Production of Primordial Black Holes in the Double D3-Brane - anti-D3-Brane Inflation Model

A natural extension of the successful $D3$-$\bar{D}3$-brane inflation model in string theory is one with two $D3$-$\bar{D}3$-brane pairs, giving rise to a novel feature in string-theory. When the first pair annihilates, $D1$-strings and $F1$-strings are produced. Following the non-commutative geometric properties in string theory, it is shown by Myers that the presence of the $D3$-charge field strength of the remaining $D3$-$\bar{D}3$-brane pair leads to the formation of dielectric $3$-branes – neutral, finite-size bound states of $3$-branes with $D1$-strings. They behave as matter with little or no pressure. Spanning a wide range of masses, they seed primordial black holes in the early universe.