A theoretical study of nonclassical effects in optical and spin systems and their applications

by   Kishore Thapliyal, et al.

Nonclassical states, having no classical analogue, promise advantage in the performance in several fields of technology, such as computation, communication, sensing. This led to an escalated interest in the recent years for the generation and characterization of nonclassical states in various physical systems of interest. Keeping this in mind, we examined generation of various lower- and higher-order nonclassical states in both codirectional and contradirectional asymmetric nonlinear optical couplers operating under second harmonic generation with the help of moments-based criteria. Using another such system (a symmetric nonlinear optical coupler), we have also established the possibility of observing quantum Zeno and anti-Zeno effects and further reduced the obtained results to yield the corresponding expressions for the asymmetric coupler. These studies have been accomplished using a complete quantum description of the system considering all the field modes as weak. Further, characterization of nonclassicality in spin systems using quasiprobability distributions has been performed, which has also provided us the dynamics of the amount of nonclassicality (using nonclassical volume). As the reconstruction of quasiprobability distributions is possible with the help of tomograms accessible in the experiments, tomograms are computed here for both finite and infinite dimensional systems. Finally, a set of controlled quantum communication (both insecure and secure) schemes with minimum number of entangled qubits has been proposed, which is also analyzed over Markovian channels. The optimized controlled secure quantum communication scheme is observed to be reducible to several cryptographic tasks. Using this interesting observation, we obtained the performance of a set of cryptographic schemes over non-Markovian channels, too.


page 1

page 2

page 3

page 4


Optical designs for realization of a set of schemes for quantum cryptography

Several quantum cryptographic schemes have been proposed and realized ex...

Continuous variable direct secure quantum communication using Gaussian states

Continuous Variable one-way and controlled-two-way secure direct quantum...

Experimental machine learning quantum homodyne tomography

Complete characterization of states and processes that occur within quan...

Experimental quantum advantage with quantum coupon collector

An increasing number of communication and computational schemes with qua...

Verifiable Quantum Secure Modulo Summation

We propose a new cryptographic task, which we call verifiable quantum se...

Quantum and Semi-Quantum Lottery: Strategies and Advantages

Lottery is a game in which multiple players take chances in the hope of ...

Interferometry-based modal analysis with finite aperture effects

We analyze the effects of aperture finiteness on interferograms recorded...

Please sign up or login with your details

Forgot password? Click here to reset