Credit: © 2009 APS

In 1961 Rolf Landauer showed that erasing a single bit of information costs a non-zero amount of entropy. Like the second law of thermodynamics, Landauer's principle has implications for many areas of physics. Now, Raoul Dillenschneider and Eric Lutz of the University of Augsburg have shown that Landauer's principle — like the second law — needs to be generalized to apply at the nanoscale1.

Using a double-well potential to model a single-bit memory, they calculate that full-bit erasure in small systems can be achieved with an entropy dissipation that is smaller than the standard Landauer limit. This breach of the Landauer limit is caused by thermal fluctuations that can be ignored on macroscopic scales, but become important at shorter length scales.

Dillenschneider and Lutz also propose an experiment to test their predictions: the use of fluorescence microscopy combined with real-time feedback to study the Brownian motion of a nanoparticle in a driven double-well potential. Similar experiments have already been performed on nanoparticles in static double-well potentials.