Universal transition between Hamiltonian and dissipative chaos

Universal Tunnelling Time in photonic Barriers

Universal Velocity and Universal Force

Universality

Universality of the de Broglie-Einstein velocity equation

Universality of the isospecial relativity for the invariant description of arbitrary speeds of light

Universality of the Lorentz-Poincare'-Santilli isosymmetry for the invariant description of all possible spacetimes

Universality of the self gravitational potential energy of any fundamental particle

Universe creation on a computer

Universe Without Singularities. A Group Approach to De Sitter Cosmology

Universes with and without a center

Unless Connected to Relativity the First and Second Laws of Thermodynamics are Incompatible

Unphysical Gauge Fixing in Higgs Mechanism

Unravelling Lorentz Covariance and the Spacetime Formalism

Unravelling the Dark Matter - Dark Energy Paradigm

Unreduced Dynamic Complexity: Towards the Unified Science of Intelligent Communication Networks and Software

Unsuitability of the moving light clock system for the Lorentz factor derivation

Unusual formations of the free electromagnetic field in vacuum

Upper limit of the energy of the photon and the phase change of photon to material particles at the Scwartzschild radius

Uranio impoverito: perché? (Depleted uranium: why?)