Magnetic chips consume a million times less energy than electronic transistors. Landauer Principle

In 1961, Rolf Landauer from IBM formulated a principle that was later named after him: in any computing system, regardless of its physical implementation, if 1 bit of information is lost, heat is released in an amount of at least W joule:

W = k _B T ln 2,
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where k _B is the Boltzmann constant, T is the absolute temperature of the computing system in kelvins.

Physicists from the University of California at Berkeley were able to conduct a successful experiment with bit operations in magnetic memory and come close to this theoretical limit.

On March 11, 2016, Science Advances magazine published an open-access scientific paper describing an experiment in which physicists checked the physical properties of magnetic memory bits, in which the state of magnetization of small nanoparticles plays the role of zeros and ones. It was assumed that changing the direction of the magnetization of a particle would require a very small amount of energy.

The experiment showed that only 4 zeptojoules (4 * 10 ^–21 J) are spent on recording and reading one bit of information from a magnetized nanoparticle, that is, about a million times less than it is spent on processing one bit in modern computers.


The experimental setup and photographs of individual single-domain nanomagnets with different directions of magnetization

“The main problem in the development of modern computers, and, in principle, of all existing electronics are the energy savings of these devices. Increasing the speed of transistors requires more and more energy. The chips have become so hot that they literally melt while working, ”said Jeffrey Bokor, one of the authors of the paper.

According to calculations, the resulting value of energy costs is close to the theoretical minimum from the Landauer principle .

Reducing the power consumption of computers a million times, of course, would be a very significant achievement. For example, powerful computers might work from small photovoltaic cells.