Two Nature reports describe experiments in which water-suspended carbon nanotubes slow down when illuminated. In one study, researchers observe that carbon nanotubes in water move more slowly under green light. The authors attribute the effect to interactions between excited electrons in the nanotubes and the surrounding water, described as “quantum friction.” In a related report, the team focuses on near‑infrared fluorescent carbon nanotubes and reports that light-induced quantum friction occurs in water by means of exciton interactions. According to the articles, these exciton-related interactions generate a friction-like coupling that reduces nanoscale motion. The findings are presented as evidence that optical excitation can be used to control diffusion and aspects of fluid dynamics at the nanoscale. Both pieces emphasize that the observed slowing links changes in nanotube motion to specific light conditions, and they frame the mechanism in terms of quantum interactions between the nanotubes and water rather than macroscopic heating or bulk fluid effects. The work points to a route for tuning nanoscale transport in fluids using light.