208051552
An Off-Shell Formulation for Internally Gauged D = 5, N = 2 Supergravity from Superconformal Methods
We use the superconformal method to construct a new formulation for pure off-shell D = 5, N = 2 Poincaré supergravity and present its internal gauging. The main difference between the traditional formulation and our new formulation is the choice of the Dilaton Weyl Multiplet as the background Weyl Multiplet and the choice of a Linear compensating Multiplet. We do not introduce an external Vector Multiplet to gauge the theory, but instead use the internal vector of the Dilaton Weyl Multiplet. We show that the corresponding onshell theory is Einstein-Maxwell supergravity. We believe that this gauging method can be applied in more complicated scenarios such as the inclusion of off-shell higher derivative invariants.
207983158
Extension of Starobinsky Model in Old Minimal Supergravity
We provide a succinct way to construct the supersymmetric completion of R (n ≥ 3) in components using superconformal formulation of old minimal supergravity. As a consequence, we obtain the polynomial f(R) supergravity extending the supersymmetric Starobinsky model to any higher power of R. The supersymmetric vacua in polynomial f(R) supergravity are studied. We also present the R extended Minimal Volkov-Akulov-Starobinsky Model.
119181131
Supersymmetric completion of Gauss-Bonnet combination in five dimensions
A bstractBased on superconformal tensor calculus in five dimensions, we construct the supersymmetric completion of Gauss-Bonnet combination. We study the vacuum solutions with AdS2 × S3 and AdS3 × S2 structures. We also analyze the spectrum around a maximally supersymmetric Minkowski5.
119108645
3D Born-Infeld gravity and supersymmetry
A bstractWe construct the most general parity-even higher-derivative N$$ \mathcal{N} $$ = 1 off-shell supergravity model in three dimensions with a maximum of six derivatives. Excluding terms quadratic in the curvature tensor with two explicit derivatives and requiring the absence of ghosts in a linearized approximation around an AdS3 background, we find that there is a unique supersymmetric invariant which we call supersymmetric ‘cubic extended’ New Massive Gravity. The purely gravitational part of this invariant is in agreement with an earlier analysis based upon the holographic c-theorem and coincides with an expansion of Born-Infeld gravity to the required order.Our results lead us to propose an expression for the bosonic part of off-shell N$$ \mathcal{N} $$ = 1 Born-Infeld supergravity in three dimensions that is free of ghosts. We show that different truncations of a perturbative expansion of this expression gives rise to the bosonic part of (i) Einstein supergravity; (ii) supersymmetric New Massive Gravity and (iii) supersymmetric ‘cubic extended’ New Massive Gravity.
119341678
X-ray spectral variations of U Gem from quiescence to outburst
In this paper, we report the discovery of a high-energy component of the X-ray spectra of U Gem, which can be observed while the source is in outburst. We used Chandra and XMM Newton observations to compare the quiescence and outburst X-ray spectra of the source. The additional component may be the result of the reflection of X-rays emitted from an optically thin plasma close to the white dwarf, from the optically thick boundary layer during the outburst. Another possible explanation is that some magnetically channelled accretion may occur on to the equatorial belt of the primary causing shocks similar to the ones in the intermediate polars as it was suggested by Warner and Woudt. We have also found a timing structure at about 73 mHz (∼13.7 s) in the RXTE observation, resembling dwarf novae oscillations.