Gravity In Light-cone Gauge Research Articles

Higher derivative quartic vertex of f(R) gravity in light-cone gauge

In the recent studies of four-dimensional Einstein–Hilbert action, quite a few interesting results such as the Kawai–Lewellen–Tye (KLT) relations, MHV-Lagrangian and quadratic forms have been reported. These results naturally raise an important question: Whether these results are valid for the modified theories of gravity in 4-dimensions? In this work, we consider R+αR2 gravity and derive the complete quartic interaction vertex in light-cone gauge. We then discuss the implications of the results for KLT relations, and computing MHV amplitudes.

Tweaking one-loop determinants in AdS3

We revisit the subject of one-loop determinants in AdS3 gravity via the quasi-normal mode method. Our goal is to evaluate a one-loop determinant with chiral boundary conditions for the metric field; chirality is achieved by imposing Dirichlet boundary conditions on certain components while others satisfy Neumann. Along the way, we give a generalization of the quasinormal mode method for stationary (non-static) thermal backgrounds, and propose a treatment for Neumann boundary conditions in this framework. We evaluate the graviton one-loop determinant on the Euclidean BTZ background with parity-violating boundary conditions (CSS), and find excellent agreement with the dual warped CFT. We also discuss a more general falloff in AdS3 that is related to two dimensional quantum gravity in lightcone gauge. The behavior of the ghost fields under both sets of boundary conditions is novel and we discuss potential interpretations.

An sl(2, $ \mathbb{R} $ ) current algebra from AdS 3 gravity

We provide a set of chiral boundary conditions for three-dimensional gravity that allow for asymptotic symmetries identical to those of two-dimensional induced gravity in light-cone gauge considered by Polyakov. These are the most general boundary conditions consistent with the boundary terms introduced by Compère, Song and Strominger recently. We show that the asymptotic symmetry algebra of our boundary conditions is a Virasoro algebra with Brown-Henneaux central charge c and an sl(2, $ \mathbb{R} $ ) current algebra with level given by c/6. The fully non-linear solution in Fefferman-Graham coordinates is also provided along with its charges.

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.

Free field realization of two-dimensional quantum gravity in light-cone gauge and green functions on the torus

We investigate the free field representation of Polyakov's quantum gravity theory found by Al.B. Zamolodchikov. We represent the gravity field by a bilinear combination of free fields. We discuss the geometrical meaning of the KPZ ghost from this viewpoint. Since our free fields can be regarded as the primary fields in the light-cone gauge geometry, it is relatively easy to construct their Green function on the torus explicitly. The propagator for the KPZ ghost gives the building block to construct the Ward identity on the torus.