Matrix t2*K(2) in Subspace 36 with Dimension 4

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

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