9 papers
Covariant variation for point-particle Lagrangians
Finnian Gray, Sebastian Murk, Daniel R. Terno
Structureless test particles in general relativity follow geodesics. For extended bodies, higher-order multipole moments lead to departures from geodesic motion; in particular, spi…
Apparent horizon as a membrane
Daniel R. Terno
The requirement that a trapped spacetime domain forms in finite time for distant observers is logically possible and sometimes unavoidable, but its consequences are not yet fully u…
Classical-quantum gravity as quantum gravity in disguise
Masahiro Hotta, Sebastian Murk, Daniel R. Terno
Whether gravity must be quantized remains one of the biggest open problems in fundamental physics. Classical-quantum hybrid theories have recently attracted attention as a possible…
Exotic Encounters: Buchdahl's Conditions and Physical Black Holes
Ioannis Soranidis, Daniel R. Terno
Black holes are among the most well-known astrophysical objects, yet their physical realisation remains conceptually subtle. We analyse physical black holes -- light-trapping regio…
Padé metrics for black hole perturbations and light rings
Swayamsiddha Maharana, Fil Simovic, Ioannis Soranidis +1
Most distinguishing features of black holes and their mimickers are concentrated near the horizon. In contrast, astrophysical observations and theoretical considerations primarily…
Gravity-induced birefringence in spherically symmetric spacetimes
Sebastian Murk, Daniel R. Terno, Rama Vadapalli
Geometric optics effectively describes the propagation of electromagnetic waves when the wavelength is much smaller than the characteristic length scale of the medium, making wave…