Implications of the Spectrum of Dynamically Generated String Tension Theories

TL;DR

This paper explores how dynamically generated string tensions vary among strings and influence cosmological scenarios, including non-singular universes and warped spacetimes, by introducing a tension scalar background field.

Contribution

It introduces a framework where string tension is a dynamical degree of freedom, varying per string and influenced by a new scalar field, affecting cosmological models.

Findings

Different string tensions lead to non-singular cosmologies.

The tension scalar field can be determined by conformal invariance.

Scenarios avoiding the Hagedorn temperature in early universe.

Abstract

The string tension does not have to be put in by hand, it can be dynamically generated, as in the case when we formulate string theory in the modified measure formalism, and other formulations as well. Then string tension appears, but as an additional dynamical degree of freedom . It can be seen however that this string tension is not universal, but rather each string generates its own string tension, which can have a different value for each string. We also define a new Tension scalar background field which change locally the value of the string tension along the world sheets of the strings. When there are many strings with different string tensions this Tension field can be determined from the requirement of world sheet conformal invariance and for two types of string tensions depending on the relative sign of the tensions we obtain non singular cosmologies and warp space scenarios and when the two string tensions are positive, we obtain scenarios where the Hagedorn temperature is avoided in the early universe or in regions of warped space time where the string tensions become very big.