In a breakthrough for energy-efficient computing, engineers at the University of California, Berkeley, have shown for the first time that magnetic chips can operate with the lowest fundamental level of energy dissipation possible under the laws of thermodynamics.
The findings, to be published Friday, March 11, 2016 in the peer-reviewed journal Science Advances, mean that dramatic reductions in power consumption are possible—as much as one-millionth the amount of energy per operation used by transistors in modern computers.
This is critical for mobile devices, which demand powerful processors that can run for a day or more on small, lightweight batteries.
Minimizing energy dissipation has emerged as the key challenge in continuing to scale the performance of digital computers. The question of whether there exists a fundamental lower limit to the energy required for digital operations is therefore of great interest. A well-known theoretical result put forward by Landauer states that any irreversible single-bit operation on a physical memory element in contact with a heat bath at a temperature T requires at least kBT ln(2) of heat be dissipated from the memory into the environment, where kB is the Boltzmann constant. We report an experimental investigation of the intrinsic energy loss of an adiabatic single-bit reset operation using nanoscale magnetic memory bits, by far the most ubiquitous digital storage technology in use today. Through sensitive, high-precision magnetometry measurements, we observed that the amount of dissipated energy in this process is consistent (within 2 SDs of experimental uncertainty) with the Landauer limit. This result reinforces the connection between “information thermodynamics” and physical systems and also provides a foundation for the development of practical information processing technologies that approach the fundamental limit of energy dissipation. The significance of the result includes insightful direction for future development of information technology.