非惯性系下的多粒子纠缠态

发布时间：2018-05-01 22:18

  本文选题：非惯性系 + 三粒子纠缠态　； 参考：《华东师范大学》2016年硕士论文

【摘要】：人们已经对惯性系下的量子信息问题做过大量的研究,建立了一套较完备的关于量子信息的理论；而且纠缠态在量子信息理论里面扮演着重要角色,它被人们认为是量子信息处理任务的主要资源。现在人们进行量子信息处理实验采用的都是一些速度非常大的光子和粒子,并且我们现在所处的世界都是在不停地旋转因而是有加速的,因此我们就要考虑相对论效应会对我们的实验所带来的影响。更重要的是,随着量子理论与广义相对论和量子场的结合日渐紧密,所以研究相对论框架下的多粒子纠缠态就变得很重要。首先在学习了非惯性系下的两粒子纠缠态的基础之上,我们利用相同的方法来研究三粒子纠缠随观测者加速的变化情况,经过计算我们发现三粒子纠缠会随着观测者加速度的增加而减少,而且三个观测者都加速时π-tangle减小最快,但在加速度趋近于无穷大的情况下它也不会衰减到零；而这种物理特性对于标量场和狄拉克场都是成立的。然而在加速度趋近于无穷大的时候,非惯性系中标量场的两粒子纠缠却会衰减到零,因此我们认为在处理量子信息任务时用三粒子纠缠态会比两粒子纠缠态更加优越。其次,我们研究了量子信息的分布,发现随着观测者加速度的增加,观测者可以获取的纠缠在逐渐减少,但观测者无法获取的纠缠却在逐渐增加。由此可知,在非惯性系中系统量子纠缠的减少是由于Unruh效应而使纠缠从Ⅰ区域进入到了Ⅱ区域,即纠缠进入到了物理上因果不相联通的区域而导致的。当三个观测者都加速时纠缠衰减是三种情况下最快的,这是由于纠缠以更快地方式进入了观测者不可到达的区域。最后,我们还研究了互信息和保真度的问题,发现纠缠和互信息都会重新分布到物理上不可到达的区域,信息不会无缘无故地轻易消失；并且,随着加速度的增加,保真度也逐渐减小；和纠缠的性质类似,当三个观测者都加速时,保真度减小最快。这也从一定程度上说明了纠缠和保真度是有关联的。
[Abstract]:People have done a lot of research on quantum information problem under inertial system, and have established a set of relatively complete theory about quantum information, and entangled state plays an important role in quantum information theory. It is regarded as the main resource of quantum information processing task. Now people are doing quantum information processing experiments using very fast photons and particles, and the world we're living in is constantly spinning and accelerating. So we have to consider the impact of relativistic effects on our experiments. More importantly, with the combination of quantum theory with general relativity and quantum field, the study of multi-particle entangled states in relativistic framework becomes more and more important. Firstly, based on the study of two-particle entangled states in non-inertial systems, we use the same method to study the change of three-particle entanglement with the acceleration of the observer. It is found that the three-particle entanglement decreases with the increase of the acceleration of the observer, and the 蟺 -tangle decreases fastest when all the three observers accelerate, but it does not decay to zero when the acceleration approaches infinity. This physical property is true for both scalar and Dirac fields. However, when the acceleration approaches infinity, the two-particle entanglement of scalar field in the non-inertial system will be reduced to zero, so we think that the three-particle entangled state is better than the two-particle entangled state in dealing with the quantum information task. Secondly, we study the distribution of quantum information. It is found that with the increase of the acceleration of the observer, the entanglement that the observer can obtain is decreasing gradually, but the entanglement that the observer can not get is increasing gradually. It can be concluded that the reduction of quantum entanglement in non-inertial systems is due to the Unruh effect, which leads to entanglement from region I to region 鈪，

本文编号：1831252