Quasi-local energy from a Minkowski reference
arXiv:1811.05640
Abstract
The specification of energy for gravitating systems has been an unsettled issue since Einstein proposed his pseudotensor. It is now understood that energy-momentum is \emph{quasi-local} (associated with a closed 2-surface). Here we consider quasi-local proposals (including pseudotensors) in the Lagrangian-Noether-Hamiltonian formulations. There are two ambiguities: (i) there are many possible expressions, (ii) they depend on some non-dynamical structure, e.g., a reference frame. The Hamiltonian approach gives a handle on both problems. The Hamiltonian perspective helped us to make a remarkable discovery: with an isometric Minkowski reference a large class of expressions---namely all those that agree with the Einstein pseudotensor's Freud superpotential to linear order---give a common quasi-local energy value. Moreover, with a best-matched reference on the boundary this is the Wang-Yau mass value.
14 pages, accepted by Gen Rel Grav, selected as an Editor's Choice
References in corpus (6)
- Quasilocal mass in general relativity
- Isometric embeddings into the Minkowski space and new quasi-local mass
- Gravitational energy is well defined
- Energy-momentum density in small regions: the classical pseudotensors
- On Freud's superpotential in General Relativity and in Einstein-Cartan theory
- Chen-Nester-Tung quasi-local energy and Wang-Yau quasi-local mass