Dmitri Sorokin

Bio: Dmitri Sorokin is an academic researcher from University of Padua. The author has contributed to research in topics: Supergravity & Supersymmetry. The author has an hindex of 45, co-authored 168 publications receiving 7303 citations. Previous affiliations of Dmitri Sorokin include Russian Academy of Sciences & Humboldt University of Berlin.

Covariant Action for the Super-Five-Brane of M Theory

Abstract: We propose a complete, $d\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}6$ covariant and kappa-symmetric, action for the $M$ theory five-brane propagating in $D\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}11$ supergravity background. This opens a direct way of relating a wide class of super- $p$-brane solutions of string theory with the five-brane of $M$ theory, which should be useful for studying corresponding dualities and nonperturbative aspects of these theories.

Lorentz-invariant actions for chiral p-forms

Abstract: We demonstrate how a Lorentz-covariant formulation of the chiral p-form model in D=2(p+1) containing infinitely many auxiliary fields is related to a Lorentz-covariant formulation with only one auxiliary scalar field entering a chiral p-form action in a nonpolynomial way. The latter can be regarded as a consistent Lorentz-covariant truncation of the former. We make the Hamiltonian analysis of the model based on the nonpolynomial action and show that the Dirac constraints have a simple form and are all first class. In contrast with the Siegel model the constraints are not the square of second-class constraints. The canonical Hamiltonian is quadratic and determines the energy of a single chiral p-form. In the case of D=2 chiral scalars the constraint can be improved by use of a {open_quotes}twisting{close_quotes} procedure (without the loss of the property to be first class) in such a way that the central charge of the quantum constraint algebra is zero. This points to the possible absence of an anomaly in an appropriate quantum version of the model. {copyright} {ital 1997} {ital The American Physical Society}

Introduction to the Classical Theory of Higher Spins

Abstract: We review main features and problems of higher spin field theory and flash some ways along which it has been developed over last decades.

Theoretical Aspects of Massive Gravity

Abstract: 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.

Transcendentality and crossing

Abstract: 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.