Non-Gaussian fluctuations and non-Markovian effects in the nuclear fusion process: Langevin dynamics emerging from quantum molecular dynamics simulations.
Non-Gaussian fluctuations and non-Markovian effects in the nuclear fusion process: Langevin dynamics emerging from quantum molecular dynamics simulations.
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DOI：
10.1103/physrevlett.111.012501
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发表时间：
2013-05
影响因子：
8.6
通讯作者：
K. Wen;F. Sakata;Zhu-xia Li;Xi-zhen Wu;Y. Zhang;Shan-Gui Zhou
中科院分区：
文献类型：
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作者：
K. Wen;F. Sakata;Zhu-xia Li;Xi-zhen Wu;Y. Zhang;Shan-Gui Zhou
利用改进的量子分子动力学的数值模拟，从单个核子的微观动力学中提取宏观参数以及表征库仑势垒周围核聚变过程的Langevin型描述的随机力的精确信息。结果表明，两个聚变核之间相对运动的耗散动力学是由随机力的非高斯分布引起的。我们发现，摩擦系数以及随机力的时间相关函数需要特别大的值在一个区域内的库仑势垒一点点。在随机力的时间相关函数中观察到明显的非马尔可夫效应。进一步表明，通过随机力及其时间关联函数适当地引入单个核子的微观信息，融合过程的涌现动力学可以用具有记忆效应的广义Langevin方程描述.
Macroscopic parameters as well as precise information on the random force characterizing the Langevin-type description of the nuclear fusion process around the Coulomb barrier are extracted from the microscopic dynamics of individual nucleons by exploiting the numerical simulation of the improved quantum molecular dynamics. It turns out that the dissipation dynamics of the relative motion between two fusing nuclei is caused by a non-Gaussian distribution of the random force. We find that the friction coefficient as well as the time correlation function of the random force takes particularly large values in a region a little bit inside of the Coulomb barrier. A clear non-Markovian effect is observed in the time correlation function of the random force. It is further shown that an emergent dynamics of the fusion process can be described by the generalized Langevin equation with memory effects by appropriately incorporating the microscopic information of individual nucleons through the random force and its time correlation function.