Clockwork Quantum Universe
  Besides the purely digital or analog interpretation of reality there is a third possibility which incorporates important aspects of both. This is the cyclic formulation of elementary systems, in which elementary particles are represented as classical strings vibrating in compact space-time dimensions with periodic boundary conditions. We will address these cyclic solutions as "de Broglie internal clocks". They constitute the deterministic gears of a consistent semi-classical description of quantum relativistic physics, providing in addition an appealing formulation of the notion of time. 
Donatello Dolce
gr-qc hep-th quant-ph