Searcharxiv⌕ Search

arXiv subjects

Takeshi Sato

Publications and source records attributed to Takeshi Sato.

62 records · Page 4Linked to original sources
arXiv2003

A Quantum Analysis on Recombination of D-branes and its Implications for an Inflation Model

A quantum-mechanical technique is used within the framework of U(2) super-Yang-Mills theory to investigate processes after recombination of two D-p-branes at one angle. Two types of initial conditions are considered, one of which with $p=4$ is a candidate of inflation mechanism. It is shown that the branes' shapes come to have three extremes due to localization of tachyon condensation. ``Pair-creations'' of open stings connecting the recombined branes is also observed. The appearance of closed strings is also discussed; the decaying branes are shown to radiate non-vanishing gravitational wave, which may be interpreted as evidence of closed string appearance. A few speculations are also given on implications of the above phenomena for an inflation model.

hep-th↗
arXiv2000

On dimensional reductions of the M-9-brane

We discuss the relations of the M-9-brane with other branes via dimensional reductions, mainly focusing on their Wess-Zumino (WZ) actions. It is shown that on three kinds of dimensional reductions, the WZ action of the M-9-brane respectively gives those of the D-8-brane, the ``KK-8A brane'' (which we regard as a kind of D-8-brane) and the ``NS-9A brane'', the last two actions of which were obtained via dualities. Based on these results, we conclude that the relation of p-branes for $p\ge 8$, proposed previously, is consistent from the viewpoint of worldvolume actions.

hep-th↗
arXiv2000

The mass formula for a fundamental string as a BPS solution of a D-brane's worldvolume

We propose a (generalized) ``mass formula'' for a fundamental string described as a BPS solution of a D-brane's worldvolume. The mass formula is obtained by using the Hamiltonian density on the worldvolume, based on transformation properties required for it. Its validity is confirmed by investigating the cases of point charge solutions of D-branes in a D-8-brane (i.e. curved) background, where the mass of each of the corresponding strings is proportional to the geodesic distance from the D-brane to the point parametrized by the (regularized) value of a transverse scalar field. It is also shown that the mass of the string agrees with the energy defined on the D-brane's worldvolume only in the flat background limit, but the agreement does not always hold when the background is curved.

hep-th↗
arXiv2000

A 10-form Gauge Potential and an M-9-brane Wess-Zumino Action in Massive 11D Theory

We discuss some properties of an M-9-brane in ``massive 11D theory'' proposed by Bergshoeff, Lozano and Ortin. A 10-form gauge potential is consistently introduced into the massive 11D supergravity, and an M-9-brane Wess-Zumino action is constructed as that of a gauged $σ$-model. Using duality relations is crucial in deriving the action, which we learn from the study of a 9-form potential in 10D massive IIA theory. A target space solution of an M-9-brane with a non-vanishing 10-form gauge field is also obtained, whose source is shown to be the M-9-brane effective action.

hep-th↗
arXiv1999

Superalgebras in Many Types of M-Brane Backgrounds and Various Supersymmetric Brane Configurations

We derive superalgebras in many types of supersymmetric M-brane backgrounds. The backgrounds examined here include the cases of the M-wave and the M-Kaluza-Klein monopole. On the basis of the obtained algebras, we deduce all the supersymmetric non-orthogonal intersections of the M-Kaluza-Klein monopole and the M-5-brane at angles. In addition, we present a 1/4 supersymmetric worldvolume 3-brane soliton on the M-5-brane in the M-5-brane background as an extended solution of the 3-brane solitons of the M-5-brane by Howe, Lambert and West. This soliton can be interpreted as a certain intersection of three M-5-branes.

hep-th↗
arXiv1998

The Spacetime Superalgebras from M-branes in M-brane Backgrounds

We derive the spacetime superalgebras explicitly from ``test'' M-brane actions in M-brane backgrounds to the lowest order in $θ$ via canonical formalism, and discuss various BPS saturated configurations on the basis of their central charges which depend on the harmonic functions determined by the backgrounds. All the 1/4 supersymmetric intersections of two M-branes obtained previously are deduced from the requirement of the test branes to be so ``gauge fixed'' in the brane backgrounds as to preserve 1/4 supersymmetry. Furthermore, some of 1/2-supersymmetric bound states of two M-branes are deduced from the behavior of the harmonic functions in the limits of vanishing distances of the two branes. The possibilities of some triple intersections preserving 1/4 supersymmetry are also discussed.

hep-th↗
arXiv1998

The Spacetime Superalgebras in a Massive IIA Background via Brane Probes

We derive the spacetime superalgebras explicitly from ``test'' p-brane actions in a D-8-brane (i.e. a massive IIA) background to the lowest order in $θ$ via canonical formalism, and show that the forms of the superalgebras are the same as those in all the other D-brane (i.e. massless IIA) backgrounds, that is, they are indifferent to the presence of the Chern-Simons terms which are proportional to the mass and added to the D-brane actions in the case of massive IIA backgrounds. Thus, we can say that all the D-brane background solutions including a D-8-brane are on equal footing from the viewpoint of the superalgebras via brane probes. We also deduce from the algebra all the previously known 1/4 supersymmetric intersections of a p-brane or a fundamental string with a D-8-brane, as the supersymmetric ``gauge fixings'' of the test branes in the D-8-brane background.

hep-th↗