Matrix t2*K(2) in Subspace 144 with Dimension 3

(K(2) is the second-order Grosse operator)

-6*t*U (3*(1 + I*Sqrt[3])*t*U)/(2*Sqrt[2]) (-I)*Sqrt[3/2]*U^2
(3*(1 - I*Sqrt[3])*t*U)/(2*Sqrt[2]) (-9*t*U)/2 ((3 + I*Sqrt[3])*U^2)/4
I*Sqrt[3/2]*U^2 ((3 - I*Sqrt[3])*U^2)/4 (-15*t*U)/2