arXiv subjects

Katsumi Itoh

Publications and source records attributed to Katsumi Itoh.

23 records · Page 2Linked to original sources

arXiv1998

Self-duality in Super D3-brane Action

We establish self-duality of super D3-brane theory as an exact symmetry of the action both in the Lagrangian and Hamiltonian formalism. In the Lagrangian formalism, the action is shown to satisfy the Gaillard-Zumino condition. This algebraic relation is recognized in our previous paper to be a necessary and sufficient condition for generic action of U(1) gauge field strength coupled with gravity and matters to be self-dual. For the super D3-brane action, SO(2) duality transformation of a world-volume gauge field should be associated with SO(2) rotation of fermionic brane coordinates in N=2 SUSY multiplet. This SO(2) duality symmetry is lifted to SL(2,R) symmetry in the presence of a dilaton and an axion background fields. In the canonical formalism, we show that the duality rotation is described by a canonical transformation, and the Hamiltonian of the D3-brane action is invariant under the transformation.

hep-th↗

arXiv1998

Canonical Equivalence between Super D-string and Type IIB Superstring

We show that the super D-string action is canonically equivalent to the type IIB superstring action with a world-sheet gauge field. Canonical transformation to the type IIB theory with dynamical tension is also constructed to establish the SL(2,Z) covariance beyond the semi-classical approximations.

hep-th↗

arXiv1993

BRST Analysis of Physical States in Two-Dimensional Black Hole

We study the BRST cohomology for $SL(2,R)/U(1)$ coset model, which describes an exact string black hole solution. It is shown that the physical spectrum could contain not only the extra discrete states corresponding to those in $c=1$ two-dimensional gravity but also many additional new states with ghost number $N_{FP}= -1 \sim 2$. We also discuss characters for nonunitary representations and the relation of our results to other approaches.

hep-th↗

arXiv1992

Spectrum of Two-Dimensional (Super)Gravity

We review the BRST analysis of the system of a (super)conformal matter coupled to 2D (super)gravity. The spectrum and its operator realization are reported. In particular, the operators associated with the states of nonzero ghost number are given. We also discuss the ground ring structure of the super-Liouville coupled to ${\hat c}=1$ matter. In appendices, hermiticities, states for $c<1$ conformal matter coupled to gravity and the proof for the spectrum are discussed.

hep-th↗

arXiv1991

Brst Cohomology and Physical States in 2D Supergravity Coupled to ${\hat c} \leq 1$ Matter

We study the BRST cohomology for two-dimensional supergravity coupled to $\hat c \leq 1$ superconformal matter in the conformal gauge. The super-Liouville and superconformal matters are represented by free scalar fields $ϕ^L$ and $ϕ^M$ and fermions $ψ^L$ and $ψ^M$, respectively, with suitable background charges, and these are coupled in such a way that the BRST charge is nilpotent. The physical states of the full theory are determined for NS and R sectors. It is shown that there are extra states with ghost number $N_{FP}=0,\pm 1$ for discrete momenta other than the degree of freedom corresponding to the ``center of mass", and that these are closely related to the ``null states" in the minimal models with $\hat c<1$.

hep-th↗