Electronics has revolutionized the modern world, owing to continuous improvements in microprocessor technology since the 1960s. However, this process of refinement is projected to stall in the near future, due to constraints imposed by the laws of physics. Some of these bottlenecks have already taken effect: for instance, the clock rate (the rate at which transistors perform digital operations) has been unable to exceed a few gigahertz, or several operations per nanosecond, for the past twenty years, a limitation stemming from the electrical resistance of silicon. Read more