Anomalous quantum friction from fractional coupling to a reservoir

What is it about?

Quantum friction describes the loss of energy due to heating, at the scale of individual atoms. Sometimes this friction deviates from the standard, and it is then known as anomalous diffusion. Previously, this was shown to happen in a class of materials known as non-Ohmic materials. Here, we show that anomalous diffusion can also occur in regular (Ohmic) materials when the interaction with a reservoir becomes fractional. We demonstrate that this fractional coupling can describe a large variety of diffusions. Our work hints that anomalous diffusion could be much more common than previously thought.

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Photo by Dynamic Wang on Unsplash

Photo by Dynamic Wang on Unsplash

Why is it important?

Friction leads the loss of energy to the environment, typically in the form of heat. Its understanding is therefore of great importance for building energy efficient devices. The effects of friction can be understood by studying diffusion, the random movement of particles inside a material. Our findings demonstrate that known deviations from this diffusion (anomalous diffusion) can occur even in ordinary materials when the interaction is altered. This fractional friction is known to have some remarkable properties such as memory, which could be used, for example, to minimize friction for the most costly tasks.

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