arXiv subjects

Alexander Wurm

Publications and source records attributed to Alexander Wurm.

3 recordsLinked to original sources

arXiv2020

A class of three-dimensional gyroviscous magnetohydrodynamic models

A Hamiltonian and action principle formalism for deriving three-dimensional gyroviscous magnetohydrodynamic models is presented. The uniqueness of the approach in constructing the gyroviscous tensor from first principles and its ability to explain the origin of the gyromap and the gyroviscous terms are highlighted. The procedure allows for the specification of free functions, which can be used to generate a wide range of gyroviscous models. Through the process of reduction, the noncanonical Hamiltonian bracket is obtained and briefly analysed.

physics.plasm-ph↗

arXiv2002

Wick Calculus

In quantum field theory, physicists routinely use "normal ordering" of operators, which just amounts to shuffling all creation operators to the left. Potentially confusing, then, is the occurrence in the literature of normal-ordered functions, sometimes called "Wick transforms". We aim to introduce the reader to some basic results and ideas around this theme, if not the mathematical subtleties; our intended audience are instructors who want to add something to their quantum field theory course, or researchers who are interested but not specialists in mathematical physics. For rigorous proofs and careful mathematical discussions we only give references.

physics.ed-ph↗

arXiv2002

Fourier Transforms of Lorentz Invariant Functions

Fourier transforms of Lorentz invariant functions in Minkowski space, with support on both the timelike and the spacelike domains are performed by means of direct integration. The cases of 1+1 and 1+2 dimensions are worked out in detail, and the results for 1+n dimensions are given.

math-ph↗