  Analyzing new experiments with ultracold neutrons (UCNs) we show that
physical adsorption of nanoparticles/nano-droplets, levitating in high-excited
states in a deep and broad potential well formed by van der
Waals/Casimir-Polder (vdW/CP) forces results in new effects on a cross-road of
fundamental interactions, neutron, surface and nanoparticle physics. Accounting
for the interaction of UCNs with nanoparticles explains a recently discovered
intriguing small heating of UCNs in traps. It might be relevant to the striking
conflict of the neutron lifetime experiments with smallest reported
uncertainties by adding false effects there.
