A 3d-3d appetizer

Abstract

We test the 3d-3d correspondence for theories that are labeled by Lens spaces. We find a full agreement between the index of the 3d N= 2 “Lens space theory” T [L(p, 1)] and the partition function of complex Chern-Simons theory on L(p, 1). In particular, for p = 1, we show how the familiar S3 partition function of Chern-Simons theory arises from the index of a free theory. For large p, we find that the index of T[L(p, 1)] becomes a constant independent of p. In addition, we study T[L(p, 1)] on the squashed three-sphere Sb3. This enables us to see clearly, at the level of partition function, to what extent Gℂ complex Chern-Simons theory can be thought of as two copies of Chern-Simons theory with compact gauge group G.