Non-Bloch Transients in Solids: Free Induction Decay and Transient Nutations

Abstract

Free induction decay and transient nutations are investigated in a system of two-level particles with an inhomogeneously broadened spectrum. The influence of the x (real) and y (imaginary) parts of the complex amplitude of the noise, induced by the driving field in the sample, is considered. It is shown that both noises affect ${T}_{1}$ and ${T}_{2}$ relaxation processes. When field-noise contributions to ${1/T}_{2}$ and ${1/T}_{1}$ relaxation rates are dominant and equal to each other, Bloch's saturation is changed to Redfield's saturation. This effect also accelerates transient nutation decay. Comparison with experimentally observed free induction decay and transient nutation in color centers in quartz is discussed.