QUANTUM TRANSITIONS IN EARLY UNIVERSE IN THE STRING THEORY WITH TDUALITY
Project/Area Number  08640372 
Research Category 
GrantinAid for Scientific Research (C)

Allocation Type  Singleyear Grants 
Section  一般 
Research Field 
素粒子・核・宇宙線

Research Institution  Osaka University 
Principal Investigator 
KIKKAWA Keiji Graduate School of Science, Osaka University, Professor, 大学院・理学研究科, 教授 (10011545)

CoInvestigator(Kenkyūbuntansha) 
KUNITOMO Hiroshi Research Institute for Fandamental Physics, Kyoto U., Associate Professor, 基礎物理学研究所, 助教授 (20202046)

Project Period (FY) 
1996 – 1997

Project Status 
Completed(Fiscal Year 1997)

Budget Amount *help 
¥2,000,000 (Direct Cost : ¥2,000,000)
Fiscal Year 1997 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1996 : ¥1,300,000 (Direct Cost : ¥1,300,000)

Keywords  Tduality / string cosmology / winding mode / Winding number conjugate space / Type ISST / Type I'SST / Topological Field Theory / D5 brane / Instanton / Dbrane / 結合状態 / ディラトン 
Research Abstract 
(1) We have studied the time development of a universe with a torus structure in a string theory. In such a topologically nontrivial space, the Tduality plays as essential role for its time development. When the space is large enough most of closed strings stay there as small loop gas. The space there, which we call the xspace, is defined as the one canonically conjugate to the center of mass momentum of the small loops. As the size of the xspace becomes small, the string winding modes around the torus dominate and the dynamics there is better described by the new space coodinate x, which is conjugate to the winding number w. In the first article in the publication list, we have studied the time development of the torus space with a special care for the transition from xspace to xspace in 2+1 dimensional model, taking account of the back ground gravity and torsion fields. In the fourth article, we studied the possibility of signal exchange between the xspace and xspace through the shinkage of the universe which occurs at the transition period from x to xspace. Although the statistical average of coordinate correlation DELTAx・DELTAx approaches to zero, time development in the xspace after the transition makes it difficult to observe the information from the x space at the present time. (2) In the superstring theory Kunitomo et.al.constructed a generating functional of scattering amplitudes for Type ISST,and found the mechanism how the divergence cancellation in Type ISST can be interpreted in the dual theory Type I'. In the latter, the disk amplitudes which have boundaries on the orbifoled precisely cancel those associated with tadpole amplitudes. (3) Kunitomo et al also constructed a topological field theory which describes the ground states of D5 branes. As a result they showed that the Heisenberg algebras in the instanton moduli space can be interpreted as creation and annihilation operators of the D5 branes.

Report
(3results)
Research Output
(13results)