http://inspirehep.net/record/499969/files/arXiv:hep-th_9905111.pdf

Large N Field Theories, String Theory and Gravity

Superstring theoryをめぐって(放談室)

Massive gravity has seen a resurgence of interest due to recent progress which has overcome its traditional problems, yielding an avenue for addressing important open questions such as the cosmological constant naturalness problem. The possibility of a massive graviton has been studied on and off for the past 70 years. During this time, curiosities such as the van Dam, Veltman, and Zakharov (vDVZ) discontinuity and the Boulware-Deser ghost were uncovered. These results are rederived in a pedagogical manner and the St\"uckelberg formalism to discuss them from the modern effective field theory viewpoint is developed. Recent progress of the last decade is reviewed, including the dissolution of the vDVZ discontinuity via the Vainshtein screening mechanism, the existence of a consistent effective field theory with a stable hierarchy between the graviton mass and the cutoff, and the existence of particular interactions which raise the maximal effective field theory cutoff and remove the ghosts. In addition, some peculiarities of massive gravitons on curved space, novel theories in three dimensions, and examples of the emergence of a massive graviton from extra dimensions and brane worlds are reviewed.

Theoretical Aspects of Massive Gravity

We discuss possible phase factors for the S-matrix of planar gauge theory, leading to modifications at four-loop order as compared to an earlier proposal. While these result in a four-loop breakdown of perturbative BMN scaling, Kotikov?Lipatov transcendentality in the universal scaling function for large-spin twist operators may be preserved. One particularly natural choice, unique up to one constant, modifies the overall contribution of all terms containing odd-zeta functions in the earlier proposed scaling function based on a trivial phase. Excitingly, we present evidence that this choice is non-perturbatively related to a recently conjectured crossing-symmetric phase factor for perturbative string theory on AdS5 ? S5 once the constant is fixed to a particular value. Our proposal, if true, might therefore resolve the long-standing AdS/CFT discrepancies between gauge and string theory.

/pdf/transcendentality-and-crossing-2wc82m8065.pdf

Transcendentality and crossing

Flux compactifications in string theory: A Comprehensive review

The standard eleven-dimensional supergravity action depends on a three-form gauge field and does not allow direct coupling to five-branes. Using previously developed methods, we construct a covariant eleven-dimensional supergravity action depending on a three-form and six-form gauge field in a duality-symmetric manner. This action is coupled to both the M-theory two-brane and five-brane, and corresponding equations of motion are obtained. Consistent coupling relates D=11 duality properties with self-duality properties of the M-5-brane. From this duality-symmetric formulation, one can derive an action describing coupling of the M-branes to standard D=11 supergravity.

Duality-Symmetric Eleven-Dimensional Supergravity and its Coupling to M-Branes

Using examples of a D=2 chiral scalar and a duality-symmetric formulation of D=4 Maxwell theory we study duality properties of actions for describing chiral bosons. In particular, in the D=4 case, upon performing a duality transform of an auxiliary scalar field, which ensures Lorentz covariance of the action, we arrive at a new covariant duality-symmetric Maxwell action, which contains a two-form potential as an auxiliary field. When the two-form field is gauge fixed this action reduces to a duality-symmetric action for Maxwell theory constructed by Zwanziger. We consider properties of this new covariant action and discuss its coupling to external dyonic sources. We also demonstrate that the formulations considered are self-dual with respect to a dualization of the field-strengths of the chiral fields.

Duality of Self-Dual Actions

It is shown that all the known compact vacuum configurations of d = 11 supergravity, as well as a number of new ones which occur as a result of Freund-Rubin spontaneous compactification, have the structure of the fiber bundle P(M/sup 6/, S/sup 1/) with the standard Kaluza-Klein metric. The most interesting vacuum states of those that are found preserve the N = 3, 1 supersymmetries in the effective 4-dimensional theory and are invariant with respect to the transformations of the supergroups OSp(4, 3) x SU(3) and OSp(4, 1) x SU(3) x SU(2), respectively. New N = 2 supersymmetric vacuum configurations are also found; these possess the symmetry groups OSp(4, 2) x SO(5) and OSp(4, 2) x SU(2) x SU(2) x SU(2).

On Geometrical structure of compactified subspaces in D = 11 supergravity

It is advocated that the superembedding approach is a generic covariant method for the description of superbranes as models of (partial) spontaneous supersymmetry breaking. As an illustration we construct (in the framework of superembeddings) an n=1, d=3 worldvolume superfield action for a supermembrane propagating in N=1, D=4,5,7 and 11-dimensional supergravity backgrounds. We then show how in the case of an N=1, D=4 target superspace gauge fixing local worldvolume superdiffeomorphisms in the covariant supermembrane action results in an effective N=2, d=3 supersymmetric field theory with N=2 supersymmetry being spontaneously broken down to N=1. The broken part of N=2, d=3 supersymmetry is nonlinearly realized when acting on Goldstone N=1, d=3 superfields, which describe physical degrees of freedom of the model. As an introduction to the formalism, the procedure of getting effective field theories with partially broken supersymmetry by gauge fixing covariant superbrane actions is also demonstrated with a simpler example of a massive N=2, D=2 superparticle.

Superembeddings, Partial Supersymmetry Breaking and Superbranes

We prove several universal properties of charge transport in generic CFTs holographic to nonminimal extensions of four-dimensional Einstein-Maxwell theory with exact electromagnetic duality invariance. First, we explicitly verify that the conductivity of these theories at zero momentum is a universal frequency-independent constant. Then, we derive their analytical expressions for non-zero momentum in any holographic duality-invariant theory for large frequencies and in the limit of small frequencies and momenta. Next, in the absence of terms that couple covariant derivatives of the curvature to gauge field strengths, two universal features are proven. On the one hand, it is shown that for a general-relativity neutral black-hole background the conductivities at any frequency and momentum are independent of the choice of duality-invariant theory, thus coinciding with those in the Einstein-Maxwell case. On the other hand, if higher-curvature terms affect the gravitational background, the conductivities get modified, but the contributions from nonminimal couplings of the gauge field to gravity are subleading. We illustrate this feature with an example.

Dmitri Sorokin

Papers

Duality-Symmetric Eleven-Dimensional Supergravity and its Coupling to M-Branes

Duality of Self-Dual Actions

On Geometrical structure of compactified subspaces in D = 11 supergravity

Superembeddings, Partial Supersymmetry Breaking and Superbranes

Universal aspects of holographic quantum critical transport with self-duality