Trident pair production in strong laser pulses

Understand

We calculate the trident pair production amplitude in a strong laser background.

• We allow for finite pulse duration, while still treating the laser fields nonperturbatively in strong-field QED.
• Our approach reveals explicitly the individual contributions of the one-step and two-step processes.
• We also expose the role gauge invariance plays in the amplitudes and discuss the relation between our results and the optical theorem.