Matrix t2*K(2) in Subspace 43 with Dimension 3

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

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