Abelian vector fields non-minimally coupled to uncharged scalar fields arise in many contexts. We investigate here through algebraic methods their consistent deformations ("gaugings"), i.e., the deformations that preserve the number (but not necessarily the form or the algebra) of the gauge symmetries. Infinitesimal consistent deformations are given by the BRST cohomology classes at ghost number zero. We parametrize explicitly these classes in terms of various types of global symmetries and corresponding Noether currents through the characteristic cohomology related to antifields and equations of motion. The analysis applies to all ghost numbers and not just ghost number zero. We also provide a systematic discussion of the linear and quadratic constraints on these parameters that follow from higher-order consistency. Our work is relevant to the gaugings of extended supergravities.

The asymptotic dynamics of AdS 3 gravity with two asymptotically anti-de Sitter regions is investigated, paying due attention to the zero modes, i.e., holonomies along non-contractible circles and their canonically conjugates. This situation covers the eternal black hole solution. We derive how the holonomies around the non-contractible circles couple the fields on the two different boundaries and show that their canonically conjugate variables, needed for a consistent dynamical description of the holonomies, can be related to Wilson lines joining the boundaries. The action reduces to the sum of four free chiral actions, one for each boundary and each chirality, with additional non-trivial couplings to the zero modes which are explicitly written. While the Gauss decomposition of the SL(2, R) group elements is useful in order to treat hyperbolic holonomies, the Iwasawa decomposition turns out to be more convenient in order to deal with elliptic and parabolic holonomies. The connection with the geometric action is also made explicit. Although our paper deals with the specific example of two asymptotically anti-de Sitter regions, most of our global considerations on holonomies and radial Wilson lines qualitatively apply whenever there are multiple boundaries, independently of the form that the boundary conditions explicitly take there.An interesting feature of the analysis is that the holonomy is dynamical and possesses a conjugate momentum. This conjugate momentum can be related to the radial Wilson lines connecting the boundaries. The phase space of the system is therefore not just two copies of the phase spaces of the boundary theories, but there is in addition the global dynamical zero modes described by the holonomy and the radial Wilson lines. In the quantum theory, the Hilbert space does not factorize into the mere tensor product of the boundary Hilbert spaces, but involves also the zero modes. The non-trivial link between the boundary Hilbert spaces does not need to be implemented by hand since it follows from the action, which is not given by mere multiple copies of one boundary action, but possesses an extra piece coupling the dynamical global zero modes to the boundary fields.It turns out that the resulting reduced boundary theory can be viewed as a dynamical theory of the boundary Virasoro charges, which, together with the zero modes, completely capture the physics of the system. These charges transform in the coadjoint representation of the Virasoro group and the boundary dynamics takes place on the coadjoint orbits.This leads to two different descriptions of the boundary dynamics. One is in terms of chiral bosons, which can be viewed as providing Darboux-like coordinates on the coadjoint orbits. Since there are two SL(2, R) factors and two boundaries, one ends up with four chiral bosons theories, one per SL(2, R) factor and boundary. We show that the chiral bosons corresponding to the same SL(2, R) at two different boundaries are linked by the fact that the conjugate momentum to the holonomy (which is ...

We consider the gravitational collapse of a spherically symmetric homogeneous matter distribution consisting of a Weyssenhoff fluid in the presence of a negative cosmological constant. Our aim is to investigate the effects of torsion and spin averaged terms on the final outcome of the collapse. For a specific interior space-time setup, namely the homogeneous and isotropic FLRW metric, we obtain two classes of solutions to the field equations where depending on the relation between spin source parameters, (i) the collapse procedure culminates in a space-time singularity or (ii) it is replaced by a non-singular bounce. We show that, under certain conditions, for a specific subset of the former solutions, the formation of trapped surfaces is prevented and thus the resulted singularity could be naked. The curvature singularity that forms could be gravitationally strong in the sense of Tipler. Our numerical analysis for the latter solutions shows that the collapsing dynamical process experiences four phases, so that two of which occur at the pre-bounce and the other two at post-bounce regimes. We further observe that there can be found a minimum radius for the apparent horizon curve, such that the main outcome of which is that there exists an upper bound for the size of the collapsing body, below which no horizon forms throughout the whole scenario.