Proof that erasing information produces heat

March 12, 2012

To test Landauer's principle, the researchers created a simple two-state bit: a single microscopic silica bead held in a "light trap" by a laser beam. The trap contains two "valleys" where the particle can rest, one representing a 1 and the other a 0. It could jump between the two if the energy "hill" separating them is not too high. (Credit: Nanosystems Initiative Munich)

Results of an experiment that validates an important principle for information theory and computer science have been published in Nature.

Nanosystems Initiative Munich (NIM) member Eric Lutz and his colleagues show that erasing information produces heat, as predicted by Rolf Landauer fifty years ago, and demonstrates the intimate link between information theory and thermodynamics.

Landauer’s principle applies thermodynamic reasoning to information processing and states that any logically irreversible transformation, such as the deletion of a classical bit of information, dissipates heat.

Experimental validation of Landauer’s erasure principle has been difficult to achieve, owing to the difficulty of realizing single-particle experiments with low heat dissipation.

Eric Lutz and colleagues now overcome such difficulties, using an optically trapped silicon bead as a generic model of a one-bit memory. They measure the average heat dissipated over many erasure cycles, showing that it converges to (but never exceeds) the limit set by Landauer’s principle.

See also: The unavoidable cost of computation revealed, Nature News.

Ref.: Antoine Bérut et al., Experimental verification of Landauer’s principle linking information and thermodynamics, Nature, 2012 [DOI: 10.1038/nature10872]