Abstract. We address a long standing problem: the description of energy–momentum (including also angular momentum and the centre-of-mass moment) for gravitating systems. We begin by reconsidering the traditional 'pseudotensor' approaches, both via Noether symmetry and via the field equations. A new general construction for such expressions is presented. The pseudotensor expressions are shown to be quasilocal. By connecting the results to the Hamiltonian, its boundary term and its symplectic variational structure, their significance and their ambiguities are clarified. Our investigations into quasilocal quantities associated with the Hamiltonian boundary term are briefly reviewed; the main achievements are summarized, and some outstanding challenges are noted.

PACS numbers: 04.20.−q, 04.20.Cv, 04.20.Fy

Print publication: Issue 3 (7 February 2004)
Received 21 October 2003
Published 13 January 2004