
Martina Havenith-Newen, Sebastian Kruss, and Marialore Sulpizi (from left) work together in the RESOLV Cluster of Excellence.
Photo Credit: © RUB, Marquard
Scientific Frontline: Extended "At a Glance" Summary: Light-Induced Quantum Friction
The Core Concept: Light-induced quantum friction is an unexpected phenomenon in which irradiating nanoscale particles—specifically fluorescent carbon nanotubes in aqueous solutions—with visible light decelerates their movement rather than accelerating or heating them.
Key Distinction/Mechanism: Contrary to classical expectations where light imparts kinetic energy, this deceleration is caused by the direct coupling between excitons (mobile electronic excitations within the solid nanotube) and the fluctuating dipole moments of the surrounding water molecules. This dynamic creates a microscopic momentum transfer that acts as surface resistance, effectively braking the particle and decreasing its diffusion constant as light intensity increases.
Major Frameworks/Components:
- Fluorescent Carbon Nanotubes: Ultra-thin carbon meshes (100,000 times thinner than a human hair) serving as the solid nanoscale framework.
- Excitons: Electronic excitations whose mobility along the nanotube is responsible for the direct exchange with the fluid environment.
- Terahertz (THz) Spectroscopy: An advanced measurement technique utilized to observe real-time friction and energy dissipation after electronic excitation.
- Atomistic Simulations: Computational models used to numerically visualize the momentum transfer and collective molecular movements at the liquid-solid interface.









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