750 research outputs found
Holography in 4D (Super) Higher Spin Theories and a Test via Cubic Scalar Couplings
The correspondences proposed previously between higher spin gauge theories
and free singleton field theories were recently extended into a more complete
picture by Klebanov and Polyakov in the case of the minimal bosonic theory in
D=4 to include the strongly coupled fixed point of the 3d O(N) vector model.
Here we propose an N=1 supersymmetric version of this picture. We also
elaborate on the role of parity in constraining the bulk interactions, and in
distinguishing two minimal bosonic models obtained as two different consistent
truncations of the minimal N=1 model that retain the scalar or the
pseudo-scalar field. We refer to these models as the Type A and Type B models,
respectively, and conjecture that the latter is holographically dual to the 3d
Gross-Neveu model. In the case of the Type A model, we show the vanishing of
the three-scalar amplitude with regular boundary conditions. This agrees with
the O(N) vector model computation of Petkou, thereby providing a non-trivial
test of the Klebanov-Polyakov conjecture.Comment: 30p
On the statistical Analysis of Feigenbaum Constants
Cataloged from PDF version of article.We present statistical analysis of blocks in the binary expansions of Feigenbaum constants a and d
for the logistic map. The analysis is carried out on both 1016 and 3400 bit expansions. A w2 test is
applied for lumping data and a serial test is applied on gliding data. Contrary to a previous research
by Karamanos and Kotsireas, our test results did not indicate any evidence to reject randomness of
these constants. Additional 25 randomness tests also support the conjecture of randomness of these
constants having transcendental character.
r 2006 The Franklin Institute. Published by Elsevier Ltd. All rights reserved
The supermembrane revisited
The M2-brane is studied from the perspective of superembeddings. We review
the derivation of the M2-brane dynamics and the supergravity constraints from
the standard superembedding constraint and we discuss explicitly the induced
d=3, N=8 superconformal geometry on the worldvolume. We show that the gauged
supermembrane, for a target space with a U(1) isometry, is the standard
D2-brane in a type IIA supergravity background. In particular, the D2-brane
action, complete with the Dirac-Born-Infeld term, arises from the gauged
Wess-Zumino worldvolume 4-form via the brane action principle. The discussion
is extended to the massive D2-brane considered as a gauged supermembrane in a
massive D=11 superspace background. Type IIA supergeometry is derived using
Kaluza-Klein techniques in superspace.Comment: Latex, 46 pages, clarifying remarks and references adde
Yang-Mills-Chern-Simons Supergravity
N=(1,0) supergravity in six dimensions admits AdS_3\times S^3 as a vacuum
solution. We extend our recent results presented in hep-th/0212323, by
obtaining the complete N=4 Yang-Mills-Chern-Simons supergravity in D=3, up to
quartic fermion terms, by S^3 group manifold reduction of the six dimensional
theory. The SU(2) gauge fields have Yang-Mills kinetic terms as well as
topological Chern-Simons mass terms. There is in addition a triplet of matter
vectors. After diagonalisation, these fields describe two triplets of
topologically-massive vector fields of opposite helicities. The model also
contains six scalars, described by a GL(3,R)/SO(3) sigma model. It provides the
first example of a three-dimensional gauged supergravity that can obtained by a
consistent reduction of string-theory or M-theory and that admits AdS_3 as a
vacuum solution. There are unusual features in the reduction from
six-dimensional supergravity, owing to the self-duality condition on the 3-form
field. The structure of the full equations of motion in N=(1,0) supergravity in
D=6 is also elucidated, and the role of the self-dual field strength as torsion
is exhibited.Comment: Latex, 22 pages, hep-th number correcte
Twistor Superstring in 2T-Physics
By utilizing the gauge symmetries of Two-Time Physics (2T-physics), a
superstring with linearly realized global SU(2,2|4) supersymmetry in 4+2
dimensions (plus internal degrees of freedom) is constructed. It is shown that
the dynamics of the Witten-Berkovits twistor superstring in 3+1 dimensions
emerges as one of the many one time (1T) holographic pictures of the 4+2
dimensional string obtained via gauge fixing of the 2T gauge symmetries. In
2T-physics the twistor language can be transformed to usual spacetime language
and vice-versa, off shell, as different gauge fixings of the same 2T string
theory. Further holographic string pictures in 3+1 dimensions that are dual
theories can also be derived. The 2T superstring is further generalized in the
SU(4)=SO(6) sector of SU(2,2|4) by the addition of six bosonic dimensions, for
a total of 10+2 dimensions. Excitations of the extra bosons produce a SU(2,2|4)
current algebra spectrum that matches the classification of the high spin
currents of N=4, d=4 super Yang Mills theory which are conserved in the weak
coupling limit. This spectrum is interpreted as the extension of the SU(2,2|4
classification of the Kaluza-Klein towers of typeII-B supergravity compactified
on AdS{5}xS(5), into the full string theory, and is speculated to have a
covariant 10+2 origin in F-theory or S-theory. Further generalizations of the
superstring theory to 3+2, 5+2 and 6+2 dimensions, based on the supergroups
OSp(8|4), F(4), OSp(8*|4) respectively, and other cases, are also discussed.
The OSp(8|4) case in 6+2 dimensions can be gauge fixed to 5+1 dimensions to
provide a formulation of the special superconformal theory in six dimensions
either in terms of ordinary spacetime or in terms of twistors.Comment: 26 pages, LaTeX. In version 3, section 5, it is argued that the 6+2
2T-superstring with OSp(8*|4) supersymmetry provides a description of the
special d=6 superconformal theory based on the tensor supermultiplet (not d=6
SYM as mentioned in version 2
Test particles behavior in the framework of a lagrangian geometric theory with propagating torsion
Working in the lagrangian framework, we develop a geometric theory in vacuum
with propagating torsion; the antisymmetric and trace parts of the torsion
tensor, considered as derived from local potential fields, are taken and, using
the minimal action principle, their field equations are calculated. Actually
these will show themselves to be just equations for propagating waves giving
torsion a behavior similar to that of metric which, as known, propagates
through gravitational waves. Then we establish a principle of minimal
substitution to derive test particles equation of motion, obtaining, as result,
that they move along autoparallels. We then calculate the analogous of the
geodesic deviation for these trajectories and analyze their behavior in the
nonrelativistic limit, showing that the torsion trace potential has a
phenomenology which is indistinguishable from that of the gravitational
newtonian field; in this way we also give a reason for why there have never
been evidence for it.Comment: 12 pages, no figures, to appear on Int. Journ. Mod. Phys.
Unfolding Mixed-Symmetry Fields in AdS and the BMV Conjecture: I. General Formalism
We present some generalities of unfolded on-shell dynamics that are useful in
analysing the BMV conjecture for mixed-symmetry fields in constantly curved
backgrounds. In particular we classify the Lorentz-covariant Harish-Chandra
modules generated from primary Weyl tensors of arbitrary mass and shape, and in
backgrounds with general values of the cosmological constant. We also discuss
the unfolded notion of local degrees of freedom in theories with and without
gravity and with and without massive deformation parameters, using the language
of Weyl zero-form modules and their duals.Comment: Corrected typos, references added, two figures, some remarks and two
subsections added for clarit
Massive higher spins and holography
We review recent progress towards the understanding of higher spin gauge
symmetry breaking in AdS space from a holographic vantage point. According to
the AdS/CFT correspondence, N=4 SYM theory at vanishing coupling constant
should be dual to a theory in AdS which exhibits higher spin gauge symmetry
enhancement. When the SYM coupling is non-zero, all but a handful of HS
currents are violated by anomalies, and correspondingly local higher spin
symmetry in the bulk gets spontaneously broken. In agreement with previous
results and holographic expectations, we find that, barring one notable
exception (spin 1 eating spin 0), the Goldstone modes responsible for HS
symmetry breaking in AdS have non-vanishing mass even in the limit in which the
gauge symmetry is restored. We show that spontaneous breaking a' la
Stueckelberg implies that the mass of the relevant spin s'=s-1 Goldstone field
is exactly the one predicted by the correspondence.Comment: 8 pages, talk presented by M.B. at the "Fourth Meeting on Constrained
Dynamics and Quantum gravity" held in Cala Gonone (Sardinia, Italy),
September 12-16, 200
On the covariant quantization of tensionless bosonic strings in AdS spacetime
The covariant quantization of the tensionless free bosonic (open and closed)
strings in AdS spaces is obtained. This is done by representing the AdS space
as an hyperboloid in a flat auxiliary space and by studying the resulting
string constrained hamiltonian system in the tensionless limit. It turns out
that the constraint algebra simplifies in the tensionless case in such a way
that the closed BRST quantization can be formulated and the theory admits then
an explicit covariant quantization scheme. This holds for any value of the
dimension of the AdS space.Comment: 1+16 pages; v4 two clarifications adde
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