U(N) and holomorphic methods for LQG and Spin Foams

U(N) Coherent States for Loop Quantum Gravity

U(N) invariant dynamics for a simplified Loop Quantum Gravity model

U(N) tools for Loop Quantum Gravity: The Return of the Spinor

U(N)-monopoles on Kerr black hole and its entropy

U. Leonhardt and P. Piwnicki reply to the ``Comment on `Relativistic Effects of Light in Moving Media with Extremely Low Group Velocity ' '' by M. Visser

Uber das Gravitationsfeld eines Massenpunktes nach der Einstenschen Theorie

Ultimate gravitational mass defect

Ultimate Internets

Ultimately Schwarzschildean Spacetimes and the Black Hole Stability Problem

Ultra Relativistic Particle Collisions

Ultra--cold gases and the detection of the Earth's rotation: Bogoliubov space and gravitomagnetism

Ultra-hard fluid and scalar field in the Kerr-Newman metric

Ultra-high energy cosmic rays threshold in Randers-Finsler space

Ultra-high energy particle collisions in a regular spacetime without blackholes or naked singularities

Ultra-relativistic grazing collisions of black holes

Ultra-stable performance of an underground-based laser interferometer observatory for gravitational waves

Ultracompact stars with multiple necks

Ultralight particle creation during fresh inflation

Ultralocal energy density in massive gravity