Holographic Nuclei : Supersymmetric Examples

We provide a dual gravity description of a supersymmetric heavy nucleus, following the idea of our previous paper arXiv:0809.3141. The supersymmetric nucleus consists of a merginal bound state of $A$ baryons distributed over a ball in 3 dimensions. In the gauge/string duality, the baryon in N=4 super Yang-Mills (SYM) theory corresponds to a D5-brane wrapping S^5 of the AdS_5 x S^5 spacetime, so the nucleus corresponds to a collection of $A$ D5-branes. We take a large $A$ and a near horizon limits of a back-reacted geometry generated by the wrapped $A$ D5-branes, where we find a gap in the supergravity fluctuation spectrum. This spectrum is a gravity dual of giant resonances of heavy nuclei, in the supersymmetric toy example of QCD.