Nonperturbative formulation of string theory by fermions and the study of black holes
Project/Area Number  10640286 
Research Category 
GrantinAid for Scientific Research (C).

Section  一般 
Research Field 
素粒子・核・宇宙線

Research Institution  RIKKYO UNIVERSITY 
Principal Investigator 
YAHIKOZAWA Shigeaki RIKKYO UNIV., COLLEGE OF SCIENCE, ASSIST.PROFESSOR, 理学部, 助教授 (00192790)

Project Fiscal Year 
1998 – 2000

Project Status 
Completed(Fiscal Year 2000)

Budget Amount *help 
¥3,200,000 (Direct Cost : ¥3,200,000)
Fiscal Year 2000 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1999 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1998 : ¥1,800,000 (Direct Cost : ¥1,800,000)

Keywords  string theory / black hole / Dbrane / noncritical string / spacetime singularity / soliton / shock wave / AichelburgSexl spacetime / 弦理論 / ブラックホール / Dブレイン / 時空特異点 / ソリトン / 衝撃波 / ストリング理論 / ホライズン / AichelburgSexl時空 / D6D2 / enhancon / noncritical string / Dinstanton / nonperturbative effect / string field theory / 非摂動的定式化 / DInstanton / 非臨界弦 / String field / 組み合わせ論 / string equation 
Research Abstract 
The purpose of this research is to construct a nonperturbative formulation of string theory by studying it from the viewpoints of solitons. Dbranes. fermions. singularities of spacetime and black holes. First, we suggest that the boundary cosmological constant ζ in c<1 unitary string theory be regarded as the onedimensional complex coordinate of the target space on which the boundaries of worldsheets can live. From this viewpoint we explicitly construct analogues of Dinstantons which satisfy Polchinsk's "combinatories of boundaries." We further show that our operator formalism developed in the preceding articles is powerful in evaluating Dinstanton effects, and also demonstrate for simple cases that these effects exactly coincide with the stringy nonperturbative effects found in the exact solutions of string equations. Next, we investigate how much a firstquantized charged bosonic test string gets excited after crossing a shock wave generated by a charged particle with mass M^^ and charge Q^^. The shock wave is given by a charged AichelburgSexl (CAS) spacetime where Q^^ = 0 corresponds to the ordinary AichelburgSexl one. We compute the mass expectation value of the charged test string after passing through the shock wave in the CAS spacetime. In the case of small Q^^, gravitational and Coulomb forces are canceled out each other and hence the excitation of the string remains very small. In the case of large Q^^, however, every charged string gets highly excited by quantum fluctuation in the extradimension caused by both the gauge and the axion fields. We have been also studying the enhancon mechanism for the D6D2 system.

Report
(5results)
Research Output
(7results)