부산대학교 도서관

Quantum information processing exploits non-local functionality that has led to significant breakthroughs in the successful deployment of quantum mechanical protocols. In this regard, we address the dynamics of entanglement and coherence for three non-interacting qubits initially prepared as maximally entangled GHZ-like state coupled with independent classical environments. Two different Gaussian noises in pure and mixed noisy situations, namely, pure power-law noise, pure fractional Gaussian noise, power-law noise maximized and fractional Gaussian noise maximized cases are assumed to characterize the environments. With the help of time-dependent entanglement witnesses, purity, and decoherence measures, within the full range of parameters, we show that the current mixed noise cases are more detrimental than pure ones where entanglement and coherence are found short-lived. The power-law noise phase, in particular, appears to be more flexible and exploitable for long-term preservation effects. In contrast, we find that in both pure and mixed noise cases, where entanglement and coherence degrade at a relatively high rate, there is no ultimate solution for avoiding the detrimental dephasing effects of fractional Gaussian noise. The three-qubit state becomes disentangled and decoherent within independent classical environments driven by both pure and mixed Gaussian noises, either in long or short interaction time. In addition, due to the lack of the entanglement revival phenomenon, there is no information exchange between the system and the environment. The three-qubit GHZ-like states have thus been realized to be an excellent resource for long enough quantum correlations, coherence, and quantum information preservation in classical independent channels driven by pure power-law noise with extremely low parameter values.
Comment: 24 pages, 9 figures