Realizations of Hybrid Inflation in Supergravity with natural initial conditions

We present viable F-term realizations of the hybrid inflationary scenario in the context of supergravity addressing at the same time the well-known problems of the initial conditions and of the adequate suppression of the inflaton mass. An essential role in our construction is played by "decoupled" superheavy fields without superpotential acquiring large vevs due to D-terms associated with "anomalous" U(1) gauge symmetries. The naturalness of the initial conditions is achieved through a "chaotic" inflation starting at energies close to the Planck scale and driven by the "anomalous" D-terms. We discuss two distinct mechanisms leading to such an early "chaotic" D-term inflation which depend on the choice of the K\"ahler potential involving the superheavy fields. The one relies on a choice of the K\"ahler potential of the $SU(1,1)/U(1)$ K\"ahler manifold of the type encountered in no-scale supergravity whereas the other employs a more "conventional" choice for the K\"ahler potential of the $SU(1,1)/U(1)$ or $SU(2)/U(1)$ K\"ahler manifold but invokes rather specific valuesof the Fayet-Iliopoulos $\xi$ term.Comment: 32 pages LATEX, no figure

Sustainability management : insights from the viable system model

A review of current literature on sustainability standards reveals a significant gap between their adoption and the implementation of sustainability into every level of the organisation. In this paper, it is argued that in order to overcome this challenge, an appropriate model of an organisation is needed. The Viable System Model (VSM) is proposed as such a model and, in order to illustrate this argument, it is used to interpret the ISO 26000 standard on Social Responsibility (SR). First, the VSM theory is introduced and presented by modelling the hypothetical company Widget Co. Then, the clauses of ISO 26000 are mapped on the Widget Co. model, together with detailed descriptions and examples on the organisational and managerial implications of its adopting the standard's guidelines. The result is the identification of generic SR functions that need to be performed by the various organisational governance systems, as well as their dynamic interrelations, thus clarifying implementation issues. Moreover, by identifying different SR management layers, VSM is suggested as a way forward to develop an integration model for SR issues and respective sustainability tools. Finally, a discussion is given on the implications of using this approach to integrate sustainability standards and the way this research contributes to recent developments in sustainability research

Fine tuning of the initial conditions for hybrid inflation

We study the evolution of regions of space with various initial field values for a simple theory that can support hybrid inflation. Only very narrow domains within the range of initial field values below the Planck scale lead to the onset of inflation. This implies a severe fine tuning for the initial configuration that will produce inflation.Comment: 11 pages, LaTeX, 8 figures in eps forma

Dirac Relation and Renormalization Group Equations for Electric and Magnetic Fine Structure Constants

The quantum field theory describing electric and magnetic charges and revealing a dual symmetry was developed in the Zwanziger formalism. The renormalization group (RG) equations for both fine structure constants - electric $\alpha$ and magnetic $\tilde \alpha$ - were obtained. It was shown that the Dirac relation is valid for the renormalized $\alpha$ and $\tilde \alpha$ at the arbitrary scale, but these RG equations can be considered perturbatively only in the small region: $0.25 \stackrel{<}{\sim} \alpha, \tilde \alpha \stackrel{<}{\sim} 1$ with $\tilde \alpha$ given by the Dirac relation: $\alpha {\tilde \alpha}$ = 1/4.Comment: 15 pages, 4 figures, made corrections of physics after comments from Kim Milto

Two-Stage Inflation in Supergravity

We investigate the viability of a two-stage inflationary scenario in the context of supergravity, so as to resolve the problem of initial conditions for hybrid inflation. We allow for non-renormalizable terms in the superpotential and consider the most general form of the Kahler potential and the gauge kinetic function. We construct a model with two stages of inflation, the first driven by D-term and the second by F-term energy density. The viability of this scenario depends on the non-minimal terms in the Kahler potential, for which we derive the necessary constraints.Comment: 25 pages, LaTeX file, 2 figures in eps format, minor corrections to the tex

Supersymmetry breaking and loop corrections at the end of inflation

We show that quantum corrections to the effective potential in supersymmetric hybrid inflation can be calculated all the way from the inflationary period - when the Universe is dominated by a false vacuum energy density - till the fields settle down to the global supersymmetric minimum of the potential. These are crucial for getting a continuous description of the evolution of the fields.Comment: minor corrections; version to be published in Phys. Rev.

Inflation with Non-minimal Gravitational Couplings and Supergravity

We explore in the supergravity context the possibility that a Higgs scalar may drive inflation via a non-minimal coupling to gravity characterised by a large dimensionless coupling constant. We find that this scenario is not compatible with the MSSM, but that adding a singlet field (NMSSM, or a variant thereof) can very naturally give rise to slow-roll inflation. The inflaton is necessarily contained in the doublet Higgs sector and occurs in the D-flat direction of the two Higgs doublets.Comment: 13 pages, 1 figur