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“Unitarity of Born-Infeld Gravities”

By

Tahsin Çağrı Şişman

Abstract: We develop techniques of analyzing the unitarity of
general Born-Infeld (BI) gravity actions in
D-dimensional spacetimes. Determinantal
form of the action allows us to find a compact expression quadratic in the
metric fluctuations around constant curvature backgrounds. This is highly
nontrivial since for the BI actions around constant curvature backgrounds, in
principle, infinitely many terms in the curvature expansion should contribute
to the quadratic action in the metric fluctuations which would render the unitarity analysis intractable. Moreover in even
dimensions, unitarity of the theory depends only on
finite number of terms built from the powers of the curvature tensor. We apply
our techniques to in some four-dimensional examples.

Date:
October 21, 2010 Thursday

Time: 15.40

Place: Mathematics Seminar Room,
SA-141