Matrix H in Subspace 118 with Dimension 12

H is the Hamiltonian. Here we set µ=0. For grand-canonical calculations add -6µ to the main diagonal.
2*h + U -(((-4 + Sqrt[6])*t)/Sqrt[6 + Sqrt[6]]) -(((4 + Sqrt[6])*t)/Sqrt[6 - Sqrt[6]]) 0 0 0 2*t 0 -2*Sqrt[2]*t 0 ((11*Sqrt[4 - 4*Sqrt[2/11]] + 14*Sqrt[121 - 11*Sqrt[22]] - 22*Sqrt[22 - 2*Sqrt[22]])*t)/(22*Sqrt[52 - 8*Sqrt[22]]) ((1001*Sqrt[2 + 2*Sqrt[2/11]] + Sqrt[11 + Sqrt[22]]*(264 + 5*Sqrt[22]))*t)/(264*Sqrt[26 + 4*Sqrt[22]])
-(((-4 + Sqrt[6])*t)/Sqrt[6 + Sqrt[6]]) 2*h 0 0 0 0 0 0 0 (-2*(1 + Sqrt[6])*t)/Sqrt[6 + Sqrt[6]] 0 0
-(((4 + Sqrt[6])*t)/Sqrt[6 - Sqrt[6]]) 0 2*h 0 0 0 0 0 0 (-2*(-1 + Sqrt[6])*t)/Sqrt[6 - Sqrt[6]] 0 0
0 0 0 2*(h + U) 0 -(Sqrt[3]*t) 0 Sqrt[3]*t 0 0 0 0
0 0 0 0 2*(h + U) 0 0 -(Sqrt[6]*t) 0 0 0 0
0 0 0 -(Sqrt[3]*t) 0 2*h + U t 0 0 0 Sqrt[2 - 2*Sqrt[2/11]]*t (-2*(11 + Sqrt[22])*t)/(11*Sqrt[2 + 2*Sqrt[2/11]])
2*t 0 0 0 0 t 2*(h + U) t 0 2*t 0 0
0 0 0 Sqrt[3]*t -(Sqrt[6]*t) 0 t 2*(h + U) -(Sqrt[2]*t) 0 ((11*Sqrt[4 - 4*Sqrt[2/11]] + 14*Sqrt[121 - 11*Sqrt[22]] - 22*Sqrt[22 - 2*Sqrt[22]])*t)/(22*Sqrt[52 - 8*Sqrt[22]]) ((1001*Sqrt[2 + 2*Sqrt[2/11]] + Sqrt[11 + Sqrt[22]]*(264 + 5*Sqrt[22]))*t)/(264*Sqrt[26 + 4*Sqrt[22]])
-2*Sqrt[2]*t 0 0 0 0 0 0 -(Sqrt[2]*t) 2*(h + U) 0 0 0
0 (-2*(1 + Sqrt[6])*t)/Sqrt[6 + Sqrt[6]] (-2*(-1 + Sqrt[6])*t)/Sqrt[6 - Sqrt[6]] 0 0 0 2*t 0 0 2*h + U ((132*Sqrt[4 - 4*Sqrt[2/11]] + Sqrt[484 - 44*Sqrt[22]] + 70*Sqrt[121 - 11*Sqrt[22]] + 264*Sqrt[22 - 2*Sqrt[22]])*t)/(264*Sqrt[52 - 8*Sqrt[22]]) ((517*Sqrt[2 + 2*Sqrt[2/11]] + (-264 + Sqrt[22])*Sqrt[11 + Sqrt[22]])*t)/(264*Sqrt[26 + 4*Sqrt[22]])
((11*Sqrt[4 - 4*Sqrt[2/11]] + 14*Sqrt[121 - 11*Sqrt[22]] - 22*Sqrt[22 - 2*Sqrt[22]])*t)/(22*Sqrt[52 - 8*Sqrt[22]]) 0 0 0 0 Sqrt[2 - 2*Sqrt[2/11]]*t 0 ((11*Sqrt[4 - 4*Sqrt[2/11]] + 14*Sqrt[121 - 11*Sqrt[22]] - 22*Sqrt[22 - 2*Sqrt[22]])*t)/(22*Sqrt[52 - 8*Sqrt[22]]) 0 ((132*Sqrt[4 - 4*Sqrt[2/11]] + Sqrt[484 - 44*Sqrt[22]] + 70*Sqrt[121 - 11*Sqrt[22]] + 264*Sqrt[22 - 2*Sqrt[22]])*t)/(264*Sqrt[52 - 8*Sqrt[22]]) (11*(13*Sqrt[2] - 4*Sqrt[11])*(2*h + U))/(Sqrt[2]*(-11 + Sqrt[22])^2) 0
((1001*Sqrt[2 + 2*Sqrt[2/11]] + Sqrt[11 + Sqrt[22]]*(264 + 5*Sqrt[22]))*t)/(264*Sqrt[26 + 4*Sqrt[22]]) 0 0 0 0 (-2*(11 + Sqrt[22])*t)/(11*Sqrt[2 + 2*Sqrt[2/11]]) 0 ((1001*Sqrt[2 + 2*Sqrt[2/11]] + Sqrt[11 + Sqrt[22]]*(264 + 5*Sqrt[22]))*t)/(264*Sqrt[26 + 4*Sqrt[22]]) 0 ((517*Sqrt[2 + 2*Sqrt[2/11]] + (-264 + Sqrt[22])*Sqrt[11 + Sqrt[22]])*t)/(264*Sqrt[26 + 4*Sqrt[22]]) 0 2*h + U