Problem in time dependent hamiltonian

[ham as]

Hi everyone,

I have problem in writing the following time dependent Hamiltonian:

how can correct this code?

omega_n, b and A are operators in matrix form!

thanks

[Boxi Li]

Hi,

Two points:

- If Omega_n is an operator, it cannot be given as coefficients. The coefficient should be a function that returns a float/complex number. In this case, there is no need to distinguish between coefficients and Hamiltonian. You can write a Python function that returns HI and give it to the solver.

```

def HI(t, args):

    # type the equation of HI here.

mesolve(HI, ...)

```

- For exponentiation of operators, np.exp is wrong. One should use `(-1.j * Omega * times).expm()`, which is same as scipy.linalg.expm

Best, Boxi

[Saumya biswas]

Hi. Hamsad.

You only gave us the interaction part, H_I of the Hamiltonian.

I am guessing the complete Hamiltonian has a part H_0 with either  (A+A.dag())   or   i(A.dag()-A) in it?

If so, you can move to a rotating frame and have a time independent Hamiltonian. Simulations are easier to do with time independent Hamiltonians. Are you familiar with this trick called Rotating Wave Approximation (RWA)?

Saumya

 

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[ham as]

THAT'S TRUE! THANK YOU VERY MUCH!

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[ham as]

Thanks Saumya biswas, yes i familiar with (RWA), but this hamiltonian is in the RWA, can not be eliminate time dependency,
thanks anywaye

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