# What happens when two D-branes annihilate?

What happens when two D-branes annihilate? Do we get a radiation of strings?

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D-branes usually carry charges, so either you have unstable branes (which can decay individually), or brane and anti-brane annihilating. This results in radiation of closed strings, in some cases you can even calculate the rate precisely. Or, in other words, the answer is yes. – user566 Feb 24 '11 at 15:13
Interesting question. This scenario was considered 10 years ago in a PRD paper: Inflation from DD brane annihilation. – user346 Feb 24 '11 at 15:21
@Hiatus: To my mind, your comment seems sufficient for an answer. – qftme Jun 15 '11 at 14:51

## 1 Answer

My answer to your question is in the context of brane inflation. The mechanism is as follows: A pair of D3 and Anti D3 separated by a warped dimension (Bulk), move closer until the separation of the branes is about the string length scale, then a stretched tachyon forms creating an instability that destroys both branes, releasing all the energy to closed string states. Since radiation is included in the spectrum of closed strings, both particles and radiation are produced.

http://arxiv.org/abs/hep-th/0610221

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This is interesting +1, I almost suspected that this should have applications in cosmology, such as inflation for example. The general machanism of tachyon condensation and D-brane anti D-brane annihilation and its variants in different contexts are pedagogically described here. – Dilaton Aug 4 '12 at 21:01