Date: July 22, 2026
Time: 15:15-16:30
Place: 理学部E棟1階E101室
Speaker: Cheng-Tsung WANG (KEK/SOKENDAI)
Title: Emergence of Classical and Quantum Spacetimes in IKKT Matrix Models
Abstract:
The Ishibashi-Kawai-Kitazawa-Tsuchiya (IKKT) matrix model is a promising nonperturbative formulation of type IIB superstring theory, in which spacetime is expected to emerge dynamically from the distribution of matrix eigenvalues, which are interpreted as the positions of D-instantons. Understanding how these matrix degrees of freedom organize into different spacetime structures is one of the central questions in the model.
In this talk, I will present a series of recent works that address this question from several complementary perspectives. I will first discuss the supersymmetric mass-deformed (polarized) IKKT model with Monte-Carlo numerical method, which reveal the interplay among fuzzy-sphere, IKKT, and commuting-matrix saddle configurations and their implications for emergent spacetime.
I will then show how the Wilson loop in two-dimensional bosonic IKKT (Hoppe) matrix model reproduces continuum Yang-Mills theory through large-N reduction. Finally, we move on to the higher-dimensional bosonic IKKT model, where recent progress sheds new light on the nonperturbative dynamics of D-instantons and the microscopic structure of quantum spacetime.
Together, these studies illustrate how the dynamics of matrix eigenvalues provides a unified framework for understanding the emergence of both classical and quantum spacetime in IKKT matrix models.