Nonperturbative Effects in Superstring Theory
Project/Area Number  09640380 
Research Category 
GrantinAid for Scientific Research (C).

Section  一般 
Research Field 
素粒子・核・宇宙線

Research Institution  High Energy Accelerator Research Organization (KEK) 
Principal Investigator 
ISHIBASHI Nobuyuki High Energy Accelerator Research Organization Institute of particle and nuclear Studies, assistant professor, 素粒子原子核研究所, 助教授 (70211729)

Project Fiscal Year 
1997 – 2000

Project Status 
Completed(Fiscal Year 2000)

Budget Amount *help 
¥2,600,000 (Direct Cost : ¥2,600,000)
Fiscal Year 2000 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1999 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1998 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1997 : ¥800,000 (Direct Cost : ¥800,000)

Keywords  Superstring Theory / Dbranes / Matrix Model / Noncommutative YangMills Theory / 超弦理論 / Dブレーン / 行列模型 / 非可換センミルズ理論 / 非可換ヤンミルズ理論 / Dブレーン 
Research Abstract 
The main topic, we have studied is the relation between the noncommutative field theory and the nature of the configurations of infinitely many Dbranes. Dbranes are soliton solutions in string theory. A Dbrane in certain dimensions can be described as a configuration of infinitely many lower dimensional Dbranes. we have shown this fact using perturbative string theory. We also discussed how the geometrical aspects of a Dbrane such as reparametrization invariance are realized in the description using lower dimensional branes. Usually the fluctuations of Dbranes are described by using YangMills theory. However, in a background of constant NS antisymmetric tensor field, we should use socalled noncommutative YangMills theory, which is a generalization of YangMills theory on a space with noncommutative coordinates. We showed that this fact can be understood naturally if one consider the Dbrane as a configuration of infinitely many lower dimensional branes or by using matrix models. We also showed that such descriptions are useful in constructing the gauge invariant observables of the theory, or understanding the perturbative aspects of the theory. Moreover, in the matrix model context, 4 dimensional noncommutative YangMills theory can be considered as a realization of the matrix model in 4 spacetime dimensions. We have discussed how gravitational interactions are realized in such a theory. We also studied string theory on a noncompact curved manifold.

Report
(6results)
Research Output
(16results)