More QuTiP notebook examples for correlations

[Kevin Fischer]

Hi developers,

I added some QuTiP examples that feature the time-dependent correlator, in a pull request that has been hanging for a few months. Would someone who has commit access please review and merge if OK?

Thanks,

Kevin

[Jitendra Verma]

 Hi Dear Kelvin,

     Can you help me for generating the correlations and emission probability for a time dependent Hamiltonian. I am attaching the quip code written by me. The address of paper is which I am trying to produce is  PHYSICA REVIEW B 94, 085309 (2016).
  I shall be very grateful for your help.

[Kevin Fischer]

Dear Jitendra,

I'm happy to help. I'm away for a bit, and can look at your simulations once I'm back late next week.

Kevin

[Jitendra Verma]

  Hello dear fisher are you returned.

On Wednesday, 11 January 2017 09:46:46 UTC+5:30, Kevin Fischer wrote:

[Kevin Fischer]

Did changing you args to the correct format like Paul suggested fix your issue?

Kevin

[Kevin Fischer]

Hi Jitendra,

I recommend against using the function callback form of the Hamiltonian - it's not really supported anymore and I couldn't make it work for your scenario for some reason.

Instead, you can use the following lines. Your code runs with these two modifications and seems to produce results like what I think you're expecting. Hope this helps.

    wp = lambda t, args: (0.132)*exp(-((t-2.5*tau)**2)/tau**2)

    output = mesolve([H0, [H1, wp]], psi0, tlist, c_op_list,

                     [gg0*gg0.dag(), uu0*uu0.dag(), xx0*xx0.dag(), yy0*yy0.dag(),

                      yy1*yy1.dag(), gg1*gg1.dag(), gg2*gg2.dag(), gg3*gg3.dag()])

As an aside, I don't think the expressions for P_0/P_1/P_2 in that paper are correct - I've been working on rigorously deriving exact solutions for the generic of problem of a system scattering light under coherent laser pulses. I don't see how my results can even reduce to what is written in this paper in some limit. Rather the quantities in that paper seem like heuristics. I'll be positing my manuscript soon on the arXiv if you're interested.

Regards,

Kevin

On Wednesday, October 4, 2017 at 3:43:28 AM UTC-7, Jitendra Verma wrote:

 Dear Kelvin,
   I have seen modifications done by Paul. But, problem I am facing is that I want to simulate the emission probability from the cavity leakage such as 2 photon emission probability from the state |g,2> by integrating with varying limit from 0 to t. Equation is attached in file. This is for same code attached in previous files.

  Looking forward for your help.

 Thank You,

 Kind Regards,
 Jitendra

On Wednesday, 11 January 2017 09:46:46 UTC+5:30, Kevin Fischer wrote: