Issues with Two Level systems

[latifeh iri]

Hi all,

I have been trying to understand what will be the behavior of population for different values of detuning in two level systems. Physically, we should see some changes but for the program I attached here, cannot see any changes! I got stuck in this part and have no clue about that, I would appreciate if somebody can look at the code and give me suggestions to what I should consider. Note that I have to start initial start from level 2  (excited state), I dont want to work with random state.

For delta = 0 and delta= 0.07, I got the same results (both of them are at resonance)!

Best,

[latifeh iri]

[j794...@uwaterloo.ca]

Hi!

I guess what you want to calculate is the occupation photons of a qubit(2-level system) and a resonator connected to it. (known as JC model, which you can find explanation here and there). 

The expectation value you input into the program is sigma+sigma- and sigma-sigma+. The first one means the occupation photons of qubit, and the second implies the photons leaked from qubit to any elsewhere.  

You may want to calculate a.dagger*a for the replacement.

You may check the tutorial notebooks of qutip, one of them there shows the calculation of JC model. Or you may check this very well-structured notebook:

https://nbviewer.org/github/caidish/Quantum-Optics-with-Python/blob/master/course2/Quantum_Optics.ipynb