15:00
In this talk, we will discuss two-dimensional theories with discrete
one-form symmetries, examples (which we have been studying
since 2005), their properties, and gauging of the one-form symmetry.
Their most important property is that such theories decompose into a
disjoint union of theories, recently deemed `universes.'
This decomposition has the effect of restricting allowed nonperturbative
sectors, in a fashion one might deem a `multiverse interference effect,'
which has had applications in topics including Gromov-Witten theory and
gauged linear sigma model phases. After reviewing one-form symmetries
and decomposition in general, we will discuss a particular
example in detail to explicitly illustrate these properties and
to demonstrate how
gauging the one-form symmetry projects onto summands in the
decomposition. If time permits, we will briefly review
analogous phenomena in four-dimensional theories with three-form symmetries,
as recently studied by Tanizaki and Unsal.