Flat Supergravity Research Articles

Simplifying (super-)BMS algebras

We show that the non-linear BMS5 symmetry algebra of asymptotically flat Einstein gravity in five dimensions, as well as the super-BMS4 superalgebra of asymptotically flat supergravity, can be redefined so as to take a direct sum structure. In the new presentation of the (super-)algebra, angle-dependent translations and angle-dependent supersymmetry transformations commute with the (super-)Poincaré generators. We also explain in detail the structure and charge-integrability of asymptotic symmetries with symmetry parameters depending on the fields (through the charges themselves), a topic relevant for nonlinear asymptotic symmetry algebras.

Dual theory for maximally mathcal{N} extended flat supergravity

Maximally mathcal{N} extended 2 + 1 dimensional flat supergravity theories exist for a class of super-Poincaré algebras for arbitrary mathcal{N} . They have rich asymptotic structures and contain all interesting topological supergravity solutions in presence of non-trivial holonomy. For the asymptotic symmetry algebra being a suitable flat limit of the superconformal algebra, which is an infinite dimensional extension of two copies of Osp( mathcal{N} |2; R) group, we have found the 1 + 1 dimensional chiral WZW model as the dual quantum field theory that describes the dynamics of these solutions. In the Hamiltonian analysis, the reduced phase space resembles a flat super Liouville theory.

New mathcal{N} = 2 SuperBMS3 algebra and invariant dual theory for 3D supergravity

We have constructed a two dimensional theory dual to 3D asymptotically flat Supergravity in presence of two supercharges with(out) internal R-symmetry. The duals in both the cases are identified with chiral Wess-Zumino-Witten models. Further gauging the theories, we show that the dual of the one without R-symmetry is invariant under the well known mathcal{N} = 2 SuperBMS3 introduced in Banerjee et al. arXiv:1609.09210, while for the one with R-symmetry, the dual is invariant under the most generic, so far unknown, quantum mathcal{N} = 2 SuperBMS3 symmetry. We have also commented on the phase space description of the duals.

On the supersymmetry invariance of flat supergravity with boundary

The supersymmetry invariance of flat supergravity (i.e., supergravity in the absence of any internal scale in the Lagrangian) in four dimensions on a manifold with non-trivial boundary is explored. Using a geometric approach we find that the supersymmetry invariance of the Lagrangian requires to add appropriate boundary terms. This is achieved by considering additional gauge fields to the boundary without modifying the bulk Lagrangian. We also construct an enlarged supergravity model from which, in the vanishing cosmological constant limit, flat supergravity with a non-trivial boundary emerges properly.

N=4 supersymmetric BMS3 algebras from asymptotic symmetry analysis

We consider three dimensional $N=4$ flat supergravity, with an abelian R-symmetry enhancing the gravitational phase space. We obtain the field configuration whose asymptotic symmetries at null infinity coincide with the centrally extended $N=4$ super Bondi-Metzner-Sachs (BMS) algebra .The killing spinors for this generic configuration are obtained together with the energy bounds imposed by supersymmetry. It is explicitly shown that the same algebra can be obtained as a flat (AdS radius $\rightarrow \infty$ ) limit of the combined $(2,0)$ and $(0,2)$ sectors of AdS supergravity.

Super-BMS3 invariant boundary theory from three-dimensional flat supergravity

The two-dimensional super-BMS3 invariant theory dual to three-dimensional asymptotically flat mathcal{N}=1 supergravity is constructed. It is described by a constrained or gauged chiral Wess-Zumino-Witten action based on the super-Poincaré algebra in the Hamiltonian, respectively the Lagrangian formulation, whose reduced phase space description corresponds to a supersymmetric extension of flat Liouville theory.

D 3 ¯ $$ \overline{\mathrm{D}3} $$ and dS

The role of the $\overline{\rm D3}$ brane in providing de Sitter vacua with spontaneously broken supersymmetry in the KKLT construction is clarified. The first step in this direction was explained in arXiv:hep-th/0301240, arXiv:hep-th/0308055: it was shown there that in the GKP background the bosonic contributions to the vacuum energy from the DBI and WZ term cancel for a D3 brane, but double for a $\overline{\rm D3}$ brane, leading to de Sitter vacua. The next step was taken in arXiv:1411.1121 where the analogous mechanism of the doubling (cancelation) of the $\overline{\rm D3}$ (D3) DBI and WZ terms was discovered in the presence of Volkov-Akulov fermions living on the brane, in a flat supergravity background. Here we confirm this mechanism of doubling/cancelation for the $\overline{\rm D3}$/D3 brane in the GKP supergravity background preserving $\mathcal{N}=1$, $d=4$ supersymmetry. We find that imaginary self-dual $G_{(3)}$ flux of type $(2,1)$ nicely removes the $SU(3)$ fermion triplet by giving it a large mass, while leaving the Volkov-Akulov goldstino, which is the $SU(3)$ singlet, massless. This makes the de Sitter landscape in D-brane physics clearly related to de Sitter vacua in effective $d=4$ supergravity with a nilpotent multiplet and spontaneously broken supersymmetry.

Asymptotic symmetries and dynamics of three-dimensional flat supergravity

A consistent set of asymptotic conditions for the simplest supergravity theory without cosmological constant in three dimensions is proposed. The canonical generators associated to the asymptotic symmetries are shown to span a supersymmetric extension of the BMS$_3$ algebra with an appropriate central charge. The energy is manifestly bounded from below with the ground state given by the null orbifold or Minkowski spacetime for periodic, respectively antiperiodic boundary conditions on the gravitino. These results are related to the corresponding ones in AdS$_3$ supergravity by a suitable flat limit. The analysis is generalized to the case of minimal flat supergravity with additional parity odd terms for which the Poisson algebra of canonical generators form a representation of the super-BMS$_3$ algebra with an additional central charge.

Black branes on the linear dilaton background

We show that the complete static black p-brane supergravity solution with a single charge contains two and only two branches with respect to behavior at infinity in the transverse space. One branch is the standard family of asymptotically flat black branes, and another is the family of black branes which asymptotically approach the linear dilaton background with antisymmetric form flux (LDB). Such configurations were previously obtained in the near-horizon near-extreme limit of the dilatonic asymptotically flat p-branes, and used to describe the thermal phase of field theories involved in the DW/QFT dualities and the thermodynamics of little string theory in the case of the NS5-brane. Here we show by direct integration of the Einstein equations that the asymptotically LDB p-branes are indeed exact supergravity solutions, and we prove a new uniqueness theorem for static p-brane solutions satisfying cosmic censorship. In the non-dilatonic case, our general non-asymptotically flat p-branes are uncharged black branes on the background $AdS_{p+2}\times S^{D-p-2}$ supported by the form flux. We develop the general formalism of quasilocal quantities for non-asymptotically flat supergravity solutions with antisymmetric form fields, and show that our solutions satisfy the first law of theormodynamics. We also suggest a constructive procedure to derive rotating asymptotically LDB brane solutions.

Flat supergravity potentials with non-zero potential energy due to D-terms

We show that SU(1,1) supergravity models, with naturally flat potentials V, may possess a non-zero V when supplemented with a U(1) D-term. Such a non-zero potential is of interest in the construction of no-scale GUTs, being perhaps a natural feature of such models.

Primordial inflation with flat supergravity potentials

A new class of primordial inflation models (PRIMO) is presented, based upon the possibility of getting naturally flat potentials in N = 1 supergravity. These models may be considered as the natural cosmological extension of some recently proposed no-scale particle physics models, where all mass scales are derived from the Planck mass (Mp). PRIMO seem to satisfy all presently known cosmological constraints and they are guaranteed (a) to be void of SUSY minima with negative cosmological constant, (b) of a stable (around the origin) potential form against finite temperature effects.

Rapid phase transitions in primordial inflation with flat supergravity potentials

We demonstrate that the recently proposed naturally flat N = 1 supergravity potentials not only provide a working primordial inflation scenario, but they also considerably facilitate the GUT phase transition. Towards the late stages of inflation, a rapid (second order) phase transition occurs naturally to the SU(3) × SU(2) × U(1) phase, thus gracefully and simultaneously ending the reign of the inflationary as well as GUT eras.