Decoherence: a numerical study
Decoherence: a numerical study
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DOI：
10.1088/1751-8121/acb977
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发表时间：
2020-10
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影响因子：
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通讯作者：
Chris Nagele;Oliver Janssen;M. Kleban
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文献类型：
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作者：
Chris Nagele;Oliver Janssen;M. Kleban
我们研究量子退相干数值系统组成的相对论量子场论耦合到测量设备，本身耦合到一个环境。测量设备和环境被视为量子、非相对论粒子。我们使用精确对角化来求解这三重系统的波函数的薛定谔方程。虽然希尔伯特空间的大小的计算限制阻止我们探索的制度，设备和环境组成的一个真正的宏观自由度，但我们仍然看到了明显的证据退相干：在跟踪出的环境，描述系统和测量设备的密度矩阵迅速演变到一个矩阵，接近对角线的指针状态的子空间。我们测量的速度与退相干传播的相对论量子场论的参数范围。我们发现它小于光速，但比初始状态下的大质量电荷的速度快。
We study quantum decoherence numerically in a system consisting of a relativistic quantum field theory coupled to a measuring device that is itself coupled to an environment. The measuring device and environment are treated as quantum, non-relativistic particles. We solve the Schrödinger equation for the wave function of this tripartite system using exact diagonalization. Although computational limitations on the size of the Hilbert space prevent us from exploring the regime where the device and environment consist of a truly macroscopic number of degrees of freedom, we nevertheless see clear evidence of decoherence: after tracing out the environment, the density matrix describing the system and measuring device evolves quickly towards a matrix that is close to diagonal in a subspace of pointer states. We measure the speed with which decoherence spreads in the relativistic quantum field theory for a range of parameters. We find that it is less than the speed of light but faster than the speed of the massive charges in the initial state.