Dynamics of quantum correlations and their protection using novel dynamical decoupling sequences

Abstract

The core of this thesis focuses on the experimental demonstration of the dynamics newline of quantum resources, such as quantum correlations and quantum coherence, as well newline as their protection through the implementation of novel dynamical decoupling (DD) newline sequences. These sequences are applied to both nuclear spin-based nuclear magnetic newline resonance (NMR) quantum processors and superconducting qubit-based IBM quan newlinetum processors. Quantum coherence and quantum correlation, particularly quantum newline entanglement as well as quantum discord are crucial quantum resources for a range of newline tasks in quantum computation, information processing, and communication. The study newline undertaken in this thesis primarily addresses two key areas: first, it experimentally newline demonstrates the enhancement of quantum discord (QD) and quantum coherence (QC) newline in a two-qubit entangled states through the application of quantum weak measurement newline operator and PT-symmetric Hamiltonian, respectively. The non-unitary characteristics newline of these operators pose significant challenges for their experimental implementation. newline To address these challenges, various dilation-based techniques have been proposed, newline including Stinespring dilation, the duality method, and Sz.-Nagy s dilation techniques. newline In this thesis, the duality quantum algorithm based on dilation techniques is used to newline simulate a weak measurement operator where a three-qubit system is employed with newline the first two qubits serve as work qubits to generate a two-qubit entangled state, while newline the third qubit acts as an ancillary qubit. The weak measurement operator is applied to newline the first qubit of the two-qubit entangled state using the ancillary qubit, thereby reveal newlineing two weak variants of quantum discord: super quantum discord and weak quantum newline discord. As the name SQD suggests, QD increases with the strength of weak mea newlinesurement, thereby enhancing non-classical correlation. Conversely, WQD decreases newline with increasing measurement strength. Additionally, this thesis explores both theoreti newlinecally and experiment