Please use this identifier to cite or link to this item: http://theses.iitj.ac.in:8080/jspui/handle/123456789/87
Title: Discord, Quantum Correlations and Bell-type Inequality for Multi-qubit Systems
Researcher : Faujdar, Jyoti
Supervisor: Atul Kumar
Department: Center for Information Communication and Technology
Issue Date: May-2015
Citation: Faujdar, Jyoti. (2015). Discord, Quantum Correlations and Bell-type Inequality for Multi-qubit Systems (Master's thesis). Indian Institute of Technology Jodhpur, Jodhpur.
Abstract: The classification and quantification of multiqubit entangled states in different classes always allow us to understand the usefulness of these states in quantum information processing based on the properties of the classes they belong to. We analyze the non-classicality of a class of two-qubit mixed entangled states and its relation with the classification of three-qubit purified states obtained from a purification protocol of two-qubit mixed entangled states. We further show that the sufficient condition for the success of our purification protocol requires one of the subsystems of the mixed two-qubit entangled state to be a pure state. Our results show that the purified state can be classified into GHZ class, W class, product states, or biseparable states. The new classification scheme proposed in this part of the Thesis is in one to one correspondence with the standard classification scheme of three-qubit pure states based on the Von-Neumann entropy and three tangle in addition to the nonlocality as confirmed by the Svetlichny inequality. In another part of the Thesis, we address the problem of distinguishing between bipartite and tripartite nonlocality. Such studies are important not only to satisfy the foundational quest in quantum mechanics and quantum information, but also to identify efficient quantum resources for information processing. Bell-type inequalities for bipartite as well as tripartite systems clearly delimit the border between classical and quantum correlations. Mermins inequality, for instance, is used to characterize tripartite nonlocality. However, in addition to its failure to identify all the GHZ class states for the complete range of degree of entanglement, both biseparable and tripartite entangled states violate this inequality. We propose a new inequality based on cluster coefficients to overcome both the above problems. Our study shows that the new inequality clearly distinguishes between biseparable and genuinely entangled three-qubit states. Moreover, our inequality also identifies all the GHZ class states for the complete range of degree of entanglement of the pure three-qubit state.
Pagination: ix, 37p.
URI: http://theses.iitj.ac.in:8080/jspui/handle/123456789/87
Accession No.: TM00082
Appears in Collections:M. Tech. Theses

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