Chinese scientists achieve breakthrough, detect rare quantum friction in folded graphene

> A surprising discovery in 2022 revealed that water **flows faster through narrower carbon nanotubes**—reversing what we see in everyday plumbing. Researchers linked this counterintuitive behavior to quantum friction, where fewer electrons in narrower tubes reduce resistance to flow.

> Inspired by those findings, the Chinese scientists developed an approach which allowed them to probe the elusive effects of quantum friction at solid interfaces with unprecedented control. As the researchers increased the number of graphene layers in each fold, friction behaved unexpectedly. They used precise nanomanipulation to create folded graphene edges with controlled curvature and layer numbers, enabling detailed measurements of friction at the nanoscale.

> Their findings revealed that friction at the folded edges of graphene does not follow a linear pattern as layer numbers increase. Instead, it changes in a highly nonlinear fashion—raising **fundamental questions about the limits of classical friction models** when applied to solid-solid quantum interfaces.

> By folding the graphene, the researchers **induced internal strain that altered how electrons moved through the material.** This strain forced the electrons into fixed energy states, known as pseudo-Landau levels, which reduced energy loss as heat and ultimately lowered the friction at the interface.

> The researchers conducted their experiment using a carefully engineered graphene system cooled to ultra-low temperatures. Looking ahead, they plan to explore whether the same quantum friction effects can be observed in other materials and under conditions more relevant to real-world applications.