6 papers
Bessel-Hagen currents for linearised Weyl-squared gravity
Michael Hobson, Will Barker, Anthony Lasenby
For the Fierz-Pauli action the Bessel-Hagen construction does not produce a preferred local gauge-invariant energy-momentum tensor; it identifies only a gauge-invariant equivalence…
Numerical polology: towards next-generation model-building for cosmology
Will Barker, Will Handley, Michael Hobson +4
The dark sector need not be restricted to simple field content. Indeed, simple bosonic configurations, such as scalar-tensor or dark photon models, contrast with the much richer pi…
Bessel-Hagen currents for the Fierz-Pauli action
Michael Hobson, Will Barker, Anthony Lasenby
For electromagnetism in Minkowski spacetime, the Bessel-Hagen method gives a particularly direct Noetherian derivation of the standard gauge-invariant energy-momentum tensor. The k…
The radial metric function does not identify null surfaces
Yi-Hsiung Hsu, Will Barker, Michael Hobson +1
We investigate the conditions under which a hypersurface becomes null through the use of coordinate transformations. We demonstrate that, in static spacetimes, the correct criterio…
Every Poincaré gauge theory is conformal: a compelling case for dynamical vector torsion
Will Barker, Michael Hobson, Anthony Lasenby +2
The Poincaré gauge theory (PGT) of gravity provides a viable formulation of general relativity (Einstein-Cartan theory), and a popular model-building framework for modified gravit…
Buchdahl bound, photon ring, ISCO and radial acceleration in Einstein-æther theory
Yi-Hsiung Hsu, Anthony Lasenby, Will Barker +2
Spherically symmetric Einstein-æther (EÃ) theory with a Maxwell-like kinetic term is revisited. We consider a general choice of the metric and the æther field, finding that:~(i)…