The basic charged excitations in carbon nanotubes are plasmons, in a
similar fashion as in ordinary transmission lines. Owing to their small
density of conduction electrons, however, carbon nanotubes display rather
extraordinary line parameters.
Tunnelling conductance at high voltages was used to determine the
transmission-line parameters of the arc-discharge-grown multiwalled carbon
nanotube samples. The fits yield a characteristic impedance of 1.3 - 7.7 kOhm
and kinetic inductance of 0.1 - 4.2 nH/micron for the measured samples.
At low voltages, the tunneling conductance obeys non-Ohmic power law,
which is predicted both by the Luttinger liquid and the environment-quantum-
uctuation theories. However, at higher voltages we observe a crossover to
Ohm's law with a Coulomb-blockade offset, which agrees with the
environmental quantum-fluctuation theory, but cannot be explained by the
Luttinger-liquid theory
. 
