7.9: And beyond?

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Researchers are currently pursuing a few ideas:

1. Reversible computing

The absence of power dissipation makes this a big prize, but concerns remain as to its noise immunity and fundamental practicality.

2. New information tokens

Transistors today use electrons to carry information. Instead, we might seek to use a different information token such as the spin of an electron or position in a mechanical switch. A change in information token could revolutionize electronics. But at present it is not clear what, for example, a spin-in spin-out transistor might look like, nor do we have a clear idea of the potential benefits of spin-based technology. For example, could it escape the Shannon-Von Neumann-Landauer limit?

3. Integration

More transistors per chip have traditionally meant more computing power. If we can't make transistors any smaller, perhaps we could shift to three dimensional circuits? A transition from two to three dimensional circuits could massively increase integration densities. But apart from the difficulty of fabricating such structures, we must also figure out how to cool them.

4. Architecture

The computing power of the brain clearly demonstrates the virtue of different approaches to certain problems such as pattern recognition. But it is not clear that our current model of electronics is suited to say, a shift to a neural network type architecture.

Whatever happens the stakes are high. As we approach the limits of CMOS, slow technological progress may reduce the need to update computers every few years. But the economic model of the electronics industry has come to rely on rapid technological change. Consequently, the rewards may be especially great for the next revolution in electronics technology.