Vanishing of cosmological constant and fully localized gravity in a Brane World with extra time(s)

TL;DR

This paper presents a six-dimensional intersecting brane model with one extra space-like and one extra time-like dimension, achieving a vanishing four-dimensional cosmological constant and localized gravity without tachyonic instabilities.

Contribution

It introduces a symmetric configuration in extra dimensions that automatically nullifies the cosmological constant and removes problematic graviton modes, advancing brane world models with extra time dimensions.

Findings

Effective four-dimensional cosmological constant vanishes.

Gravity is fully localized at the brane intersection.

Tachyonic graviton states are eliminated.

Abstract

We construct an intersecting brane configuration in six-dimensional space with one extra space-like and one extra time-like dimensions. With a certain additional symmetry imposed on the extra space-time we have found that effective four-dimensional cosmological constant vanishes automatically, providing the static solution with gravity fully localized at the intersection region as there are no propagating massive modes of graviton. In this way, the same symmetry allows us to eliminate tachyonic states of graviton from the spectrum of the effective four-dimensional theory, thus avoiding phenomenological difficulties comming from the matter instability usually induced in theories with extra time-like dimensions.