Results 71 to 80 of about 1,466 (235)

A Re‐Examination of Foundational Elements of Cosmology

Fortschritte der Physik, Volume 74, Issue 3, March 2026.
ABSTRACT This paper undertakes a conceptual re‐examination of several foundational elements of cosmology through the lens of spacetime symmetries. A new derivation of the Friedmann–Lemaître–Robertson–Walker metric is obtained by a careful conceptual examination of rotations and translations on generic manifolds, followed by solving the rotational and ...
Lavinia Heisenberg
wiley   +1 more source

High Voltage DC Active Current Injection to Simulate Geomagnetically Induced Currents in New Zealand

Space Weather, Volume 24, Issue 3, March 2026.
Abstract This study investigates the effects of geomagnetically induced currents (GIC) on New Zealand's electrical infrastructure via an intentional ground injection of direct current (DC) from a high voltage DC converter station. GIC manifests as quasi‐DC currents within power systems, potentially causing transformer saturation, increased reactive ...
Soren Subritzky, Andrew Lapthorn, Stewart Hardie, Paul Agger, Mike Dalzell, Mark A. Clilverd, Neil Cobbett, Ciaran Beggan, Juliane Hübert, Eliot Eaton, James B. Brundell, Craig J. Rodger   +11 more
wiley   +1 more source

On universal‐homogeneous hyperbolic graphs and spaces and their isometry groups

Bulletin of the London Mathematical Society, Volume 58, Issue 3, March 2026.
Abstract The Urysohn space is the unique separable metric space that is universal and homogeneous for finite metric spaces, that is, it embeds any finite metric space any isometry between finite subspaces extends to an isometry of the whole space. We here consider the existence of a universal‐homogeneous hyperbolic space. We show that for δ>0$\delta >0$
Katrin Tent
wiley   +1 more source

Linear Diophantine equations and conjugator length in 2‐step nilpotent groups

Bulletin of the London Mathematical Society, Volume 58, Issue 3, March 2026.
Abstract We establish upper bounds on the lengths of minimal conjugators in 2‐step nilpotent groups. These bounds exploit the existence of small integral solutions to systems of linear Diophantine equations. We prove that in some cases these bounds are sharp.
M. R. Bridson, T. R. Riley
wiley   +1 more source

Quantum noncommutative ABJM theory: first steps

Journal of High Energy Physics, 2018
We introduce ABJM quantum field theory in the noncommutative spacetime by using the component formalism and show that it is N $$ \mathcal{N} $$ = 6 supersymmetric. For the U(1) κ × U(1)−κ case, we compute all one-loop 1PI two and three point functions in
Carmelo P. Martin, Josip Trampetic, Jiangyang You   +2 more
doaj   +1 more source

Quantization of infinitesimal braidings and pre‐Cartier quasi‐bialgebras

Journal of the London Mathematical Society, Volume 113, Issue 3, March 2026.
Abstract In this paper, we extend Cartier's deformation theorem of braided monoidal categories admitting an infinitesimal braiding to the nonsymmetric case. The algebraic counterpart of these categories is the notion of a pre‐Cartier quasi‐bialgebra, which extends the well‐known notion of quasi‐triangular quasi‐bialgebra given by Drinfeld.
Chiara Esposito, Andrea Rivezzi, Jonas Schnitzer, Thomas Weber   +3 more
wiley   +1 more source

Symplectic groupoids and Poisson electrodynamics

Journal of High Energy Physics
We develop a geometric approach to Poisson electrodynamics, that is, the semi-classical limit of noncommutative U(1) gauge theory. Our framework is based on an integrating symplectic groupoid for the underlying Poisson brackets, which we interpret as the
Vladislav G. Kupriyanov, Alexey A. Sharapov, Richard J. Szabo   +2 more
doaj   +1 more source

A fuzzy bipolar celestial sphere

Journal of High Energy Physics, 2019
We introduce a non-commutative deformation of the algebra of bipolar spherical harmonics supporting the action of the full Lorentz algebra. Our construction is close in spirit to the one of the non-commutative spherical harmonics associated to the fuzzy ...
Francesco Alessio, Michele Arzano
doaj   +1 more source

On the Euler characteristic of S$S$‐arithmetic groups

Journal of the London Mathematical Society, Volume 113, Issue 3, March 2026.
Abstract We show that the sign of the Euler characteristic of an S$S$‐arithmetic subgroup of a simple algebraic group depends on the S$S$‐congruence completion only, except possibly in type 6D4${}^6 D_4$. Consequently, the sign is a profinite invariant for such S$S$‐arithmetic groups with the congruence subgroup property. This generalizes previous work
Holger Kammeyer, Giada Serafini
wiley   +1 more source

Osculating geometry and higher‐order distance Loci

Journal of the London Mathematical Society, Volume 113, Issue 3, March 2026.
Abstract We discuss the problem of optimizing the distance function from a given point, subject to polynomial constraints. A key algebraic invariant that governs its complexity is the Euclidean distance degree, which pertains to first‐order tangency. We focus on the data locus of points possessing at least one critical point of the distance function ...
Sandra Di Rocco, Kemal Rose, Luca Sodomaco   +2 more
wiley   +1 more source