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Sudarshan Ananth

Publications and source records attributed to Sudarshan Ananth.

At least 37 records · Page 2Linked to original sources
arXiv2017

Exceptional versus superPoincaré algebra as the defining symmetry of maximal supergravity

We describe how one may use either the superPoincaré algebra or the exceptional algebra to construct maximal supergravity theories in the light-cone formalism. The d=4 construction shows both symmetries albeit in a non-linearly realized manner. In d=11, we find that we have to choose which of these two symmetries to use, in constructing the theory. In order to understand the other "unused" symmetry, one has to perform a highly non-trivial field redefinition. We argue that this shows that one cannot trust counterterm arguments that do not take the full symmetry of the theory into account. Finally we discuss possible consequences for Superstring theory and M-theory.

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arXiv2015

Yang-Mills theories and quadratic forms

We show that the Hamiltonian of (N=1;d=10) super Yang-Mills can be expressed as a quadratic form in a very similar manner to that of the (N=4;d=4) theory. We find a similar quadratic form structure for pure Yang-Mills theory but this feature, in the non-supersymmetric case, seems to be unique to four dimensions. We discuss some consequences of this feature.

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arXiv2015

Light-cone gravity in dS$_4$

We derive a closed form expression for the light-cone Lagrangian describing pure gravity on a four-dimensional de Sitter background. We provide a perturbative expansion, of this Lagrangian, to cubic order in the fields.

hep-th↗
arXiv2015

Fermi-Bose cubic couplings in light-cone field theories

We derive light-cone cubic interaction vertices involving fermions and bosons of arbitrary spin by demanding closure of the Poincaré algebra. We derive the three-point scattering amplitude corresponding to these interaction vertices and find that they possess interesting factorization properties, identical to the case of three boson scattering.

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arXiv2014

Factorization of cubic vertices involving three different higher spin fields

We derive a class of cubic interaction vertices for three higher spin fields, with integer spins $λ_1$, $λ_2$, $λ_3$, by closing commutators of the Poincaré algebra in four-dimensional flat spacetime. We find that these vertices exhibit an interesting factorization property which allows us to identify off-shell perturbative relations between them.

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arXiv2014

Cubic interaction vertices in higher spin theories

Based purely on symmetry considerations, we derive the following result: in momentum space, the coefficient of the cubic interaction vertex for a spin $λ$ field is equal to the corresponding Yang-Mills (spin 1) coefficient, raised to the power $λ$. This result is valid for all $λ$ for Lagrangians that contain a cubic interaction vertex of the form $λ$-$λ$-$λ$, in four-dimensional flat spacetime. For $λ=3$, we present an additional derivation of this result.

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arXiv2014

Light-cone gravity in AdS$_{4}$

We obtain a closed form expression for the Action describing pure gravity, in light-cone gauge, in a four-dimensional Anti de Sitter background. We perform a perturbative expansion of this closed form result to extract the cubic interaction vertex in this gauge.

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arXiv2012

Spinor helicity structures in higher spin theories

It is shown that the coefficient of the cubic interaction vertex, in higher spin Lagrangians, has a very simple form when written in terms of spinor helicity products. The result for a higher-spin field, of spin $λ$, is equal to the corresponding Yang-Mills coefficient raised to the power $λ$. Among other things, this suggests perturbative ties, similar to the KLT relations, between higher spin theories and pure Yang-Mills. This result is obtained in four-dimensional flat spacetime.

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arXiv2012

Gauge-invariant correlation functions in light-cone superspace

We initiate a study of correlation functions of gauge-invariant operators in N=4 super Yang-Mills theory using the light-cone superspace formalism. Our primary aim is to develop efficient methods to compute perturbative corrections to correlation functions. This analysis also allows us to examine potential subtleties which may arise when calculating off-shell quantities in light-cone gauge. We comment on the intriguing possibility that the manifest N=4 supersymmetry in this approach may allow for a compact description of entire multiplets and their correlation functions.

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arXiv2011

A manifestly MHV Lagrangian for N=4 Yang-Mills

We derive a manifestly MHV Lagrangian for the N=4 supersymmetric Yang-Mills theory in light-cone superspace. This is achieved by constructing a canonical redefinition which maps the N=4 superfield and its conjugate to a new pair of superfields. In terms of these new superfields the N=4 Lagrangian takes a (non-polynomial) manifestly MHV form, containing vertices involving two superfields of negative helicity and an arbitrary number of superfields of positive helicity. We also discuss constraints satisfied by the new superfields, which ensure that they describe the correct degrees of freedom in the N=4 supermultiplet. We test our derivation by showing that an expansion of our superspace Lagrangian in component fields reproduces the correct gluon MHV vertices.

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arXiv2010

Gravity and Yang-Mills theory

Three of the four forces of Nature are described by quantum Yang-Mills theories with remarkable precision. The fourth force, gravity, is described classically by the Einstein-Hilbert theory. There appears to be an inherent incompatibility between quantum mechanics and the Einstein-Hilbert theory which prevents us from developing a consistent quantum theory of gravity. The Einstein-Hilbert theory is therefore believed to differ greatly from Yang-Mills theory (which does have a sensible quantum mechanical description). It is therefore very surprising that these two theories actually share close perturbative ties. This article focuses on these ties between Yang-Mills theory and the Einstein-Hilbert theory. We discuss the origin of these ties and their implications for a quantum theory of gravity.

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arXiv2009

LC_2 formulation of supergravity

We formulate (N=1, d=11) supergravity in components in light-cone gauge (LC_2) to order $κ$. In this formulation, we use judicious gauge choices and the associated constraint relations to express the metric, three-form and gravitino entirely in terms of the physical degrees of freedom in the theory.

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arXiv2009

Gravity as the square of Yang-Mills: implications for N=8 Supergravity

The pure gravity Lagrangian can be written as the "square" of the pure Yang-Mills Lagrangian to second order in coupling constants. This paper uses this form of the gravity Lagrangian as a starting point to arrive at a compact light-cone superspace Lagrangian for N=8 Supergravity to order $κ$^2.

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arXiv2008

The quintic interaction vertex in light-cone gravity

We consider pure gravity in light-cone gauge and derive the complete quintic interaction vertex. Up to quartic order, the Kawai-Lewellen-Tye (KLT) relations can be made manifest at the level of the Einstein-Hilbert Lagrangian. The quintic interaction vertex represents an essential first step in further extending the off-shell validity of the KLT relations to higher order vertices.

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arXiv2007

Proof of ultra-violet finiteness for a planar non-supersymmetric Yang-Mills theory

This paper focuses on a three-parameter deformation of N=4 Yang-Mills that breaks all the supersymmetry in the theory. We show that the resulting non-supersymmetric gauge theory is scale invariant, in the planar approximation, by proving that its Green functions are ultra-violet finite to all orders in light-cone perturbation theory.

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arXiv2007

Proof of all-order finiteness for planar beta-deformed Yang-Mills

We study a marginal deformation of N=4 Yang-Mills, with a real deformation parameter beta. This beta-deformed model has only N=1 supersymmetry and a U(1)xU(1) flavor symmetry. The introduction of a new superspace star-product allows us to formulate the theory in N=4 light-cone superspace, despite the fact that it has only N=1 supersymmetry. We show that this deformed theory is conformally invariant, in the planar approximation, by proving that its Green functions are ultra-violet finite to all orders in perturbation theory.

hep-th↗
arXiv2007

KLT relations from the Einstein-Hilbert Lagrangian

The Kawai-Lewellen-Tye (KLT) relations derived from string theory tell us that perturbative gravity amplitudes are the "square" of the corresponding amplitudes in gauge theory. Starting from the light-cone Lagrangian for pure gravity we make these relations manifest off-shell, for three- and four-graviton vertices, at the level of the action.

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