Speaker
Description
The type IIB matrix model is a promising candidate for a nonperturbative formulation of superstring theory. In this model, the eigenvalue distribution of the bosonic matrices represents an emergent spacetime, which is determined by the nonperturbative dynamics of the model in the large-N limit. Numerical simulations are therefore indispensable for revealing the structure of the emergent spacetime. In this talk, I first review the model and the idea of emergent spacetime. I then explain the complex Langevin method, which we use to overcome the sign problem in our simulations of the Lorentzian version of the model, and a deformation of the model, which is introduced to avoid the singular-drift problem caused by the Pfaffian. This deformation is inspired by the supersymmetric deformation used to define the "polarized type IIB matrix model" in the Euclidean case. Finally, I present the results of our simulations, which show that the deformed model exhibits a phase in which a (3+1)-dimensional expanding spacetime emerges, with both space and time being smooth and real.