Urchin writes to tell us that physicists working in a new field called "phononics" claim that waste heat from a processor could actually be used to add to its power. "Crunching data coded using photons — photonic computing — is one example, and in 2007 researchers built the first workable optical transistor. But now the idea of computing using heat flow is gaining popularity among applied physicists. Heat travels through solid materials by means of phonons — ripples of vibration passing through a series of atoms. Those ripples can be used to send and store data in digital form: one temperature is read as 0 or 'off' while a second, higher temperature is interpreted as 1 or 'on.' Provided that the thermal memory is well insulated, it can keep its temperature — and data — intact for a long time."