33 research outputs found
Deformed General Relativity and Torsion
We argue that the natural framework for embedding the ideas of deformed, or
doubly, special relativity (DSR) into a curved spacetime is a generalisation of
Einstein-Cartan theory, considered by Stelle and West. Instead of interpreting
the noncommuting "spacetime coordinates" of the Snyder algebra as endowing
spacetime with a fundamentally noncommutative structure, we are led to consider
a connection with torsion in this framework. This may lead to the usual
ambiguities in minimal coupling. We note that observable violations of charge
conservation induced by torsion should happen on a time scale of 10^3 s, which
seems to rule out these modifications as a serious theory. Our considerations
show, however, that the noncommutativity of translations in the Snyder algebra
need not correspond to noncommutative spacetime in the usual sense.Comment: 20 pages, 1 figure, revtex; expanded sections 3 and 4 for clarity,
moved material to appendix B, corrected a few minor error