Matrix t*K(1) in Subspace 141 with Dimension 3

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

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