  Dielectric relaxation has been investigated within the framework of a
modified mean field theory, in which the dielectric response of an arbitrary
condensed matter system to the applied electric field is assumed to consist of
two parts, a collective response and a slowly fluctuating response; the former
corresponds to the cooperative response of the crystalline or noncrystalline
structures composed of the atoms or molecules held together by normal chemical
bonds and the latter represents the slow response of the strongly correlated
high-temperature structure precursors or a partially ordered nematic phase.
These two dielectric responses are not independent of each other but rather
constitute a dynamic hierarchy, in which the slowly fluctuating response is
constrained by the collective response. It then becomes clear that the
dielectric relaxation of the system is actually a specific characteristic
relaxation process modulated by the slow relaxation of the nematic phase and
its corresponding relaxation relationship should be regarded as the universal
dielectric relaxation law. Furthermore, we have shown that seemingly different
relaxation relationships, such as the Debye relaxation law, the Cole-Cole
equation, the Cole-Davidson equation, the Havriliak-Negami relaxation, the
Kohlrausch-Williams-Watts function, Jonscher's universal dielectric relaxation
law, etc., are only variants of this universal law under certain circumstances.
