Tootfinder

Polar Bear's Cafe, episode 32.
#Gentoo

The first case of a walrus dying from bird flu has been detected on one of Norway’s Arctic islands, a researcher has said.
The walrus was found last year on Hopen island in the Svalbard archipelago, Christian Lydersen, of the Norwegian Polar Institute, told AFP.
Tests carried out by a German laboratory revealed the presence of bird flu, Lydersen said. The sample was too small to determine whether it was the H5N1 or the H5N8 strain.
“It is the first time that bird flu has be…

Polar: Premium-Uhr Grit X2 Pro mit neuen Funktionen und mehr Leistung
Die Polar-Smartwatch für Outdoor-Enthusiasten erhält eine Breadcrumb-Navigation und Strava-Routen. Das AMOLED lässt sich auch als Taschenlampe nutzen.

Phase transition and polar cluster behavior above Curie temperature in ferroelectric BaTi$_{0.8}$Zr$_{0.2}$O$_3$
Oktay Aktas, Francisco Javier Romero, Zhengwang He, Gan Linyu, Xiangdong Ding, Jos\'e-Mar\'ia Mart\'in-Olalla, Maria-Carmen Gallardo, Turab Lookman
https://arxiv.org/abs/2404.19558

Phase transition and polar cluster behavior above Curie temperature in ferroelectric BaTi$_{0.8}$Zr$_{0.2}$O$_3$
We study the phase transition behavior of the ferroelectric BaTi$_{0.8}$Zr$_{0.2}$O$_3$ in the paraelectric region. The temperature dependencies of thermal, polar, elastic and dielectric properties indicate the presence of local structures above the paraelectric-ferroelectric transition temperature Tc = 292 K. The non-zero remnant polarization is measured up to a characteristic temperature T* ~350 K, which coincides with the temperature where the dielectric constant deviates from Curie-Weiss la…

This https://arxiv.org/abs/2305.05637 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

Signed tropicalization of polar cones
We study the tropical analogue of the notion of polar of a cone, working over the semiring of tropical numbers with signs. We characterize the cones which arise as polars of sets of tropically nonnegative vectors by an invariance property with respect to a tropical analogue of Fourier-Motzkin elimination. We also relate tropical polars with images by the nonarchimedean valuation of classical polars over real closed nonarchimedean fields and show, in particular, that for semi-algebraic sets over…

Two-axis twisting using Floquet-engineered XYZ spin models with polar molecules
Calder Miller, Annette N. Carroll, Junyu Lin, Henrik Hirzler, Haoyang Gao, Hengyun Zhou, Mikhail D. Lukin, Jun Ye
https://arxiv.org/abs/2404.18913

Two-axis twisting using Floquet-engineered XYZ spin models with polar molecules
Polar molecules confined in an optical lattice are a versatile platform to explore spin-motion dynamics based on strong, long-range dipolar interactions. The precise tunability of Ising and spin-exchange interactions with both microwave and dc electric fields makes the molecular system particularly suitable for engineering complex many-body dynamics. Here, we used Floquet engineering to realize interesting quantum many-body systems of polar molecules. Using a spin encoded in the two lowest rota…

An Eccentric Planet Orbiting the Polar V808 Aurigae
McKenna Leichty, Peter Garnavich, Colin Littlefield, Axel D. Schwope, Jan Kurpas, Paul A. Mason, Klaus Beuermann
https://arxiv.org/abs/2402.16959

An Eccentric Planet Orbiting the Polar V808 Aurigae
We analyze 15 years of eclipse timings of the polar V808 Aur. The rapid ingress/egress of the white dwarf and bright accretion region provide timings as precise as a few tenths of a second for rapid cadence photometric data. We find that between 2015 and 2018, the eclipse timings deviated from a linear ephemeris by more than 30 s. The rapid timing change is consistent with the periastron passage of a planet in an eccentric orbit about the polar. The best fit orbital period is 11$\pm 1$ yr and w…

This https://arxiv.org/abs/2401.09829 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

Polarized QED Cascades over Pulsar Polar Caps
The formation of $e^\pm$ plasmas within pulsar magnetospheres through quantum electrodynamics (QED) cascades in vacuum gaps is widely acknowledged. This paper aims to investigate the effect of photon polarization during the QED cascade occurring over the polar cap of a pulsar. We employ a Monte Carlo-based QED algorithm that accurately accounts for both spin and polarization effects during photon emission and pair production in both single-particle and particle-in-cell (PIC) simulations. Our fi…

Deformed neutron stars
Jonathan Tejeda Quartuccio, Pedro Henrique Ribeiro da Silva Moraes, Jos\'e Domingo Arba\~nil Vela
https://arxiv.org/abs/2402.18550

Deformed neutron stars
We present solutions for non-spherically symmetric neutron stars. We begin by deriving the Tolman-Oppenheimer-Volkoff equations from a parameterized metric that takes into account the deformation of the star due to differences in equatorial and polar pressures, expressed in terms of a parameter D, which is the ratio between polar and equatorial radius. The stellar structure is solved using the GM1 equation of state and the Tolman-Oppenheimer-Volkoff equations for deformed objects are numericall…

Real-fluid Transport Property Computations Based on the Boltzmann-weighted Full-dimensional Potential Model
Xin Zhang, Junfeng Bai, Bowen Liu, Tong Zhu, Hao Zhao
https://arxiv.org/abs/2404.18700 https://arxiv.org/pdf/2404.18700
arXiv:2404.18700v1 Announce Type: new
Abstract: The intermolecular potential plays crucial roles in real-fluid interactions away from the ideal-gas equilibrium, such as supercritical fluid, high-enthalpy fluid, plasma interactions, etc. We propose a Boltzmann-weighted Full-dimensional (BWF) potential model for real-fluid computations. It includes diverse intermolecular interactions so as to determine the potential well, molecular diameter, dipole moment, polarizability of species without introducing bath gases, allowing more accurate descriptions of potential surfaces with more potential parameters. The anisotropy and temperature dependence of potential parameters are also considered by applying the Boltzmann weighting on all orientations. Through the high-level Symmetry-Adapted Perturbation Theory calculations, full-dimensional potential energy surface datasets are obtained in 432 orientations for each species. Subsequently, the Boltzmann-weighted Full-dimensional potential parameters are derived by training the dataset exceeding 5*106 data, including nonpolar and polar molecules, radicals, long-chain molecules, and ions. These BWF transport properties calculated by the BWF potential have been compared against the Lennard-Jones transport properties as well as experimental viscosity, mass diffusivity, and thermal conductivity coefficients. It shows discrepancies of viscosity coefficients within 1% and 5% for nonpolar and polar molecules, respectively. Furthermore, this potential model is applied to study radicals, long-chain molecules, and ions, for which the experimental data is rarely accessed in high accuracy. It indicates significant prediction improvements of complex interactions between various particles. The new transport properties are also embedded to predict the laminar flame speeds and the flame extinction limits of methane, dimethyl ether, and n-heptane at elevated pressures, confirming its predictivity and effectiveness.

This https://arxiv.org/abs/2206.10405 has been replaced.
link: https://scholar.google.com/scholar?q=a

Typhon: a polar stream from the outer halo raining through the Solar neighborhood
We report on the discovery in the Gaia DR3 astrometric and spectroscopic catalog of a new polar stream that is found as an over-density in action space. This structure is unique as it has an extremely large apocenter distance, reaching beyond 100 kpc, and yet is detected as a coherent moving structure in the Solar neighborhood with a width of $\sim 4$ kpc. A sub-sample of these stars that was fortuitously observed by LAMOST has a mean spectroscopic metallicity of $\langle {\rm [Fe/H]}\rangle = …

Pizzlyberen! Ik ben meteen fan. https://social.rebellion.global/@ExtinctionR/112352762245271137

Extinction Rebellion Global (@ExtinctionR@social.rebellion.global)
Attached: 1 image A melting Arctic is driving polar bears South in search of food while grizzly bears are moving North. In some cases they have mated producing a fertile hybrid called a "pizzly" bear. #climate #ClimateCollapse #environment https://www.loe.org/shows/segments.html?programID=21-P13-00041&segmentID=5

Phase diagrams and polarization reversal in nanosized HfxZr1-xO2-y
Eugene A. Eliseev, Yuri O. Zagorodniy, Victor N. Pavlikov, Oksana V. Leshchenko, Hanna V. Shevilakova, M. V. Karpec, N. I. Danilenko, Andrei D. Yaremkevych, Olena M. Fesenko, Sergei V. Kalinin, Anna N. Morozovska
https://arxiv.org/abs/2402.18336

Phase diagrams and polarization reversal in nanosized HfxZr1-xO2-y
To describe the polar properties of the nanosized HfxZr1-xO2-y, we evolve the "effective" Landau-Ginzburg-Devonshire (LGD) model based on the parametrization of the Landau expansion coefficients for the polar and antipolar orderings. We have shown that the effective LGD model can predict the influence of screening conditions and size effects on phase diagrams, polarization reversal and structural properties of the nanosized HfxZr1-xO2-y of various shape and sizes. To verify the model, we use av…

Santal\'o Geometry of Convex Polytopes
Dmitrii Pavlov, Simon Telen
https://arxiv.org/abs/2402.18955 https://arxiv.org/pdf/2402.18…

Santaló Geometry of Convex Polytopes
The Santaló point of a convex polytope is the interior point which leads to a polar dual of minimal volume. This minimization problem is relevant in interior point methods for convex optimization, where the logarithm of the dual volume is known as the universal barrier function. When translating the facet hyperplanes, the Santaló point traces out a semi-algebraic set. We describe and compute this geometry using algebraic and numerical techniques. We exploit connections with statistics, optimi…

This https://arxiv.org/abs/2311.17774 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_csIT_…

Enumeration of Minimum Weight Codewords of Pre-Transformed Polar Codes by Tree Intersection
Pre-transformed polar codes (PTPCs) form a class of codes that perform close to the finite-length capacity bounds. The minimum distance and the number of minimum weight codewords are two decisive properties for their performance. In this work, we propose an efficient algorithm for determining the number of minimum weight codewords of general PTPCs that eliminates all redundant visits to nodes of the search tree, thus reducing the computational complexity typically by several orders of magnitude…

Adaptation or Starvation? Polar Bears’ Struggle With Climate Shifts
https://scitechdaily.com/adaptation-or-starvation-polar-bears-struggle-with-climate-shifts/

Adaptation or Starvation? Polar Bears’ Struggle With Climate Shifts
More time stranded on land means greater risk of starvation for polar bears, a new study indicates. During three summer weeks, 20 polar bears closely observed by scientists tried different strategies to maintain energy reserves, including resting, scavenging, and foraging. Yet nearly all of them

Deformed neutron stars
Jonathan Tejeda Quartuccio, Pedro Henrique Ribeiro da Silva Moraes, Jos\'e Domingo Arba\~nil Vela
https://arxiv.org/abs/2402.18550

Deformed neutron stars
We present solutions for non-spherically symmetric neutron stars. We begin by deriving the Tolman-Oppenheimer-Volkoff equations from a parameterized metric that takes into account the deformation of the star due to differences in equatorial and polar pressures, expressed in terms of a parameter D, which is the ratio between polar and equatorial radius. The stellar structure is solved using the GM1 equation of state and the Tolman-Oppenheimer-Volkoff equations for deformed objects are numericall…

Observation of two-level critical-state in a van-der-Waals superconductor Pt(Bi$_{1-x}$Se$_x$)$_2$
Y. Samukawa, M. Maeda, N. Jiang, R. Nakamura, M. Watanabe, K. Takaki, Y. Moriyasu, K. Kudo, Y. Niimi
https://arxiv.org/abs/2404.19278 https://arxiv.org/pdf/2404.19278
arXiv:2404.19278v1 Announce Type: new
Abstract: Trigonal PtBi$_2$ is one of the attractive van-der-Waals materials because of the enhancement of its superconducting transition temperature $T_{\rm{c}}$ by doping chalcogen elements such as Se and Te. Recently, it has been reported that $T_{\rm{c}}$ of Pt(Bi$_{1-x}$Se$_x$)$_2$ is enhanced by a factor of 4, compared to the pristine PtBi$_2$, together with the polar-nonpolar structural phase transition. Thus, it is desirable to study electrical transport properties for this new superconducting compound. Here, we have performed magnetotransport measurements for Pt(Bi$_{1-x}$Se$_x$)$_2$ ($x$ = 0.06 and 0.08) thin-film devices and have observed a peculiar magnetoresistance where a finite hysteresis appears when the superconducting state is broken. By measuring the magnetoresistance systematically, we have attributed this magnetoresistance to the two-level critical-state where fluxons pinned in Pt(Bi$_{1-x}$Se$_x$)$_2$ play an important role.

So, where were the Spiders … https://www.esa.int/Science_Exploration/Space_Science/Mars_Express/Signs_of_spiders_from_Mars

Signs of spiders from Mars
No sign of Ziggy Stardust – but ESA’s Mars Express has snapped the telltale traces of ‘spiders’ scattered across the southern polar region of Mars.

This https://arxiv.org/abs/2404.18913 has been replaced.
initial toot: https://mastoxiv.page/@…

Two-axis twisting using Floquet-engineered XYZ spin models with polar molecules
Polar molecules confined in an optical lattice are a versatile platform to explore spin-motion dynamics based on strong, long-range dipolar interactions. The precise tunability of Ising and spin-exchange interactions with both microwave and dc electric fields makes the molecular system particularly suitable for engineering complex many-body dynamics. Here, we used Floquet engineering to realize interesting quantum many-body systems of polar molecules. Using a spin encoded in the two lowest rota…

Please will the press stop giving air time to the idiot tech-bros. I beg you! 🙏 This is the height of ridiculousness. Just stop burning carbon! 🙄
To be clear, this *will not* prevent the melting of the polar ice. It will however burn more carbon... #ClimateChange
Posting for the information (but suggest people take calming breaths while reading this garbage).

Imagine being a time metereologist and part of a task force that has to decide if and when we need a negative leap second to align our timekeeping with the Earth's rotation. A decision that could cause many critical computer systems to malfunction.

And then, because of the magnitude of that decision, being semi-relieved that the decision can be delayed by approximately 3 years because… wait for it.… the melting polar ice is slowing down the planet's rotation as it is moving mas…

This https://arxiv.org/abs/2402.18550 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_grqc_…

Deformed neutron stars
We present solutions for non-spherically symmetric neutron stars. We begin by deriving the Tolman-Oppenheimer-Volkoff equations from a parameterized metric that takes into account the deformation of the star due to differences in equatorial and polar pressures, expressed in terms of a parameter D, which is the ratio between polar and equatorial radius. The stellar structure is solved using the GM1 equation of state and the Tolman-Oppenheimer-Volkoff equations for deformed objects are numericall…

Statistical relations between spectropolarimetric observables and the polar strength of the stellar dipolar magnetic field
O. Kochukhov
https://arxiv.org/abs/2404.17517

Statistical relations between spectropolarimetric observables and the polar strength of the stellar dipolar magnetic field
Global magnetic fields of early-type stars are commonly characterised by the mean longitudinal magnetic field $\langle B_{\rm z} \rangle$ and the mean field modulus $\langle B \rangle$, derived from the circular polarisation and intensity spectra, respectively. Observational studies often report a root mean square (rms) of $\langle B_{\rm z} \rangle$ and an average value of $\langle B \rangle$. In this work, I used numerical simulations to establish statistical relationships between these cumul…

Ĉar la klimato de la Tero varmiĝas, la glacio ĉe la polusoj fandiĝas, kio vice transdonas mason de akvo al la ekvatoro, kaj do la rotacio de la Tero malrapidiĝas; fakte sufiĉe ke ni eble devos perdi sekundon iam. Ni scias kiel toleri supersekundojn - ni faris tion antaŭe kelkfoje - sed ni neniam devis faligi sekundon.
https://www.…

Tactical decompositions in finite polar spaces and non-spreading classical group actions
John Bamberg, Michael Giudici, Jesse Lansdown, Gordon F. Royle
https://arxiv.org/abs/2403.17576

Tactical decompositions in finite polar spaces and non-spreading classical group actions
For finite classical groups acting naturally on the set of points of their ambient polar spaces, the symmetry properties of \emph{synchronising} and \emph{separating} are equivalent to natural and well-studied problems on the existence of certain configurations in finite geometry. The more general class of \emph{spreading} permutation groups is harder to describe, and it is the purpose of this paper to explore this property for finite classical groups. In particular, we show that for most finit…

Alignment Transport Between Ultracold Polar Molecules
Jonathan Smucker, Jesus P\'erez-R\'ios
https://arxiv.org/abs/2402.15626 https://

Alignment Transport Between Ultracold Polar Molecules
We propose an array of ultracold polar molecules as a platform to study alignment transport between molecules. We envision a polar molecule being aligned with an intense off-resonant laser field whose alignment migrates to a nearby molecule due to dipole-dipole interactions. Our results show that the transport of the alignment is due to a complex interplay between electric field-driven excitations and dipole-dipole interactions. All mechanisms for transfer are elucidated and analyzed, and using…

Startup secures €7.6M for sand battery that can heat a small town
https://thenextweb.com/news/startup-sand-battery-funding-polar-night-finland?page=all&single=1

Startup secures €7.6M for sand battery that can heat a small town
Last month, Finnish startup Polar Night Energy announced that it is building a giant sand battery capable of heating a town of 5,000 people for up to a month. That's on a single charge.  Polar ...

This https://arxiv.org/abs/2403.02293 has been replaced.
link: https://scholar.google.com/scholar?q=a

A new HOC scheme for computation of flow and heat transfer in nonuniform polar grids
In this work, a higher order compact (HOC) discretization is developed on the nonuniform polar grid. The discretization conceptualized using the unsteady convection-diffusion equation (CDE) is further extended to flow problems governed by the Navies-Stokes (N-S) equations as well as the Boussinesq equations. The scheme developed here combines the advantages of body-fitted mesh with grid clustering, thereby making it efficient to capture flow gradients on polar grids. The scheme carries a spatia…

heise | heise Update vom 22. März 2024: Lesetipps zum Wochenende
Der wöchentliche Newsletter von heise : über Klavier lernen mit VR, eine Polar-Expedition, einen smarten Nistkasten, Heizungsförderung und Heimnetzabsicherung.

From Kharkiv to Antarctica: How Scientists of Vernadsky Research Base Study Coldest Continent : https://benborges.xyz/2024/03/24/from-kharkiv-to.html

On the Performance of Low-complexity Decoders of LDPC and Polar Codes
Qingqing Peng, Dawei Yin, Dongxu Chang, Yuan Li, Huazi Zhang, Guiying Yan, Guanghui Wang
https://arxiv.org/abs/2403.19266

On the Performance of Low-complexity Decoders of LDPC and Polar Codes
Efficient decoding is crucial to high-throughput and low-power wireless communication scenarios. A theoretical analysis of the performance-complexity tradeoff toward low-complexity decoding is required for a better understanding of the fundamental limits in the above-mentioned scenarios. This study aims to explore the performance of decoders with complexity constraints. Specifically, we investigate the performance of LDPC codes with different numbers of belief-propagation iterations and the per…

This https://arxiv.org/abs/2401.08162 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

A New Window for Studying Intermediate Polars and Tilted Accretion Disk Precession
TV Col is a long-period eclipsing intermediate polar (IPs) prototype star for the negative superhump (NSH) system. We investigate the eclipse minima, eclipse depth, and NSH amplitude based on TESS photometry. Using the same analytical method as SDSS J081256.85+191157.8, we find periodic variations of the O-C for eclipse minima and NSH amplitudes with periods of 3.939(25) d and 3.907(30) d, respectively. The periodic variation of the NSH amplitude of TV Col confirms that periodic NSH amplitude c…

This https://arxiv.org/abs/2305.06285 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

Some non-existence results on $m$-ovoids in classical polar spaces
In this paper we develop non-existence results for $m$-ovoids in the classical polar spaces $Q^-(2r+1,q), W(2r-1,q)$ and $H(2r,q^2)$ for $r>2$. In [4] a lower bound on $m$ for the existence of $m$-ovoids of $H(4,q^2)$ is found by using the connection between $m$-ovoids, two-character sets, and strongly regular graphs. This approach is generalized in [3] for the polar spaces $Q^-(2r+1,q), W(2r-1,q)$ and $H(2r,q^2)$, $r>2$. In [1] an improvement for the particular case $H(4,q^2)$ is obtained by e…

Magnetophononics and the Chiral Phonon Misnomer
R. Merlin
https://arxiv.org/abs/2404.19593 https://arxiv.org/pdf/2404.19593

Magnetophononics and the Chiral Phonon Misnomer
The direct, ultrafast excitation of polar phonons with electromagnetic radiation is a potent strategy for controlling the properties of a wide range of materials, particularly in the context of influencing their magnetic behavior. Here, we show that, contrary to common perception, the origin of phonon-induced magnetic activity does not stem from the motion of ions themselves; instead, it arises from the effect their motion exerts on the electron subsystem. Through the mechanism of electron-phon…

A reminder the joint #EC #ESA coordinated European Polar Science Week will be held in Copenhagen 3rd-6th September 2024.
You can just make it to submit a session proposal and/or poster abstract... deadline 15th March

This https://arxiv.org/abs/2305.02094 has been replaced.
initial toot: https://mastoxiv.page/@a…

Speed limits of the laser-induced phase transition in FeRh
We use ultrafast x-ray diffraction (UXRD) and the polar time-resolved magneto-optical Kerr effect (tr-MOKE) to study the laser-induced metamagnetic phase transition in two FeRh films with thicknesses below and above the optical penetration depth. In the thin film, we identify an intrinsic timescale for the light-induced nucleation of ferromagnetic (FM) domains in the antiferromagnetic material of $8\,\text{ps}$ that is substantially slower than the speed of sound. For the inhomogeneously excite…

"I have a stylish personality."
(Polar Bear Cafe, episode 19)
#Gentoo #anime

Polar breeze ❄️

On SVD and Polar Decomposition in Real and Complexified Clifford Algebras
D. S. Shirokov
https://arxiv.org/abs/2404.11920 https://arx…

On SVD and Polar Decomposition in Real and Complexified Clifford Algebras
In this paper, we present a natural implementation of singular value decomposition (SVD) and polar decomposition of an arbitrary multivector in nondegenerate real and complexified Clifford geometric algebras of arbitrary dimension and signature. The new theorems involve only operations in geometric algebras and do not involve matrix operations. We naturally define these and other related structures such as Hermitian conjugation, Euclidean space, and Lie groups in geometric algebras. The results…

This https://arxiv.org/abs/2206.05622 has been replaced.
link: https://scholar.google.com/scholar?q=a

Meromorphic Functions with a Polar Asymptotic Value
This paper is part of a general program in complex dynamics to understand parameter spaces of transcendental maps with finitely many singular values. The simplest families of such functions have two asymptotic values and no critical values. These families, up to affine conjugation, depend on two complex parameters. Understanding their parameter spaces is key to understanding families with more asymptotic values, just as understanding quadratic polynomials was for rational maps more generally.…

This https://arxiv.org/abs/2403.02293 has been replaced.
link: https://scholar.google.com/scholar?q=a

A new HOC scheme for computation of flow and heat transfer in nonuniform polar grids
In this work, a higher order compact (HOC) discretization is developed on the nonuniform polar grid. The discretization conceptualized using the unsteady convection-diffusion equation (CDE) is further extended to flow problems governed by the Navies-Stokes (N-S) equations as well as the Boussinesq equations. The scheme developed here combines the advantages of body-fitted mesh with grid clustering, thereby making it efficient to capture flow gradients on polar grids. The scheme carries a spatia…

Extremal affine surface areas in a functional setting
Stephanie Egler, Elisabeth M. Werner
https://arxiv.org/abs/2402.16130 https://a…

Extremal affine surface areas in a functional setting
We introduce extremal affine surface areas in a functional setting. We show their main properties. Among them are linear invariance, isoperimetric inequalities and monotonicity properties. We establish a new duality formula, which shows that the maximal (resp. minimal) inner affine surface area of an $s$-concave function on $\mathbb{R}^n$ equals the maximal (resp. minimal) outer affine surface area of its Legendre polar. We estimate the ``size" of these quantities: up to a constant depending on…

Emergent Anti-Ferroelectric Ordering and the Coupling of Liquid Crystalline and Polar Order
Jordan Hobbs, Calum J. Gibb, Richard. J. Mandle
https://arxiv.org/abs/2404.12271

Emergent Anti-Ferroelectric Ordering and the Coupling of Liquid Crystalline and Polar Order
Polar liquid crystals possess three dimensional orientational order coupled with unidirectional electric polarity, yielding fluid ferroelectrics. Such polar phases are generated by rod-like molecules with large electric dipole moments. 2,5-Disubstituted 1,3-dioxane is commonly employed as a polar motif in said systems, and here we show this to suffer from thermal instability as a consequence of equatorial-trans to axial-trans isomerism at elevated temperatures. We utilise isosteric building blo…

This https://arxiv.org/abs/2402.18779 has been replaced.
initial toot: https://mastoxiv.page/@a…

Nanoscale variation of the Rashba energy in BiTeI
BiTeI is a polar semiconductor with strong spin-orbit coupling (SOC) that produces large Rashba spin splitting. Due to its potential utility in spintronics and magnetoelectrics, it is essential to understand how defects impact the spin transport in this material. Using scanning tunneling microscopy and spectroscopy, we image ring-like charging states of single-atom defects on the iodine surface of BiTeI. We observe nanoscale variations in the Rashba energy around each defect, which we correlate…

The Neural Network First-Level Hardware Track Trigger of the Belle II Experiment
S. B\"ahr, H. Bae, J. Becker, M. Bertemes, M. Campajola, T. Ferber, G. Inguglia, Y. Iwasaki, T. J\"ulg, C. Kiesling, Y. -T. Lai, Y. Liu, A. Knoll, T. Koga, A. Lenz, F. Meggendorfer, H. Nakazawa, M. Neu, J. Schieck, E. Schmidt, J. -G. Shiu, S. Skambraks, K. Unger, J. Yin

The Neural Network First-Level Hardware Track Trigger of the Belle II Experiment
We describe the principles and performance of the first-level ("L1") hardware track trigger of Belle II, based on neural networks. The networks use as input the results from the standard Belle II trigger, which provides "2D" track candidates in the plane transverse to the electron-positron beams. The networks then provide estimates for the origin of the 2D track candidates in direction of the colliding beams ("$z$-vertex"), as well as their polar emission angles $θ$. Given the $z$-vertices of …

Nodal precession of a hot Jupiter transiting the edge of a late A-type star TOI-1518
Noriharu Watanabe, Norio Narita, Yasunori Hori
https://arxiv.org/abs/2402.17325

Nodal precession of a hot Jupiter transiting the edge of a late A-type star TOI-1518
TOI-1518b, a hot Jupiter around a late A-type star, is one of the few planetary systems that transit the edge of the stellar surface (the impact parameter $b\sim0.9 $) among hot Jupiters around hot stars (Cabot et al. 2021). The high rotation speed of the host star ($\sim85$ km s$^{-1}$) and the nearly polar orbit of the planet ($\sim 120$ deg) may cause a nodal precession. In this study, we report the nodal precession undergone by TOI-1518\,b. This system is the fourth planetary system in whic…

This https://arxiv.org/abs/2402.05004 has been replaced.
link: https://scholar.google.com/scholar?q=a

Near-Optimal Generalized Decoding of Polar-like Codes
We present a framework that can exploit the tradeoff between the undetected error rate (UER) and block error rate (BLER) of polar-like codes. It relies on a novel approximation that we call codebook probability, which is based on an auxiliary distribution that mimics the dynamics of decoding algorithms following a successive cancellation (SC) decoding schedule. Simulation results demonstrates that, in the case of SC list (SCL) decoding, the proposed framework outperforms the state-of-art approx…

Ultrastrong coupling between polar distortion and optical properties in ferroelectric MoBr$_2$O$_2$
Zhaojun Li, Lorenzo Varrassi, Yali Yang, Cesare Franchini, Laurent Bellaiche, Jiangang He
https://arxiv.org/abs/2402.15949

Ultrastrong coupling between polar distortion and optical properties in ferroelectric MoBr$_2$O$_2$
Tuning the properties of materials using external stimuli is crucial for developing versatile smart materials. A strong coupling among order parameters within a single-phase material constitutes a potent foundation for achieving precise property control. However, cross-coupling is pretty weak in most single materials. Leveraging first principles calculations, we demonstrate the layered mixed anion compound MoBr$_2$O$_2$ exhibits electric-field switchable spontaneous polarization and ultrastrong…

It's winter half term holiday I'm on my way to #Norway, not sadly with family but for a high level meeting of the #WMO #polar and high mountain regions committee.
Interesting important meeti…

This https://arxiv.org/abs/2403.11188 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

Designs in finite classical polar spaces
Combinatorial designs have been studied for nearly 200 years. 50 years ago, Cameron, Delsarte, and Ray-Chaudhury started investigating their $q$-analogs, also known as subspace designs or designs over finite fields. Designs can be defined analogously in finite classical polar spaces, too. The definition includes the $m$-regular systems from projective geometry as the special case where the blocks are generators of the polar space. The first nontrivial such designs for $t > 1$ were found by De…

Weekend #Plankton #Factoid 🦐🦠
For #zooplankton, there are few true rules about feeding. Herbivores will consume prey, and omnivores will consume anything they can handle - live or dead.

This https://arxiv.org/abs/2401.10198 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

Polar multiplicities and integral dependence
We provide new criteria for the integrality and birationality of an extension of graded algebras in terms of the general notion of polar multiplicities of Kleiman and Thorup. As an application, we obtain a new criterion for when a module is a reduction of another in terms of certain mixed Buchsbaum-Rim multiplicities. Furthermore, we prove several technical results regarding polar multiplicities.

Lecker 😱 Die #Arktis und #Antarktis sind nicht vor Verschmutzung durch #Mikroplastik sicher. Eine Studie zeigt, dass 13 Seevogelarten von 1983 bis 2023 Mikroplastik verschluckt haben. Am häufigste…

Seabirds from the poles: microplastics pollution sentinels
The Arctic and Antarctica represent two of the most inhospitable and poorly investigated biomes in the world. Although polar regions are still perceived as some of the most pristine places still in existence, these remote places are no longer immune to anthropogenic pollution, in particular, micro- and nanoplastics. Seabirds, avian species feeding mainly at sea, are indicators of change in the environment and represent an early study group of ecological indicators for plastic pollution. The goa…

It looks like only one of the three yard cats (feral cats that live in the neighborhood) survived the polar vortex, last month. Either that or somebody nabbed the other two and brought them indoors.

This https://arxiv.org/abs/2402.10976 has been replaced.
initial toot: https://mastoxiv.page/@arX…

Dirac field, van der Waals gas, Weyssenhoff fluid, Newton particle
We consider the Dirac field in polar formulation, showing that when torsion is taken in effective approximation the theory has the thermodynamic properties of a van der Waals gas, that when the limit of zero chiral angle is taken the theory reduces to that of a Weyssenhoff fluid, and that under the spinless condition it gives the Newtonian particle. This nesting of approximations will allow us to interpret the various objects pertaining to the spinor, with torsion providing a form of negative p…

Dust beyond the torus: Revealing the mid-infrared heart of local Seyfert ESO 428-G14 with JWST/MIRI
Houda Haidar, David J. Rosario, Almudena Alonso-Herrero, Miguel Pereira-Santaella, Ismael Garc\'ia-Bernete, Stephanie Campbell, Sebastian F. H\"onig, Cristina Ramos Almeida, Erin Hicks, Daniel Delaney, Richard Davies, Claudio Ricci, Chris M. Harrison, Mason Leist, Enrique Lopez-Rodriguez, Santiago Garcia-Burillo, Lulu Zhang, Chris Packham, Poshak Gandhi, Anelise Audibert, Enrica…

Dust beyond the torus: Revealing the mid-infrared heart of local Seyfert ESO 428-G14 with JWST/MIRI
Polar dust has been discovered in a number of local Active Galactic Nuclei (AGN), with radiation-driven torus models predicting a wind to be its main driver. However, little is known about its characteristics, spatial extent, or connection to the larger scale outflows. We present the first JWST/MIRI study aimed at imaging polar dust by zooming onto the heart of ESO 428-G14, part of the GATOS survey of local AGN. We clearly detect extended mid-infrared (MIR) emission within 200 pc from the nucle…

On Modeling Tear Breakup Dynamics with a Nematic Lipid Layer
M. J. Taranchuk, R. J. Braun
https://arxiv.org/abs/2404.17003 https://ar…

On Modeling Tear Breakup Dynamics with a Nematic Lipid Layer
One of the main roles of the lipid layer (LL) of the tear film (TF) is to help prevent evaporation of the aqueous layer (AL). The LL thickness, composition, and structure all contribute to its barrier function. It is believed that the lipid layer is primarily nonpolar with a layer of polar lipids at the LL/AL interface. There is evidence that the nonpolar region of the LL may have liquid crystalline characteristics. We investigate the structure and function of the LL via a model of the tear fil…

"#Starmer’s insistence that “when business profits, we all do” is the polar opposite of what has actually been happening in the economy, actively and aggressively belied by the current cost of living crunch. Sellers’ inflation and corporate profiteering have been occurring at the expense of the vast majority"
The Corruption Behind Starmer’s Rise Has Finally Been Exposed | Novara Me…

The Corruption Behind Starmer’s Rise Has Finally Been Exposed
Details are starting to emerge of the most secretive and dishonest leadership campaign in the history of British politics.

On a Neural Implementation of Brenier's Polar Factorization
Nina Vesseron, Marco Cuturi
https://arxiv.org/abs/2403.03071 https://…

On a Neural Implementation of Brenier's Polar Factorization
In 1991, Brenier proved a theorem that generalizes the $QR$ decomposition for square matrices -- factored as PSD $\times$ unitary -- to any vector field $F:\mathbb{R}^d\rightarrow \mathbb{R}^d$. The theorem, known as the polar factorization theorem, states that any field $F$ can be recovered as the composition of the gradient of a convex function $u$ with a measure-preserving map $M$, namely $F=\nabla u \circ M$. We propose a practical implementation of this far-reaching theoretical result, and…

This https://arxiv.org/abs/2309.10386 has been replaced.
initial toot: https://mastoxiv.page/@a…

Guest-induced phase transition leads to polarization enhancement in MHyPbCl3
We present a detailed first-principles investigation of the structural and polar properties of 3D hybrid perovskite, methylhydrazinium lead chloride, MHyPbCl3, as it transitions from a highly polar Phase-I (high temperature, HT) to less polar Phase-II (low temperature, LT) from the perspective of host/guest interactions. Structurally, the two phases vary in the orientation of the guest and the two differently distorted host layers. The transition character (TC) across the path of phase transiti…

"Ice-free summers in Arctic possible within next decade, scientists say"
#Arctic #Climate #ClimateChange

"""
- Co robicie?
- Grilla.
- Nie mówiłeś, że jesteś pełen, Lama-san?
- Jedzenie z grilla idzie do osobnego żołądka.
"""
(Pingwin-san do Lama-sana, Polar Bear's Cafe, odcinek 15)
Szczera prawda. Pomijając błędy anatomiczne.

Emergent Anti-Ferroelectric Ordering and the Coupling of Liquid Crystalline and Polar Order
Jordan Hobbs, Calum J. Gibb, Richard. J. Mandle
https://arxiv.org/abs/2404.12271

Emergent Anti-Ferroelectric Ordering and the Coupling of Liquid Crystalline and Polar Order
Polar liquid crystals possess three dimensional orientational order coupled with unidirectional electric polarity, yielding fluid ferroelectrics. Such polar phases are generated by rod-like molecules with large electric dipole moments. 2,5-Disubstituted 1,3-dioxane is commonly employed as a polar motif in said systems, and here we show this to suffer from thermal instability as a consequence of equatorial-trans to axial-trans isomerism at elevated temperatures. We utilise isosteric building blo…

Formation of Polar Crown Filaments Magnetic Fields by Supergranular Helicity Injection
Huanxin Chen, Chun Xia, Hechao Chen
https://arxiv.org/abs/2403.12497

Formation of Polar Crown Filaments Magnetic Fields by Supergranular Helicity Injection
To understand the magnetic fields of the polar crown filaments (PCFs) at high latitudes near polar regions of the Sun, we perform magnetofrictional numerical simulations on the long-term magnetic evolution of bipolar fields with roughly east-west polarity inversion lines (PILs) in a three-dimensional (3D) spherical wedge domain near polar regions. The Coriolis effect induced vortical motions at the boundaries of several supergranular cells inject magnetic helicity from the photospheric boundary…

This https://arxiv.org/abs/2309.01847 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

A Unified Geometric Model of Repeating and Non-Repeating Fast Radio Bursts
Fast radio bursts (FRBs) are millisecond-duration extragalactic radio transients. They apparently fall into repeaters and non-repeaters. However, such a classification has lacked a motivation on the physical picture. Here we propose a unified geometric model to distinguish between the repeaters and non-repeaters, in which the quasi-tangential (QT) propagation effect within the magnetospheric polar cap of a neutron star is considered. In this model, the non-repeaters arise from the sources whose…

Weight Structure of Low/High-Rate Polar Codes and Its Applications
Mohammad Rowshan, Vlad-Florin Dr\u{a}goi, Jinhong Yuan
https://arxiv.org/abs/2402.12707 …

Weight Structure of Low/High-Rate Polar Codes and Its Applications
The structure of a linear block code is pivotal in defining fundamental properties, particularly weight distribution, and code design. In this study, we characterize the Type II structure of polar codewords with weights less than twice the minimum weight $w_{min}$, utilizing the lower triangular affine (LTA) transform. We present a closed-form formula for their enumeration. Leveraging this structure and additionally characterizing the structure of weight $2w_{min}$, we ascertain the complete we…

Anisotropic auxetic composite laminates: a polar approach
Paolo Vannucci
https://arxiv.org/abs/2403.16057 https://arxiv.org/pdf/2403.…

Anisotropic auxetic composite laminates: a polar approach
The problem of obtaining anisotropic auxetic composite laminates, i.e. having a negative Poisson's ratio for at least some directions, is examined in this paper. In particular, the possibility of obtaining auxeticity stacking uni-directional identical plies is considered. It is shown that if the ply is composed by isotropic matrix and fibers, then it is impossible to obtain totally auxetic orthotropic laminates, i.e. auxeticity for each direction, unless at least one among matrix and fibers is …

Dynamics of Polar-Core Spin Vortices in Inhomogeneous Spin-1 Bose-Einstein Condensates
Zachary L. Stevens-Hough, Matthew J. Davis, Lewis A. Williamson
https://arxiv.org/abs/2404.13800

Dynamics of Polar-Core Spin Vortices in Inhomogeneous Spin-1 Bose-Einstein Condensates
In the easy-plane phase, a ferromagnetic spin-1 Bose-Einstein condensate is magnetized in a plane transverse to the applied Zeeman field. This phase supports polar-core spin vortices (PCVs), which consist of phase windings of transverse magnetization. Here we show that spin-changing collisions cause a PCV to accelerate down density gradients in an inhomogeneous condensate. The dynamics is well-described by a simplified model adapted from scalar systems, which predicts the dependence of the dyna…

Equatorial blowup and polar caps in drop electrohydrodynamics
Gunnar G. Peng, Rodolfo Brandao, Ehud Yariv, Ory Schnitzer
https://arxiv.org/abs/2403.14876 h…

Equatorial blowup and polar caps in drop electrohydrodynamics
We illuminate effects of surface-charge convection intrinsic to leaky-dielectric electrohydrodynamics by analyzying the symmetric steady state of a circular drop in an external field at arbitrary electric Reynolds number $\mathrm{Re}_E$. In formulating the problem, we identify an exact factorization that reduces the number of dimensionless parameters from four -- $\mathrm{Re}_E$ and the conductivity, permittivity and viscosity ratios -- to two: a modified electric Reynolds number $\widetilde{\m…

DeepPolar: Inventing Nonlinear Large-Kernel Polar Codes via Deep Learning
S Ashwin Hebbar, Sravan Kumar Ankireddy, Hyeji Kim, Sewoong Oh, Pramod Viswanath
https://arxiv.org/abs/2402.08864

DeepPolar: Inventing Nonlinear Large-Kernel Polar Codes via Deep Learning
Polar codes, developed on the foundation of Arikan's polarization kernel, represent a breakthrough in coding theory and have emerged as the state-of-the-art error-correction-code in short-to-medium block length regimes. Importantly, recent research has indicated that the reliability of polar codes can be further enhanced by substituting Arikan's kernel with a larger one, leading to a faster polarization. However, for short-to-medium block length regimes, the development of polar codes that effe…

On a Neural Implementation of Brenier's Polar Factorization
Nina Vesseron, Marco Cuturi
https://arxiv.org/abs/2403.03071 https://…

On a Neural Implementation of Brenier's Polar Factorization
In 1991, Brenier proved a theorem that generalizes the $QR$ decomposition for square matrices -- factored as PSD $\times$ unitary -- to any vector field $F:\mathbb{R}^d\rightarrow \mathbb{R}^d$. The theorem, known as the polar factorization theorem, states that any field $F$ can be recovered as the composition of the gradient of a convex function $u$ with a measure-preserving map $M$, namely $F=\nabla u \circ M$. We propose a practical implementation of this far-reaching theoretical result, and…

This https://arxiv.org/abs/2403.05712 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

Higher-Order Reverse Isoperimetric Inequalities for Log-concave Functions
The Rogers-Shephard and Zhang's projection inequalities are two reverse, affine isoperimetric inequalities relating the volumes of a convex body and its difference body and polar projection body, respectively. Following a classical work by Schneider, both inequalities have been extended to the so-called higher-order setting. In this work, we establish the higher-order analogues for these inequalities in the setting of log-concave functions.

This https://arxiv.org/abs/2401.07954 has been replaced.
initial toot: https://mastoxiv.page/@a…

Oxygen tilt-driven polar super-orders in BiFeO3-based superlattices
Ferroelectric-dielectric superlattices have attracted renewed interest for their ability to frustrate the polar order, leading to the emergence of exotic polar textures. The electrostatic depolarization, thought to be responsible for the complex polar textures in these superlattices can be alleviated by replacing the dielectric layer with a metallic one. One would thus expect that a close to uniform polarization state be recovered in the ferroelectric layer. However, here we show, using Density…

This https://arxiv.org/abs/2305.00091 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

A Theory of the NEPv Approach for Optimization On the Stiefel Manifold
The NEPv approach has been increasingly used lately for optimization on the Stiefel manifold arising from machine learning. General speaking, the approach first turns the first order optimality condition, also known as the KKT condition, into a nonlinear eigenvalue problem with eigenvector dependency (NEPv) or a nonlinear polar decomposition with orthogonal factor dependency (NPDo) and then solve the nonlinear problem via some variations of the self-consistent-field (SCF) iteration. The difficu…

Dynamics of Polar-Core Spin Vortices in Inhomogeneous Spin-1 Bose-Einstein Condensates
Zachary L. Stevens-Hough, Matthew J. Davis, Lewis A. Williamson
https://arxiv.org/abs/2404.13800

Dynamics of Polar-Core Spin Vortices in Inhomogeneous Spin-1 Bose-Einstein Condensates
In the easy-plane phase, a ferromagnetic spin-1 Bose-Einstein condensate is magnetized in a plane transverse to the applied Zeeman field. This phase supports polar-core spin vortices (PCVs), which consist of phase windings of transverse magnetization. Here we show that spin-changing collisions cause a PCV to accelerate down density gradients in an inhomogeneous condensate. The dynamics is well-described by a simplified model adapted from scalar systems, which predicts the dependence of the dyna…

Beyond the Rings: Polar Ring Galaxy NGC 4262 and its Globular Cluster System
Akhil Krishna R, Sreeja S Kartha, Blesson Mathew
https://arxiv.org/abs/2404.10059

Beyond the Rings: Polar Ring Galaxy NGC 4262 and its Globular Cluster System
In the context of the hierarchical model of galaxy evolution, polar ring galaxies (PRGs) are considered the intermediate phase between ongoing mergers and quiescent galaxies. This study explores the globular cluster system (GCS) and its properties in the nearest PRG, NGC4262, serving as a pilot investigation to study GCS in nearby PRGs. We utilize wide and deep field observations of the CFHT as part of the NGVS to investigate the GCS of NGC4262. We presented the first optical image of NGC4262 w…

Spontaneous Symmetry Breaking in Polar Fluids
Calum Gibb, Jordan Hobbs, Diana Nikolova, Tom Raistrick, Helen Gleeson, Richard Mandle
https://arxiv.org/abs/2402.07305

Spontaneous Symmetry Breaking in Polar Fluids
Spontaneous symmetry breaking and emergent polar order are each of fundamental importance to a range of scientific disciplines, as well as generating rich phase behaviour in liquid crystals (LCs). Here, we show the union of these phenomena to lead to two previously undiscovered polar liquid states of matter. Both phases have a lamellar structure with an inherent polar ordering of their constituent molecules. The first of these phases is characterised by polar order and a local tilted structure;…

Variabilities in the polar field and solar cycle due to irregular properties of Bipolar Magnetic Regions
Pawan Kumar, Bidya Binay Karak, Anu Sreedevi
https://arxiv.org/abs/2404.10526

Variabilities in the polar field and solar cycle due to irregular properties of Bipolar Magnetic Regions
Decay and dispersal of the tilted Bipolar Magnetic Regions (BMRs) on the solar surface are observed to produce large-scale poloidal field, which acts as the seed for the toroidal field and, thus, the next sunspot cycle. However, various properties of BMR, namely, the tilt, time delay between successive emergences, location, and flux, all have irregular variations. Previous studies show that these variations can lead to changes in the polar field. In this study, we first demonstrate that our 3D …

This https://arxiv.org/abs/2404.06736 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_csIT_…

New Partial Orders of Polar Codes for BMSC
In this paper, we define partial orders (POs) of polar codes based on the Bhattacharyya parameter and the bit-error probability, respectively. These POs are applicable to arbitrary binary memoryless symmetric channel (BMSC). Leveraging the extremal inequalities of polarization transformation, we derive new POs for BMSC based on the corresponding POs observed in the Binary Erasure Channel (BEC). %Additionally, we discover more special POs in the Binary Symmetric Channel (BSC). We provide example…

"""
- What are you doing?
- Barbecuing.
- Didn't you say you were full, Llama-san?
- Barbecue goes into a separate stomach.
"""
(Penguin-san to Llama-san, Polar Bear's Cafe, episode 15)
So true. Aside from the wrong anatomical details.

Polar vortex hidden in twisted bilayers of paraelectric SrTiO3
Haozhi Sha, Yixuan Zhang, Yunpeng Ma, Wei Li, Wenfeng Yang, Jizhe Cui, Qian Li, Houbing Huang, Rong Yu
https://arxiv.org/abs/2404.08145

Polar vortex hidden in twisted bilayers of paraelectric SrTiO3
Polar topologies, such as vortex and skyrmion, have attracted significant interest due to their unique physical properties and promising applications in high-density memory devices. Currently, most polar vortices are observed in heterostructures containing ferroelectric materials and constrained by substrates. In this study, we unravel arrays of polar vortices formed in twisted freestanding bilayers composed of SrTiO3, a quantum-paraelectric material. Depth-resolved structures of the bilayers a…

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…

Spontaneous Symmetry Breaking in Polar Fluids
Calum Gibb, Jordan Hobbs, Diana Nikolova, Tom Raistrick, Helen Gleeson, Richard Mandle
https://arxiv.org/abs/2402.07305

Spontaneous Symmetry Breaking in Polar Fluids
Spontaneous symmetry breaking and emergent polar order are each of fundamental importance to a range of scientific disciplines, as well as generating rich phase behaviour in liquid crystals (LCs). Here, we show the union of these phenomena to lead to two previously undiscovered polar liquid states of matter. Both phases have a lamellar structure with an inherent polar ordering of their constituent molecules. The first of these phases is characterised by polar order and a local tilted structure;…

Precoded Polar Product Codes
Mustafa Cemil Co\c{s}kun
https://arxiv.org/abs/2402.06767 https://arxiv.org/pdf/2402.06767

Precoded Polar Product Codes
Precoded polar product codes are proposed, where selected component codes enable successive cancellation list decoding to generate bit-wise soft messages efficiently for iterative decoding while targeting optimized distance spectrum as opposed to eBCH or polar component codes. Rate compatibility is a byproduct of $1$-bit granularity in the component code design.

This https://arxiv.org/abs/2401.07954 has been replaced.
initial toot: https://mastoxiv.page/@a…

Oxygen tilt-driven polar super-orders in BiFeO3-based superlattices
Ferroelectric-dielectric superlattices have attracted renewed interest for their ability to frustrate the polar order, leading to the emergence of exotic polar textures. The electrostatic depolarization, thought to be responsible for the complex polar textures in these superlattices can be alleviated by replacing the dielectric layer with a metallic one. One would thus expect that a close to uniform polarization state be recovered in the ferroelectric layer. However, here we show, using Density…

Maximal hypersurfaces and aspects of volume of the Kerr family of black holes
Suraj Maurya, Sashideep Gutti, Rahul Nigam
https://arxiv.org/abs/2404.15140 h…

Maximal hypersurfaces and aspects of volume of the Kerr family of black holes
In Schwarzschild spacetime, Reinhart (1973) has shown the hypersurface $r_R = 3M/2$ (the subscript stands for "Reinhart") to be a maximal hypersurface. This Reinhart radius $r_R$ plays a crucial role in evaluating the interior volume of a black hole. In this article, we find such a maximal hypersurface for the Kerr and Kerr-Newaman black holes. We obtain the analytical expression for the Reinhart radius as a function of the polar angle $θ$ for a small $a/M$ limit for both the Kerr and Kerr-New…

"""
- What are you doing?
- Barbecuing.
- Didn't you say you were full, Llama-san?
- Barbecue goes into a separate stomach.
"""
(Penguin-san to Llama-san, Polar Bear's Cafe, episode 15)
So true. Aside from the wrong anatomical details.

The invisible black widow PSR J1720-0534: implications for the electron density towards the North Polar Spur
Karri I. I. Koljonen, Sindre S. Lindseth, Manuel Linares, Alice K. Harding, Marco Turchetta
https://arxiv.org/abs/2402.09010

The invisible black widow PSR J1720-0534: implications for the electron density towards the North Polar Spur
Radio emission from pulsars can be used to map out their distances through dispersion measure (DM), which quantifies the amount of radio pulse dispersion. However, this method relies on accurately modeling the free electron density in the line of sight. Here, we present a detailed study of the multi-wavelength emission from PSR J1720-0534, a black widow compact binary millisecond pulsar discovered in 2021, which the latest electron density model of the Galaxy (YMW16; Yao et al. 2017) places at …

Shortened Polar Codes under Automorphism Ensemble Decoding
Charles Pillet, Ilshat Sagitov, Valerio Bioglio, Pascal Giard
https://arxiv.org/abs/2403.00622 h…

Shortened Polar Codes under Automorphism Ensemble Decoding
In this paper, we propose a low-latency decoding solution of shortened polar codes based on their automorphism groups. The automorphism group of shortened polar codes, designed according to two existing shortening patterns, are shown to be limited but non-empty, making the Automorphism Ensemble (AE) decoding of shortened polar codes possible. Extensive simulation results for shortened polar codes under AE are provided and are compared to the SC-List (SCL) algorithm. The block-error rate of shor…

Infinite quantum twisting at the Cauchy horizon of rotating black holes
Christiane Klein, Mojgan Soltani, Marc Casals, Stefan Hollands
https://arxiv.org/abs/2402.14171

Infinite quantum twisting at the Cauchy horizon of rotating black holes
We present a numerical calculation of the expectation value of the quantum angular-momentum current flux density for a scalar field in the Unruh state near the inner horizon of a Kerr-de Sitter black hole. Our results indicate that this flux diverges as $V_-^{-1}$ in a suitable Kruskal coordinate such that $V_-=0$ at the inner horizon. Depending on the parameter values of the scalar field and black hole that we consider, and depending on the polar angle (latitude), this flux can have different …

Ferroelectricity at the extreme thickness limit in the archetypal antiferroelectric PbZrO$_3$
Nikhilesh Maity, Milan Haddad, Nazanin Bassiri-Gharb, Amit Kumar, Lewys Jones, Sergey Lisenkov, Inna Ponomareva
https://arxiv.org/abs/2402.14176

Ferroelectricity at the extreme thickness limit in the archetypal antiferroelectric PbZrO$_3$
Size-driven transition of an antiferroelectric into a polar ferroelectric or ferrielectric state is a strongly debated issue from both experimental and theoretical perspectives. While critical thickness limits for such transitions have been explored, a bottom-up approach in the ultrathin limit considering few atomic layers could provide insight into the mechanism of stabilization of the polar phases over the antipolar phase seen in bulk PbZrO$_3$. Here, we use first-principles density functiona…

Non-reciprocal alignment induces asymmetric clustering in active repulsive mixtures
Kim L. Kreienkamp, Sabine H. L. Klapp
https://arxiv.org/abs/2403.19291 …

Non-reciprocal alignment induces asymmetric clustering in active repulsive mixtures
Heterogeneity is a ubiquitous feature in many biological and synthetic active matter systems that are inherently out of equilibrium. In addition to conservative interactions between active constituents, a non-equilibrium environment often induces effective non-reciprocal (NR) couplings. The full consequences, especially for systems with order parameters of different symmetries, still remain elusive. Here, we study a minimal active NR mixture exhibiting both, polar ordering and clustering using …

"""
I'm popular with animals, kids, and old people.
No luck with girls, though.
"""
(Handa-san, from Polar Bear Cafe, episode 12)
Sounds familiar…

The invisible black widow PSR J1720-0534: implications for the electron density towards the North Polar Spur
Karri I. I. Koljonen, Sindre S. Lindseth, Manuel Linares, Alice K. Harding, Marco Turchetta
https://arxiv.org/abs/2402.09010

The invisible black widow PSR J1720-0534: implications for the electron density towards the North Polar Spur
Radio emission from pulsars can be used to map out their distances through dispersion measure (DM), which quantifies the amount of radio pulse dispersion. However, this method relies on accurately modeling the free electron density in the line of sight. Here, we present a detailed study of the multi-wavelength emission from PSR J1720-0534, a black widow compact binary millisecond pulsar discovered in 2021, which the latest electron density model of the Galaxy (YMW16; Yao et al. 2017) places at …

This https://arxiv.org/abs/2306.02332 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_grqc_…

The Quasinormal Modes and Isospectrality of Bardeen (Anti-) de Sitter Black Holes
Black holes (BHs) exhibiting coordinate singularities but lacking essential singularities throughout the entire spacetime are referred to as regular black holes (RBHs). The initial formulation of RBHs was presented by Bardeen, who considered the Einstein equation coupled with a nonlinear electromagnetic field. In this study, we investigate the gravitational perturbations, including the axial and polar sectors, of the Bardeen (Anti-) de Sitter black holes. We derive the master equations with sou…

New Partial Orders of Polar Codes for BMSC
Liuquan Yao, Zhichao Liu, Yuan Li, Huazi Zhang, Jun Wang, Guiying Yan, Zhiming Ma
https://arxiv.org/abs/2404.06736

New Partial Orders of Polar Codes for BMSC
In this paper, we define partial orders (POs) of polar codes based on the Bhattacharyya parameter and the bit-error probability, respectively. These POs are applicable to arbitrary binary memoryless symmetric channel (BMSC). Leveraging the extremal inequalities of polarization transformation, we derive new POs for BMSC based on the corresponding POs observed in the Binary Erasure Channel (BEC). %Additionally, we discover more special POs in the Binary Symmetric Channel (BSC). We provide example…

Geometrically-Controlled Microscale Patterning and Epitaxial Lateral Overgrowth of Nitrogen-Polar GaN
Pietro Pampili, Vitaly Z. Zubialevich, Peter J. Parbrook
https://arxiv.org/abs/2402.09385

Geometrically-Controlled Microscale Patterning and Epitaxial Lateral Overgrowth of Nitrogen-Polar GaN
In this study we report on a novel two-step epitaxial growth technique that enables a significant improvement of the crystal quality of nitrogen-polar GaN. The starting material is grown on 4° vicinal sapphire substrates by metal organic vapour phase epitaxy, with an initial high-temperature sapphire nitridation to control polarity. The material is then converted into a regular array of hexagonal pyramids by wet-etch in a KOH solution, and subsequently regrown to coalesce the pyramids back int…

Study of Adaptive Reweighted Sparse Belief Propagation Decoders for Polar Codes
R. M. Oliveira, R. C. de Lamare
https://arxiv.org/abs/2404.04674 https://…

Study of Adaptive Reweighted Sparse Belief Propagation Decoders for Polar Codes
In this paper, we present an adaptive reweighted sparse belief propagation (AR-SBP) decoder for polar codes. The AR-SBP technique is inspired by decoders that employ the sum-product algorithm for low-density parity-check codes. In particular, the AR-SBP decoding strategy introduces reweighting of the exchanged log-likelihood-ratio in order to refine the message passing, improving the performance of the decoder and reducing the number of required iterations. An analysis of the convergence of AR-…

Design of Magnetic Polar Double-Double Perovskite Oxides through Cation Ordering
Monirul Shaikh, Duo Wang, Saurabh Ghosh
https://arxiv.org/abs/2403.05498 h…

Design of Magnetic Polar Double-Double Perovskite Oxides through Cation Ordering
Commencing from the centrosymmetric MnRMnSbO$_6$ compound, we explore the realm of magnetic polar double-double perovskite oxides characterized by significant ferroelectric polarization. Employing symmetry operations, first-principles methodologies, and Monte Carlo simulations, our investigation delves into the structural, magnetic, ferroelectric, and electronic attributes of the polar LaFeMnNiO$_6$ and LaTiMnNiO$_6$ compounds. The structural analysis uncovers that the paraelectric-ferroelectri…