Theses
Permanent URI for this community
Browse
Browsing Theses by Supervisor "Banerjee, Subhashish"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Conflicts in Geometry(Indian Institute of Technology Jodhpur, 2017-11) Banik, Aritra; Banerjee, SubhashishThe thesis is motivated by what are called choice problems in computer science literature. Here, we define conflicts on the objects in some underlying classical problem such that it precludes some objects from being part of the solutionon if some others are in the solution.Item Quantum Communication Under Noisy Environment: From Theory to Applications(Indian Institute of Technology Jodhpur, 2018-07) Banerjee, SubhashishQuantum information is based on the laws of quantum mechanics to solve the issues related to information theory. Any communication system based on the principles of the quantum information technology deploys microscopic information carriers which have comparatively less signal to noise ratio. From the technology point of view, the construction and real eld implementation of such systems would be complex and challenging as one cannot neglect noise in practical applications. To make such systems reliable and e cient, the designer needs expertise in the elds of quantum electronics, communication theory, semiconductors, optoelectronics, photonics in addition to quantum optics. This doctoral thesis is the analysis of various quantum cryptography protocols under various noisy models in addition to quantum-based satellite communication under atmospheric turbulence. The research includes the calculation of delity, mutual information, key generation rate, quantum bit error ratio (QBER), entropy and engineering the communication distance. The noisy conditions between the transmitter and receiver are crucial and unavoidable for real eld applications. For this reason, we have to deal with such situations in the case of remote state preparation and various other quantum cryptography protocols. Along with this, another challenging task is atmospheric turbulence which degrades the performance of quantum-based satellite communication. The factors to deal with under such turbulence phenomena are maintaining proper synchronization between the sender and receiver, alignment of the optical instruments and remotely controlling all these complex setups for low earth orbit (LEO), medium earth orbits (MEO) and between inter-satellite communication for tracking the laser beam in case of uplink and downlink scenarios to maintain the optimum and accurate use of the whole setup.Item A Study of Nonclassicality in (Open) Quantum Systems.(Indian Institute of Technology Jodhpur, 2020-10) Banerjee, SubhashishIn this thesis, various aspects of nonclassicality are studied in different systems, bringing out an interplay of nonclassicality with the underlying dynamics. Various witnesses and measures of nonclassicality, both spatial as well as temporal, are analyzed using the lexicon of open and closed quantum systems, ranging from subatomic to quantum optical systems. This leads one to address the problem of quantification of the degree of quantumness of channels, the completely positive and trace preserving maps. Part of this thesis is devoted to the analysis of nonclassical properties of light in the context of Parity-Time (PT ) symmetric systems, i.e., the systems whose time evolution is governed by non-Hermitian Hamiltonian bearing PT symmetry. Comprising of seven chapters, the thesis starts with a broad literature survey of various concepts in chapter 1. In chapter 2, an introduction to the tools used in this thesis is made. This includes a description of open quantum systems, dynamical maps and various spatial and temporal quantum correlations. Further, a summary of various facets of nonclassicality of light is given. Chapter 3 provides a detailed analysis of various spatial and temporal quantum correlations in subatomic systems like neutrinos and neutral mesons. In chapter 4, a detailed account of the effect of non-Markovian dynamics on various facets of quantum information is presented. The subtleties arising due to non-Markovian dynamics, in computing the two time correlations are also highlighted. Further, the problem of quantifying the degree of quantumness of channels is addressed and a measure is proposed for the same. In chapter 5, the nonclassicality of light is studied in a cavity system embedded with two atomic ensembles of two level atoms. PT symmetry and its interplay with various nonclassical properties is studied in detail in chapter 6. The conclusion is made in chapter 7.