Odd-parity perturbations of the self-similar LTB spacetime

Perturbations of self-similar Bondi accretion

The question of stability of steady spherical accretion has been studied for many years and, recently, the concept of spatial instability has been introduced. Here we study perturbations of steady spherical accretion flows (Bondi solutions), restricting ourselves to the case of self-similar flow, as a case amenable to analytic treatment and with physical interest. We further restrict ourselves ...

Topological Classification of Odd-Parity Sphaleron Deformations

We discuss topological aspects of the electroweak sphaleron and its oddparity deformations. We demonstrate that they are uniquely classified in terms of their odd and even-parity pure gauge field behaviour at spatial infinity. Fermion level crossing occurs only for odd-parity configurations which are topologically disconnected from the vacuum. They contribute to the high temperature unsuppresse...

Nonlinear N-parameter spacetime perturbations: Gauge transformations

Carlos F. Sopuerta, 2 Marco Bruni, and Leonardo Gualtieri Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 2EG, Britain Institute for Gravitational Physics and Geometry and Center for Gravitational Wave Physics, Penn State University, University Park, Pennsylvania 16802, USA Dipartimento di Fisica “G. Marconi”, Università di Roma “La Sapienza” and Sezione INFN RO...

Odd-parity topological superconductor with nematic

Gauge dependence in the theory of non-linear spacetime perturbations

Diffeomorphism freedom induces a gauge dependence in the theory of spacetime perturbations. We derive a compact formula for gauge transformations of perturbations of arbitrary order. To this end, we develop the theory of Taylor expansions for one-parameter families (not necessarily groups) of diffeomorphisms. First, we introduce the notion of knight diffeomorphism, that generalises the usual co...