5,501 research outputs found
Second order formalism in Poincare gauge theory
Changing the set of independent variables of Poincare gauge theory and
considering, in a manner similar to the second order formalism of general
relativity, the Riemannian part of the Lorentz connection as function of the
tetrad field, we construct theories that do not contain second or higher order
derivatives in the field variables, possess a full general relativity limit in
the absence of spinning matter fields, and allow for propagating torsion fields
in the general case. A concrete model is discussed and the field equations are
reduced by means of a Yasskin type ansatz to a conventional Einstein-Proca
system. Approximate solutions describing the exterior of a spin polarized
neutron star are prsented and the possibility of an experimental detection of
the torsion fields is briefly discussed.Comment: final version, to appear in IJMP
One-parameter teleparallel limit of Poincare gravity
Poincare gauge theories that, in the absence of spinning matter, reduce to
the one-parameter teleparallel theory are investigated with respect to their
mathematical consistency and experimental viability. It is argued that the
theories can be consistently coupled to the known standard model particles.
Moreover, we establish the result that in the classical limit, such theories
share a large class of solutions with general relativity, containing, among
others, the four classical black hole solutions (Schwarzschild,
Reisner-Nordstrom, Kerr and Kerr-Newman), as well as the complete class of
Friedman-Robertson-Walker cosmological solutions, thereby extending older
viability results that were restricted to the correct Newtonian limit and to
the existence of the Schwarzschild solution.Comment: 8 pages, revtex4, accepted for publication in Phys. Rev.
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