SciCode / 70.2 / Write a function to compute the 3 × 3 Hamiltonian for energy-independent…

Background
The Hamiltonian for energy-independent three neutrino oscillation is:
H=(1)/(2)U⋅diag(0,Δm₂₁²,Δm₃₁²)⋅U^(†)
where m_(ij) is the mass-squared difference between flavors and U is the PMNS mixing matrix.

Background
The Hamiltonian for energy-independent three neutrino oscillation is:
$$
H = \frac{1}{2} U \cdot \text{diag}(0, \Delta m_{21}^2, \Delta m_{31}^2) \cdot U^\dagger
$$
where $m_{ij}$ is the mass-squared difference between flavors and $U$ is the PMNS mixing matrix.

Write a function to compute the 3 × 3 Hamiltonian for energy-independent three neutrino oscillation problem. Ignore the energy term E in the Hamiltonian for now. Express all values as complex numbers.

Write a function to compute the 3 $\times$ 3 Hamiltonian for energy-independent three neutrino oscillation problem. Ignore the energy term $E$ in the Hamiltonian for now. Express all values as complex numbers.