Landscape, the Scale of SUSY Breaking, and Inflation

We argue that in the simplest version of the KKLT model, the maximal value ofthe Hubble constant during inflation cannot exceed the present value of thegravitino mass, H< m_{3/2}. This may have important implications for stringcosmology and for the scale of the SUSY breaking in this model. If one wants tohave inflation on high energy scale, one must develop phenomenological modelswith an extremely large gravitino mass. On the other hand, if one insists thatthe gravitino mass should be O(1 TeV), one will need to develop models with avery low scale of inflation. We show, however, that one can avoid theserestrictions in a more general class of KKLT models based on the racetracksuperpotential with more than one exponent. In this case one can combine asmall gravitino mass and low scale of SUSY breaking with the high energy scaleof inflation.Comment: 7 pages, 4 figs, revtex, typos correcte