For an island-like distribution of matter the gravitational energy-momentum tensor is defined according to Weinberg as a source of metric. If this source is formed by selfinteractions of gravitons, so that nonphysical degrees of freedom are excluded, then this source is a reasonable candidate for the energy-momentum tensor of gravitational field. The disastrous influence of the nonphysical degr...

The transformation properties of the single complex quantity, introduced by Green and Wolf to describe the electromagnetic field, are investigated and the physical energy-momentum tensor of this field is derived in terms of the scalar theory. In particular, it is found that the energy density, as defined in the previous paper, is identical with that given by the physical energy-momentum tensor ...

The Møller tetrad gravitational energy-momentum expression was recently evaluated for a small vacuum region using orthonormal frames adapted to Riemann normal coordinates. However the result was not proportional to the Bel-Robinson tensor Bαβμν . Treating a modified quasilocal expressions in a similar way, we found one unique combination that gives a multiple of Bαβμν which provides a non-negat...

The invariant projections of the energy-momentum tensors of Lagrangian densities for tensor fields over differentiable manifolds with contravariant and covariant affine connections and metrics [(Ln, g)-spaces] are found by the use of an non-null (non-isotropic) contravariant vector field and its corresponding projective metrics. The notions of rest mass density, momentum density, energy current...

The applicability of the weak energy condition in flat space quantum field theory to expectation values of the the energy momentum tensor is reconsidered. It is shown how the usual counter arguments against the validity of any positivity condition fail if the states |ψ〉 are restricted to a suitably defined subspace. A possible natural restriction on |ψ〉 is suggested and illustrated by two quant...

In order to understand a boundary description of Hawking radiation in AdS/CFT correspondence, we investigate the trace anomaly method in AdS2 space. In this method, Hawking radiation is derived from the trace anomaly of energy-momentum tensor in the bulk. We find a correspondence between the energy-momentum tensor and a composite operator in CFT1 and understand the anomalous properties of the e...

We study the renormalization of dimension four composite operators and the energy-momentum tensor in noncommutative complex scalar field theory. The proper operator basis is defined and it is proved that the bare composite operators are expressed via renormalized ones with the help of an appropriate mixing matrix which is calculated in the one-loop approximation. The number and form of the oper...