M-theory Description Research Articles

Semiclassics of three-dimensional SCFTs from holography

We use holography to compute the large-N effective field theory along the moduli space of vacua of an infinite class of three-dimensional mathcal{N} = 2 SCFTs admitting a dual M-theory description. We focus in particular on toric models and show how the spectrum of large R-charge SCFT chiral scalar operators corresponds to a set of explicit semiclassical solutions of our effective field theory, which describe bound states of backreacting giant gravitons and baryonic-like M5-branes. Our semiclassical description allows for a direct computation of the scaling dimensions of these operators and provides a starting point for a semiclassical investigation of the SCFT data in the large R-charge sector. We consider the models corresponding to the Y12(ℙ2) and Q111 Sasaki-Einstein spaces as explicit examples.

Superconformal index for [formula omitted][formula omitted] Chern-Simons quiver gauge theories

We compute superconformal indices for N=3ADEˆ Chern-Simons quiver gauge theories with a product gauge group ∏iU(N)i, using the method of supersymmetric localization. We also perform a large N analysis of the index. This index includes contribution from non zero magnetic flux sector. The fact that these theories have a weakly coupled UV completion in terms of N=3 supersymmetric Chern-Simons Yang-Mills theories enables us to apply the localization technique. Such theories have dual M-theory description on AdS4×M7, where M7 is a tri-Sasaki Einstein manifold.

Non-simply-connected symmetries in 6D SCFTs

Six-dimensional mathcal{N} = (1, 0) superconformal field theories can be engineered geometrically via F-theory on elliptically-fibered Calabi-Yau 3-folds. We include torsional sections in the geometry, which lead to a finite Mordell-Weil group. This allows us to identify the full non-Abelian group structure rather than just the algebra. The presence of torsion also modifies the center of the symmetry groups and the matter representations that can appear. This in turn affects the tensor branch of these theories. We analyze this change for a large class of superconformal theories with torsion and explicitly construct their tensor branches. Finally, we elaborate on the connection to the dual heterotic and M-theory description, in which our configurations are interpreted as generalizations of discrete holonomy instantons.

Classifying 5d SCFTs via 6d SCFTs: arbitrary rank

According to a conjecture, all 5d SCFTs should be obtainable by rank- preserving RG flows of 6d SCFTs compactified on a circle possibly twisted by a background for the discrete global symmetries around the circle. For a 6d SCFT admitting an F-theory construction, its untwisted compactification admits a dual M-theory description in terms of a “parent” Calabi-Yau threefold which captures the Coulomb branch of the compacti- fied 6d SCFT. The RG flows to 5d SCFTs can then be identified with a sequence of flop transitions and blowdowns of the parent Calabi-Yau leading to “descendant” Calabi-Yau threefolds which describe the Coulomb branches of the resulting 5d SCFTs. An explicit description of parent Calabi-Yaus is known for untwisted compactifications of rank one 6d SCFTs. In this paper, we provide a description of parent Calabi-Yaus for untwisted compactifications of arbitrary rank 6d SCFTs. Since 6d SCFTs of arbitrary rank can be viewed as being constructed out of rank one SCFTs, we accomplish the extension to arbi- trary rank by identifying a prescription for gluing together Calabi-Yaus associated to rank one 6d SCFTs.

String theory duals of Wilson loops from Higgsing

For three-dimensional ABJ(M) theories and mathcal{N}=4 Chern-Simons-matter quiver theories, we construct two sets of 1/2 BPS Wilson loop operators by applying the Higgsing procedure along independent directions of the moduli space, and choosing different massive modes. For theories whose dual M-theory description is known, we also determine the corresponding spectrum of 1/2 BPS M2-brane solutions. We identify the supercharges in M-theory and field theory, as well as the supercharges preserved by M2-/anti-M2-branes and 1/2 BPS Wilson loops. In particular, in mathcal{N}=4 orbifold ABJM theory we find pairs of different 1/2 BPS Wilson loops that preserve exactly the same set of supercharges. In field theory they arise by Higgsing with the choice of either particles or antiparticles, whereas in the dual description they correspond to a pair of M2-/anti-M2-branes localized at different positions in the compact space. This result enlightens the origin of classical Wilson loop degeneracy in these theories, already discussed in arXiv:1506.07614. A discussion on possible scenarios that emerge by comparison with localization results is included.

E6 Yukawa couplings in F-theory as D-brane instanton effects

At weak coupling the neighborhood of a E6 Yukawa point in SU(5) GUT F-theory models is described by a non-resolvable orientifold of the conifold. We explicitly show, first directly in IIB and then via a mirror symmetry argument, that in this limit the E6 Yukawa coupling is better described as coming from the non-perturbative contribution of a euclidean D1-brane wrapping the non-resolvable cycle. We also discuss how the M-theory description interpolates between the weak and strong coupling viewpoints.

AdS5 solutions from M5-branes on Riemann surface and D6-branes sources

We describe the gravity duals of four-dimensional N=1 superconformal field theories obtained by wrapping M5-branes on a punctured Riemann surface. The internal geometry, normal to the AdS5 factor, generically preserves two U(1)s, with generators (J+,J-), that are fibered over the Riemann surface. The metric is governed by a single potential that satisfies a version of the Monge-Ampere equation. The spectrum of N=1 punctures is given by the set of supersymmetric sources of the potential that are localized on the Riemann surface and lead to regular metrics near a puncture. We use this system to study a class of punctures where the geometry near the sources corresponds to M-theory description of D6-branes. These carry a natural (p,q) label associated to the circle dual to the killing vector (p J+ + q J-) which shrinks near the source. In the generic case the world volume of the D6-branes is AdS5 X S^2 and they locally preserve N=2 supersymmetry. When p=-q, the shrinking circle is dual to a flavor U(1). The metric in this case is non-degenerate only when there are co-dimension one sources, M9-branes, obtained by smearing M5-branes that wrap the AdS5 factor and the circle dual the superconformal R-symmetry. In the IIA limit, they can interpreted as D8-branes. The D6-branes are extended along the AdS5 and on cups that end on the co-dimension one branes. In the special case when the shrinking circle is dual to the R-symmetry, the D6-branes are extended along the AdS5 and wrap an auxiliary Riemann surface with an arbitrary genus. When the Riemann surface is compact with constant curvature, the system is governed by a Monge-Ampere equation.

A new string in ten dimensions?

I suggest the possibility of a new string in ten dimensions. Evidence for this string is presented both from orientifold physics and from K-theory, along with a mystery concerning the M-theory description. Motivated by this possibility, some novel aspects of decoupling limits in heterotic/type I theories are described; specifically, the decoupled theory on type I D-strings is argued to be three-dimensional rather than two-dimensional. These decoupled theories provide the matrix model definitions of the heterotic/type I strings.

Periodic arrays of M2-branes

AbstractWe consider periodic arrays of M2-branes in the ABJM model in the spirit of a circle compactification to D2-branes in type IIA string theory. The result is a curious formulation of three-dimensional maximally supersymmetric Yang-Mills theory in terms of fermions, seven transverse scalars, a non-dynamical gauge field and an additional scalar ‘dual gluon’. Upon further T-duality on a transverse torus we obtain a non-manifest- Lorentz-invariant description of five-dimensional maximally supersymmetric Yang-Mills. Here the additional scalar field can be thought of as the components of a two-form along the torus. This action can be viewed as an M-theory description of M5-branes on${{\mathbb{T}}^3}$.

The gravity duals of $ \mathcal{N}=2 $ superconformal field theories

We study the gauge/gravity duality for theories with four dimensional $ \mathcal{N}=2 $ supersymmetries. We consider the large class of generalized quiver field theories constructed recently by one of us (D.G.). These field theories can also be viewed as the IR limit of M5 branes wrapping a Riemann surface with punctures. We give a prescription for constructing the corresponding geometries and we discuss a few special cases in detail. There is a precise match for various quantities between the field theory and the M-theory description.

Adding new hair to the 3-charge black ring

Motivated by the string theory analysis of Giusto et al (2011 JHEP1111(2011)062), we construct a class of 1/8-BPS solutions of type-IIB supergravity compactified on S1 × T4. In this duality frame, our ansatz allows for a non-trivial NS–NS B-field, which has been usually set to zero in previous studies of 1/8-BPS geometries. We provide an M-theory description of these new geometries and show that they can be interpreted as the lift of solutions of the 5D supergravity with three vector multiplets and whose scalar manifold is the symmetric space SO(1, 1)⊗(SO(1, 2)/SO(2)). Finally, we show that the non-minimal 5D black rings provide an explicit example of solutions falling in this ansatz. In particular, we point out the existence of a black ring that has an extra dipole charge with respect to the solutions of the STU model. In the near-horizon limit, this ring has an AdS3 × S3 geometry with the same radius as the one of the 3-charge black hole, and thus, its microstates should belong to the usual D1–D5 CFT.

F-theory fluxes, chirality and Chern-Simons theories

We study the charged chiral matter spectrum of four-dimensional F-theory compactifications on elliptically fibered Calabi-Yau fourfolds by using the dual M-theory description. A chiral spectrum can be induced by M-theory four-form flux on the fully resolved Calabi-Yau fourfold. In M-theory this flux yields three-dimensional Chern-Simons couplings in the Coulomb branch of the gauge theory. In the F-theory compactification on an additional circle these couplings are only generated by one-loop corrections with charged fermions running in the loop. This identification allows us to infer the net number of chiral matter fields of the four-dimensional effective theory. The chirality formulas can be evaluated by using the intersection numbers and the cones of effective curves of the resolved fourfolds. We argue that a study of the effective curves also allows to follow the resolution process at each co-dimension. To write simple chirality formulas we suggest to use the effective curves involved in the resolution process to determine the matter surfaces and to connect with the group theory at co-dimension two in the base. We exemplify our methods on examples with SU(5) and SU(5)xU(1) gauge group.

Comments on <i>N</i> = 1 Heterotic String Vacua

We analyze three aspects of N = 1 heterotic string compactications on elliptically b ered Calabi-Yau threefolds: stability of vector bundles, v e-brane instanton transitions and chiral matter. First we show that relative Fourier-Mukai transformation preserves absolute stability. This is relevant for vector bundles whose spectral cover is reducible. Then we derive an explicit formula for the number of moduli which occur in (vertical) v e-brane instanton transitions provided a certain vanishing argument applies. Such transitions increase the holonomy of the heterotic vector bundle and cause gauge changing phase transitions. In a M-theory description the transitions are associated with collisions of bulk v e-branes with one of the boundary xed planes. In F-theory they correspond to three-brane instanton transitions. Our derivation relies on an index computation with data localized along the curve which is related to the existence of chiral matter in this class of heterotic vacua. Finally, we show how to compute the number of chiral matter multiplets for this class of vacua allowing to discuss associated Yukawa couplings.

D6-branes wrapping Kähler four-cycles

We construct supergravity duals of D6-branes wrapping Kahler four-cycles inside a Calabi-Yau threefold, CY_3. We obtain the purely gravitational M-theory description, which turns out to be a Calabi-Yau fourfold, CY_4. We also analyze the dynamics of a probe D6 in this background.

Non-BPS D-branes and M-theory

A dual pair of supersymmetric string theories that involves an asymmetric orbifold and an orientifold of Type II is considered. The D-branes of the orbifold theory (that were recently determined by Gutperle) are all non-BPS and do not carry any conserved gauge charges. It is shown that they carry non-trivial K-theory charges, and that they can be understood in terms of branes wrapping certain homology classes of the M-theory compactification. Using the adiabatic argument, dual partners of some of these non-BPS D-branes are proposed. The relations between these dual states are found to be in agreement with the M-theory description of the D-branes.

D-branes, holonomy and M-theory

We show that M-theory on spaces with irreducible holonomy represent Type IIA backgrounds in which a collection of D6-branes wrap a supersymmetric cycle in a manifold with a holonomy group different from the one appearing in the M-theory description. For example, we show that D6-branes wrapping a supersymmetric four-cycle on a manifold with G_2 holonomy is described in eleven dimensions by M-theory on a space with Spin(7) holonomy. Examples of such Type IIA backgrounds which lift to M-theory on spaces with SU(3), G_2, SU(4) and Spin(7) holonomy are considered. The M-theory geometry can then be used to compute exact quantities of the gauge theory on the corresponding D-brane configuration.

M-Theory Description of 1/4 BPS States in N = 4 Supersymmetric Yang-Mills Theory

We discuss BPS states preserving 1/4 supersymmetries of N=4 supersymmetric Yang-Mills theory as M2-branes holomorphically embedded and ending on M5-branes. We use techniques in electrodynamics to find the M2-brane configurations, and give some explicit examples. In case the M2-brane worldsheet has handles, the worldsheet moduli of the M2-brane is constrained in a discrete manner. Several aspects of multi-pronged strings in type IIB string theory are beautifully reproduced in the M-theory description. We also discuss the relation between the above construction and the D2-brane dynamics in type IIA string theory.

BPS-spectra in four dimensions fromM-theory

I review my work together with Piljin Yi [1] on the spectrum of BPS-saturated states in N = 2 supersymmetric Yang-Mills theories. In an M-theory description, such states are realized as certain two-brane configurations. We first show how the central charge of the N = 2 algebra arises from the two-form central charge of the eleven-dimensional supersymmetry algebra, and derive the condition for a two-brane configuration to be BPS-saturated. We then discuss how the topology of the two-brane determines the type of BPS-multiplet. Finally, we discuss the phenomenon of marginal stability and show how it is related to the mutual non-locality of states.

Chirality-changing phase transitions in 4d string vacua

We provide evidence that some four-dimensional N = 1 string vacua with different numbers of generations are connected through phase transitions. The transitions involve going through a point in moduli space where there is a non-trivial fixed point governing the low energy field theory. In an M-theory description, the examples involve wrapped fivebranes leaving one of the ends of the world.

(0,2) Non-critical strings in six dimensions

Type IIB strings compactified on K3 have a rich structure of solitonic strings, transforming under SO(21, 5, Z) . We derive the BPS tension formula for these strings, and discuss their properties, in particular, the points in the moduli space where certain strings become tensionless. By examining these tensionless string limits, we shed some further light on the conjectured dual M-theory description of this compactification.