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

We consider the Sp(2n) invariant formulation of higher spin fields on flat and curved backgrounds of constant curvature.In this formulation an infinite number of higher spin fields are packed into single scalar and spinor master fields (hyperfields) propagating on extended spaces, to be called hyperspaces, parametrized by tensorial coordinates.We show that the free field equations on flat and AdS-like hyperspaces are related to each other by a generalized conformal transformation of the scalar and spinor master fields. We compute the four--point functions on a flat hyperspace for both scalar and spinor master fields, thus extending the two-- and three--point function results of arXiv:hep-th/0312244. Then using the generalized conformal transformation we derive two--, three-- and four--point functions on AdS--like hyperspace from the corresponding correlators on the flat hyperspace.

/pdf/higher-spins-in-hyperspace-2tqlvuxvxi.pdf

Higher Spins in Hyperspace

We consider mechanisms of spontaneous compactification for d = 10 and d = 11 supergravity theories It is shown that the interaction of the gravitational field with the three-index gauge field in d = 11 supergravity may lead to a spontaneous compactification of an eleven-dimensional subspace into a cartesian product of a five-dimensional anti-de Sitter space adS/sup 5/ and the compact manifold CP/sup 2/ x S/sup 2/ It is also proved that in d = 10 supergravity there exist solutions for the interacting gravitational, tensor, vector, and scalar fields, corresponding to the spontaneous transition of a ten-dimensional subspace into adS/sup 4/ x CP/sup 2/ x S/sup 2/

Spontaneous compactification of subspaces in d = 10, 11 supergravity

Field theories in space-time dimensions D=(1,1), (2,1) (one time dimension and one or two space dimensions) possess some interesting features connected with the configuration space nontrivial topology of the systems concerned. For instance, solitons of D=2+1 theories can possess fractional charge, statistics and spin [1,2]. The experimental consequences of such peculiar properties can be obtained in condensed matter, where there are possibilities to realize two-dimensional systems. There is well known example of a fractionally quantized Hall effect [3.1]. The recent interest in (2+1)-dimensional theories and, particularly, in nonlinear σ-models has been triggered by the hope to describe the high temperature superconductivity phenomena [4].

On the Relativistic Field Theories with Fractional Statistics and Spin in D = (2 + 1), (3 + 1)

We consider a formulation of N=1 D=3,4 and 6 superparticle mechanics, which is manifestly supersymmetric on the worldline and in the target superspace. For the construction of the action we use only geometrical objects that characterize the embedding of the worldline superspace into the target superspace, such as target superspace coordinates of the superparticle and twistor components. The action does not contain the Lagrange multipliers which may cause the problem of infinite reducible symmetries, and, in fact, is a worldline superfield generalization of the supertwistor description of superparticle dynamics.

Twistor-like superparticles revisited.

We discuss a four-dimensional Volkov-Akulov supersymmetric theory on a D3-brane with N=2 supersymmetry broken down to N=1.

Dmitri Sorokin

Papers

Higher Spins in Hyperspace

Spontaneous compactification of subspaces in d = 10, 11 supergravity

On the Relativistic Field Theories with Fractional Statistics and Spin in D = (2 + 1), (3 + 1)

Twistor-like superparticles revisited.

The Space Filling Dirichlet 3-Brane in N=2, D=4 Superspace