Makoto Sakaguchi

From super-AdS5×S5 algebra to super-pp-wave algebra

The isometry algebras of the maximally supersymmetric solutions of IIB supergravity are derived by the Inonu–Wigner contractions of the super-AdS5×S5 algebra. The super-AdS5×S5 algebra allows introducing two contraction parameters; the one for the Penrose limit to the maximally supersymmetric pp-wave algebra and the AdS5×S5 radius for the flat limit. The fact that the Jacobi identity of three supercharges holds irrespectively of these parameters reflects the fact that the number of supersymmetry is not affected under both contractions.

Super-pp-wave algebra from super-AdS×S algebras in eleven dimensions

Abstract Maximally supersymmetric spacetime algebras in eleven dimensions, which are the isometry superalgebras of Minkowski space, AdS7×S4, AdS4×S7 and pp-wave background, are related by Inonu–Wigner contractions. The super-AdS4(7)×S7(4) algebras allow to introduce two contraction parameters, the one for the flat limit to the super-Poincare algebra and the other for a Penrose limit to the super-pp-wave algebra. Under these contractions supersymmetries are maintained because the Jacobi identity of three supercharges holds for any values of contraction parameters.

D-branes of covariant AdS superstrings

Abstract We consider D-branes of open superstrings in the AdS 5 × S 5 background. The possible configurations of D-branes preserving half of supersymmetries are classified by analyzing the κ -invariance of an open superstring in a covariant manner. We also revisit the classification of D-branes in the pp-wave background. It is shown that Penrose limits of the possible D-branes in the AdS 5 × S 5 give all of the D-branes in the pp-wave. In addition, a 1/4 supersymmetric D-string, which is related to the D-string preserving 8 dynamical supersymmetries in the pp-wave, is presented. We also discuss the relation between our result and the AdS branes in a brane probe analysis.

Dirichlet branes of the covariant open supermembrane on a pp-wave background

Abstract We discuss an open supermembrane theory on the maximally supersymmetric pp-wave background in eleven dimensions. The boundary surfaces of an open supermembrane are studied by using the covariant supermembrane theory. In particular, we find the configurations of M5-branes and 9-branes preserving a half of supersymmetries at the origin.

Dirichlet branes of the covariant open supermembrane in AdS4×S7 and AdS7×S4

We discuss an open supermembrane theory in the AdS4×S7 and AdS7×S4 backgrounds. The possible Dirichlet branes of an open supermembrane are classified by analyzing the covariant Wess–Zumino term. All of the allowed configurations are related to those on the pp-wave background via the Penrose limit.

Uniqueness of M-theory pp -wave background with extra supersymmetries

We examine Killing spinor equations of the general eleven-dimensional pp-wave backgrounds, which contain a scalar H(x^m,x^-) in the metric and a three-form xi(x^m,x^-) in the flux. Considering non-harmonic extra Killing spinors, we show that if the backgrounds admit at least one extra Killing spinor in addition to the standard 16 Killing spinors, they can be reduced to the form with H=A_{mn}(x^-)x^mx^n and xi(x^-) modulo coordinate transformations. We further examine the cases in which the extra Killing spinor is characterized by a set of Cartan matrices. The super-isometry algebras of the resulting backgrounds are also derived.

osp(1|32) and extensions of super-AdS5×S5 algebra

Abstract The super-AdS5×S5xa0and the four-dimensional N =4 superconformal algebras play important roles in superstring theories. It is often discussed the roles of the osp(1|32)xa0algebra as a maximal extension of the superalgebras in flat background. In this paper we show that the su(2,2|4), the super-AdS5×S5 algebra or the superconformal algebra, is not a restriction of the osp(1|32) though the bosonic part of the former is a subgroup of the latter. There exist only two types of u(1) extension of the super-AdS5×S5xa0algebra if the bosonic AdS5×S5xa0covariance is imposed. Possible significance of the results is also discussed briefly.

Gauge-invariant action for superstring in Ramond–Ramond plane-wave background

Abstract We present an alternative form of gauge-invariant action for the superstring in the plane wave background with Ramond–Ramond (RR) five-form flux. The Wess–Zumino term is given explicitly in a bilinear form of the left-invariant currents by introducing a fermionic center to define the nondegenerate group metric. The reparametrization invariance generators, whose combinations are conformal generators, and fermionic constraints, half of which generate κ-symmetry, are obtained. Equations of motion are obtained in conformal-invariant and background-covariant manners.

M-theory on a time-dependent plane-wave

We propose a matrix model on a homogeneous plane-wave background with 20 supersymmetries. This background is anti-Mach type and is related to the time-dependent plane-wave background. We study supersymmetries of this matrix model. The vacuum energy of the abelian part is also calculated. In addition we find classical solutions such as graviton solution, fuzzy sphere and hyperboloid.

(p,q)-strings and new spacetime superalgebras

We present a geometric formulation of (p,q)-strings in which the SL(2,)-doublet of the two-form gauge potentials is constructed as second order in the supersymmetric currents. The currents are constructed using a supergroup manifold corresponding to the (p,q)-string superalgebra, which contains fermionic generators in addition to the supercharges and transforms under the SL(2,). The properties of the superalgebra and the generalizations to higher p-branes are discussed.