Someday, computers might store information using not only electric charges or magnetism, but also tiny packets of heat called phonons. Such heat-based memory is theoretically possible within the laws of physics, new research shows, and this memory would be durable and could be read without destroying the information — two key requirements for useful data storage.
Circuits based on quantum packets of heat rather than electric charges could enable computers to use waste heat — which is currently just shed to keep a processor from overheating — to perform useful computations and store information, the researchers suggest in an upcoming Physical Review Letters. A surge of research in the last few years on the physics of controlling the flow of heat packets has yielded designs for heat-based diodes, transistors and logic gates that perform AND, OR and NOT operations.
“This is a promising field,” says Baowen Li, a physicist at the National University of Singapore who, with his colleague Lei Wang of the Renmin University of China in Beijing, designed the thermal memory. Heat-based circuits are “not only an alternative way for information processing, but a new science and technology in controlling heat flow. This, we believe, will revolutionize our daily use of heat and can help human beings save energy and live in a more environmental world.”
Unlike the electrons in an electric circuit, phonons in a thermal circuit are not actually particles. Instead, phonons are discrete units of vibration among the atoms in a solid. The stronger these vibrations are, the hotter the solid will be. In materials that conduct heat, phonons travel through the substance just as electrons travel through electrical conductors.