1,721 research outputs found
Ward Identity for Membranes
Ward identities in the case of scattering of antisymmetric three form RR
gauge fields off a D2-brane target has been studied in type-IIA theory.Comment: 10 pages, Revtex, Version to appear in Phys.Lett.
The Worldsheet Perspective of T-duality Symmetry in String Theory
The purpose of this article is to present a pedagogical review of T-dualityin
in string theory. The evolution of the closed string is envisaged on the
worldsheet in the presence of its massless excitations. The duality symmetry is
studied when some of the spacial coordinates are compactified on d-dimensional
torus, . The known results are reviewed to elucidate that equations of
motion for the compact coordinates are covariant, being the number
of compact directions. Next, the vertex operators of excited massive levels are
considered in a simple compactification scheme. It is shown that the vertex
operators for each massive level can be cast in a T-duality invariant form in
such a case. Subsequently, the duality properties of superstring is
investigated in the NSR formulation for the massless backgrounds such as
graviton and antisymmetric tensor. The worldsheet superfield formulation is
found to be very suitable for our purpose. The Hassan-Sen compactification is
adopted and it is shown that the worldsheet equations of motion for compact
superfields to be very suitable for our purpose. The Hassan-Sen
compactification is adopted and it is shown that the worldsheet equations of
motion for compact superfields are covariant when the backgrounds are
independent of superfields along compact directions. The vertex operators for
excited levels are presented in the NS-NS sector and it is shown that they can
be cast in T-duality invariant form for the case of Hassan-Sen compactification
scheme. An illustrative example is presented to realize our proposal.Comment: review, 53 page
Analyticity Property of Scattering Amplitude in Theories with Compactified Space Dimensions
We consider a massive, neutral, scalar field theory of mass in a five
dimensional flat spacetime. Subsequently, one spatial dimension is compactified
on a circle, , ofradius . The resulting theory is defined in the
manifold, . The mass spectrum is a state of lowest mass,
, and a tower of massive Kaluza-Klein states. The analyticity property of
the elastic scattering amplitude is investigated in the
Lehmann-Symanzik-Zimmermann (LSZ) formulation of this theory. In the context of
nonrelativistic potential scattering, for the spatial
geometry, it was shown that the forward scattering amplitude does not satisfy
analyticity properties in some cases for a class of potentials. If the same
result is valid in relativistic quantum field theory then the consequences will
be far reaching. We show that the forward elastic scattering amplitude of the
theory, in the LSZ axiomatic approach, satisfies forward dispersion relations.
The importance of the unitarity constraint on the S-matrix, is exhibited in
displaying the properties of the absorptive part of the amplitude.Comment: 36 pages; no figure
M Theory and P-Branes
Ten dimensional type IIA and IIB theories with p-branes are compactified to
8-dimensions. It is shown that resulting branes can be classified according to
the representations of . These p-branes can also
be obtained by compactification of M theory on three torus and various
wrappings of membrane and five brane of the eleven dimensional theory. It is
argued that there is evidence for bound states of the branes in eight
dimensions as is the case in the interpretation of family of
string solutions obtained by Schwarz.Comment: 12 pages, no figures, revte
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