Thermodynamics and Optical Conductivityof a Dissipative Carrier in a Tight Binding Model

Abstract

Thermodynamics and transport properties of a dissipative particle in a tight-binding modelare studied through specific heat and optical conductivity.A weak coupling theory is constituted tostudy the crossover behavior between the low-temperatureregion and the high-temperature region analytically.We found that coherent part around zero frequencyin the optical conductivity disappears for 02K-2, where K is a dimensionless damping strength.The high frequency side of the optical conductivityis independent of temperatures, while the low frequency sidedepends on the temperature, and behaves as T^2K-2 at high temperatures. We also comment on theapplication of this model to the description of incoherentmotion in correlated electron systems.