Matrix t*K(1) in Subspace 111 with Dimension 4

(K(1) is the first-order Grosse operator)

I*Sqrt[3]*t ((3 + I*Sqrt[3])*U)/2 (-I)*Sqrt[6]*U ((-3 - I*Sqrt[3])*t)/Sqrt[2]
(I/2)*(3*I + Sqrt[3])*U I*Sqrt[3]*t ((3 - I*Sqrt[3])*t)/Sqrt[2] 0
(-I)*Sqrt[6]*U ((-3 - I*Sqrt[3])*t)/Sqrt[2] 0 0
((3 - I*Sqrt[3])*t)/Sqrt[2] 0 0 0