Dimension-changing exact solutions of string theory

Superstring theories in the critical dimension D = 10 are connected to one another by a well-explored web of dualities. In this paper we use closed-string tachyon condensation to connect the supersymmetric moduli space of the critical supersting to non-supersymmetric string theories in more than ten dimensions. We present a new set of cliassical solutions that exhibit dynamical transitions between string theories in different dimensions, with different degrees of stability and different amounts and spacetime supersymmetry. In all examples, the string-frame metric and dilation gradient readjust themselves during the transition. The central charge of the worldsheet theory remain equal to 15, one-loop diagram on the string woldsheet. Allowed supersymmetric final states include half-BPS vacua of tyep II and SO(32) heterotic string theory. We also find solutions that bypass the critical dimension altogether and proceed directly to spacelike linear dilation theories in dimensions great than or equal to two.