991 research outputs found
Brans-Dicke geometry
We reveal the non-metric geometry underlying omega-->0 Brans-Dicke theory by
unifying the metric and scalar field into a single geometric structure. Taking
this structure seriously as the geometry to which matter universally couples,
we show that the theory is fully consistent with solar system tests. This is in
striking constrast with the standard metric coupling, which grossly violates
post-Newtonian experimental constraints.Comment: 8 pages, v2 with additional comment and reference
Born-Infeld type Gravity
Generalizations of gravitational Born-Infeld type lagrangians are
investigated. Phenomenological constraints (reduction to Einstein-Hilbert
action for small curvature, spin two ghost freedom and absence of Coulomb like
Schwarschild singularity) select one effective lagrangian whose dynamics is
dictated by the tensors g_{\mu\nu} and R_{\mu\nu\rho\sigma}(not R_{\mu\nu} or
the scalar R).Comment: 7 pages, 3 figures, revte
- …