I am trying to use IBM Q to perform the following depolarizing channel on a state of 2 qubits $\rho=|\psi \rangle \langle \psi |$:
$$\rho \to (1-\lambda)\rho + \frac{\lambda}{4}I$$
This is within the limitations of the IBM Q. Namely 5 channels.
How can I come up with a combination of gates that will give this result?
A specific case I want to try would be
$$|\psi\rangle = \cos \theta |00\rangle + \sin \theta |11\rangle$$
