Signatures of Spin Degrees of Freedom in Charge Dynamics of   YBa_2Cu_3O_6.95
  Charge carrier-spin excitation spectral densities constructed from optical data and varying with temperature are used to calculate various properties of the charge carrier dynamics. Temperature (T) variations of such properties are sensitive to the changes in the spectral density brought about by the growth in the 41 meV spin resonance as T is lowered. The microwave conductivity and the thermal conductivity are stressed and comparison with experiment is given. The imaginary part of the conductivity as a function of frequency \omega is also featured. 
E. Schachinger and J.P. Carbotte