Dynamical Response of quasi one-dimensional Mott and CDW insulators.

F.H.L. Essler and A.M. Tsvelik

Physics Department, Brookhaven National Laboratory, Upton, NY 11973

We calculate the low temperature spectral function of one-dimensional
incommensurate charge density wave (CDW) states and half-filled Mott
insulators (MI). The former is characterized by a gap in the spin sector
and a gapless charge sector. At $T=0$ there are two dispersing
features associated with the spin and charge degrees of freedom
respectively. We show that already at very low  temperatures (compared
to the gap) one of these features gets severely damped. We comment on
implications of this result for photoemission experiments.
We present a scenario for the evolution from a Mott insulating state to 
a Fermi liquid as the interchain hopping is increased in a system of 
weakly coupled chains.