Blar i Vitenskapelige publikasjoner (TN-IMN) på emneord "VDP::Mathematics and natural science: 400::Physics: 430"
Viser treff 1-18 av 18
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A spacetime not characterized by its invariants is of aligned type II
(Journal article; Peer reviewed, 2011)By using invariant theory we show that a (higher-dimensional) Lorentzian metric that is not characterised by its invariants must be of aligned type II; i.e., there exists a frame such that all the curvature tensors ... -
All metrics have curvature tensors characterised by its invariants as a limit: the ϵ-property
(Journal article; Peer reviewed, 2011)We prove a generalisation of the ϵ-property, namely that for any dimension and signature, a metric which is not characterised by its polynomial scalar curvature invariants, there is a frame such that the components of the ... -
Anomalous electrodynamics of neutral pion matter in strong magnetic fields
(Journal article; Peer reviewed, 2017-03)The ground state of quantum chromodynamics in sufficiently strong external magnetic fields and at moderate baryon chemical potential is a chiral soliton lattice (CSL) of neutral pions [1]. We investigate the interplay ... -
Basis invariant measure of CP-violation and renormalization.
(Journal article; Peer reviewed, 2015-08)We analyze, in the context of a simple toy model, for which renormalization schemes the CP-properties of bare Lagrangian and its finite part coincide. We show that this is the case for the minimal subtraction and on-shell ... -
Chiral and deconfinement transitions in a magnetic background using the functional renormalization group with the Polyakov loop
(Journal article; Peer reviewed, 2014-04)We use the Polyakov loop coupled quark-meson model to approximate low energy QCD and present results for the chiral and deconfinement transitions in the presence of a constant magnetic background B at finite temperature T ... -
Chiral soliton lattice and charged pion condensation in strong magnetic fields
(Journal article; Peer reviewed, 2017-04)The Chiral Soliton Lattice (CSL) is a state with a periodic array of topological solitons that spontaneously breaks parity and translational symmetries. Such a state is known to appear in chiral magnets. We show that CSL ... -
Curvature operators and scalar curvature invariants
(Journal article; Peer reviewed, 2010)We continue the study of the question of when a pseudo-Riemannain manifold can be locally characterised by its scalar polynomial curvature invariants (constructed from the Riemann tensor and its covariant deriva- tives). ... -
Discriminating the Weyl type in higher dimensions using scalar curvature invariants
(Journal article; Peer reviewed, 2011)We consider higher dimensional Lorentzian spacetimes which are currently of interest in theoretical physics. It is possible to algebraically classify any tensor in a Lorentzian spacetime of arbitrary dimensions using ... -
Higher dimensional bivectors and classification of the Weyl operator
(Journal article; Peer reviewed, 2010)We develop the bivector formalism in higher dimensional Lorentzian spacetimes. We define the Weyl bivector operator in a manner consis- tent with its boost-weight decomposition. We then algebraically classify the Weyl ... -
Inflation with stable anisotropic hair
(Journal article; Peer reviewed, 2011)Recently an inflationary model with a vector field coupled to the inflaton was proposed and the phenomenology studied for the Bianchi type I spacetime. It was found that the model demonstrates a counter-example to the ... -
Inhomogeneous chiral condensate in the quark-meson model
(Journal article; Peer reviewed, 2017-07-24) -
Leptogenesis in crossing and runaway regimes.
(Journal article; Peer reviewed, 2014-07)We study the impact of effective thermal masses and widths on resonant leptogenesis. We identify two distinct possibilities which we refer to as ‘crossing’ and ‘runaway’ regimes. In the runaway regime the mass difference ... -
Primordial Gravitational Waves with LISA
(Journal article; Peer reviewed, 2017)Primordial Gravitational Waves are the next target of modern cosmology. They represent a window on the early Universe and the only probe of the physics and microphysics of the inflationary period. When the production of ... -
Pseudo-Riemannian VSI spaces
(Journal article; Peer reviewed, 2011)In this paper we consider pseudo-Riemannian spaces of arbitrary sig- nature for which all of their polynomial curvature invariants vanish (VSI spaces). We discuss an algebraic classification of pseudo-Riemannian spaces ... -
Pseudo-Riemannian VSI spaces II
(Journal article; Peer reviewed, 2012)In this paper we consider pseudo-Riemannian spaces of arbitrary signature for which all of the polynomial curvature invariants vanish (VSI spaces). Using an algebraic classification of pseudo-Riemannian spaces in terms of ... -
Ricci nilsoliton black holes
(Journal article; Peer reviewed, 2008)We follow a constructive approach and find higher-dimensional black holes with Ricci nilsoliton horizons. The spacetimes are solutions to the Einstein equation with a negative cosmological constant and generalise therefore, ... -
Type III and II universal spacetimes
(Journal article; Peer reviewed, 2015)We briefly summarize our recent results on universal spacetimes. We show that universal spacetimes are necessarily CSI, i.e. for these spacetimes, all curvature invariants constructed from the Riemann tensor and its ... -
Type N universal spacetimes
(Journal article; Peer reviewed, 2015)Universal spacetimes are vacuum solutions to all theories of gravity with the Lagrangian L [...]. Well known examples of universal spacetimes are plane waves which are of the Weyl type N. Here, we discuss recent results ...