I encountered some problems when using the qiskit pakage to define the 2-electron reduced density matrix (2-RDM), which is a 4-index tensor, $\langle a_i^\dagger a_j^\dagger a_k a_l\rangle$. I need to first transform each term in the tensor (2-RDM) to the qubit form by Jordan-Wigner transformation. Then, I can measure each term using the expectation feature of the VQE function in qiskit. However, the qiskit.chemistry.fermionic_operator class only support Hamiltonian to be transformed to the qubit form. Therefore, there are two questions here to finish the 2-RDM measurement job. The first is how to define general fermionic operators by qiskit, especially the one has the form of the 2-RDM. The second is that are there any build-in function in qiskit to tranform general fermionic operators to the qubit form.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.