Asynchrony in Quantum-Dot Cellular Automata Nanocomputation: Elixir or Poison?

Emerging computing technologies inherently exhibit high process and timing variation. Many researchers believe that an asynchronous approach is likely to play an enabling role in making these technologies feasible. This article compares the cost and performance of fully synchronous and mixed synchronous asynchronous implementations of quantum cellular automata, and makes the case that asynchrony is inevitable at the top levels of QCA designs.