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March 03, 2005
Class review — 3/3
Hey Class,
Boy am I tired. Expect many updates to the website tomorrow, like the last couple set of lecture notes and the pre-flights for Tuesday.
Today an issue came up about the energies of the "dressed states" of an atom interacting with light. I worked out the details very carefully after class. I was right about which state is the ground state. Remember — we're working in the interaction picture, and to get the total energy we have to add the energy from H0. This type of solution is fundamentally different that what we did with the two-level problem before. I will explain the solution very carefully on Tuesday. You can check out the lecture notes on this topic once they're up tomorrow.
Today we learned about:
T1 processes are not the same as decay. They go along with an interaction with a bath. T1 processes cannot occur without T2 processes at the same time.
A model: classical atom interacting with classical light. When the electron gets moving, it radiates. This is equivalent to a damping force, so the whole problem looks like a damped, forced harmonic oscillator. The emitted radiation has a Lorentzian lineshape. Our ability to drive the atom has the same Lorentzian lineshape.
The physics of a quantum atom interacting with classical light. This just looks like a two-level system! We looked at the physics in the limit of far detuning, where the ground state shift is
For "red-detuned" light, the atom is attracted to regions of high intensity.
Cheers,
Brian
Posted by Brian at March 3, 2005 08:15 PM
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