Würzburg Seminar on Quantum Field Theory and Gravity

In this talk, I will demonstrate that the solutions of three-dimensional gravity obtained by gluing two copies of a spacetime across a junction constituted of a tensile string are in one-to-one correspondence with the solutions of the Nambu-Goto equation in the same spacetime up to a finite number of rigid deformations. The non-linear Nambu-Goto equation satisfied by the average of the embedding coordinates of the junction emerges directly from the junction conditions along with the rigid deformations and corrections due to the tension. Our results imply that the classical motion of the fundamental string is itself a consequence of spacetime dynamics in three dimensions. Our results are valid both in three-dimensional flat and AdS spacetimes. In the context of AdS3_33/CFT2_22correspondence, our setup could be used to describe a noble class of interfaces in the conformal field theory featuring a relative time reparametrization which encodes the solution of the Nambu-Goto equation corresponding to the bulk junction. Finally, I will conclude with multiple interesting future directions emerging from our work.

Based on 2404.02149 (Published in JHEP)