3 research outputs found
Metric fluctuations and the Weak Equivalence Principle
We describe space--time fluctuations by means of small fluctuations of the
metric on a given background metric. From a minimally coupled Klein--Gordon
equation we obtain within a weak-field approximation up to second order and an
averaging procedure over a finite space--time scale given by the quantum
particle in the non--relativistic limit a modified Schr\"odinger equation. The
dominant modification consists in an anomalous inertial mass tensor which
depends on the type of particle and on the fluctuation scenario. The scenario
considered in this paper is a most simple picture of spacetime fluctuations and
gives an existence proof for an apparent violation of the weak equivalence
principle and, in general, for a violation of Lorentz invariance.Comment: 10 pages, to appear in Class. Quantum Grav. (2008
Consistent couplings between spin-2 and spin-3 massless fields
We solve the problem of constructing consistent first-order
cross-interactions between spin-2 and spin-3 massless fields in flat spacetime
of arbitrary dimension n > 3 and in such a way that the deformed gauge algebra
is non-Abelian. No assumptions are made on the number of derivatives involved
in the Lagrangian, except that it should be finite. Together with locality, we
also impose manifest Poincare invariance, parity invariance and analyticity of
the deformations in the coupling constants.Comment: LaTeX file. 29 pages, no figures. Minor corrections. Accepted for
publication in JHE
Spin three gauge theory revisited
We study the problem of consistent interactions for spin-3 gauge fields in
flat spacetime of arbitrary dimension n>3. Under the sole assumptions of
Poincar\'e and parity invariance, local and perturbative deformation of the
free theory, we determine all nontrivial consistent deformations of the abelian
gauge algebra and classify the corresponding deformations of the quadratic
action, at first order in the deformation parameter. We prove that all such
vertices are cubic, contain a total of either three or five derivatives and are
uniquely characterized by a rank-three constant tensor (an internal algebra
structure constant). The covariant cubic vertex containing three derivatives is
the vertex discovered by Berends, Burgers and van Dam, which however leads to
inconsistencies at second order in the deformation parameter. In dimensions n>4
and for a completely antisymmetric structure constant tensor, another covariant
cubic vertex exists, which contains five derivatives and passes the consistency
test where the previous vertex failed.Comment: LaTeX, 37 pages. References and comments added. Published versio