Purification and Fidelity Enhancement from Quantum Mixedness

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Sudhir Kumar Sahoo is financially supported by the Ministry of Human Resource Development (MHRD), Govt. of India. We develop algorithms for optimizing purity and fidelity from a noisy mixed quantum state through a two-step process: (a) By iteratively optimizing the cost function for purity under regularity conditions using a set of anticommutating Pauli operators, we obtain an optimal set of parameters for the unitary transformation with a significant reduction in complexity. (b) Once the desired level of purity is reached, we align the pure state to the original reference pure state via a unitary transformation. We provide an analysis into the working of the procedure along with simulation results towards validation.