Unitary IIB matrix model and the dynamical generation of the space-time Original Research Article

We propose a unitary matrix model as a regularization of the IIB matrix model of Ishibashi-Kawai-Kitazawa-Tsuchiya (IKKT). The fermionic part is incorporated using the overlap formalism in order to avoid unwanted “doublers” while preserving the global gauge invariance. This regularization, unlike the one adopted by IKKT, has manifest U(1)10 symmetry, which corresponds to the ten-dimensional translational invariance of the space-time. We calculate the one-loop effective action around some typical BPS-saturated configurations in the weak coupling limit. We also discuss a possible scenario for the dynamical generation of the four-dimensional space-time through spontaneous breakdown of the U(1)10 symmetry in the double scaling limit.