Dilatonic Inflation and Susy Breaking in String-Inspired Supergravity

Abstract

The theory of inflation will be investigated as well as supersymmetry breaking in the context of supergravity, incorporating the target-space duality and the nonperturbative gaugino condensation in the hidden sector. We found an inflationary trajectory of a dilaton field and a condensate field which breaks supersymmetry at once. The model satisfies the slow-roll condition which solves the η-problem. When the particle rolls down along the minimized trajectory of the potential V (S, Y ) at a duality invariant point of T = 1, we can obtain the e-fold value ∼ 57. And then the cosmological parameters obtained from our model well match the recent WMAP data combined with other experiments. This observation suggests one to consider the string-inspired supergravity as a fundamental theory of the evolution of the universe as well as the particle theory.

Spin, torsion and violation of null energy condition in traversable wormholes

“…In the theory of supergravity the Rarita-Schwinger field is associated with the conjectural gravitino, the supersymmetric partner of graviton [33,36,37,38]. In general, the Rarita-Schwinger Lagrangian describes a massive particle with spin− 3 2 [33,38]…”

Inflation, Gravitino and Reheating in Modified Modular invariant Supergravity

“…where η is Dedekind's η function, c is a free parameter in the theory and S is a dilaton, T is a moduli and Y is a complex scalar superfield defined by the gaugino condensation U ∼< λ λ >= Y 3 of the E 8 hidden sector [2], and α, β are new parameters that should be determined from observations. The renormalization group parameter b = 15 16π 2 can correspond to the E 8 hidden sector gauge group.…”

“…A modified string-inspired modular invariant supergravity is proposed here to apply it to inflationary cosmology. Because inflation is concerned with Planck scale physics, the dilaton can be one of the strong candidates for the inflaton [3,4]. We assume that the massless Goldstino is identified with the dilatino S because the mass of S satisfies m SS = 0, where m is defined by m ≡ e K/2 W .…”

Dilatonic Inflation and Susy Breaking in Modular-Invariant Supergravity

“…Although recently the inflation theories in string theories are extensively and promissingly investigated by various authors [5], here we concentrate on the framework of a supergravity inspired by superstrings, following previous papers [7,8,9]. The well-known difficulty of supergravity is that the potential form gives arise the ηproblem [8], which breaks the slow-roll condition.…”

“…In this paper, the angular power spectrum in modularinvariant supergravity is investigated in the model where we had shown that the inflation and the supersymmetry breaking occur at once by the interplay between the dilaton field as the inflaton and the condensated gaugesinglet field rolling down the inflationary trajectory, free from the η-problem [9].…”