Ruhr-University Bochum researchers reported in Nature that fluorescent carbon-mesh nanotubes suspended in water diffuse more slowly under illumination, with brighter light producing a lower diffusion constant.
Excitons created inside the lit nanotubes appear to couple with surrounding water molecules and transfer momentum, generating quantum friction that makes the liquid behave as if it were thicker.
THz spectroscopy detected that molecular-scale energy and motion in the water, while the slowing vanished in defect-rich nanotubes where exciton motion was hindered, tying the braking effect to exciton mobility.
The nanotubes are about 100,000 times thinner than a human hair, and the team said the finding blurs the boundary between solid-state and liquid physics at the nanoscale.
Researchers said controllable light-driven friction could eventually help steer nanorobots in liquids and fine-tune chemical reaction conditions.
Scientists made water 'thicker' for nanotubes using light. Is this quantum trick the key to creating revolutionary new materials?
If light can act as an invisible brake, could this technology lead to nanorobots performing surgery inside our bodies?
A new discovery shows light can create friction. What other fundamental forces could we control at the quantum level with just a light beam?
Light as a Quantum Brake: The Discovery and Implications of Light-Induced Friction at the Nanoscale
Overview
Scientists at Ruhr-University Bochum have discovered that light can act as a 'quantum brake' on nanoscale materials, a phenomenon called light-induced quantum friction. This breakthrough shows that light doesn't just illuminate or heat materials—it can directly slow down the movement of tiny particles like carbon nanotubes suspended in water. The effect, carefully documented in recent experiments, marks a fundamental shift in how we understand light's influence at the quantum level. By revealing a new way electromagnetic radiation can control motion at the nanoscale, this discovery opens exciting possibilities for future technologies and scientific research.