monte carlo simulation using matlab code.pdf

Appendix A Monte Carlo simulation Matlab code The following pages contain an example of Monte Carlo simulation code used for simulations shown in Chapters 3 and 5. This particular simulation is intended to provide insight into 1-D QNLC for the realistic experimental conditions described in section 3.1.3. In this case, the green quenching pulse is no longer being used to directly assist in the cooling process. This adds an additional random recoil associated with the excitation of the atom from the excited 31 state to the quenching 10 state, before it decays to the ground 11 state. Also, we do not assume in this simulation that we have enough quenching power to quench 100 % of the atoms. 206 %MATLAB 6.5 Monte Carlo simulation cool3.m %This simulation cycles num number of atoms steps times, with a cooling sequence of %a 657 nm cooling pulse from the right, then a 657 nm cooling pulse from the left, %followed by a 552 nm quenching pulse. Then the sequence is repeated with cooling %pluses first incident from the left. Switching the pulse direction %order helps maintain symmetery in the resultant velocity distribution. %The probability of quenching the excited state is no longer 100%, it is percent %Random blue, IR, and green photon recoil kicks have been included in the simulation due to the quenching. clear All % resets all variables num=100000; %sets number of atoms in simulation steps=10; %sets number of cooling cycles percent=0.3; %sets green efficiency 0.3 = 30 % %To initialize a gaussian distribution with a FWHM 82.13 cm/s %(vrms = 70 cm/s) for blue-cooled atoms Halfwidth=82.13*1.2;