Abstract
Phys. Rev. Lett 85, 1092 (2000). We study the low-temperature low-frequency conductivity sigma of an
interacting one dimensional electron system in the presence of a periodic
potential. The conductivity is strongly influenced by conservation laws, which,
we argue, need be violated by at least two non-commuting Umklapp processes to
render sigma finite. The resulting dynamics of the slow modes is studied within
a memory matrix approach, and we find exponential increase as the temperature
is lowered, sigma = (Delta n)^2 e^{T_0/(N T)} close to commensurate filling
M/N, Delta n=n-M/N << 1, and sigma = e^{(T'_0/T)^{2/3}} elsewhere.