Cosmic string production towards the end of brane inflation

Abstract

Towards the end of the brane inflationary epoch in the brane world, cosmic strings (but not texture, domain walls or monopoles) are copiously produced during brane collision. These cosmic strings are Dp-branes with (p−1) dimensions compactified. We elaborate on this prediction of the superstring theory description of the brane world. Using the data on the temperature anisotropy in the cosmic microwave background, we estimate the cosmic string tension µ to be around Gµ ≃ 10 −7 . This in turn implies that the anisotropy in the cosmic microwave background comes mostly from inflation, but with a component (of order 10%) from cosmic strings. This cosmic string effect should also be observable in gravitational wave detectors and maybe even pulsar timing measurements.

Brane inflation revisited after WMAP five-year results

“…Nevertheless, the brane/antibrane inflation scenario inspired from string theory naturally indicates that cosmic strings would have a small contribution to the CMB, which is compatible with the observational limits [9,10,15]. This has led to a significant revival of all aspects of cosmic string scenario, including new theoretical motivations, phenomenological implications and direct observational searches, see e.g.…”

Lumps in the throat

“…In brane-antibrane inflation both F-and D-strings are produced at the end of inflation [2,3,25,26]. These F-and D-strings can create (p, q)-strings, which are bound states of p F-strings and q D-strings.…”

“…Similar charge conservation also holds for the q i . To see that suppose we turn on a hypothetical background C (2) field along the (τ, σ) directions. This induces a Chern-Simons term for each string and we obtain the following extra contribution to the action…”

“…However, in our model the strings terminate at σ = 0, so this is the boundary of the strings. Upon this gauge transformation on C (2) , the string actions get a surface term…”

Reheating from Tachyon Condensation

“…Most notably, inflation may be tested more sensitively in the near future by the MAP [1] and PLANCK [2] observations of the cosmic microwave background radiation. Recently there has been significant progress in constructing stringy inflation models which make use of naturally occuring potentials between D-branes to provide the false vacuum energy [3,4,5]. However, these attempts have not adequately addressed the question of how reheating occurs after inflation.…”