Dynamical Volume Element in Scale-Invariant and Supergravity Theories

TL;DR

This paper explores the use of a metric-independent volume element in various coordinate-invariant theories, leading to new insights in cosmology, string dynamics, and supergravity, including mechanisms for cosmological constant generation and supersymmetry breaking.

Contribution

It introduces a novel measure density in the action integral that yields new results across gravity, string, and supergravity theories, including dynamical cosmological constants and tension generation.

Findings

Insights into the cosmological constant problem, inflation, and quintessence.

Dynamically induced tension in string models and non-abelian confinement.

Generation of arbitrary cosmological constants and supersymmetry breaking mechanisms.

Abstract

The use in the action integral of a volume element of the form $\Phi d^{D}x$, where $\Phi$ is a metric-independent measure density, can yield new interesting results in all types of known generally coordinate-invariant theories: (1) 4-D theories of gravity plus matter fields; (2) reparametrization invariant theories of extended objects (strings and branes); (3) supergravity theories. In case (1) we obtain interesting insights concerning the cosmological constant problem, inflation and quintessence without the fifth force problem. In case (2) the above formalism leads to dynamically induced tension and to string models of non-abelian confinement. In case (3), we show that the modified-measure supergravity generates an arbitrary dynamically induced cosmological constant, i.e., a new mechanism of dynamical supersymmetry breaking.