Classical metastable supersymmetry breaking with D-terms: Tree-level nests and vacuum towers

In this talk, we present three examples of new non-trivial vacuum structures that can occur in supersymmetric field theories, along with explicit models in which they arise. The first vacuum structure is one in which supersymmetry is broken at tree-level in a perturbative theory that also contains a supersymmetry-preserving ground state. Models realizing this structure are uniquely characterized by the fact that no flat directions appear in the classical potential, all vacua appear at finite distances in field space, and no non-perturbative physics is required for vacuum stability. The second non-trivial vacuum structure we discuss consists of large (and even infinite) towers of metastable vacua, and we show that models which give rise to such vacuum towers exhibit a rich set of instanton-induced vacuum tunneling dynamics. Finally, our third new non-trivial vacuum structure consists of an infinite number of degenerate vacua; this leads to a Bloch-wave ground state and a vacuum "band" structure. Models with such characteristics therefore experience time-dependent vacuum oscillations. Needless to say, these novel vacuum structures lead to many new potential applications for supersymmetric field theories, ranging from the cosmological-constant problem to the string landscape, supersymmetry breaking, and Z′ phenomenology.