  Role of quantum interference in the origin of higher-order nonclassical
characteristics of radiation field has been probed vis-a-vis a discrete and a
continuous superposition of coherent states. Specifically, the possibilities of
observing higher-order nonclassical properties (e.g., higher-order antibunching
(HOA), higher-order sub-Poissonian photon statistics (HOSPS), higher-order
squeezing (HOS) of Hong-Mandel type and Hillery type) have been investigated
using a shifted symmetric cat state that reduces to Yurke-Stoler, even and odd
coherent states at various limits. This shifted symmetric cat state which can
be viewed as a discrete superposition of coherent states is found to show HOA
and HOSPS. Similarly, higher-order nonclassical properties of a one-dimensional
continuous superposition of coherent states is also studied here. The
investigation has revealed the existence of HOS and HOSPS in the
one-dimensional continuous superposition of coherent states studied here.
Effect of non-Gaussianity inducing operations (e.g., photon addition and
addition followed by subtraction) on these superposition states have also been
investigated. Finally, some comparisons have been made between the higher-order
nonclassical properties of discrete and continuous superposition of coherent
states.
