They spoke about dephasing and relaxation: Anna likened them to choir members gradually losing sync and singers leaving the stage. “Homogeneous broadening is each singer’s shaky pitch; inhomogeneous broadening is when they’re all tuned differently.” She emphasized that nonlinear techniques—like photon echoes—could refocus inhomogeneous disorder, revealing homogeneous dynamics beneath.
Mukamel hides these in dense math. Here they are plain: They spoke about dephasing and relaxation: Anna likened
Ignoring the rotating wave approximation (RWA). Fix: The RWA means you drop terms that oscillate at optical frequencies (they average to zero). Without RWA, you will cry. With RWA, you get simple exponentials. you will cry. With RWA
In linear spectroscopy (absorption), you poke once, the polarization wiggles, and you measure the wiggle decay. Boring. you poke once