A relativistic transient absorption theory is derived, implemented and validated within the dipole approximation based on the time-dependent Dirac equation. In the non-relativistic limit, it is found that the absorption agrees with the well established non-relativistic theory based on the time-dependent Schrdringer equation. Time-dependent simulations have been performed using the Dirac equation and the Schrdinger equation for the hydrogen atom in two different attosecond transient absorption scenarios. These simulations validate the present relativistic theory. The presented work can be seen as a first step in the development of a more general relativistic attosecond transient absorption spectroscopy method for studying heavy atoms, but it also suggests the possibility of studying relativistic effects, such as Zitterbewegung, in the time domain.

在与时间相关的狄拉克方程的基础上，在偶极近似内推导，实现和验证了相对论的瞬态吸收理论。在非相对论极限下，发现吸收与基于时间相关的薛定rd方程的成熟的非相对论相吻合。已使用Dirac方程和Schrdinger方程对氢原子在两种不同的阿秒瞬态吸收方案中进行了时变模拟。这些模拟验证了当前的相对论。提出的工作可以看作是开发用于研究重原子的更通用的相对论阿秒瞬态吸收光谱法的第一步，但是它也暗示了研究相对论效应的可能性，例如Zitterbewegung，在时域。