2,451 research outputs found
Diffeomorphism, kappa transformations and the theory of non-linear realisations
We will show how the theory of non-linear realisations can be used to
naturally incorporate world line diffeomorphisms and kappa transformations for
the point particle and superpoint particle respectively. Similar results also
hold for a general p-brane and super p-brane, however, we must in these cases
include an additional Lorentz transformation.Comment: 19pages, no figure. References are added and typos are correcte
Dynamics of Carroll Strings
We construct the canonical action of a Carroll string doing the Carroll limit
of a canonical relativistic string. We also study the Killing symmetries of the
Carroll string, which close under an infinite dimensional algebra. The
tensionless limit and the Carroll -brane action are also discussed.Comment: Footnote and references adde
Schwarzschild Black Hole in Noncommutative Spaces
We study the effects of noncommutative spaces on the horizon, the area
spectrum and Hawking temperature of a Schwarzschild black hole. The results
show deviations from the usual horizon, area spectrum and the Hawking
temperature. The deviations depend on the parameter of space-space
noncommutativity.Comment: 4 pages, accepted for publication in Gen.Rel.Gra
A Note on Unitarity of Non-Relativistic Non-Commutative Theories
We analyze the unitarity of a non-relativistic non-commutative scalar field
theory. We show that electric backgrounds spoil unitarity while magnetic ones
do not. Furthermore, unlike its relativistic counterparts, unitarity can not be
restored (at least at the level of one-to-one scattering amplitude) by adding
new states to the theory. This is a signal that the model cannot be embedded in
a natural way in string theory.Comment: 6 pages, 2 figures. References adde
D-branes as a Bubbling Calabi-Yau
We prove that the open topological string partition function on a D-brane
configuration in a Calabi-Yau manifold X takes the form of a closed topological
string partition function on a different Calabi-Yau manifold X_b. This
identification shows that the physics of D-branes in an arbitrary background X
of topological string theory can be described either by open+closed string
theory in X or by closed string theory in X_b. The physical interpretation of
the ''bubbling'' Calabi-Yau X_b is as the space obtained by letting the
D-branes in X undergo a geometric transition. This implies, in particular, that
the partition function of closed topological string theory on certain bubbling
Calabi-Yau manifolds are invariants of knots in the three-sphere.Comment: 32 pages; v.2 reference adde
BIons in topological string theory
When many fundamental strings are stacked together, they puff up into
D-branes. BIons and giant gravitons are the examples of such D-brane
configurations that arise from coincident strings. We propose and demonstrate
analogous transitions in topological string theory. Such transitions can also
be understood in terms of the Fourier transform of D-brane amplitudes.Comment: 21 pages; v.2 references added; v.3 reference added; v.4 minor
corrections; v.5 substantial rewritin
A prediction for bubbling geometries
We study the supersymmetric circular Wilson loops in N=4 Yang-Mills theory.
Their vacuum expectation values are computed in the parameter region that
admits smooth bubbling geometry duals. The results are a prediction for the
supergravity action evaluated on the bubbling geometries for Wilson loops.Comment: 21 pages, latex; v.2 reference added; v.3 minor correction
The Gauge Dual of Gauged N=8 Supergravity Theory
The most general SU(3)-singlet space of gauged N=8 supergravity in
four-dimensions is studied recently. The SU(3)-invariant six scalar fields are
realized by six real four-forms. A family of holographic N=1 supersymmetric RG
flows on M2-branes in three-dimensions is described. This family of flows is
driven by three independent mass parameters from the N=8 SO(8) theory and is
controlled by two IR fixed points, N=1 G_2-invariant one and N=2 SU(3) x
U(1)-invariant one. The generic flow with arbitrary mass parameters is N=1
supersymmetric and reaches to the N=2 SU(3) x U(1) fixed point where the three
masses become identical. A particular N=1 supersymmetric SU(3)-preserving RG
flow from the N=1 G_2-invariant fixed point to the N=2 SU(3) x U(1)-invariant
fixed point is also discussed.Comment: 19pp; added the footnote 1, improved the conclusion and to appear in
IJMP
Noether's theorem and gauge transformations. Application to the bosonic string and CP(2,n-1) model
New results on the theory of constrained systems are applied to characterize the generators of Noethers symmetry transformations. As a byproduct, an algorithm to construct gauge transformations in Hamiltonian formalism is derived. This is illustrated with two relevant examples
Wilson Loops, Geometric Transitions and Bubbling Calabi-Yau's
Motivated by recent developments in the AdS/CFT correspondence, we provide
several alternative bulk descriptions of an arbitrary Wilson loop operator in
Chern-Simons theory. Wilson loop operators in Chern-Simons theory can be given
a description in terms of a configuration of branes or alternatively
anti-branes in the resolved conifold geometry. The representation of the Wilson
loop is encoded in the holonomy of the gauge field living on the dual brane
configuration. By letting the branes undergo a new type of geometric
transition, we argue that each Wilson loop operator can also be described by a
bubbling Calabi-Yau geometry, whose topology encodes the representation of the
Wilson loop. These Calabi-Yau manifolds provide a novel representation of knot
invariants. For the unknot we confirm these identifications to all orders in
the genus expansion.Comment: 26 pages; v.2 typos corrected, explanations clarified; v.3 typos
corrected, reference adde
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