3 papers
gr-qc2025
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…
hep-th2025
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…
gr-qc2024
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)…