论文标题
平均自旋载体的von Neumann熵
Von Neumann Entropy from Mean Spin Vector
论文作者
论文摘要
我们显示了两个两级原子的一般纯纠缠状态，可以直接从配对的单个原子的平均自旋载体的大小直接测量部分痕迹的von Neumann熵。我们强调这样一个事实，即可以在不知道两个原子的量子状态的确切形式的情况下获得该系统的部分迹线的von Neumann熵，如果我们具有一对单个原子的平均旋转矢量的大小的值。在种群光谱中，用于自旋挤压和光谱挤压的背景下，平均自旋载体在实验上是可测量的，并提供了该系统部分痕迹的von Neumann熵的精确度量。本文开发的想法可以在其他量子机械两个级别系统的背景下使用，因为两个级别系统的代数可以由spin- $ \ frac {1} {2} $粒子的代数描述。
We show for a general pure entangled state of two two-level atoms, the von Neumann entropy of the partial traces can be directly measured from the magnitude of the mean spin vector of a single atom of the pair. We emphasize the fact that the von Neumann entropy of the partial traces for such a system can be obtained without knowing the exact form of the quantum state of the two atoms, if we have the value of the magnitude of the mean spin vector of a single atom of the pair. Mean spin vector, used in the context of spin squeezing and spectroscopic squeezing in population spectroscopy, is experimentally measurable and provides an exact measure of von Neumann entropy of the partial traces for such a system. The idea developed in this paper can be used in the context of other quantum mechanical two level systems as the algebra of two level systems can be described by that of spin- $\frac{1}{2}$ particles.
