早在二十世纪，质能方程已经给出了能量与物质之间的关系。但是受到实验条件的限制，时至今日，纯能量到物质的转变依然没有得到可信的实验验证。近年来，随着CPA尤其是OPCPA技术的发展，超强激光的场强正在逐步接近Schwinger阈值，这促使高能量密度物理在理论和实验上得到迅速地发展。本项目拟对强场激发正负电子对的产生过程和产生机制进行理论和数值研究，利用计算量子场论和量子Vlasov的方法来研究强场的尺度对粒子对产生的影响以及产生过程中粒子态的变化，提出降低阈值和增加单能性的方案，为今后的实验研究提供参考。项目主要研究内容为：（1）高能量密度场下多粒子耦合态的形成和演化过程；（2）真空中激发正负电子对的能量分布研究；（3）含时场及复合场激发粒子对的尺度效应。

Since 20th century, the relationship between energy and matter has been given by the mass–energy formula. However, no experiments have proved the transition from energy to mass due to limited experimental conditions until now. By the rapid developing laser technique, named chirped pulse amplification (CPA), in recent years (especially OPCPA technique), the intensity of the laser field is about to reach the Schwinger’s critical value, while the high energy density physics is developed fast both experimentally and theoretically. This project aimed to theoretically and numerically study the process and mechanism of the electron-positron pair produced by a high energy density field. By applying the computational quantum field theory and the quantum Vlasov equation, we are going to investigate how the external field size may affect the production process, and search a way to lower the critical value and increase the concentration of produced particles’ energy. The main works of this project are listed following: (1) the mechanism and evolution of multi-pair states in high energy density field, (2) the energy distribution of produced electron-positron pairs, and (3) the size effect of the time-dependent field and combined field on the production process of pairs.