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This comprehensive theoretical study investigates different aspects of engineered
quantum states, focusing on their non-classical features. The thesis comprises ten
chapters, each contributing valuable insights to our understanding of quantum phenomena.
The study begins with an introduction in Chapter 1, providing a brief overview
of the research conducted during the specified period. Further, the literature review
and methodology for the research is given in Chapter 2 and 3.
Following this, Chapter 4 meticulously explores lower- versus higher-order nonclassicalities for a coherent superposed quantum state. Coherent states, conventionally defined in various ways, are analyzed here after operating a superposition of
field operators. This chapter uncovers nuanced insights into both lower and higherorder non-classical properties using a set of nonclassicality witnesses.
In Chapter 5, the focus shifts to the detection of nonclassicality and non-Gaussianity
of a coherent superposed quantum state. The coherent superposed quantum state
(CSQS), obtained through a coherent superposition of field operators, is examined
for its nonclassical and non-Gaussian characteristics. The computation of various
criteria including the Wigner function, linear entropy, Wigner logarithmic negativity, and skew information-based measures are employed to provide a comprehensive
analysis.
Chapter 6 undertakes a comparison between higher-order nonclassicalities of
SUP-engineered coherent and thermal states. An experimentally accessible superposition (SUP) operator is applied to coherent and thermal quantum states, resulting
in SUP-operated coherent states (SOCS) and SUP-operated thermal states (SOTS).
This chapter presents a comparative analysis of the higher-order non-classical properties exhibited by SOCS and SOTS, contributing valuable insights for potential
experimental verification.
Chapter 7 delves into a comparative study of higher-order nonclassicalities of
photon-added-then-subtracted and photon-subtracted-then-added quantum states. Photonmanipulated thermal and coherent states are examined for both higher and lowerorder non-classical features. The outcomes highlight the striking non-classical characteristics exhibited by the considered states and emphasize the preference for specific photon operations that enhance non-classicality.
In Chapter 8, the study concentrates to explore the interplay between nonclassicality and quantum non-Gaussianity of photon-subtracted displaced Fock states. A
quantitative investigation is conducted, considering the impact of the number of subiv
tracted photons and the Fock parameter on nonclassical and quantum non-Gaussian
characteristics. The dynamics of the Wigner function under a photon loss channel
is analyzed to record the dissipation due to interaction with a vacuum reservoir as
well as inefficient detectors with efficiency coefficient η = 1−T.
Chapter 9 switches the focus to the realistic continuous-variable quantum teleportation using a displaced Fock state channel. Ideal and non-ideal continuousvariable quantum teleportation protocols are investigated by employing an entangled displaced Fock state resource. This chapter provides insights into the challenges and optimizations for successful teleportation, considering factors such as
reflectivity, gain factor, mode damping, and the number of thermal photons.
The final chapter, Chapter 10 offers a conclusive summary of the entire research
work and outlines potential avenues for future exploration and investigation. This
thesis altogether enriches our understanding of the non-classical features of different
engineered quantum states, paving the way for advancements in quantum information processing and technology. |
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