Cosmological Creation of D-branes and anti-D-branes

TL;DR

The paper presents a cosmological mechanism for the production of D-branes via tachyonic phase transitions on an initial stack of space-filling branes, grounded in K-theory classifications of D-brane charges. As the early universe cools below a critical temperature $T_c \sim T_H/\sqrt{g_s N}$, tachyons condense and branes annihilate, leaving lower-dimensional branes as topological defects through the Kibble mechanism; entropy considerations strongly favor lower-dimensional branes, notably D3-branes, with a conservative lower bound of one brane per Hubble volume. Type IIB results are central, with Type IIA duals discussed via K-homology, and the framework provides a way to realize brane-world scenarios from fundamental string theory. The approach also highlights potential cosmological challenges, such as brane overproduction and the need for inflation or dilution mechanisms to resolve them, while offering a background-independent, topologically grounded path to brane networks in the early universe.

Abstract

We argue that the early universe may be described by an initial state of space-filling branes and anti-branes. At high temperature this system is stable. At low temperature tachyons appear and lead to a phase transition, dynamics, and the creation of D-branes. These branes are cosmologically produced in a generic fashion by the Kibble mechanism. From an entropic point of view, the formation of lower dimensional branes is preferred and $D3$ brane-worlds are exponentially more likely to form than higher dimensional branes. Virtually any brane configuration can be created from such phase transitions by adjusting the tachyon profile. A lower bound on the number defects produced is: one D-brane per Hubble volume.