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arXiv 1804.09698quant-ph
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混合态的冯诺伊曼熵

The von Neumann Entropy for Mixed States

Jorge A. Anaya-Contreras, Héctor M. Moya-Cessa, Arturo Zúñiga-Segundo

摘要:

Araki-Lieb不等式通常用于计算子系统最初处于纯态时的熵,因为这迫使两个子系统的熵在整个系统演化后相等。然后,很容易通过找到一个小的子系统的熵来计算一个大子系统的熵。据我们所知,当一个子系统最初处于混合状态时,不存在计算熵的方法。我们在这里表明,它是可能的,在这种情况下,使用Araki-Lieb不等式,并找到冯诺伊曼熵的大(无限)系统。我们在二能级原子-场相互作用中证明了这一点。

英文摘要:

The Araki-Lieb inequality is commonly used to calculate the entropy of subsystems when they are initially in pure states as this forces the entropy of the two subsystems to be equal after the complete system evolves. Then, it is easy to calculate the entropy of a large subsystem by finding the entropy of the small one. To the best of our knowledge, there does not exist a way of calculating the entropy when one of the subsystems is initially in a mixed state. We show here that it is possible to use the Araki-Lieb inequality in this case and find the von Neumann entropy for the large (infinite) system. We show this in the two-level atom-field interaction.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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