Matrix t2*K(2) in Subspace 65 with Dimension 4

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

(-7*t*U)/2 -(U^2/Sqrt[2]) 0 -((t*U)/Sqrt[2])
-(U^2/Sqrt[2]) -5*t*U (t*U)/Sqrt[2] 0
0 (t*U)/Sqrt[2] (-11*t*U)/2 -(U^2/Sqrt[2])
-((t*U)/Sqrt[2]) 0 -(U^2/Sqrt[2]) -4*t*U