821 research outputs found
Heterotic String Field Theory
We construct the Neveu-Schwarz sector of heterotic string field theory using
the large Hilbert space of the superghosts and the multi-string products of
bosonic closed string field theory. No picture-changing operators are required
as in Wess-Zumino-Witten-like open superstring field theory. The action
exhibits a novel kind of nonpolynomiality: in addition to terms necessary to
cover missing regions of moduli spaces, new terms arise from the boundary of
the missing regions and its subspaces. We determine the action up to quintic
order and a subset of terms to all orders.Comment: 15 pages, no figures, LaTeX2e; v2: minor cosmetic change
WZW-like Action for Heterotic String Field Theory
We complete the construction of the Neveu-Schwarz sector of heterotic string
field theory begun in hep-th/0406212 by giving a closed-form expression for the
action and gauge transformations. Just as the Wess-Zumino-Witten (WZW) action
for open superstring field theory can be constructed from pure-gauge fields in
bosonic open string field theory, our heterotic string field theory action is
constructed from pure-gauge fields in bosonic closed string field theory. The
construction involves a simple alternative form of the WZW action which is
consistent with the algebraic structures of closed string field theory.Comment: 22 pages, no figures, LaTeX2
Gauge theories of spacetime symmetries
Gauge theories of conformal spacetime symmetries are presented which merge
features of Yang-Mills theory and general relativity in a new way. The models
are local but nonpolynomial in the gauge fields, with a nonpolynomial structure
that can be elegantly written in terms of a metric (or vielbein) composed of
the gauge fields. General relativity itself emerges from the construction as a
gauge theory of spacetime translations. The role of the models within a general
classification of consistent interactions of gauge fields is discussed as well.Comment: 8 pages, revtex; v2: minor improvements of text and formulas; v3:
typo in formula after eq. (35) correcte
Thermal history of the string universe
Thermal history of the string universe based on the Brandenberger and Vafa's
scenario is examined. The analysis thereby provides a theoretical foundation of
the string universe scenario. Especially the picture of the initial oscillating
phase is shown to be natural from the thermodynamical point of view. A new tool
is employed to evaluate the multi state density of the string gas. This
analysis points out that the well-known functional form of the multi state
density is not applicable for the important region , and derives a
correct form of it.Comment: 39 pages, no figures, use revtex.sty, aps.sty, aps10.sty &
preprint.st
Light-cone Gauge NSR Strings in Noncritical Dimensions II -- Ramond Sector
Light-cone gauge superstring theory in noncritical dimensions corresponds to
a worldsheet theory with nonstandard longitudinal part in the conformal gauge.
The longitudinal part of the worldsheet theory is a superconformal field theory
called X^{\pm} CFT. We show that the X^{\pm} CFT combined with the
super-reparametrization ghost system can be described by free variables. It is
possible to express the correlation functions in terms of these free variables.
Bosonizing the free variables, we construct the spin fields and BRST invariant
vertex operators for the Ramond sector in the conformal gauge formulation. By
using these vertex operators, we can rewrite the tree amplitudes of the
noncritical light-cone gauge string field theory, with external lines in the
(R,R) sector as well as those in the (NS,NS) sector, in a BRST invariant way.Comment: 33 pages; v2: minor modification
Spacetime Fermions in Light-cone Gauge Superstring Field Theory and Dimensional Regularization
We consider the dimensional regularization of the light-cone gauge type II
superstring field theories in the NSR formalism. In the previous work, we have
calculated the tree-level amplitudes with external lines in the (NS,NS) sector
using the regularization and shown that the desired results are obtained
without introducing contact term interactions. In this work, we study the
tree-level amplitudes with external lines in the Ramond sector. In order to
deal with them, we propose a worldsheet theory to be used instead of that for
the naive dimensional regularization. With the worldsheet theory, we regularize
and define the tree-level amplitudes by analytic continuation. We show that the
results coincide with those of the first quantized formulation.Comment: 28 pages, 5 figures; v2: more details of our manipulations in
subsection 3.2 added, figures and references added; v3: clarifications adde
Remark about Non-BPS D-Brane in Type IIA Theory
In this paper we would like to show simple mechanisms how from the action for
non-BPS D-brane we can obtain action describing BPS D(p-1)-brane in Type IIA
theory.Comment: 13 pages, completely rewritten pape
Symmetry Factors of Feynman Diagrams for Scalar Fields
The symmetry factor of Feynman diagrams for real and complex scalar fields is
presented. Being analysis of Wick expansion for Green functions, the mentioned
factor is derived in a general form. The symmetry factor can be separated into
two ones corresponding to that of connected and vacuum diagrams. The
determination of symmetry factors for the vacuum diagrams is necessary as they
play a role in the effective action and phase transitions in cosmology. In the
complex scalar theory the diagrams different in topology may give the same
contribution, hence inverse of the symmetry factor (1/S) for total contribution
is a summation of each similar ones (1/S_i), i.e., 1/S = \sum_i (1/S_i).Comment: Journal version, new references adde
Proposal of a topological M(atrix) theory
Keeping in mind the several models of M(atrix) theory we attempt to
understand the possible structure of the topological M(atrix) theory
``underlying'' these approaches. In particular we are motivated by the issue
about the nature of the structure of the vacuum of the topological M(atrix)
theory and how this could be related to the vacuum of the electroweak theory.
In doing so we are led to a simple topological matrix model. Moreover it is
intuitively expected from the current understanding that the noncommutative
nature of ``spacetime'' and background independence should lead to a
topological Model. The main purpose of this note is to propose a simple
topological Matrix Model which bears relation to F and M theories. Suggestions
on the origin of the chemical potential term appearing in the matrix models are
given.Comment: 14 pages revte
SUSY flavor structure of generic 5D supergravity models
We perform a comprehensive and systematic analysis of the SUSY flavor
structure of generic 5D supergravity models on with multiple
-odd vector multiplets that generate multiple moduli. The SUSY flavor
problem can be avoided due to contact terms in the 4D effective K\"ahler
potential peculiar to the multi-moduli case. A detailed phenomenological
analysis is provided based on an illustrative model.Comment: 37 pages, 7 figures, Sec.4 is modifie
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