropic XY ferromagnet driven by elliptically polarized propagating magnetic field wave has been extensively investigated by Monte Carlo simulation with Metropolis single spin flip algorithm. Both the effects of the bilinear exchange type and the single site anisotropies are thoroughly investigated. The time average magnetisation (over the complete cycle of the elliptically polarized propagating magnetic field wave) components play the role of dynamic order parameter. For …

Asymptotic expansion of wave scattering in a periodic 2d-plane
Vincent Lescarret
https://arxiv.org/abs/2403.20061 https://arxiv.org/p…

Asymptotic expansion of wave scattering in a periodic 2d-plane
We give a counter part of Sommerfeld outging radiation condition for waves propagating in a 2d periodic medium under generical assumptions and provide a uniqueness theorem for outgoing solutions.

This https://arxiv.org/abs/2203.06693 has been replaced.
link: https://scholar.google.com/scholar?q=a

Continuum damping of topologically-protected edge modes at the boundary of a magnetized plasma
Recent extension of the topological ideas to continuous systems with broken time-reversal symmetry, such as magnetized plasmas, provides new insights into the nature of scattering-free topologically-protected surface plasma waves (TSPWs). We demonstrate a unique characteristic of TSPWs propagating above the electron cyclotron frequency: their collisionless damping via coupling to the continuum of resonant modes localized inside a smooth plasma-vacuum interface. Damped TSPWs retain their unidire…

Physics-Informed Neural Networks for Satellite State Estimation
Jacob Varey, Jessica D. Ruprecht, Michael Tierney, Ryan Sullenberger
https://arxiv.org/abs/2403.19736

Physics-Informed Neural Networks for Satellite State Estimation
The Space Domain Awareness (SDA) community routinely tracks satellites in orbit by fitting an orbital state to observations made by the Space Surveillance Network (SSN). In order to fit such orbits, an accurate model of the forces that are acting on the satellite is required. Over the past several decades, high-quality, physics-based models have been developed for satellite state estimation and propagation. These models are exceedingly good at estimating and propagating orbital states for non-m…

This https://arxiv.org/abs/2306.01664 has been replaced.
initial toot: https://mastoxiv.page/@a…

Chiral electrons and spin selectivity at chiral-achiral interfaces
Chiral molecules can selectively transport electrons of a particular spin orientation, yet the underlying mechanism remain poorly understood. Here, we present theoretical evidence that electrons propagating through chiral materials with screw symmetry exhibit chirality themselves and carry symmetry-induced pseudo-angular momentum (PAM) which must be characterized by both spin and orbital components. The chiral electron transport is PAM polarized, with counterpropagating states exhibiting opposi…

This https://arxiv.org/abs/2307.16485 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

Parameter Inference for Degenerate Diffusion Processes
We study parametric inference for ergodic diffusion processes with a degenerate diffusion matrix. Existing research focuses on a particular class of hypo-elliptic SDEs, with components split into `rough'/`smooth' and noise from rough components propagating directly onto smooth ones, but some critical model classes arising in applications have yet to be explored. We aim to cover this gap, thus analyse the highly degenerate class of SDEs, where components split into further sub-groups. Such model…

This https://arxiv.org/abs/2307.14960 has been replaced.
initial toot: https://mastoxiv.page/@a…

Spectroscopy and topological properties of a Haldane light system
We introduce a local spectroscopic method in real space to probe the topological properties of a circuit quantum electrodynamics (cQED) array generalizing previous approaches from one to two dimensions in the plane. As an application, we develop the theory of microwave light propagating in the local probe capacitively coupled to the cQED array associated to a bosonic Haldane model. Interestingly, we show that the measured reflection coefficient, resolved in frequency through the resonance, reve…

This https://arxiv.org/abs/2402.10906 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

Towards a sharper phase-field method: a hybrid diffuse-semisharp approach for microstructure evolution problems
A new approach is developed for computational modelling of microstructure evolution problems. The approach combines the phase-field method with the recently-developed laminated element technique (LET) which is a simple and efficient method to model weak discontinuities using nonconforming finite-element meshes. The essence of LET is in treating the elements that are cut by an interface as simple laminates of the two phases, and this idea is here extended to propagating interfaces so that the vo…

Direct and retrograde signal propagation in unidirectionally coupled Wilson-Cowan oscillators
Guy Elisha, Richard Gast, Sourav Halder, Sara A. Solla, Peter J. Kahrilas, John E. Pandolfino, Neelesh A. Patankar
https://arxiv.org/abs/2402.18100

Direct and retrograde signal propagation in unidirectionally coupled Wilson-Cowan oscillators
Certain biological systems exhibit both direct and retrograde propagating wave signals, despite unidirectional neural coupling. However, there is no model to explain this. Therefore, the underlying physics of reversing the signal's direction for one-way coupling remains unclear. Here, we resolve this issue using a Wilson-Cowan oscillators network. By analyzing the limit cycle period of various coupling configurations, we determine that intrinsic frequency differences among oscillators control w…

> If as a VC you REALLY want software eating the world, you also need devs eager to cook that world
Zing!
https://hachyderm.io/@anthrocypher/111987622160634320

Fourier analysis of near-field patterns generated by propagating polaritons
Minsoo Jang, Sergey G. Menabde, Fatemeh Kiani, Jacob T. Heiden, Vladimir A. Zenin, N. Asger Mortensen, Giulia Tagliabue, Min Seok Jang
https://arxiv.org/abs/2402.17225

Fourier analysis of near-field patterns generated by propagating polaritons
Scattering-type scanning near-field optical microscope (s-SNOM) has become an essential tool to study polaritons - quasiparticles of light coupled to collective charge oscillations - via direct probing of their near field with a spatial resolution far beyond the diffraction limit. However, extraction of the polariton complex propagation constant from the near-field images requires subtle considerations that have not received necessary attention so far. In this study, we discuss important yet ov…

This https://arxiv.org/abs/2401.15467 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_hep…

Fermions, quantum gravity and holography in two dimensions
We study a model comprising $N$ flavors of Kähler Dirac fermion propagating on a triangulated two dimensional disk which is constrained to have a negative average bulk curvature. Dirichlet boundary conditions are chosen for the fermions. Quantum fluctuations of the geometry are included by summing over all possible triangulations consistent with these constraints. We show in the limit $N\to \infty$ that the partition function is dominated by a regular triangulation of two dimensional hyperboli…

Electromagnetic signal propagation through lossy media via surface electromagnetic waves
Igor I. Smolyaninov, Quirino Balzano, Vera N. Smolyaninova, Daryna Soloviova
https://arxiv.org/abs/2402.17787

Electromagnetic signal propagation through lossy media via surface electromagnetic waves
A theory of surface electromagnetic waves in gradient media exhibiting arbitrary surface gradients of dielectric permittivity and magnetic permeability has been developed. Novel low-loss propagating surface wave solutions have been found in the gradient media in which both dielectric permittivity and magnetic permeability are dominated by their imaginary parts. Several examples of gradient geometries in which the surface wave problem may be solved analytically have been found. Examples of pract…

This https://arxiv.org/abs/2312.03221 has been replaced.
initial toot: https://mastoxiv.page/@arX…

Random walk models for the propagation of signalling molecules in one-dimensional spatial networks and their continuum limit
The propagation of signalling molecules within cellular networks is affected by network topology, but also by the spatial arrangement of cells in the networks. Understanding the collective reaction--diffusion behaviour in space of signals propagating through cellular networks is an important consideration for example for regenerative signals that convey positional information. In this work, we consider stochastic and deterministic versions of random walk models of signalling molecules propagati…

Loss-induced quantum information jet in an infinite temperature Hubbard chain
Patrik Penc, C\u{a}t\u{a}lin Pa\c{s}cu Moca, \"Ors Legeza, Toma\v{z} Prosen, Gergely Zar\'and, Mikl\'os Antal Werner
https://arxiv.org/abs/2402.19390

Loss-induced quantum information jet in an infinite temperature Hubbard chain
Information propagation in the one-dimensional infinite temperature Hubbard model with a dissipative particle sink at the end of a semi-infinite chain is studied. In the strongly interacting limit, the two-site mutual information and the operator entanglement entropy exhibit a rich structure with two propagating information fronts and superimposed interference fringes. A classical reversible cellular automaton model quantitatively captures the transport and the slow, classical part of the corre…

Lens Stochastic Diffraction: A Signature of Compact Structures in Gravitational-Wave Data
Miguel Zumalac\'arregui
https://arxiv.org/abs/2404.17405 http…

Lens Stochastic Diffraction: A Signature of Compact Structures in Gravitational-Wave Data
Every signal propagating through the universe is diffracted by the gravitational fields of intervening objects, aka gravitational lenses. Diffraction is most efficient when caused by compact lenses, which invariably produce additional images of a source. The signals associated with additional images are generically faint, but their collective effect may be detectable with coherent sources, such as gravitational waves (GWs), where both amplitude and phase are measured. Here, I describe lens stoc…

This https://arxiv.org/abs/2402.10906 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

Towards a sharper phase-field method: a hybrid diffuse-semisharp approach for microstructure evolution problems
A new approach is developed for computational modelling of microstructure evolution problems. The approach combines the phase-field method with the recently-developed laminated element technique (LET) which is a simple and efficient method to model weak discontinuities using nonconforming finite-element meshes. The essence of LET is in treating the elements that are cut by an interface as simple laminates of the two phases, and this idea is here extended to propagating interfaces so that the vo…

> If as a VC you REALLY want software eating the world, you also need devs eager to cook that world
Zing!
https://hachyderm.io/@anthrocypher/111987622160634320

Stellar wind bubbles of OB stars as Galactic cosmic-ray re-accelerators
Dominique M. -A. Meyer
https://arxiv.org/abs/2403.18484 https://

Stellar wind bubbles of OB stars as Galactic cosmic-ray re-accelerators
Cosmic rays are highly energetic messengers propagating in magnetized plasma, which are, possibly but not exclusively, accelerated at astrophysical shocks. Amongst the variety of astrophysical objects presenting shocks, the huge circumstellar stellar wind bubbles forming around very massive stars, are potential non thermal emitters. We present the 1D magnetohydrodynamical simulation of the evolving magnetized surroundings of a single, OB type main sequence 60 Mo star, which is post processed to…

Flying With Photons: Rendering Novel Views of Propagating Light
Anagh Malik, Noah Juravsky, Ryan Po, Gordon Wetzstein, Kiriakos N. Kutulakos, David B. Lindell
https://arxiv.org/abs/2404.06493

Flying With Photons: Rendering Novel Views of Propagating Light
We present an imaging and neural rendering technique that seeks to synthesize videos of light propagating through a scene from novel, moving camera viewpoints. Our approach relies on a new ultrafast imaging setup to capture a first-of-its kind, multi-viewpoint video dataset with picosecond-level temporal resolution. Combined with this dataset, we introduce an efficient neural volume rendering framework based on the transient field. This field is defined as a mapping from a 3D point and 2D direc…

This https://arxiv.org/abs/2110.04774 has been replaced.
link: https://scholar.google.com/scholar?q=a

Sewing and Propagation of Conformal Blocks
We clarify the relations between sewing and propagating conformal blocks. In particular, we show that sewing and propagation and commuting procedures. As an application, we give a geometric construction of permutation-twisted modules for tensor product VOAs. Their first (algebraic) construction is due to Barron-Dong-Mason. The results and the point of view in this article are crucial for relating the (genus-0) permutation-twisted conformal blocks associated to a tensor product VOA $V^{\otimes…

Georgia lawmaker runs secret election-conspiracy Telegram channel

A Fulton county commissioner in Georgia has been
operating a private Telegram channel for years,
propagating debunked claims about the 2020 election,
and spreading accusations of crimes by county employees,
including #Ruby #Freeman

This https://arxiv.org/abs/2402.17225 has been replaced.
initial toot: https://mastoxiv.page/@ar…

Fourier analysis of near-field patterns generated by propagating polaritons
Scattering-type scanning near-field optical microscope (s-SNOM) has become an essential tool to study polaritons - quasiparticles of light coupled to collective charge oscillations - via direct probing of their near field with a spatial resolution far beyond the diffraction limit. However, extraction of the polariton complex propagation constant from the near-field images requires subtle considerations that have not received necessary attention so far. In this study, we discuss important yet ov…

Mind the Gap: Nonlocal Cascades and Preferential Heating in High-$\beta$ Alfv\'enic Turbulence
Waverly Gorman, Kristopher G. Klein
https://arxiv.org/abs/2402.17044

Mind the Gap: Nonlocal Cascades and Preferential Heating in High-$β$ Alfvénic Turbulence
Characterizing the thermodynamics of turbulent plasmas is key to decoding observable signatures from astrophysical systems. In magnetohydrodynamic (MHD) turbulence, nonlinear interactions between counter-propagating Alfvén waves cascade energy to smaller spatial scales where dissipation heats the protons and electrons. When the thermal pressure far exceeds the magnetic pressure, linear theory predicts a spectral gap at perpendicular scales near the proton gyroradius where Alfvén waves become …

Improving the Spatial Correlation Characteristics of Antenna Arrays using Linear Operators and Wide-band Modelling
Marc Miranda, Sebastian Semper, Michael D\"obereiner, Reiner Thom\"a
https://arxiv.org/abs/2403.17654

Improving the Spatial Correlation Characteristics of Antenna Arrays using Linear Operators and Wide-band Modelling
The analysis of wireless communication channels at the mmWave, sub-THz and THz bands gives rise to difficulties in the construction of antenna arrays due to the small maximum inter-element spacing constraints at these frequencies. Arrays with uniform spacing greater than half the wavelength for a certain carrier frequency exhibit aliasing side-lobes in the angular domain, prohibiting non-ambiguous estimates of a propagating wave-front's angle of arrival. In this paper, we present how wide-ban…

This https://arxiv.org/abs/2309.15301 has been replaced.
initial toot: https://mastoxiv.page/@arXi…

Crucial Role of Obliquely Propagating Gravity Waves in the Quasi-Biennial Oscillation Dynamics
In climate modelling, the reality of simulated flows in the middle atmosphere is largely affected by the model's representation of gravity wave processes that are unresolved, while these processes are usually simplified to facilitate computations. The simplification commonly applied in existing climate models is to neglect wave propagation in horizontal direction and time. Here we use a model that fully represents the propagation of unresolved waves in all directions, thereby elucidating its dy…

This https://arxiv.org/abs/2312.00445 has been replaced.
initial toot: https://mastoxiv.page/@arX…

Nonlinear interaction of two cross-propagating plane waves
An ideal contrast-enhanced ultrasound image should display microbubble-induced nonlinearities while avoiding wave propagation nonlinearities. One of the most successful ultrasound pulse sequences to disentangle these nonlinear effects relies on the transmission of cross-propagating plane waves. However, theory describing the noncollinear nonlinear interaction of two finite plane waves has not been fully developed and a better understanding of these effects would improve contrast-enhanced ultras…

This https://arxiv.org/abs/2212.09439 has been replaced.
link: https://scholar.google.com/scholar?q=a

Confined phase singularities reveal the spin-to-orbital angular momentum conversion of sound waves
We identify an acoustic process in which the conversion of angular momentum between its spin and orbital form takes place. The interaction between an evanescent wave propagating at the interface of two immiscible fluids and an isolated droplet is considered. The elliptical motion of the fluid supporting the incident wave is associated with a simple state of spin angular momentum, a quantity recently introduced for acoustic waves in the literature. We experimentally observe that this field predo…

Random Multi-Type Spanning Forests for Synchronization on Sparse Graphs
Hugo Jaquard, Pierre-Olivier Amblard, Simon Barthelm\'e, Nicolas Tremblay
https://arxiv.org/abs/2403.19300

Random Multi-Type Spanning Forests for Synchronization on Sparse Graphs
Random diffusions are a popular tool in Monte-Carlo estimations, with well established algorithms such as Walk-on-Spheres (WoS) going back several decades. In this work, we introduce diffusion estimators for the problems of angular synchronization and smoothing on graphs, in the presence of a rotation associated to each edge. Unlike classical WoS algorithms, these estimators allow for global estimations by propagating along the branches of multi-type spanning forests, and we show that they can …

Negative magnetoresistance induced by longitudinal photons in Dirac/Weyl semimetals
J. L. Acosta Avalo, H. P\'erez Rojas
https://arxiv.org/abs/2402.16859

Negative magnetoresistance induced by longitudinal photons in Dirac/Weyl semimetals
A low-energy model is built to study systems such as Dirac/Weyl semimetals, according to statistical quantum electrodynamics formalism. We report that the introduction of a pseudoscalar, associated to longitudinal photons propagating along a magnetic field B, could transforms a Dirac semimetal into a Weyl semimetal with a pair of Weyl nodes for each point of Dirac. The nodes are separated by a pseudovector electric field induced dynamically along B associated to a chiral effect on the Fermi sur…

3D characterization of kinematic fields and poroelastic swelling near the tip of a propagating crack in a hydrogel
Chenzhuo Li, Damien Delespaul, John M. Kolinski
https://arxiv.org/abs/2404.13331

3D characterization of kinematic fields and poroelastic swelling near the tip of a propagating crack in a hydrogel
In fracture mechanics, polyacrylamide hydrogels have been widely used as a model material for experiments, benefited from its optical transparency, fracture brittleness, and low Rayleigh wave velocity. To describe the brittle fracture in the hydrogels, linear elastic fracture mechanics comes as the first choice. However, in soft materials such as hydrogels, the crack opening can be extremely large, leading to substantial geometric nonlinearity and material nonlinearity at the crack tip. Further…

Interesting: Binary type inference in Ghidra.
https://blog.trailofbits.com/2024/02/07/binary-type-inference-in-ghidra/

Binary type inference in Ghidra
By Ian Smith Trail of Bits is releasing BTIGhidra, a Ghidra extension that helps reverse engineers by inferring type information from binaries. The analysis is inter-procedural, propagating and res…

This https://arxiv.org/abs/2305.15243 has been replaced.
initial toot: https://mastoxiv.page/@ar…

Photonic Time Crystals and Parametric Amplification: similarity and distinction
Photonic Time crystals (PTC) arise in time-modulated media when the frequency of modulation of permittivity is on the order of twice the frequency of light and are manifested by the generation and amplification of so-called time reversed waves propagating in the direction opposite to the incoming light. Superficially, the observed phenomenon bears resemblance to the widely known phenomena of optical parametric generation (OPG) and amplification (OPA) using second or third order optical nonlinea…

This https://arxiv.org/abs/2306.02504 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_grqc_…

Scalar field instabilities in charged BTZ black holes
We investigate the charged scalar field propagating in a (2+1) charged BTZ black hole. The conditions for stability are studied unveiling, for each black hole geometry, the existence of a critical scalar charge as of the evolution is unstable. The existence of growing profiles is substantiated by the deep in the effective potential that intensifies as the scalar charge increases. The phenomenum happens in every black hole geometry even for small geometry charge. In the small scalar charge regim…

Laser cooling $^{88}$Sr to microkelvin temperature with an integrated-photonics system
Andrew R. Ferdinand, Zheng Luo, Sindhu Jammi, Zachary Newman, Grisha Spektor, Okan Koksal, Parth B. Patel, Daniel Sheredy, William Lunden, Akash Rakholia, Travis C. Briles, Wenqi Zhu, Martin M. Boyd, Amit Agrawal, Scott B. Papp
https://arxiv.org/abs/2404.13210 https://arxiv.org/pdf/2404.13210
arXiv:2404.13210v1 Announce Type: new
Abstract: We report on experiments generating a magneto-optical trap (MOT) of 88-strontium ($^{88}$Sr) atoms at microkelvin temperature, using integrated-photonics devices. With metasurface optics integrated on a fused-silica substrate, we generate six-beam, circularly polarized, counter-propagating MOTs on the blue broad-line, 461 nm, and red narrow-line, 689 nm, Sr cooling transitions without bulk optics. By use of a diverging beam configuration, we create up to 10 mm diameter MOT beams at the trapping location. To frequency stabilize and linewidth narrow the cooling lasers, we use fiber-packaged, integrated nonlinear waveguides to spectrally broaden a frequency comb. The ultra-coherent supercontinuum of the waveguides covers 650 nm to 2500 nm, enabling phase locks of the cooling lasers to hertz level linewidth. Our work highlights the possibility to simplify the preparation of an ultracold 88Sr gas for an optical-lattice clock with photonic devices. By implementing a timing sequence for control of the MOT lasers and the quadrupole magnetic-field gradient, we collect atoms directly from a thermal beam into the blue MOT and continuously cool into a red MOT with dynamic detuning and intensity control. There, the red MOT temperature is as low as $2~{\mu}$K and the overall transfer efficiency up to 16%. We characterize this sequence, including an intermediate red MOT with modulated detuning. Our experiments demonstrate an integrated photonics system capable of cooling alkaline-earth gases to microkelvin temperature with sufficient transfer efficiencies for adoption in scalable optical clocks and quantum sensors.

This https://arxiv.org/abs/2310.02529 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_csSI_…

MIDDAG: Where Does Our News Go? Investigating Information Diffusion via Community-Level Information Pathways
We present MIDDAG, an intuitive, interactive system that visualizes the information propagation paths on social media triggered by COVID-19-related news articles accompanied by comprehensive insights, including user/community susceptibility level, as well as events and popular opinions raised by the crowd while propagating the information. Besides discovering information flow patterns among users, we construct communities among users and develop the propagation forecasting capability, enabling …

The hunt of PeVatrons as the origin of the most energetic photons observed in our Galaxy
Emma de O\~na Wilhelmi, Rub\'en L\'opez-Coto, Felix Aharonian, Elena Amato, Zhen Cao, Stefano Gabici, Jim Hinton
https://arxiv.org/abs/2404.16591

The hunt of PeVatrons as the origin of the most energetic photons observed in our Galaxy
Ultrarelativistic particles called cosmic rays permeate the Milky Way, propagating through the Galactic turbulent magnetic fields. The mechanisms under which these particles increase their energy can be reasonably described by current theories of acceleration and propagation of cosmic rays. There are, however, still many open questions as to how to reach petaelectronvolt (PeV) energies, the maximum energy believed to be attained in our Galaxy, and in which astrophysical sources (dubbed {\it PeV…

This https://arxiv.org/abs/2401.04434 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_hept…

Gravitons in a gravitational plane wave
Gravitational plane waves (when Ricci flat) belong to the VSI family. The achronym VSI stands for vanishing scalar invariants, meaning that all scalar invariants built out of Riemann tensor and its derivatives vanish, although the Riemann tensor itself does not. In the particular case of plane waves many interesting phenomena have been uncovered for strings propagating in this background. Here we comment on gravitons propagating in such a spacetime, which itself presumably consists of an Avogad…

This https://arxiv.org/abs/2305.15243 has been replaced.
initial toot: https://mastoxiv.page/@ar…

Photonic Time Crystals and Parametric Amplification: similarity and distinction
Photonic Time crystals (PTC) arise in time-modulated media when the frequency of modulation of permittivity is on the order of twice the frequency of light and are manifested by the generation and amplification of so-called time reversed waves propagating in the direction opposite to the incoming light. Superficially, the observed phenomenon bears resemblance to the widely known phenomena of optical parametric generation (OPG) and amplification (OPA) using second or third order optical nonlinea…

I accidentally deleted an apex A record. Sorry about that.
Fixes propagating outward at the speed of #dns

This https://arxiv.org/abs/2301.07370 has been replaced.
initial toot: https://mastoxiv.page/@a…

Phase transitions of wave packet dynamics in disordered non-Hermitian systems
Disorder can localize the eigenstates of one-dimensional non-Hermitian systems, leading to an Anderson transition with a critical exponent of 1. We show that, due to the lack of energy conservation, the dynamics of individual, real-space wave packets follows a different behavior. Both transitions between localization and unidirectional amplification, as well as transitions between distinct propagating phases become possible. The critical exponent of the transition equals $1/2$ in propagating-pr…

The number of toots just wanting to see how many boosts or likes they can get is increasing. Please stop propagating such and recognise them for what they are: #spam. No matter what the context is and how well-meaning it seems. Like the Craig Shergold thing back in the days.

Uncertainty quantification in $(p,n)$ reactions
A. J. Smith, C. Hebborn, F. M. Nunes, R. G. T. Zegers
https://arxiv.org/abs/2403.18629 https://

Uncertainty quantification in $(p,n)$ reactions
Charge-exchange reactions are versatile probes for nuclear structure. In particular, when populating isobaric analog states, these reactions are used to study isovector nuclear densities and neutron skins. The quality of the information extracted from charge-exchange data depends on the accuracy of the reaction models and their inputs; this work addresses these two points. First, we quantify the uncertainties due to effective nucleon-nucleus interactions by propagating the parameter posterior d…

This https://arxiv.org/abs/2403.10975 has been replaced.
link: https://scholar.google.com/scholar?q=a

Nonequilibrium tricritical behaviour in anisotropic XY ferromagnet driven by elliptically polarised propagating magnetic field wave
Three dimensional anisotropic XY ferromagnet driven by elliptically polarized propagating magnetic field wave has been extensively investigated by Monte Carlo simulation with Metropolis single spin flip algorithm. Both the effects of the bilinear exchange type and the single site anisotropies are thoroughly investigated. The time average magnetisation (over the complete cycle of the elliptically polarized propagating magnetic field wave) components play the role of dynamic order parameter. For …

This https://arxiv.org/abs/2309.15301 has been replaced.
initial toot: https://mastoxiv.page/@arXi…

Crucial Role of Obliquely Propagating Gravity Waves in the Quasi-Biennial Oscillation Dynamics
In climate modelling, the reality of simulated flows in the middle atmosphere is largely affected by the model's representation of gravity wave processes that are unresolved, while these processes are usually simplified to facilitate computations. The simplification commonly applied in existing climate models is to neglect wave propagation in horizontal direction and time. Here we use a model that fully represents the propagation of unresolved waves in all directions, thereby elucidating its dy…

This https://arxiv.org/abs/2311.08986 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_grqc_…

Physical scale adiabatic regularization in cosmological spacetimes
We develop a new regularization method for the stress-energy tensor and the two-point function of free quantum scalar fields propagating in cosmological spacetimes. We proceed by extending the adiabatic regularization scheme with the introduction of two additional mass scales. By setting them to the order of the physical scale of the studied scenario, we obtain ultraviolet-regularized quantities that do not distort the power spectra amplitude at the infrared scales amplified by the expansion of…

This https://arxiv.org/abs/2212.09439 has been replaced.
link: https://scholar.google.com/scholar?q=a

Confined phase singularities reveal the spin-to-orbital angular momentum conversion of sound waves
We identify an acoustic process in which the conversion of angular momentum between its spin and orbital form takes place. The interaction between an evanescent wave propagating at the interface of two immiscible fluids and an isolated droplet is considered. The elliptical motion of the fluid supporting the incident wave is associated with a simple state of spin angular momentum, a quantity recently introduced for acoustic waves in the literature. We experimentally observe that this field predo…

This https://arxiv.org/abs/2403.12444 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_nli…

Weakly nonlinear analysis of Turing pattern dynamics on curved surfaces
Pattern dynamics on curved surfaces are ubiquitous. Although the effect of surface topography on pattern dynamics has gained much interest, there is a limited understanding of the roles of surface geometry and topology in pattern dynamics. Recently, we reported that a static pattern on a flat plane can become a propagating pattern on a curved surface [Nishide and Ishihara, Phys. Rev. Lett. 2022]. By examining reaction-diffusion equations on axisymmetric surfaces, certain conditions for the onse…

Transformation and amplification of light in optical waveguides and resonators modulated by a low frequency traveling wave
M. Sumetsky
https://arxiv.org/abs/2402.19117

Transformation and amplification of light in optical waveguides and resonators modulated by a low frequency traveling wave
We investigate the transformation and amplification of a light wave with phase velocity $v$ and frequency $ω$ propagating through an optical waveguide and a racetrack resonator parametrically modulated by a travelling wave with phase velocity $v_p$ and frequency $ω_p \ll ω$. We consider the propagation within a small bandwidth $Δω\ll ω$ where the waveguide is assumed to be dispersionless and low loss. Close to the luminal condition, $v_p=v$, the bandwidth of the output frequency comb spec…

A Novel Mutual Insurance Model for Hedging Against Cyber Risks in Power Systems Deploying Smart Technologies
Pikkin Lau, Lingfeng Wang, Wei Wei, Zhaoxi Liu, Chee-Wooi Ten
https://arxiv.org/abs/2403.11054

A Novel Mutual Insurance Model for Hedging Against Cyber Risks in Power Systems Deploying Smart Technologies
In this paper, a novel cyber-insurance model design is proposed based on system risk evaluation with smart technology applications. The cyber insurance policy for power systems is tailored via cyber risk modeling, reliability impact analysis, and insurance premium calculation. A stochastic Epidemic Network Model is developed to evaluate the cyber risk by propagating cyberattacks among graphical vulnerabilities. Smart technologies deployed in risk modeling include smart monitoring and job thread…

This https://arxiv.org/abs/2403.12442 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_nli…

Oscillatory and chaotic pattern dynamics driven by surface curvature
Patterns on curved surfaces are ubiquitous, yet the influence of surface geometry on pattern dynamics remains elusive. We recently reported a new mechanism of pattern propagation in which a static pattern on a flat plane becomes a propagating pattern on a curved surface [Nishide and Ishihara, Phys. Rev. Lett. 2022]. Here, we address whether surface curvature can drive more complex pattern dynamics beyond propagation. By employing a combination of weakly nonlinear analysis and numerical simulati…

Gravitational wave luminosity distance-weighted anisotropies
A. Begnoni, L. Valbusa Dall Armi, D. Bertacca, A. Raccanelli
https://arxiv.org/abs/2404.12351 …

Gravitational wave luminosity distance-weighted anisotropies
Measurements of the luminosity distance of propagating gravitational waves can provide invaluable information on the geometry and content of our Universe. Due to the clustering of cosmic structures, in realistic situations we need to average the luminosity distance of events coming from patches inside a volume. In this work we evaluate, in a gauge-invariant and fully-relativistic treatment, the impact of cosmological perturbations on such averaging process. We find that clustering, lensing and …

Handedness manipulation of propagating antiferromagnetic magnons
Yoichi Shiota, Tomohiro Taniguchi, Daiju Hayashi, Hideki Narita, Shutaro Karube, Ryusuke Hisatomi, Takahiro Moriyama, Teruo Ono
https://arxiv.org/abs/2403.06549

Handedness manipulation of propagating antiferromagnetic magnons
Antiferromagnetic magnons possess a distinctive feature absent in their ferromagnetic counterparts: the presence of two distinct handedness modes, the right-handed (RH) and left-handed (LH) precession modes. The magnon handedness determines the sign of spin polarization carried by the propagating magnon, which is indispensable for harnessing the diverse functionalities. However, the control of coherently propagating magnon handedness in antiferromagnets has remained elusive so far. Here we demo…

Coupled Nonlinear Schr\"odinger (CNLS) Equations for two interacting electrostatic wavepackets in a non-Maxwellian fluid plasma model
N. Lazarides, Ioannis Kourakis
https://arxiv.org/abs/2403.17772

Coupled Nonlinear Schrödinger (CNLS) Equations for two interacting electrostatic wavepackets in a non-Maxwellian fluid plasma model
The nonlinear dynamics of two co-propagating electrostatic wavepackets, characterized by different wavenumbers and amplitudes, in a 1D non-magnetized plasma fluid model is considered, from first principles. The original plasma model, consisting of κ-distributed electrons evolving against a cold ion background, is reduced, by means of a multiple-scale perturbation method to a pair of asymmetric coupled nonlinear Schrödinger (CNLS) equations for the dynamics of the wavepacket envelopes. Exact…

Alfv\'en Waves at Mars
Norberto Romanelli, Christopher M. Fowler, Gina A. DiBraccio, Jared R. Espley, Jasper S. Halekas
https://arxiv.org/abs/2403.17304

Alfvén Waves at Mars
The solar wind upstream of Mars's bow shock can be described in terms of Alfvénic turbulence, with an incompressible energy cascade rate of $10^{-17}$ J m$^{-3}$ s$^{-1}$ at magnetohydrodynamics (MHD) scales. The solar wind has more Alfvén waves propagating outwards from the Sun (than inwards) and a median Alfvén ratio of $\sim0.33$. Newly ionized planetary protons associated with the extended hydrogen corona generate waves at the local proton cyclotron frequency. These 'proton cyclotron wav…

Cosmic-ray Acceleration in Core-Collapse Supernova Remnants with the Wind Termination Shock
Shoma F. Kamijima, Yutaka Ohira
https://arxiv.org/abs/2403.17335

Cosmic-ray Acceleration in Core-Collapse Supernova Remnants with the Wind Termination Shock
We investigate the attainable maximum energy of particles accelerated in the core-collapse supernova remnant (SNR) shock propagating in the free wind region with the Parker-spiral magnetic field, current sheet, and the wind termination shock (WTS) by using test particle simulations. This work focuses on Wolf-Rayet stars as progenitors. The magnetic field amplification in the free wind region (shock upstream region) is not considered in this work. Test particle simulations show that particles es…

Stable Inversion of Piecewise Affine Systems with Application to Feedforward and Iterative Learning Control
Isaac A. Spiegel, Nard Strijbosch, Robin de Rozario, Tom Oomen, Kira Barton
https://arxiv.org/abs/2404.09845

Stable Inversion of Piecewise Affine Systems with Application to Feedforward and Iterative Learning Control
Model inversion is a fundamental technique in feedforward control. Unstable inverse models present a challenge in that useful feedforward control trajectories cannot be generated by directly propagating them. Stable inversion is a process for generating useful trajectories from unstable inverses by handling their stable and unstable modes separately. Piecewise affine (PWA) systems are a popular framework for modeling complicated dynamics. The primary contributions of this article are closed-for…

This https://arxiv.org/abs/2309.08045 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_csNE_…

Traveling Waves Encode the Recent Past and Enhance Sequence Learning
Traveling waves of neural activity have been observed throughout the brain at a diversity of regions and scales; however, their precise computational role is still debated. One physically inspired hypothesis suggests that the cortical sheet may act like a wave-propagating system capable of invertibly storing a short-term memory of sequential stimuli through induced waves traveling across the cortical surface, and indeed many experimental results from neuroscience correlate wave activity with me…

A Categorical Treatment of Open Linear Systems
Dario Stein, Richard Samuelson
https://arxiv.org/abs/2403.03934 https://arxiv.org/pdf/…

A Categorical Treatment of Open Linear Systems
An open stochastic system à la Willems is a system affected two qualitatively different kinds of uncertainty -- one is probabilistic fluctuation, and the other one is nondeterminism caused by lack of information. We give a formalization of open stochastic systems in the language of category theory. A new construction, which we term copartiality, is needed to model the propagating lack of information (which corresponds to varying sigma-algebras). As a concrete example, we discuss extended Gau…

Emission of fast-propagating spin waves by an antiferromagnetic domain wall driven by spin current
Roman V. Ovcharov, B. A. Ivanov, Johan \r{A}kerman, Roman S. Khymyn
https://arxiv.org/abs/2403.13949

Emission of fast-propagating spin waves by an antiferromagnetic domain wall driven by spin current
Antiferromagnets (AFMs) have great benefits for spintronic applications such as high frequencies (up to THz), high speeds (up to tens of km/s) of magnetic excitations, and field-free operation. Advanced devices will require high-speed propagating spin waves (SWs) as signal carriers, i.e., SWs with high k-vectors, the excitation of which remains challenging. We show that a domain wall (DW) in anisotropic AFM driven by the spin current can be a source of such propagating SWs with high frequencies…

Multimode Interferometers: an Analytical Method for Determining the Accumulated Phase Difference Between the Fundamental Mode and One Arbitrary High-Order Mode
Yuri Hayashi Isayama
https://arxiv.org/abs/2402.18408

Multimode Interferometers: an Analytical Method for Determining the Accumulated Phase Difference Between the Fundamental Mode and One Arbitrary High-Order Mode
In multimode interferometers, the interaction between several modes brings a high level of complexity to the interpretation of its light patterns. With recent advances, it is possible to selectively excite only a couple of modes inside the device. This paper presents an analytical method for determining the phase difference between two propagating modes in the multimode interferometer, in an effort to simplify the usage and expand the range of applications for this type of optical devices.

Laser cooling $^{88}$Sr to microkelvin temperature with an integrated-photonics system
Andrew R. Ferdinand, Zheng Luo, Sindhu Jammi, Zachary Newman, Grisha Spektor, Okan Koksal, Parth B. Patel, Daniel Sheredy, William Lunden, Akash Rakholia, Travis C. Briles, Wenqi Zhu, Martin M. Boyd, Amit Agrawal, Scott B. Papp
https://arxiv.org/abs/2404.13210 https://arxiv.org/pdf/2404.13210
arXiv:2404.13210v1 Announce Type: new
Abstract: We report on experiments generating a magneto-optical trap (MOT) of 88-strontium ($^{88}$Sr) atoms at microkelvin temperature, using integrated-photonics devices. With metasurface optics integrated on a fused-silica substrate, we generate six-beam, circularly polarized, counter-propagating MOTs on the blue broad-line, 461 nm, and red narrow-line, 689 nm, Sr cooling transitions without bulk optics. By use of a diverging beam configuration, we create up to 10 mm diameter MOT beams at the trapping location. To frequency stabilize and linewidth narrow the cooling lasers, we use fiber-packaged, integrated nonlinear waveguides to spectrally broaden a frequency comb. The ultra-coherent supercontinuum of the waveguides covers 650 nm to 2500 nm, enabling phase locks of the cooling lasers to hertz level linewidth. Our work highlights the possibility to simplify the preparation of an ultracold 88Sr gas for an optical-lattice clock with photonic devices. By implementing a timing sequence for control of the MOT lasers and the quadrupole magnetic-field gradient, we collect atoms directly from a thermal beam into the blue MOT and continuously cool into a red MOT with dynamic detuning and intensity control. There, the red MOT temperature is as low as $2~{\mu}$K and the overall transfer efficiency up to 16%. We characterize this sequence, including an intermediate red MOT with modulated detuning. Our experiments demonstrate an integrated photonics system capable of cooling alkaline-earth gases to microkelvin temperature with sufficient transfer efficiencies for adoption in scalable optical clocks and quantum sensors.

This https://arxiv.org/abs/2310.19533 has been replaced.
initial toot: https://mastoxiv.page/@ar…

Role of wave scattering in instability-induced Langmuir circulation
We consider a classical problem about dynamic instability that leads to the Langmuir circulation. The problem statement assumes that there is initially a wind-driven shear flow and a plane surface wave propagating in the direction of the flow. The unstable mode is a superposition of i) shear flow and ii) surface waves both modulated in the horizontal spanwise direction and iii) circulation that is made up with vortices forming near-surface rolls whose axis are coaligned along the shear flow str…

Handedness manipulation of propagating antiferromagnetic magnons
Yoichi Shiota, Tomohiro Taniguchi, Daiju Hayashi, Hideki Narita, Shutaro Karube, Ryusuke Hisatomi, Takahiro Moriyama, Teruo Ono
https://arxiv.org/abs/2403.06549

Handedness manipulation of propagating antiferromagnetic magnons
Antiferromagnetic magnons possess a distinctive feature absent in their ferromagnetic counterparts: the presence of two distinct handedness modes, the right-handed (RH) and left-handed (LH) precession modes. The magnon handedness determines the sign of spin polarization carried by the propagating magnon, which is indispensable for harnessing the diverse functionalities. However, the control of coherently propagating magnon handedness in antiferromagnets has remained elusive so far. Here we demo…

Magnetically propagating Hund's exciton in van der Waals antiferromagnet NiPS3
W. He, Y. Shen, K. Wohlfeld, J. Sears, J. Li, J. Pelliciari, M. Walicki, S. Johnston, E. Baldini, V. Bisogni, M. Mitrano, M. P. M. Dean
https://arxiv.org/abs/2404.10827

Magnetically propagating Hund's exciton in van der Waals antiferromagnet NiPS3
Magnetic van der Waals (vdW) materials have opened new frontiers for realizing novel many-body phenomena. Recently NiPS3 has received intense interest since it hosts an excitonic quasiparticle whose properties appear to be intimately linked to the magnetic state of the lattice. Despite extensive studies, the electronic character, mobility, and magnetic interactions of the exciton remain unresolved. Here we address these issues by measuring NiPS3 with ultra-high energy resolution resonant inelas…

This https://arxiv.org/abs/2310.19533 has been replaced.
initial toot: https://mastoxiv.page/@ar…

Role of wave scattering in instability-induced Langmuir circulation
We consider a classical problem about dynamic instability that leads to the Langmuir circulation. The problem statement assumes that there is initially a wind-driven shear flow and a plane surface wave propagating in the direction of the flow. The unstable mode is a superposition of i) shear flow and ii) surface waves both modulated in the horizontal spanwise direction and iii) circulation that is made up with vortices forming near-surface rolls whose axis are coaligned along the shear flow str…

Interference patterns of propagating spin wave in spin Hall oscillator arrays
Mohammad Haidar
https://arxiv.org/abs/2403.15060 https://

Interference patterns of propagating spin wave in spin Hall oscillator arrays
In this study, we discuss the observation of spin wave interference generated by magnetic oscillators. We employ micromagnetic simulations for two coherent spin Hall nanowire oscillators positioned nearby, horizontally or vertically. The two nanowires produce circular waves with short wavelengths on the order of 100 nm, which interfere with each other. In the horizontal configuration, the spin waves exhibit constructive and destructive fringes, indicating amplification or cancellation of the am…

Modulational electrostatic wave-wave interactions in plasma fluids modeled by asymmetric coupled nonlinear Schr\"odinger (CNLS) equations
N. Lazarides, Giorgos P. Veldes, Amaria Javed, Ioannis Kourakis
https://arxiv.org/abs/2403.16715

Modulational electrostatic wave-wave interactions in plasma fluids modeled by asymmetric coupled nonlinear Schrödinger (CNLS) equations
The interaction between two co-propagating electrostatic wavepackets characterized by arbitrary carrier wavenumber is considered. A one-dimensional (1D) non-magnetized plasma model is adopted, consisting of a cold inertial ion fluid evolving against a thermalized (Maxwell-Boltzmann distributed) electron background. A multiple-scale perturbation method is employed to reduce the original model equations to a pair of coupled nonlinear Schrödinger (CNLS) equations governing the dynamics of the wav…

Discovering Command and Control (C2) Channels on Tor and Public Networks Using Reinforcement Learning
Cheng Wang, Christopher Redino, Abdul Rahman, Ryan Clark, Daniel Radke, Tyler Cody, Dhruv Nandakumar, Edward Bowen
https://arxiv.org/abs/2402.09200

Discovering Command and Control (C2) Channels on Tor and Public Networks Using Reinforcement Learning
Command and control (C2) channels are an essential component of many types of cyber attacks, as they enable attackers to remotely control their malware-infected machines and execute harmful actions, such as propagating malicious code across networks, exfiltrating confidential data, or initiating distributed denial of service (DDoS) attacks. Identifying these C2 channels is therefore crucial in helping to mitigate and prevent cyber attacks. However, identifying C2 channels typically involves a m…

This https://arxiv.org/abs/2402.01042 has been replaced.
link: https://scholar.google.com/scholar?q=a

Nonlinear electrodynamics for the vacuum of Dirac materials. Photon magnetic properties and radiation pressures
We investigate the magnetic properties of photons propagating through Dirac materials in the presence of a magnetic field, taking into account both medium and vacuum contributions. The vacuum photon propagation properties are obtained through a second-order expansion of nonlinear Euler-Heisenberg electrodynamics considering Dirac material parameters (effective structure constant, band gap and Fermi velocity, respectively). Total magnetization and effective magnetic moment are obtained. Observab…

This https://arxiv.org/abs/2403.12680 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

Plasma motions and compressive wave energetics in the solar corona and solar wind from radio wave scattering observations
Radio signals propagating via the solar corona and solar wind are significantly affected by compressive waves, impacting properties of solar bursts as well as sources viewed through the turbulent solar atmosphere. While static fluctuations scatter radio waves elastically, moving, turbulent or oscillating density irregularities act to broaden the frequency of the scattered waves. Using a new anisotropic density fluctuation model from the kinetic scattering theory for solar radio bursts, we deduc…

Simulation of radio signals from cosmic-ray cascades in air and ice as observed by in-ice Askaryan radio detectors
Simon De Kockere, Dieder Van den Broeck, Uzair Abdul Latif, Krijn D. de Vries, Nick van Eijndhoven, Tim Huege, Stijn Buitink
https://arxiv.org/abs/2403.15358

Simulation of radio signals from cosmic-ray cascades in air and ice as observed by in-ice Askaryan radio detectors
A new generation of neutrino observatories, including RNO-G and RET, will search for PeV-EeV neutrinos interacting in the ice by detecting radio pulses. Extended air showers propagating into the ice will form an important background and could be a valuable calibration signal. We present results from a Monte-Carlo simulation framework developed to fully simulate radio emission from cosmic-ray particle cascades as observed by in-ice radio detectors in the polar regions. The framework involves a m…

This https://arxiv.org/abs/2404.05592 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_grqc_…

Unruh-DeWitt Particle Detectors in Bouncing Cosmologies
We study semi-classical particle production in non-singular bouncing cosmologies by employing the Unruh-DeWitt model of a particle detector propagating in this class of spacetimes. The scale factor for the bouncing cosmology is derived analytically and is inspired by the modified Friedmann equation employed in the loop quantum cosmology literature. We examine how the detector response varies with the free parameters in this model such as the equation of state during the contraction phase and th…

Characterization of Turbulent Fluctuations in the Sub-Alfvenic Solar Wind
Gary P. Zank, Lingling Zhao, Laxman Adhikari, Daniele Telloni, Prashant Baruwal, Prashrit Baruwal, Xingyu Zhu, Masaru Nakanotani, Alexander Pitna, Justin C. Kasper, Stuart D. Bale
https://arxiv.org/abs/2403.14861 <…

Characterization of Turbulent Fluctuations in the Sub-Alfvenic Solar Wind
Parker Solar Probe (PSP) observed sub-Alfvenic solar wind intervals during encounters 8 - 14, and low-frequency magnetohydrodynamic turbulence in these regions may differ from that in super-Alfvenic wind. We apply a new mode-decomposition analysis (Zank et al 2023) to the sub-Alfvénic flow observed by PSP on 2021 April 28, identifying and characterizing entropy, magnetic islands, forward and backward Alfvén waves, including weakly/non-propagating Alfvén vortices, forward and backward fast an…

Bell Instability-Mediated Diffusive Shock Acceleration at Supernova Blast Wave Shock Propagating in the ISM
Tsuyoshi Inoue, Alexandre Marcowith, Gwenael Giacinti
https://arxiv.org/abs/2404.03903

Bell Instability-Mediated Diffusive Shock Acceleration at Supernova Blast Wave Shock Propagating in the ISM
Supernova blast wave shock is a very important site of cosmic-ray acceleration. However, the detailed physical process of acceleration, in particular, non-linear interplay between cosmic-ray streaming and magnetic field amplification has not been studied under a realistic environment. In this paper, using a unique and novel numerical method, we study cosmic-ray acceleration at supernova blast wave shock propagating in the interstellar medium with well-resolved magnetic field amplification by no…

Coupled circularly polarized electromagnetic soliton states in magnetized plasmas
G. P. Veldes, N. Lazarides, D. J. Frantzeskakis, I. Kourakis
https://arxiv.org/abs/2403.15005

Coupled circularly polarized electromagnetic soliton states in magnetized plasmas
The interaction between two co-propagating electromagnetic pulses in a magnetized plasma is considered, from first principles, relying on a fluid-Maxwell model. Two circularly polarized wavepackets by same group velocities are considered, characterized by opposite circular polarization, to be identified as left-hand- or right hand circularly polarized (i.e. LCP or RCP, respectively). A multiscale perturbative technique is adopted, leading to a pair of coupled nonlinear Schrodinger-type (NLS) eq…

Non-linear media in weakly curved spacetime: optical solitons and probe pulses for gravimetry
Alessio Belenchia, Felix Spengler, Dennis R\"atzel, Daniel Braun
https://arxiv.org/abs/2402.09930

Non-linear media in weakly curved spacetime: optical solitons and probe pulses for gravimetry
That light propagating in a gravitational field gets frequency-shifted is one of the basic consequences of any metric theory of gravity rooted in the equivalence principle. At the same time, also a time dependent material's refractive index can frequency-shift light propagating in it. The mathematical analogy between the two effects is such that the latter has been used to study the optical analogue of a black-hole spacetime. Here, we combine these two effects by showing that light propagation …

This https://arxiv.org/abs/2402.01042 has been replaced.
link: https://scholar.google.com/scholar?q=a

Nonlinear electrodynamics for the vacuum of Dirac materials. Photon magnetic properties and radiation pressures
We investigate the magnetic properties of photons propagating through Dirac materials in the presence of a magnetic field, taking into account both medium and vacuum contributions. The vacuum photon propagation properties are obtained through a second-order expansion of nonlinear Euler-Heisenberg electrodynamics considering Dirac material parameters (effective structure constant, band gap and Fermi velocity, respectively). Total magnetization and effective magnetic moment are obtained. Observab…

This https://arxiv.org/abs/2401.04977 has been replaced.
initial toot: https://mastoxiv.page/@ar…

Nonreciprocal spontaneous parametric process
Mediated by the interaction with quantum vacuum fields, a laser field propagating in a nonlinear optical medium can generate new light fields via spontaneous parametric process. Such process is inherent independent of the propagation direction of light and reciprocal thus far, due to the direction-independent field-vacuum interaction. In this work, we experimentally demonstrate a nonreciprocal spontaneous parametric four-wave mixing process in sodium atomic vapors with dispersive nonlinearity a…

This https://arxiv.org/abs/2401.02392 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

Long-term Evolution of Relativistic Unmagnetized Collisionless Shocks
We study a relativistic collisionless electron-positron shock propagating into an unmagnetized ambient medium using 2D particle-in-cell simulations of unprecedented duration and size. The shock generates intermittent magnetic structures of increasingly larger size as the simulation progresses. Toward the end of our simulation, at around 26,000 plasma times, the magnetic coherence scale approaches $λ\sim 100$ plasma skin depths, both ahead and behind the shock front. We anticipate a continued g…

Observations of Locally Excited Waves in the Low Solar Atmosphere Using the Daniel K. Inouye Solar Telescope (DKIST)
Shah Mohammad Bahauddin, Catherine E. Fischer, Mark P. Rast, Ivan Milic, Friedrich Woeger, Matthias Rempel, Peter H. Keys, Thomas R. Rimmele
https://arxiv.org/abs/2403.13987…

Observations of Locally Excited Waves in the Low Solar Atmosphere Using the Daniel K. Inouye Solar Telescope (DKIST)
We present an interpretation of the recent Daniel K. Inouye Solar Telescope (DKIST) observations of propagating wavefronts in the lower solar atmosphere. Using MPS/University of Chicago MHD (MURaM) radiative magnetohydrodynamic simulations spanning solar photosphere, overshoot region, and lower chromosphere, we identify three acoustic-wave source mechanisms, each occurring at a different atmospheric height. We synthesize the DKIST Visible Broadband Imager (VBI) G-band, blue-continuum, and CaIIK…

Environmental monitoring using orbital angular momentum mode decomposition enhanced machine learning
Zhaozhong Chen, Ultan Daly, Aleksandr Boldin, Lenny Hirsch, Mingjian Cheng, Martin P. J. Lavery
https://arxiv.org/abs/2403.19179

Environmental monitoring using orbital angular momentum mode decomposition enhanced machine learning
Atmospheric interaction with light has been an area of fascination for many researchers over the last century. Environmental conditions, such as temperature and wind speed, heavily influence the complex and rapidly varying optical distortions propagating optical fields experience. The continuous random phase fluctuations commonly make deciphering the exact origins of specific optical aberrations challenging. The generation of eddies is a major contributor to atmospheric turbulence, similar in g…

Environmental monitoring using orbital angular momentum mode decomposition enhanced machine learning
Zhaozhong Chen, Ultan Daly, Aleksandr Boldin, Lenny Hirsch, Mingjian Cheng, Martin P. J. Lavery
https://arxiv.org/abs/2403.19179

Environmental monitoring using orbital angular momentum mode decomposition enhanced machine learning
Atmospheric interaction with light has been an area of fascination for many researchers over the last century. Environmental conditions, such as temperature and wind speed, heavily influence the complex and rapidly varying optical distortions propagating optical fields experience. The continuous random phase fluctuations commonly make deciphering the exact origins of specific optical aberrations challenging. The generation of eddies is a major contributor to atmospheric turbulence, similar in g…

Radio surface fluctuations in radio relics
Paola Dom\'inguez-Fern\'andez, Dongsu Ryu, Hyesung Kang
https://arxiv.org/abs/2402.12375 https://…

Radio surface fluctuations in radio relics
Recent observations have revealed detailed structures of radio relics in a wide range of frequencies. In this work, we perform three-dimensional magnetohydrodynamical simulations of merger shocks propagating through a turbulent magnetized intracluster medium, and employ on-the-fly Lagrangian particles to explore the physical processes originating radio substructures and their appearances in high and low-frequency observations. We employ two cosmic-ray (CR) electron acceleration models: the fres…

Plasma motions in the solar corona and solar wind to 1 au, as inferred from radio wave scattering observations
Francesco Azzollini, A. Gordon Emslie, Daniel L. Clarkson, Nicolina Chrysaphi, Eduard P. Kontar
https://arxiv.org/abs/2403.12680

Plasma motions in the solar corona and solar wind to 1 au, as inferred from radio wave scattering observations
Radio signals propagating via the solar corona and solar wind are significantly affected by compressive waves, impacting solar burst properties as well as sources viewed through the turbulent atmosphere. While static fluctuations scatter radio waves elastically, moving, turbulent or oscillating density irregularities act to broaden the frequency of the scattered waves. Using a new anisotropic density fluctuation model based on solar radio bursts, we deduce the plasma velocities required to expl…

An efficient multimode vectorial nonlinear propagation solver beyond the weak guidance approximation
Pierre B\'ejot
https://arxiv.org/abs/2402.16492 ht…

An efficient multimode vectorial nonlinear propagation solver beyond the weak guidance approximation
In this article, we present an efficient numerical model able to solve the vectorial nonlinear pulse propagation equation in circularly symmetric multimode waveguides. The algorithm takes advantage of the conservation of total angular momentum of light upon propagation and takes into account the vectorial nature of the propagating modes, making it particularly relevant for studies in ring-core fibers. While conventional propagation solvers exhibit a computational complexity scaling as N^4_{mode…

Radio surface fluctuations in radio relics
Paola Dom\'inguez-Fern\'andez, Dongsu Ryu, Hyesung Kang
https://arxiv.org/abs/2402.12375 https://…

Radio surface fluctuations in radio relics
Recent observations have revealed detailed structures of radio relics in a wide range of frequencies. In this work, we perform three-dimensional magnetohydrodynamical simulations of merger shocks propagating through a turbulent magnetized intracluster medium, and employ on-the-fly Lagrangian particles to explore the physical processes originating radio substructures and their appearances in high and low-frequency observations. We employ two cosmic-ray (CR) electron acceleration models: the fres…

This https://arxiv.org/abs/2404.07740 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

The solar dynamo begins near the surface
The Sun's magnetic dynamo cycle features a distinct pattern: a propagating region of sunspot emergence appears around 30 degrees latitude and vanishes near the equator every 11 years. Moreover, longitudinal flows called ``torsional oscillations" closely shadow sunspot migration, undoubtedly sharing a common. Contrary to theories suggesting deep origins for these phenomena, helioseismology pinpoints low-latitude torsional oscillations to the Sun's outer 5-10 percent, the ``Near-Surface Shear Lay…

This https://arxiv.org/abs/2403.09834 has been replaced.
initial toot: https://mastoxiv.page/@ar…

Area theorem for surface plasmons interacting of with resonant atoms
We show how the area theorem is applicable to the analytical description of the nonlinear interaction of surface plasmon modes with resonant two-level atoms. A closed analytical solution is obtained, which shows that surface plasmons can form long-propagating $2π$ pulses when interacting with an optically dense two-level atomic ensemble. The possible applications of the surface pulse area theorem and the conditions for the detection of $2π$ surface plasmon pulses are discussed.

This https://arxiv.org/abs/2403.06422 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

Bounding the Photon Mass with Ultra-Wide Bandwidth Pulsar Timing Data and De-dispersed Pulses of Fast Radio Bursts
Exploring the concept of a massive photon has been an important area in astronomy and physics. If photons have mass, their propagation in non-vacuum space would be affected by both the non-zero mass $m_γ$ and the presence of a plasma medium. This would lead to a delay time proportional to $m_γ^2ν^{-4}$, which deviates from the classical dispersion relation (proportional to $ν^{-2}$). For the first time, we have derived the dispersion relation of a photon with a non-zero mass propagating in …

Observation of Alfv\'en Wave Reflection in the Solar Chromosphere: Ponderomotive Force and First Ionization Potential Effect
Mariarita Murabito, Marco Stangalini, J. Martin Laming, Deborah Baker, Andy S. H. To, David M. Long, David H. Brooks, Shahin Jafarzadeh, David B. Jess, Gherardo Valori
https://arxiv.org/abs/2404.08305<…

Observation of Alfvén Wave Reflection in the Solar Chromosphere: Ponderomotive Force and First Ionization Potential Effect
We investigate the propagation of Alfvén waves in the solar chromosphere, distinguishing between upward and downward propagating waves. We find clear evidence for the reflection of waves in the chromosphere and differences in propagation between cases with waves interpreted to be resonant or nonresonant with the overlying coronal structures. This establishes the wave connection to coronal element abundance anomalies through the action of the wave ponderomotive force on the chromospheric plasma…

This https://arxiv.org/abs/2403.06422 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

Bounding the Photon Mass with Ultra-Wide Bandwidth Pulsar Timing Data and De-dispersed Pulses of Fast Radio Bursts
Exploring the concept of a massive photon has been an important area in astronomy and physics. If photons have mass, their propagation in non-vacuum space would be affected by both the non-zero mass $m_γ$ and the presence of a plasma medium. This would lead to a delay time proportional to $m_γ^2ν^{-4}$, which deviates from the classical dispersion relation (proportional to $ν^{-2}$). For the first time, we have derived the dispersion relation of a photon with a non-zero mass propagating in …

Tracking solar radio bursts using Bayesian multilateration
L. A. Ca\~nizares, S. T. Badman, S. A. Maloney, M. J. Owens, D. M. Weigt, E. P. Carley, P. T. Gallagher
https://arxiv.org/abs/2402.08590

Tracking solar radio bursts using Bayesian multilateration
Solar radio bursts (SRBs), are emitted by electrons propagating through the corona and interplanetary space. Tracking such bursts is key to understanding the properties of accelerated electrons and radio wave propagation as well as the local plasma environment that they propagate through. Here, we present a novel multilateration algorithm called BayEsian LocaLisation Algorithm (BELLA). In addition, apparent SRB positions from BELLA are compared with comparable localisation methods and the predi…

This https://arxiv.org/abs/2403.01054 has been replaced.
link: https://scholar.google.com/scholar?q=a

Quantum theory of orbital angular momentum in spatiotemporal optical vortices
Spatiotemporal Optical Vortices (STOVs) are structured electromagnetic fields propagating in free space with phase singularities in the space-time domain. Depending on the tilt of the helical phase front, STOVs can carry both longitudinal and transverse orbital angular momentum (OAM). Although STOVs have gained significant interest in the recent years, the current understanding is limited to the semi-classical picture. Here, we develop a quantum theory for STOVs with an arbitrary tilt, extendin…

Probability of high intensities of the light wave propagating in turbulent atmosphere
Igor V. Kolokolov, Vladimir V. Lebedev
https://arxiv.org/abs/2403.03738

Probability of high intensities of the light wave propagating in turbulent atmosphere
We examine statistics of fluctuations of the laser beam intensity at its propagating in turbulent atmosphere. We are interested in relatively large propagating distances and the remote tail of the probability density function. The tail is determined by the stretched exponent, we find its index.