QDFT - V 0.1.0

Quantum Density Functional Theory: a quantum algorithm to solve the Kohn-Sham self-consistent equations.

Whats new

The Code is upgraded to adopt QISKIT V 1.1.0.

Few modulus are removed from qiskit. (Check https://docs.quantum.ibm.com/api/migration-guides/qiskit-1.0 for more details).

The changes in the current version of QDFT are as follows,

version 0.0.0	Version 0.1.0
qiskit.Aer	qiskit_aer.Aer
qiskit.algorithms	qiskit_algorithms
qiskit.opflow.StateFn	qiskit.quantum_info.Statevector
qiskit.opflow.I,X,Y	qiskit.quantum_info.Pauli
qiskit.circuits.bind_parameters	qiskit.circuits.assign_parameters

• Pauli operations are carried out with qiskit.quantum_info.Operators.
• Note that the expectation values in the previous version is calculated using StateFn whereas, in the current release it is substituted with qiskit.quantum_info.Statevector. (We tried qiskit.primitives.Estimator as an alternative but it didn't workout well)
• New function called decompose_operator_to_pauli_list is added in the operators to change operators into pauli_list.
• Major changes are carried out in Operators.py (fun: transformation_Hmatrix_Hqubit) and measurements.py (fun: cost_function_energy).

Installation

export QDFT_DIR=pwd

pip install -e .

execution

cd examples

python3 DFT_Hchain.py

python3 QDFT_Hchain.py

python3 QDFT_Hubbard.py

Prerequisites:

• PSI4 should be installed and exported to the python path.

• For Hubbard, one requires to clone and install [email protected]:bsenjean/SOFT.git (Note: Make sure you define working directory and code directory correctly.)