| Quantum mechanics has aroused a lot of controversies ever since its birth. It has exhibited some viewpoints which are incompatible with classical physics Moreover, some effects, which can never been achieved in the framework of classical physics, have been predicted by quantum theory and tested through experiments that it is indeed the case. One of the most famous controversies is the EPR paradox which was proposed by Einstein, Podolsky and Rosen in1935. After half a century, it is recognized that quantum entangled states can exhibit nonlocal relations which can not be explained by classical physics. What’s more, with the developing of quantum information theory, quantum nonlocality plays an important role in quantum computing and quantum in-formation transmission, and may have a prosperous prospects for application. Therefore, quantum noiiloealitv becomes a very important issue in quantum information theory. In this paper, we briefly explain the relationship between quantum entanglement and nonlocality at the beginning. Then we study how the acceleration affects the nonlocality in non-inerlial systems, and the vari-ation of the system’s nonlocality under various kinds of noisy environments. The main results of this article are as follows.(1)We show that there is no equivalent relations between entanglement and nonlocality through two simple examples. We study the relationship be-tween concurrence, which is a measure of entanglement, and nonlocality for NOON state and αOOα state, respectively. For NOON state, we have found that nonlocality is an explicit function of concurrence, and the nonlocality varies with concurrence monotonously. However, for αOOα state, when the concur-rence gets its maximum, the corresponding nonlocality is weak, and vice versa. So we can conclude that there is no equivalent relations between entanglement and nonlocality through such two typical examples.(2)Without considering the effect of environment, we have investigate what influence the acceleration has put on the nonlocality of the given Bell state in the noninertial system which has the maximal violation for the CHSH Ⅳ inequality in inertial system. For the Bell state,there exists a eritical ac-celeration. When the acceleration is less than the critical acceleration, the nonlocality of this state decreases rapidly as the acceleration increases. If the acceleration is larger than the critical value, the nonlocality of the Bell state disappears.(3)In the case that only the accelerated qubit of the EPR pair is put in a noisy environment, we have studied the impacts of both the acceleration and the environmental noise on the nonlocality of the Bell state. The influence of the phase flip channel, phase damping channel, amplitude damping channel and depolarization channel on the nonlocality of the state have been investi-gated, respectively. It has also been found that, for the phase flip channel, the nonlocality can be restored after diminishing for a period of time. How-ever, for the other three kinds of channels, the environmental noise accelerates the decreasing of the nonlocality. What’s more, the nonlocality can never be recovered no matter how long it takes(1)In the case that both qubits of the EPR. pair are in the same nois situation, we have investigated the effect of both the acceleration and the environmental noise on the nonlocality of the Bell state. When both qubits are in the phase flip channel, it has been found that the nonlocality of the system can be recovered to its maximum under the environmental noise after a period of dead time. Compared with the former case, we have discovered that the nonlocality disappearing time is longer. For the other three kinds of channels, there are similar results. |
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