arXiv subjects

Sunil Gadhia

Publications and source records attributed to Sunil Gadhia.

3 recordsLinked to original sources

arXiv2009

Half-BPS quotients in M-theory: ADE with a twist

We classify Freund-Rubin backgrounds of eleven-dimensional supergravity of the form AdS_4 x X^7 which are at least half BPS; equivalently, smooth quotients of the round 7-sphere by finite subgroups of SO(8) which admit an (N>3)-dimensional subspace of Killing spinors. The classification is given in terms of pairs consisting of an ADE subgroup of SU(2) and an automorphism defining its embedding in SO(8). In particular we find novel half-BPS quotients associated with the subgroups of type D_n (for n>5), E_7 and E_8 and their outer automorphisms.

hep-th↗

arXiv2007

M-theory preons cannot arise by quotients

M-theory preons -- solutions of eleven-dimensional supergravity preserving 31 supersymmetries -- have recently been shown to be locally maximally supersymmetric. This implies that if preons exist they are quotients of maximally supersymmetric solutions. In this paper we show that no such quotients exist. This is achieved by reducing the problem to quotients by cyclic groups in the image of the exponential map, for which there already exists a partial classification, which is completed in the present paper.

hep-th↗

arXiv2005

Supersymmetry and spin structures

We construct examples of isometric M-theory backgrounds which preserve a different amount of supersymmetry depending on the choice of spin structure. These examples are of the form AdS_4 x L, where L is a seven-dimensional lens space whose fundamental group is cyclic of order 4k.

hep-th↗