Researchers have built a logic gate — a building block for computers — that uses vibrations instead of electrons. As a result, it processes information very energy-efficiently.
Scientists have created a computer component that does not use electrons, but vibrations. As a result, the component can meet the physical lower limit for energy consumption when processing and transmitting information to approach.
The minimum amount of energy a computer needs to perform a calculation step is called the ‘Landauer limit’, after the 1960s physicist Rolf Landauer. In his calculations, Landauer took into account not computer design, but the energy costs needed to manipulate information, such as erasing or rewriting a bit.
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Vibrations
Ordinary computers consist of semiconductors. They work by regulating the flow of electrons within various circuits to perform operations. In order to prevent fluctuations in heat from affecting the movements of the electrons and causing errors, energy is consumed. The energy consumption of computers is therefore about ten thousand times higher than the Landauer limit.
So-called nanomechanical computers, which use tiny vibrations instead of electrons, would not have these extra energy costs. Warwick Bowen, quantum scientist and nanotechnologist at the University of Queensland in Australia, has now teamed up with colleagues to create a nanomechanical logic gate. That is a basic building block of such a nanomechanical computer.
The gate contains a membrane a thousand times thinner than a human hair. Bowen says it’s like a “nanoscopic trampoline” that can vibrate over low or high distances, or amplitudes. The two amplitudes can have the values 0 and 1 in an electronic computer, so that the computer can perform calculations by amplifying or damping the vibrations.
Information is entered into the gate by a sound wave, a moving vibration. The output of the gate, a very simple calculation, then enters another gate of the same design via a sound wave. Instead of electrons passing through a wire, sound now moves between chips in a computer.
Application
“Anything you can do with an electronic semiconductor computer, you can do with these computers,” Bowen says. At the same time, he says that the new gate does not yet work at the Landauer limit: his team relies on theoretical calculations showing that the gate needs to be about a thousand times smaller to get there.
According to nanotechnologist Raj Mohanty from Boston University, whose team created one of the first nanomechanical gates more than fifteen years ago, it is now also possible to mass-produce nanomechanical gates on silicon chips in commercial facilities.
Nanomechanical computers probably won’t replace the computers of everyday life, but they could be suitable for satellites, Bowen said. A nanomechanical computer without wires and electronics would be able to withstand extreme conditions such as solar flares, so that it would not lose any information in such a case.