Optical trap: Basically just the calibration part and the dynamics, not much about the biology part (I'm still a noob). I think I need help, too, in preparing for this 'public oral' (worse than public oral, or maybe about the same, not sure). I can talk a lot about the trapping mechanism (messy mie scattering, optical earnshaw theorem), or other unholy stuff like violation of 2nd law of thermodynamics at short time scale. 21cm (very unprepared): I can talk about my re-implementation of the 'state-of-the-art' method in getting the rotation curve (actually, it has been 5years old ). The default method from the lab guide is usually called 'envelope-tracing' method, and this is not that reliable. I think some people in jlab use gaussian / intensity averaged method .. And this 'new' method is called iteration method. Not sure if this is appropriate I WILL SUCK ... So my only motivation is to have more in-depth discussion with people about the experiments. Latex syntax:

ψ(\skew0 → r   ) = ψ0(\skew0 → r   ) − m 2πħ2 ⌠ ⌡ all \skew0→r ′  eik |\skew0→r−\skew0→r ′| |\skew0 → r   −\skew0 → r    ′   | V(\skew0 → r    ′   ) ψ(\skew0 → r    ′   )  d3\skew0 → r    ′