‘Quantum friction’ slows water flow through carbon
nanotubes, resolving long-standing fluid dynamics mystery

For 15 years, scientists have been baffled by the
mysterious way water flows through the tiny passages of carbon
nanotubes—pipes with walls that can be just one atom thick. The
streams have confounded all theories of fluid dynamics;
paradoxically, fluid passes more easily through narrower nanotubes,
and in all nanotubes it moves with almost no friction. What
friction there is has also defied explanation.