- #1

Lizzie Mann

- 9

- 0

In the formula above, on the left hand side, ρ(0) is a system's density operator in its initial state. a is the annihilator operator of the system, and a+ is the create operator of the system. ρss is the system's density operator in its steady state.

But I don't understand why this formula writes in this way. Could anyone tell me what is the physics behind this formula?

Many thanks!