Junction conditions in scalar–tensor theories.

We analyze junction conditions at a null or non-null hypersurface in a large class of scalar–tensor theories in arbitrary dimensions. After showing that the metric and a scalar field must be continuous at as the first junction conditions, we derive the second junctions conditions from the Einstein equations and the equation of motion for the scalar field. Subsequently, we study C1 regular matching conditions as well as vacuum conditions at both in the Jordan and Einstein frames. Our result suggests that the following configurations may be possible; (i) a vacuum thin-shell at null in the Einstein frame, (ii) a vacuum thin-shell at null and non-null in the Jordan frame, and (iii) a non-vacuum C1 regular matching at null in the Jordan frame. Lastly, we clarify the relations between the conditions for C1 regularity and also for vacuum in the Jordan and Einstein frames. [ABSTRACT FROM AUTHOR]

Copyright of Classical & Quantum Gravity is the property of IOP Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)