| dc.description.abstract |
This comprehensive theoretical study investigates quantum states generated via atomfield interactions, and their non-classical properties. The thesis includes nine chapters,
each contributing valuable insights to our perception of quantum phenomena.
The journey begins with an introduction in Chapter 1 that provides a brief overview
of the research conducted during the specified period.
Chapter 2 provides a comprehensive overview of prior research on quantum states
generated through atom-field interactions, emphasizing their non-classical properties.
This chapter highlights the significant contributions of various authors to the
understanding and advancement of this domain.
Chapter 3 outlines the systematic approach undertaken to investigate quantum states
generated by atom-cavity field interactions and their non-classical properties.
Following this, Chapter 4 explores the statistical analysis of the cavity field state
manufactured by the interplay between atom and cavity field. It delves into
understanding the behaviour of such system under the influence of an external driven
field with a special focus on the statistical characteristics exhibited by the resulting
cavity field state. The research primarily concerns to examine different statistical
properties such as photon number distribution, Wigner function, Mandel’s Q
parameter, and squeezing.
Chapter 5 looks into a non-classical state generated by an atom-cavity field
interaction in presence of a driven field. In the scheme, the two-level atom is moved
through the cavity and driven by a classical field. The atom interacts dispersively with
the cavity field which results in a photon-number-dependent Stark shift. Assuming that
the atom enters the cavity in the excited state |a⟩, the output cavity field is taken into
account. The state vector |ψ(t)⟩ describes the entire atom-field system but in our work,
we deal with the statistical aspects of the cavity field only. The quantum state that
corresponds to the output cavity field is obtained by tracing out the atom part from
|ψ(t)⟩ ⟨ψ(t)|. Different quantum phase properties such as quantum phase distribution,
angular Q phase function, phase dispersion are evaluated for the obtained radiation
field. The second-order correlation function g
2
(0), an indirect phase characteristic, is
also considered.
Chapter 6 accomplishes the analysis of a non-classical state generated through the
interaction between an atom and a single-mode electromagnetic cavity field. Using a
nonlinear Hamiltonian approach, we have extended the conventional
Jaynes-Cummings model by introducing non-linearity and deforming the field
operators. The study focuses on exploring the system dynamics under these
modifications. The main emphasis of this study is to analyze the statistical features
displayed by the emerging cavity field state. This research delves into investigating
iv
statistical metrics like the distribution of photon numbers, Wigner function, Mandel’s
Q parameter, squeezing properties, Qf function, and lower-order antibunching which
are essential for understanding the quantum characteristics embedded into the
dynamics of the cavity field system.
In Chapter 7, we have investigated non-classical properties of a state generated by
the interaction of a three-level atom with a quantized cavity field and an external
classical driving field. In this study, the fields being degenerate in frequency, are highly
detuned from the atom. The atom interacts with the quantized field in a dispersive
manner. The experimental set-up involves a three-level atom passing through a cavity
and interacting dispersively with the cavity field mode. Simultaneously, the atom
interacts with an external classical field that is in resonance with the cavity field. The
three-level atom can enter the cavity either in one of the bare states |e⟩, | f⟩ or |g⟩ or in
a superposition of two of these states. We consider a superposition of |e⟩ and | f⟩. In
our analysis, we have focused on the statistical properties of the cavity field after
interacting with the atom. The state vector |ψ(t)⟩ describes the entire atom-field
system but we have analyzed the properties of the cavity field independently after
neglecting the atomic component of the system. For this, the atom part is traced out
from |ψ(t)⟩ to acquire the cavity field state only, denoted by
ψf(t)
. We have
evaluated different non-classical measures including photon number distribution,
Mandel’s QM parameter, squeezing properties Sx and Sp, Wigner distribution, Qf
function, and second-order correlation function g
2
(0) of the derived cavity field state.
In Chapter 8, we have considered a system resulting from the interaction of two
two-level atoms and a two-mode field inside an optical cavity that is embedded with a
nonlinear Kerr-like medium. The study includes the effect of detuning parameter, Stark
shift, atom-field coupling and third-order susceptibility of the Kerr medium on light
intensity. We have obtained the exact solution of the Schrödinger equation after
assuming that the atoms and the field are initially in superposition and coherent states,
respectively. Our study aims to understand the dynamics of the system by finding out
the exact analytical form of the state vector. Some statistical properties such as
photon-number distribution, second-order correlation, Mandel’s QM and squeezing are
investigated.
Finally Chapter 9 offers a conclusive summary of the entire research work and
outlines potential avenues for future exploration and investigation. The thesis
collectively enriches our understanding of the non-classical features of different
atom-field quantum states, paving the way for advancements in quantum information
processing and technology |
en_US |