Mobility and its temperature dependence in LSCO: viscous motion?

We argue that charges in underdoped La${}_{2-x}$Sr${}_x$CuO${}_4$ move in a dissipative environment of strong spatial and temporal fluctuations. The unusual temperature dependence of the Hall angle known as “the separation of lifetimes” is reinterpreted and attributed to the appearance of the thermally activated component in the effective number of carriers with the temperature increase. We consider the temperature interval above $T_c$ where localization effects can be neglected.