2 papers
physics.class-ph2026
What if active and passive gravitational masses were not equal?
Domenico Giulini
At first glance, combining Newton's laws of motion with his law of gravitation seems straightforward. Students learn to distinguish inertial from gravitational mass and that their…
gr-qc2026
The trace-free Einstein tensor is not variational for the metric as field variable
Arian L. von Blanckenburg, Domenico Giulini, Philip K. Schwartz
It is well-known that the trace-free Einstein tensor of a pseudo-Riemannian metric cannot arise by variation of a local diffeomorphism-invariant action functional with the (inverse…