This function helps to covert Pennylane Hamiltonian to QISKit Hamiltonian
Prepare a qubit hamiltonian in Pennylane:
print(h_pennylane)
(-0.10633119275955037) [I0]
+ (0.1702977824748741) [Z0]
+ (0.1702977824748741) [Z1]
+ (-0.2200940322812765) [Z2]
+ (-0.22009403228127644) [Z3]
+ (0.16834151984303647) [Z0 Z1]
+ (0.045404703169106816) [Y0 X1 X2 Y3]
+ (-0.045404703169106816) [Y0 Y1 X2 X3]
+ (-0.045404703169106816) [X0 X1 Y2 Y3]
+ (0.045404703169106816) [X0 Y1 Y2 X3]
+ (0.1202071443598718) [Z0 Z2]
+ (0.1656118475289786) [Z0 Z3]
+ (0.1656118475289786) [Z1 Z2]
+ (0.1202071443598718) [Z1 Z3]
+ (0.17407821153636974) [Z2 Z3]
Then convert it to QISKit hamiltonian. And they are ready to be solved in QISKit VQE:
h_qiskit = to_qiskit_hamiltonian(h_pennylane,4)
print(h_qiskit.print_details())
IIII (-0.10633119275955037+0j)
ZIII (0.1702977824748741+0j)
IZII (0.1702977824748741+0j)
IIZI (-0.2200940322812765+0j)
IIIZ (-0.22009403228127644+0j)
ZZII (0.16834151984303647+0j)
YXXY (0.045404703169106816+0j)
YYXX (-0.045404703169106816+0j)
XXYY (-0.045404703169106816+0j)
XYYX (0.045404703169106816+0j)
ZIZI (0.1202071443598718+0j)
ZIIZ (0.1656118475289786+0j)
IZZI (0.1656118475289786+0j)
IZIZ (0.1202071443598718+0j)
IIZZ (0.17407821153636974+0j)