Using the single-mode approximation, we first calculate entanglement measures such as negativity (1–3 and 1–1 tangles) and von Neumann entropy for a tetrapartite W-Class system in noninertial frame and then analyze the whole entanglement measures, the residual π₄ and geometric Π₄ average of tangles. Notice that the difference between π₄ and Π₄ is very small or disappears with the increasing accelerated observers. The entanglement properties are compared among the different cases from one accelerated observer to four accelerated observers. The results show that there still exists entanglement for the complete system even when acceleration r tends to infinity. The degree of entanglement is disappeared for the 1–1 tangle case when the acceleration r > 0.472473. We reexamine the Unruh effect in noninertial frames. It is shown that the entanglement system in which only one qubit is accelerated is more robust than those entangled systems in which two or three or four qubits are accelerated. It is also found that the von Neumann entropy S of the total system always increases with the increasing accelerated observers, but the S_κξ and S_κζδ with two and three involved noninertial qubits first increases and then decreases with the acceleration parameter r, but they are equal to constants 1 and 0.811278 respectively for zero involved noninertial qubit.

中文翻译：

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均匀加速度下W级态的四方缠结特征

使用单模逼近，我们首先计算非惯性框架中四方W类系统的诸如负性（1-3和1-1缠结）和冯·诺依曼熵之类的纠缠量度，然后分析整个纠缠量度，剩余π ₄和几何Π ₄平均缠结。请注意，之间的区别π ₄和Π ₄是非常小的或日益增加的加速观察家消失。比较了从一个加速观察者到四个加速观察者的不同情况下的纠缠特性。结果表明，即使加速度为r，整个系统仍然存在纠缠。趋于无穷大。当加速度r > 0.472473时，对于1–1纠缠情况，纠缠度消失。我们重新检查非惯性帧中的Unruh效应。结果表明，仅加速一个量子比特的纠缠系统比那些加速两个或三个或四个量子比特的纠缠系统更健壮。它也发现，冯·诺依曼熵小号整个系统始终以提高加速观察家增加，但小号_κξ和小号_κζδ有两个和三个涉及非惯性的量子位先增大后减小与加速度参数[R，但对于零相关非惯性量子位，它们分别等于常数1和0.811278。