Past Events | Particle Theory | The University of Chicago

2025

Particle Theory Seminar: Building up quantum spacetimes with BCFT tensor networks and symmetric quantum RG. - Yikun Jiang, Northeastern University

1:30 pm MCP 201

Building up quantum spacetimes with BCFT tensor networks and symmetric quantum RG.

Tensor network toy models have been invaluable in illustrating various aspects of the AdS/CFT correspondence. But can we construct more realistic tensor networks directly from a CFT and observe the emergence of a higher-dimensional bulk? In this talk, I will present a new step-by-step framework within CFT2 that constructs an exact CFT2 and at the same time AdS3 spacetime tensor network, using “BCFT Legos.” I will illustrate this procedure with explicit examples that exhibit an emergent 3D quantum gravity dual and demonstrate how geometry naturally arises from the BCFT OPE algebra. A key ingredient in this construction is the recent development of generalized global symmetries, which enables a built-in, symmetry-preserving real-space RG flow. This naturally transforms the holographic tensor network into an exact MERA-like structure. Additionally, I will discuss the implications for the factorization puzzle and show how this approach recovers key features of earlier tensor network toy models—those describing wavefunctions on fixed time slices and connected to derivations of the Ryu-Takayanagi formula.

Apr 23