M. M. Som

Static conformally invariant scalar field

For a massless conformally invariant scalar field, a class of solutions is obtained to the Einstein equations for which the geometry of the space‐time admits one timelike and two spacelike Killing vectors. The class of solutions admit plane‐symmetric and conformally flat solutions as special cases. The metrics can be interpreted as static cylindrically symmetric solutions if one of the spacelike Killing vectors is associated with the rotational motion.

A General Class of Static Solutions of the Einstein-Maxwell-Conformally Invariant Scalar Field Equations

On trouve une classe generale de solutions du champ electromagnetique et scalaire conformement invariant combine dans un espace-temps admettant des isometries le long des axes t, y et z

Spatially homogeneous isotropic models with nonminimally coupled electromagnetic field

In the spatially homogeneous isotropic space–time the consequences of the nonminimal coupling of the electromagnetic vector potential with gravity have been studied. One obtains an equation of state that depends on the scale factor.

Nonminimal coupling via stationary cylindrically symmetric conformally invariant scalar field

SummaryA general class of solutions of the coupled Einstein conformally invariant scalar-field equations is found in the stationary cylindrically symmetric case. The solutions resemble those given by van Stöckum for the Lewis metric. For suitable values of the constants, the azimuthal co-ordinate lines (ϕ-lines) are not closed.RiassuntoSi trova una classe generale di soluzioni delle equazioni di campo scalari conformemente invarianti accoppiate di Einstein nel caso stazionario a simmetria cilindrica. Le soluzioni somigliano a quelle date da Van Stöckum per la metrica di Lewis. Per valori appropriati delle costanti, le linee di coordinate azimutali (linee ϕ) non sono chiuse.

Static, spherically symmetric coupled Einstein-Maxwell conformally invariant scalar field in general relativity

SummaryStatic, spherically symmetric solutions are obtained for Einstein’s field equations with the energy-momentum tensor of a conformally invariant massless scalar field and an electromagnetic field.RiassuntoSi ottengono soluzioni statiche a simmetria sferica per equazioni di campo di Einstein con il tensore energia-impulso di un campo scalare conformemente invariante e di un campo elettromagnetico.