Light-induced quantum friction slows carbon nanotubes in water
Researchers discovered that carbon nanotubes suspended in water move more slowly when exposed to green light, suggesting a quantum mechanical coupling between excited electrons in the tubes and water molecules. This phenomenon, called quantum friction, involves non-adiabatic interactions between electronic modes in the nanotubes and collective modes of water dipoles. The finding advances understanding of liquid-solid friction at the nanoscale and could have applications in biosensing and nanotechnology.
Scientists studying single-walled carbon nanotubes (SWCNTs) in water observed that light excitation causes the nanotubes to diffuse more slowly through the liquid, a counterintuitive result explained by quantum friction. This type of friction arises from coupling between the electronic excitations (excitons) in the carbon nanotubes and the vibrational modes of water, particularly in the terahertz frequency range. The mechanism involves non-adiabatic interactions that go beyond classical friction models, with the water's librational, intermolecular stretch, and Debye modes playing key roles. Researchers used single-molecule fluorescence measurements, terahertz spectroscopy, and molecular dynamics simulations to characterize the phenomenon. The work builds on prior evidence of anomalous friction at water-carbon interfaces and suggests that quantum effects significantly influence nanoscale hydrodynamics in aqueous environments.
What different sources said
- Nature NewsCenter
Light-induced quantum friction of carbon nanotubes in water
- Nature NewsCenter
Light slows down carbon nanotubes in water
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