非线性啁啾频率对势阱产生正负电子对的增强

Enhancement of nonlinear chirped frequency on electron-positron pair production in the potential well

用计算量子场论方法研究了非线性啁啾频率对势阱中正负电子对产生的增强效应。研究了由静态势阱和动态势阱组成的组合势阱中产生的正负电子对的密度、产额和能谱等性质随着啁啾参数的变化,分析了组合势阱的频谱和瞬时束缚态。发现非线性啁啾效应对低频区域比较敏感,与固定频率情况相比可以使粒子数增加2~3倍。与组合势阱相比,非线性啁啾效应对单个振荡势阱更敏感。在低频下单个振荡的势阱中正负电子对产额可提高多个数量级。这是因为在低频下单个振荡的势阱中,主要通过量子隧穿过程产生的正负电子对数目非常低。非线性啁啾效应增加了高频场成分,提高了多光子过程和动力学辅助机制。由于高频抑制作用,所以非线性啁啾效应对高频区域粒子的增量不大,甚至会抑制正负电子对的产生。

Enhancement of nonlinear chirped frequency on electron-positron pair creation in the potential well is studied by the computational quantum field theory. The density, number and energy spectrum of electrons created under a single oscillating potential well and combined potential wells are investigated. The frequency spectrum and instantaneous bound states are also analyzed. It is found that nonlinear chirp effect is more sensitive to the low frequency region. When appropriate chirp parameters are selected, compared with the fixed frequency, the number of electrons created under combined potential wells can be increased by 2 to 3 times. For a single oscillating potential well, the number can be increased by several orders of magnitude. In the subcritical field at low frequencies,Schwinger mechanism dominates pair creation, and the production is very low. After modulation, the frequency spectrum widens. The high frequency component enhances the multiphoton processes and the dynamical assisted mechanism, while the ultrahigh frequency component inhibits pair creation.