Interaction picture

Okay, let me try to explain it in a simple way. Imagine you and your friend are playing a game of catch. When you throw the ball to your friend, it moves through the air until he catches it. This is called the Schrödinger picture. However, if you wanted to describe the ball's movement from your perspective (how it looks to you), you would use the interaction picture. This means that you would focus on how the ball is interacting with you, taking into account your movement and position.

In quantum mechanics, we use the Schrödinger picture to represent the motion of particles or systems independent of their surroundings. However, when we want to focus on how particles are interacting with each other, we use the interaction picture. This helps us understand quantum mechanics better, making it easier to solve complex problems. So, the interaction picture helps scientists study the interaction of particles in a more simplified and easier-to-understand way.