1,958 research outputs found
Duality invariance of all free bosonic and fermionic gauge fields
We give a simple general extension to all free bosonic and fermionic massless
gauge fields of a recent proof that spin 2 is duality invariant in flat space.
We also discuss its validity in (A)dS backgrounds and the relevance of
supersymmetry.Comment: 3 page
Some Interesting Properties of Field theories with an Infinite Number of Fields
We give an indication that gravity coupled to an infinite number of fields
might be a renormalizable theory. A toy model with an infinite number of
interacting fermions in four-dimentional space-time is analyzed. The model is
finite at any order in perturbation theory. However, perturbation theory is
valid only for external momenta smaller than , where
is the coupling constant.Comment: 12 pages, LaTe
Dual descriptions of spin two massive particles in via master actions
In the first part of this work we show the decoupling (up to contact terms)
of redundant degrees of freedom which appear in the covariant description of
spin two massive particles in . We make use of a master action which
interpolates, without solving any constraints, between a first, second and
third order (in derivatives) self-dual model. An explicit dual map between
those models is derived. In our approach the absence of ghosts in the third
order self-dual model, which corresponds to a quadratic truncation of
topologically massive gravity, is due to the triviality (no particle content)
of the Einstein-Hilbert action in . In the second part of the work, also
in , we prove the quantum equivalence of the gauge invariant sector of a
couple of self-dual models of opposite helicities (+2 and -2) and masses
and to a generalized self-dual model which contains a quadratic
Einstein-Hilbert action, a Chern-Simons term of first order and a Fierz-Pauli
mass term. The use of a first order Chern-Simons term instead of a third order
one avoids conflicts with the sign of the Einstein-Hilbert action.Comment: title and abstract slightly modified, 3 references added, comments on
interactions include
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
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
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
Chern-Simons Modification of General Relativity
General relativity is extended by promoting the three-dimensional
gravitational Chern-Simons term to four dimensions. This entails choosing an
embedding coordinate v_\mu -- an external quantity, which we fix to be a
non-vanishing constant in its time component. The theory is identical to one in
which the embedding coordinate is itself a dynamical variable, rather than a
fixed, external quantity. Consequently diffeomorphism symmetry breaking is
hidden in the modified theory: the Schwarzschild metric is a solution;
gravitational waves possess two polarizations, each traveling at the velocity
of light; a conserved energy-momentum (pseudo-) tensor can be constructed. The
modification is visible in the intensity of gravitational radiation: the two
polarizations of a gravity wave carry intensities that are suppressed/enchanced
by the extension.Comment: 19 pages, added references, an addition in section
Curvature invariants of static spherically symmetric geometries
We construct all independent local scalar monomials in the Riemann tensor at
arbitrary dimension, for the special regime of static, spherically symmetric
geometries. Compared to general spaces, their number is significantly reduced:
the extreme example is the collapse of all invariants ~ Weyl^k, to a single
term at each k. The latter is equivalent to the Lovelock invariant L_k.
Depopulation is less extreme for invariants involving rising numbers of Ricci
tensors, and also depends on the dimension. The corresponding local
gravitational actions and their solution spaces are discussed.Comment: 14 page
Gravity from self-interaction redux
I correct some recent misunderstandings about, and amplify some details of,
an old explicit non-geometrical derivation of GR.Comment: Final, amplified, published version; GRG (2009
Mass and angular momentum of asymptotically AdS or flat solutions in the topologically massive gravity
We study the conserved charges of supersymmetric solutions in the
topologically massive gravity theory for both asymptotically flat and constant
curvature geometries.Comment: REVTEX4, 8 pages, no figures, added 2 references and a few clarifying
remark
- âŠ