Tachyon Condensation and Graviton Production in Matrix Theory

Abstract

We study a membrane -- anti-membrane system in Matrix theory. It in fact exhibits the tachyon instability. By suitably representing this configuration, we obtain a (2+1)-dimensional U(2) gauge theory with a 't Hooft's twisted boundary condition. We identify the tachyon field with a certain off-diagonal element of the gauge fields in this model. Taking into account the boundary conditions carefully, we can find vortex solutions which saturate the Bogomol'nyi-type bound and manifest the tachyon condensation. We show that they can be interpreted as gravitons in Matrix theory.

14 pages, LaTeX, Considerable improvements have been made in the arguments on the effective theory of the membrane - antimembrane system. Accordingly the statement on the mechanism of the tachyon condensation and the graviton production has been refined. Abstract and References also corrected