David S. Pereira

Jordan-like invariant representations of scalar-tensor gravity and the return of imperfect-fluid thermodynamics

It has been shown that the thermodynamics of frame-invariant scalar-tensor gravity admits an Einstein-frame-like invariant representation, in which the scalar sector is minimally coupled and behaves as a perfect fluid with vanishing temperature. We show that this is not the only...

Buchdahl solution generator for Einstein-sigma gravity and multiscalar-tensor gravity

Buchdahl transformations provide a geometric route from vacuum spacetimes to scalar-field solutions. We formulate this mechanism as a target-covariant solution generator for Einstein gravity coupled to nonlinear sigma models in $D>3$ dimensions. On any connected region in which a...