A positive Bondi-type mass in asymptotically de Sitter spacetimes

作者：Szabados Laszlo B^*; Tod Paul

来源：Classical and Quantum Gravity, 2015, 32(20): 205011.

DOI：10.1088/0264-9381/32/20/205011

• de Sitter spacetime
• Bondi mass
• two-surface twistors

The general structure of the conformal boundary J(+) of asymptotically de Sitter spacetimes is investigated. First we show that Penrose's quasi-local mass, associated with a cut. of the conformal boundary, can be zero even in the presence of outgoing gravitational radiation. On the other hand, following a Witten-type spinorial proof, we show that an analogous expression based on the Nester-Witten form is finite only if the Witten spinor field solves the two-surface twistor equation on S, and it yields a positive functional on the twosurface twistor space on S, provided the matter fields satisfy the dominant energy condition. Moreover, this functional is vanishing if and only if the domain of dependence of the spacelike hypersurface which intersects J(+) in the cut. is locally isometric to the de Sitter spacetime. For non-contorted cuts this functional yields an invariant analogous to the Bondi mass.

• 出版日期2015-10-22