Matrix t2*K(2) in Subspace 111 with Dimension 4

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

(-9*t*U)/2 ((1 - I*Sqrt[3])*(8*t^2 - U^2))/4 U^2/Sqrt[2] (t*(Sqrt[2]*U - I*Sqrt[6]*U))/4
((1 + I*Sqrt[3])*(8*t^2 - U^2))/4 (-17*t*U)/2 (((-3*I)/2)*(-I + Sqrt[3])*t*U)/Sqrt[2] 0
U^2/Sqrt[2] (((3*I)/2)*(I + Sqrt[3])*t*U)/Sqrt[2] -6*t*U (2 - (2*I)*Sqrt[3])*t^2
(t*(Sqrt[2]*U + I*Sqrt[6]*U))/4 0 (2 + (2*I)*Sqrt[3])*t^2 -8*t*U