A supersymmetric D-brane Model of Space-Time Foam

TL;DR

This paper develops a supersymmetric D-brane model of space-time foam where D0-branes induce quantum fluctuations, potentially explaining dark energy and affecting the propagation of certain particles.

Contribution

It introduces a novel supersymmetric D-brane framework with D0-branes causing quantum fluctuations, linking space-time foam to dark energy and particle propagation effects.

Findings

Vacuum energy remains zero in static configuration

Recoil of D0-branes can generate non-zero vacuum energy

Propagation of massless states is affected by foam, but chiral matter is not

Abstract

We present a supersymmetric model of space-time foam with two stacks of eight D8-branes with equal string tensions, separated by a single bulk dimension containing D0-brane particles that represent quantum fluctuations in the space-time foam. The ground state configuration with static D-branes has zero vacuum energy. However, gravitons and other closed-string states propagating through the bulk may interact with the D0-particles, causing them to recoil and the vacuum energy to become non zero. This provides a possible origin of dark energy. Recoil also distorts the background metric felt by energetic massless string states, which travel at less than the usual (low-energy) velocity of light. On the other hand, the propagation of chiral matter anchored on the D8 branes is not affected by such space-time foam effects.