New chip concepts There remain new ways to dramatically speed up not just specialized accelerators but also general-purpose chips. Tom Conte, a computer scientist at Georgia Tech in Atlanta who leads the IEEE Rebooting Computing Initiative, points to two paradigms. The first is superconduction, in which chips run at a temperature low enough to eliminate electrical resistance. The second paradigm is reversible computing, in which bits are reused instead of expelled as heat. In 1961, IBM physicist Rolf Landauer merged information theory and thermodynamics, the physics of heat. He noted that when a logic gate takes in two bits and outputs one, it destroys a bit, expelling it as entropy, or randomness, in the form of heat. When billions of transistors operate at billions of cycles per second, the wasted heat adds up, and the machine needs more electricity for computing and cooling. Michael Frank, a computer scientist at Sandia National Laboratories in Albuquerque who works on reversible computing, wrote in 2017: “A conventional computer is, essentially, an expensive electric heater that happens to perform a small amount of computation as a side effect.” But in reversible computing, logic gates have as many outputs as inputs. This means that if you ran the logic gate in reverse, you could use, say, three out-bits to obtain the three in-bits. Some researchers have conceived of reversible logic gates and circuits that could not only save those extra out-bits but also recycle them for other calculations. Physicist Richard Feynman had concluded that, aside from energy loss during data transmission, there’s no theoretical limit to computing efficiency. Combine reversible and superconducting computing, Conte says, and “you get a double whammy.” Efficient computing allows you to run more operations on the same chip without worrying about power use or heat generation. Conte says that, eventually, one or both of these methods “probably will be the backbone of a lot of computing.”