5,960 research outputs found
Frame-like Geometry of Double Field Theory
We relate two formulations of the recently constructed double field theory to
a frame-like geometrical formalism developed by Siegel. A self-contained
presentation of this formalism is given, including a discussion of the
constraints and its solutions, and of the resulting Riemann tensor, Ricci
tensor and curvature scalar. This curvature scalar can be used to define an
action, and it is shown that this action is equivalent to that of double field
theory.Comment: 35 pages, v2: minor corrections, to appear in J. Phys.
High Spin Gauge Fields and Two-Time Physics
All possible interactions of a point particle with background
electromagnetic, gravitational and higher-spin fields is considered in the
two-time physics worldline formalism in (d,2) dimensions. This system has a
counterpart in a recent formulation of two-time physics in non-commutative
field theory with local Sp(2) symmetry. In either the worldline or field theory
formulation, a general Sp(2) algebraic constraint governs the interactions, and
determines equations that the background fields of any spin must obey. The
constraints are solved in the classical worldline formalism (h-bar=0 limit) as
well as in the field theory formalism (all powers of h-bar). The solution in
both cases coincide for a certain 2T to 1T holographic image which describes a
relativistic particle interacting with background fields of any spin in (d-1,1)
dimensions. Two disconnected branches of solutions exist, which seem to have a
correspondence as massless states in string theory, one containing low spins in
the zero Regge slope limit, and the other containing high spins in the infinite
Regge slope limit.Comment: LaTeX 22 pages. Typos corrected in version
Collective pinning of the vortex lattice by columnar defects in layered superconductors
The mixed phase of layered superconductors with no magnetic screening is
studied through a partial duality analysis of the corresponding frustrated XY
model in the presence of random columnar pins. A small fraction of pinned
vortex lines is assumed. Thermally induced plastic creep of the vortex lattice
within isolated layers results in an intermediate Bose glass phase that
exhibits weak superconductivity across layers in the limit of weak Josephson
coupling. The correlation volume of the vortex lattice is estimated in the
strongly-coupled Bose-glass regime at lower temperature. In the absence of
additional point pins, no peak effect in the critical current density is
predicted to occur on this basis as a function of the Josephson coupling. Also,
the phase transition observed recently inside of the vortex-liquid phase of
high-temperature superconductors pierced by sparse columnar defects is argued
to be a sign of dimensional cross-over.Comment: 16 pages, 1 figure, account of transition to ``nanoliquid'' in BSCCO,
to appear in PR
STRINGY EVIDENCE FOR D=11 STRUCTURE IN STRONGLY COUPLED TYPE II-A SUPERSTRING
Witten proposed that the low energy physics of strongly coupled D=10 type-IIA
superstring may be described by D=11 supergravity. To explore the stringy
aspects of the underlying theory we examine the stringy massive states. We
propose a systematic formula for identifying non-perturbative states in D=10
type-IIA superstring theory, such that, together with the elementary excited
string states, they form D=11 supersymmetric multiplets multiplets in SO(10)
representations. This provides hints for the construction of a weakly coupled
D=11 theory that is dual to the strongly coupled D=10 type IIA superstring.Comment: LaTeX, revtex, 2-column, 10 pages
A Double Sigma Model for Double Field Theory
We define a sigma model with doubled target space and calculate its
background field equations. These coincide with generalised metric equation of
motion of double field theory, thus the double field theory is the effective
field theory for the sigma model.Comment: 26 pages, v1: 37 pages, v2: references added, v3: updated to match
published version - background and detail of calculations substantially
condensed, motivation expanded, refs added, results unchange
Backreacted T-folds and non-geometric regions in configuration space
We provide the backreaction of the T-fold doubly T-dual to a background with
NSNS three-form flux on a three-torus. We extend the backreacted T-fold to
include cases with a flux localized in one out of three directions. We analyze
the resulting monodromy domain walls and vortices. In these backgrounds, we
give an analysis of the action of T-duality on observables like charges and
Wilson surfaces. We analyze arguments for the existence of regions in the
configuration space of second quantized string theory that cannot be reduced to
geometry. Finally, by allowing for space-dependent moduli, we find a
supergravity solution which is a T-fold with hyperbolic monodromies.Comment: 25 pages, 4 figures; v2: minor changes, reference adde
The many faces of OSp(1|32)
We show that the complete superalgebra of symmetries, including central
charges, that underlies F-theories, M-theories and type II string theories in
dimensions 12, 11 and 10 of various signatures correspond to rewriting of the
same OSp(1|32) algebra in different covariant ways. One only has to distinguish
the complex and the unique real algebra. We develop a common framework to
discuss all signatures theories by starting from the complex form of OSp(1|32).
Theories are distinguished by the choice of basis for this algebra. We
formulate dimensional reductions and dualities as changes of basis of the
algebra. A second ingredient is the choice of a real form corresponding to a
specific signature. The existence of the real form of the algebra selects
preferred spacetime signatures. In particular, we show how the real d=10 IIA
and IIB superalgebras for various signatures are related by generalized
T-duality transformations that not only involve spacelike but also timelike
directions. A third essential ingredient is that the translation generator in
one theory plays the role of a central charge operator in the other theory. The
identification of the translation generator in these algebras leads to the star
algebras of Hull, which are characterized by the fact that the positive
definite energy operator is not part of the translation generators. We apply
our results to discuss different T-dual pictures of the D-instanton solution of
Euclidean IIB supergravity.Comment: 30 pages, Latex, using lscape.st
Superstring partition functions in the doubled formalism
Computation of superstring partition function for the non-linear sigma model
on the product of a two-torus and its dual within the scope of the doubled
formalism is presented. We verify that it reproduces the partition functions of
the toroidally compactified type--IIA and type--IIB theories for appropriate
choices of the GSO projection.Comment: 15 page
Heterotic-type IIA duality with fluxes
In this paper we study a possible non-perturbative dual of the heterotic
string compactified on K3 x T^2 in the presence of background fluxes. We show
that type IIA string theory compactified on manifolds with SU(3) structure can
account for a subset of the possible heterotic fluxes. This extends our
previous analysis to a case of a non-perturbative duality with fluxes.Comment: 26 pages, minor corrections; version to appear in JHE
The Signature Triality of Majorana-Weyl Spacetimes
Higher dimensional Majorana-Weyl spacetimes present space-time dualities
which are induced by the Spin(8) triality automorphisms. Different signature
versions of theories such as 10-dimensional SYM's, superstrings, five-branes,
F-theory, are shown to be interconnected via the S_3 permutation group.
Bilinear and trilinear invariants under space-time triality are introduced and
their possible relevance in building models possessing a space-versus-time
exchange symmetry is discussed. Moreover the Cartan's ``vector/chiral
spinor/antichiral spinor" triality of SO(8) and SO(4,4) is analyzed in detail
and explicit formulas are produced in a Majorana-Weyl basis. This paper is the
extended version of hep-th/9907148.Comment: 28 pages, LaTex. Extended version of hep-th/990714
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