825 research outputs found
Graviton-Form Invariants in D=11 Supergravity
We complete an earlier derivation of the 4-point bosonic scattering
amplitudes, and of the corresponding linearized local supersymmetric invariants
in D=11 supergravity, by displaying the form-curvature, F^2 R^2, terms.Comment: 2 pages. One typo corrected; note added on comparison with D=10
string expansion invariants. Accepted for publication in Phys. Rev. D1
Free Spin 2 Duality Invariance Cannot be Extended to GR
We show by explicit computation that the recently discovered duality
invariance of D=4 linearized gravity fails, already at first self-interacting,
cubic, approximation of GR. In contrast, the cubic Yang-Mills correction to
Maxwell does admit a simple deformed duality.Comment: 11 Page
Counterterms/M-theory Corrections to D=11 Supergravity
We construct a local on-shell invariant in D=11 supergravity from the
nonlocal four-point tree scattering amplitude.Its existence, together with
earlier arguments, implies non-renormalizability of the theory at lowest
possible, two loop, level. This invariant, whose leading bosonic terms are
exhibited, may also express the leading, "zero-slope", Mtheory corrections
to its D=11 supergravity limit.Comment: 16 pages RevTe
Definition of Chern-Simons Terms in Thermal QED_3 Revisited
We present two compact derivations of the correct definition of the
Chern-Simons term in the topologically non trivial context of thermal .
One is based on a transgression descent from a D=4 background connection, the
other on embedding the abelian model in SU(2). The results agree with earlier
cohomology conclusions and can be also used to justify a recent simple
heuristic approach. The correction to the naive Chern-Simons term, and its
behavior under large gauge transformations are displayed.Comment: 9 pages, RevTex, no figures, new derivation from non abelian
embedding adde
No Cosmological D=11 Supergravity
We show, in two complementary ways, that D=11 supergravity---in contrast to
all its lower dimensional versions---forbids a cosmological extension. First,
we linearize the putative model about an Anti de Sitter background and show
that it cannot even support a "global" supersymmetry invariance; hence there is
no Noether construction that can lead to a local supersymmetry. This is true
with the usual 4-form field as well as for a "dual", 7-form, starting point.
Second, a cohomology argument, starting from the original full nonlinear
theory, establishes the absence of deformations involving spin 3/2 mass and
cosmological terms. In both approaches, it is the form field that is
responsible for the obstruction. ``Dualizing'' the cosmological constant to an
11-form field also fails
Duality invariance of s ≥ 3/2 fermions in AdS
We show that in D = 4 AdS, s ≥ 3/2 partially massless (PM) fermions retain the duality invariances of their flat space massless counterparts. They have tuned ratios m^2/M^2 ≠0 that turn them into sums of effectively massless unconstrained helicity ±(s,···, 3/2) excitations, shorn of the lowest (non-dual) helicity ±1/2-rung and — more generally — of succeeding higher rung as well. Each helicity mode is separately duality invariant, like its flat space counterpart
BPS Wilson loops and Bremsstrahlung function in ABJ(M): a two loop analysis
We study a family of circular BPS Wilson loops in N=6 super
Chern-Simons-matter theories, generalizing the usual 1/2-BPS circle. The scalar
and fermionic couplings depend on two deformation parameters and these
operators can be considered as the ABJ(M) counterpart of the DGRT latitudes
defined in N=4 SYM. We perform a complete two-loop analysis of their vacuum
expectation value, discuss the framing dependence and propose a general
relation with cohomologically equivalent bosonic operators. We make an all-loop
proposal for computing the Bremsstrahlung function associated to the 1/2-BPS
cusp in terms of these generalized Wilson loops. When applied to our two-loop
result it reproduces the known expression. Finally, we comment on the
generalization of this proposal to the bosonic 1/6-BPS case.Comment: 46 pages, 6 figures; references adde
A matrix model for the latitude Wilson loop in ABJM theory
In ABJ(M) theory, we propose a matrix model for the exact evaluation of BPS
Wilson loops on a latitude circular contour, so providing a new weak-strong
interpolation tool. Intriguingly, the matrix model turns out to be a particular
case of that computing torus knot invariants in Chern-Simons
theory. At weak coupling we check our proposal against a three-loop
computation, performed for generic framing, winding number and representation.
The matrix model is amenable of a Fermi gas formulation, which we use to
systematically compute the strong coupling and genus expansions. For the
fermionic Wilson loop the leading planar behavior agrees with a previous string
theory prediction. For the bosonic operator our result provides a clue for
finding the corresponding string dual configuration. Our matrix model is
consistent with recent proposals for computing Bremsstrahlung functions exactly
in terms of latitude Wilson loops. As a by-product, we extend the conjecture
for the exact Bremsstrahlung function to generic
representations and test it with a four-loop perturbative computation. Finally,
we propose an exact prediction for at unequal gauge group ranks.Comment: 73 pages; v2: several improvements, JHEP published versio
Correlators of Hopf Wilson loops in the AdS/CFT correspondence
We study at quantum level correlators of supersymmetric Wilson loops with
contours lying on Hopf fibers of . In SYM theory the
strong coupling analysis can be performed using the AdS/CFT correspondence and
a connected classical string surface, linking two different fibers, is
presented. More precisely, the string solution describes oppositely oriented
fibers with the same scalar coupling and depends on an angular parameter,
interpolating between a non-BPS configuration and a BPS one. The system can be
thought as an alternative deformation of the ordinary antiparallel lines giving
the static quark-antiquark potential, that is indeed correctly reproduced, at
weak and strong coupling, as the fibers approach one another.Comment: 38 pages, 5 figure
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