type error when my essolve function runs

[saaru darshini]

I am trying to solve an ion trap model's Hamiltonian using essolve function using QuTip,but it outputs an error saying ,first argument needs to be a Hamiltonian but I have provided the essolve my Hamiltonian which is of a list datatype,what is the problem here

 and this is how i defined my hamiltonian \

eta = 0.5

omega_rabi = epsilon / (4 * eta)

N = 15

a = tensor(qeye(2), qeye(2), destroy(N))

sigma_a = tensor(sigmay(), qeye(2), qeye(N))

sigma_b = tensor(qeye(2), sigmay(), qeye(N))

Ha = -eta * omega_rabi * a.dag() * (sigma_a + sigma_b)

Hb = -eta * omega_rabi * a * (sigma_a + sigma_b)

sigma_1 = tensor(sigmax(), qeye(2), qeye(N))

sigma_2 = tensor(qeye(2), sigmax(), qeye(N))

H1 = -eta * omega_rabi * a.dag() * (sigma_1 + sigma_2)

H2 = -eta * omega_rabi * a * (sigma_1 + sigma_2)

H = [[Ha, drive_a], [Hb, drive_b], [H1 + H2, coupling]]

[Éric Giguère]

essolve does not support time dependent system. H must be a single Qobj.

You could probably use sesolve instead.

[saaru darshini]

yes thankyou very much, I just used mesolve and it seemed to work

I am pretty new to this haha, so I am trying to apply a Unitary gate to my Hamiltonian H which acts as a Hermitian Operator, is there any Unitary gate method available on QuTip??

[Éric Giguère]

There are gates in qutip.qip.operations:

https://qutip.readthedocs.io/en/qutip-4.7.x/apidoc/functions.html?highlight=gates#module-qutip.qip.operations.gates

[saaru darshini]

I meant sesolve**, I couldn't find anything related to dyson series or any time-dependent perturbation theory expansions in the docs, is there anything relevant in QuTip??

[Éric Giguère]

No there is nothing about dyson series, pertubation theory. There isn't much of anything close to field theory in general.

[saaru darshini]

Thankyou Eric, this was very helpful.