Massive Type IIA String Theory Research Articles

A quantum mechanics for magnetic horizons

We construct an mathcal{N} = 2 supersymmetric gauged quantum mechanics, by starting from the 3d Chern-Simons-matter theory holographically dual to massive Type IIA string theory on AdS4× S6, and Kaluza-Klein reducing on S2 with a background that is dual to the asymptotics of static dyonic BPS black holes in AdS4. The background involves a choice of gauge fluxes, that we fix via a saddle-point analysis of the 3d topologically twisted index at large N. The ground-state degeneracy of the effective quantum mechanics reproduces the entropy of BPS black holes, and we expect its low-lying spectrum to contain information about near-extremal horizons. Interestingly, the model has a large number of statistically-distributed couplings, reminiscent of SYK models.

Kaluza-Klein fermion mass matrices from exceptional field theory and mathcal{N} = 1 spectra

Using Exceptional Field Theory, we determine the infinite-dimensional mass matrices for the gravitino and spin-1/2 Kaluza-Klein perturbations above a class of anti-de Sitter solutions of M-theory and massive type IIA string theory with topologically-spherical internal spaces. We then use these mass matrices to compute the spectrum of Kaluza-Klein fermions about some solutions in this class with internal symmetry groups containing SU(3). Combining these results with previously known bosonic sectors of the spectra, we give the complete spectrum about some mathcal{N} = 1 and some non-supersymmetric solutions in this class. The complete spectra are shown to enjoy certain generic features.

The 5d superconformal index at large N and black holes

We study the large N limit of the superconformal index of a large class of 5d mathcal{N} = 1 superconformal field theories and show it is given by the square of the partition function on the squashed five-sphere. We show this simple relation implies a Cardy formula in 5d, which is valid in an “extended” regime in which fugacities are finite and N is large. For theories with weakly coupled gravity duals we conjecture this large N Cardy formula universally accounts for the microscopic entropy of spinning black holes in AdS6. We check this explicitly for known black hole solutions in massive type IIA and type IIB string theory, carrying two angular momenta and one electric charge, and predict the entropy of black holes carrying multiple electric charges, yet to be constructed. We also discuss large N properties of the {S}_b^3times {Sigma}_{mathfrak{g}} partition function, extending previous results to theories with type IIB duals.

On SUSY-breaking moduli spaces of AdS7 vacua and 6D SCFTs

We study supersymmetric AdS7 vacua of massive type IIA string theory, which were argued to describe the near-horizon limit of NS5/D6/D8-brane intersections and to be holographically dual to 6D (1,0) theories. We show, for the case without D8-brane charges, that such vacua do not admit any supersymmetry-breaking deformations. Our result implies that the dual (1, 0) theories do not have a conformal manifold, thus extending previously known results for supersymmetric deformations. It is also in line with the recent conjecture that non-supersymmetric AdS vacua are in the swampland.

A universal counting of black hole microstates in AdS4

Many three-dimensional mathcal{N}=2 SCFTs admit a universal partial topological twist when placed on hyperbolic Riemann surfaces. We exploit this fact to derive a universal formula which relates the planar limit of the topologically twisted index of these SCFTs and their three-sphere partition function. We then utilize this to account for the entropy of a large class of supersymmetric asymptotically AdS4 magnetically charged black holes in M-theory and massive type IIA string theory. In this context we also discuss novel AdS2 solutions of eleven-dimensional supergravity which describe the near horizon region of large new families of supersymmetric black holes arising from M2-branes wrapping Riemann surfaces.

6d surface defects from massive type IIA

We present a new BPS flow within minimal mathcal{N}=1 supergravity in seven dimensions describing a warped AdS3 background supported by a “dyonic” profile of the three-form. Furthermore, we discuss the holographic interpretation of the above solution in terms of a defect SCFT2 inside the 6d (1, 0) theory dual to the AdS in the asymptotic region. Finally we provide the brane picture of the aforementioned defect CFT as D2- and wrapped D4-branes ending on a D6 - NS5 - D8 funnel in massive type IIA string theory.

Universal isolation in the AdS landscape

We study the universal conditions for quantum non-perturbative stability against bubble nucleation for pertubatively stable AdS vacua based on positive energy theorems. We also compare our analysis with the pre-existing ones in the literature carried out within the thin-wall approximation. The aforementioned criterion is then tested in two explicit examples describing massive type IIA string theory compactified on $S^3$ and $S^3\,\times\,S^3$, respectively. The AdS landscape of both classes of compactifications is known to consist of a set of isolated points. The main result is that all critical points respecting the Breitenlohner-Freedaman (BF) bound also turn out be stable at a non-perturbative level. Finally, we speculate on the possible universal features that may be extracted from the above specific examples.

String Theory Origin of Dyonic N=8 Supergravity and Its Chern-Simons Duals.

We clarify the higher-dimensional origin of a class of dyonic gaugings of D=4 N=8 supergravity recently discovered, when the gauge group is chosen to be ISO(7). This dyonically gauged maximal supergravity arises from consistent truncation of massive IIA supergravity on S^6, and its magnetic coupling constant descends directly from the Romans mass. The critical points of the supergravity uplift to new four-dimensional anti-de Sitter space (AdS4) massive type IIA vacua. We identify the corresponding three-dimensional conformal field theory (CFT3) duals as super-Chern-Simons-matter theories with simple gauge group SU(N) and level k given by the Romans mass. In particular, we find a critical point that uplifts to the first explicit N=2 AdS4 massive IIA background. We compute its free energy and that of the candidate dual Chern-Simons theory by localization to a solvable matrix model, and find perfect agreement. This provides the first AdS4/CFT3 precision match in massive type IIA string theory.

Curvature-induced resolution of anti-brane singularities

We study AdS7 vacua of massive type IIA string theory compactified on a 3-sphere with H 3 flux and anti-D6-branes. In such backgrounds, the anti-brane backreaction is known to generate a singularity in the H 3 energy density, whose interpretation has not been understood so far. We first consider supersymmetric solutions of this setup and give an analytic proof that the flux singularity is resolved there by a polarization of the anti-D6-branes into a D8-brane, which wraps a finite 2-sphere inside of the compact space. To this end, we compute the potential for a spherical probe D8-brane on top of a background with backreacting anti-D6-branes and show that it has a local maximum at zero radius and a local minimum at a finite radius of the 2-sphere. The polarization is triggered by a term in the potential due to the AdS curvature and does therefore not occur in non-compact setups where the 7d external spacetime is Minkowski. We furthermore find numerical evidence for the existence of non-supersymmetric solutions in our setup. This is supported by the observation that the general solution to the equations of motion has a continuous parameter that is suggestive of a modulus and appears to control supersymmetry breaking. Analyzing the polarization potential for the non-supersymmetric solutions, we find that the flux singularities are resolved there by brane polarization as well.

Massive type IIA string theory cannot be strongly coupled

Understanding the strong coupling limit of massive type IIA string theory is a longstanding problem. We argue that perhaps this problem does not exist; namely, there may be no strongly coupled solutions of the massive theory. We show explicitly that massive type IIA string theory can never be strongly coupled in a weakly curved region of space-time. We illustrate our general claim with two classes of massive solutions in AdS4xCP3: one, previously known, with N = 1 supersymmetry, and a new one with N = 2 supersymmetry. Both solutions are dual to d = 3 Chern-Simons-matter theories. In both these massive examples, as the rank N of the gauge group is increased, the dilaton initially increases in the same way as in the corresponding massless case; before it can reach the M-theory regime, however, it enters a second regime, in which the dilaton decreases even as N increases. In the N = 2 case, we find supersymmetry-preserving gauge-invariant monopole operators whose mass is independent of N. This predicts the existence of branes which stay light even when the dilaton decreases. We show that, on the gravity side, these states originate from D2-D0 bound states wrapping the vanishing two-cycle of a conifold singularity that develops at large N.

Searching for slow-roll moduli inflation in massive type IIA supergravity with metric fluxes

We derive several no-go theorems in the context of massive type IIA string theory compactified to four dimensions in a way that, in the absence of fluxes, preserves $\mathcal{N}=1$ supersymmetry. Our derivation is based on the dilaton, K\ahler and complex structure moduli dependence of the potential of the four-dimensional effective field theory, that is generated by the presence of $D6$-branes, $O6$-planes, RR fluxes, NSNS 3-form flux, and geometric fluxes. To demonstrate the usefulness of our theorems, we apply them to the most commonly studied class of toroidal orientifolds. We show that for all but two of the models in this class the slow-roll parameter $ϵ$ is bounded from below by numbers of order unity as long as the fluxes satisfy the Bianchi identities, ruling out slow-roll inflation and even the existence of de Sitter extrema in these models. For the two cases that avoid the no-go theorems, we provide some details of our numerical studies, demonstrating that small $ϵ$ can indeed be achieved. We stress that there seems to be an $\ensuremath{\eta}$-problem, suggesting that none of the models in this class are viable from a cosmological point of view at least at large volume, small string coupling, and leading order in the ${\ensuremath{\alpha}}^{\ensuremath{'}}$-expansion.

GeneralN=1Supersymmetric Flux Vacua of Massive Type IIA String Theory

We derive conditions for the existence of four-dimensional N=1 supersymmetric flux vacua of massive type IIA string theory with general supergravity fluxes turned on. For an SU(3) singlet Killing spinor, we show that such flux vacua exist when the internal geometry is nearly Kähler. The geometry is not warped, all the allowed fluxes are proportional to the mass parameter, and the dilaton is fixed by a ratio of (quantized) fluxes. The four-dimensional cosmological constant, while negative, becomes small in the vacuum with the weak string coupling.

Supersymmetric intersecting D6-branes and fluxes in massive Type IIA string theory

We study N=1 supersymmetric four-dimensional solutions of massive Type IIA supergravity with intersecting D6-branes in the presence NS–NS three-form fluxes. We derive N=1 supersymmetry conditions for the D6-brane and flux configurations in an internal manifold X 6 and derive the intrinsic torsion (or SU(3)-structure) related to the fluxes. In the absence of fluxes, N=1 supersymmetry implies that D6-branes wrap supersymmetric three-cycles of X 6 that intersect at angles of SU(3) rotations and the geometry is deformed by SU(3)-structures. The presence of fluxes breaks the SU(3) structures to SU(2) and the D6-branes intersect at angles of SU(2) rotations; non-zero mass parameter corresponds to D8-branes which are orthogonal to the common cycle of all D6-branes. The anomaly inflow indicates that the gauge theory on intersecting (massive) D6-branes is not chiral.

Massive IIA string theory and Matrix theory compactification

We propose a Matrix theory approach to Romans' massive Type IIA supergravity. It is obtained by applying the procedure of Matrix theory compactifications to Hull's proposal of the massive Type IIA string theory as M-theory on a twisted torus. The resulting Matrix theory is a super-Yang–Mills theory on large N three-branes with a space-dependent noncommutativity parameter, which is also independently derived by a T-duality approach. We give evidence showing that the energies of a class of physical excitations of the super-Yang–Mills theory show the correct symmetry expected from massive Type IIA string theory in a lightcone quantization.

The stringy quantum Hall fluid

Using branes in massive Type IIA string theory, and a novel decoupling limit, we provide an explicit correspondence between non-commutative Chern-Simons theory and the fractional quantum Hall fluid. The role of the electrons is played by D-particles, the background magnetic field corresponds to a RR 2-form flux, and the two-dimensional fluid is described by non-commutative D2-branes. The filling fraction is given by the ratio of the number of D2-branes and the number of D8-branes, and therefore by the ratio rank/level of the Chern-Simons gauge theory. Quasiparticles and quasiholes are realized as endpoints of fundamental strings on the D2-branes, and are found to possess fractional D-particle charges and fractional statistics.

Gauged Six-Dimensional Supergravity from Massive Type IIA String Theory

We obtain the complete nonlinear Kaluza-Klein ansatz for the reduction of the bosonic sector of massive type IIA supergravity to the Romans F(4) gauged supergravity in six dimensions. The latter arises as a consistent warped ${S}^{4}$ reduction.

Gerbes and massive type II configurations

We find novel bound states of NS5, D6 and D8-branes in massive Type IIA string theory. As the NS gauge transformations can change the Chern class of the RR field these configurations should be thought of as nonlocal objects called gerbes. We develop a global formalism for theories that involve massive tensor fields in general, and apply it in massive Type IIA supergravity. We check the results by investigating the T-dual NS5/D5-brane configurations in Type IIB, and relate them to an F-theory compactification on a CY3. We comment on the implications to consistency conditions for brane-wrapping and the classification of D-brane charges in terms of K-theory classes.