Activities

Entanglement dynamics in the noisy environment


Manipulation of entanglement sudden death in an all-optical setup


This experiment involves the creation, characterization, and manipulation of quantum entanglement in a photonic system and its dynamics in the noisy environment. Like classical correlations, entanglement also decays with time in the presence of noise in the ambient environment. Depending on the noise, some entangled states undergo asymptotic decay whereas others undergo finite time decay of entanglement which is known as entanglement sudden death (ESD). Prolonging (longevity of) the entanglement is essential for the practical realization of entanglement-based quantum information and computation protocols. For this purpose, the local NOT operation in the computational basis on one or both qubits has been proposed. We have formulated an all-optical experimental setup involving such NOT operations that can hasten, delay, or completely avert ESD, all depending on when it is applied during the process of decoherence. Analytical expressions for these are derived in terms of parameters of the initial state’s density matrix, whether for pure or mixed entangled states. Our scheme can hasten, delay, or avoid ESD in the presence of an amplitude damping noise in a photonic system. Delay and avoidance of ESD, in particular, will find application in the practical realization of quantum information and computation protocols which might otherwise suffer due to a short lifetime of entanglement. Also, it will have implications towards such control over other physical systems. An experimental realization of our proposal will be important for practical noise engineering in quantum information processing and is underway at QuIC lab RRI.

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