Kenkyu-Honkan bldg. 1F - Kobayashi Hall
On the emergence of (3+1)-dimensional expanding space-time in the Lorentzian type IIB matrix model (I)
- Mr. Toshihiro AOKI
The type IIB matrix model was proposed as a non-perturbative formulation of superstring theory in 1997. The emergence of (3+1)-dimensional space-time was observed in Monte Carlo studies of its Lorentzian version. This implies that an expanding (3+1)-dimensional space-time naturally appears from (9+1)-dimensional space-time, in which superstring theory is defined. The expanding behavior was studied by simulating simplified versions of the model, which suggested that the expansion is exponential at the beginning, and it turns into a power law at later times. This property is reminiscent of the inflation and the FRW universe, respectively. In this work we investigate the space-time structure of the matrix configurations obtained in the simulation, and find that the expanding 3d space is described essentially by the Pauli matrices. We attribute this problem to an approximation, which is used to avoid the sign problem in Monte Carlo simulation, and discuss the possibility of obtaining a regular space-time if we investigate the original model without such an approximation.