Matrix t*K(1) in Subspace 151 with Dimension 4

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

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