Hamiltonian-based graph-state ansatz for variational quantum algorithms

One promising application of near-term quantum devices is to prepare trial wave functions using short circuits for solving different problems via variational algorithms. For this purpose, we introduce a circuit design that combines graph-based diagonalization circuits with arbitrary single-qubit rotation gates to get a Hamiltonian-based graph states ansatz. We test the accuracy of the proposed ansatz in estimating ground-state energies of various molecules of size up to 12 qubits. Additionally, we compare the gate count and parameter number complexity of the proposed ansatz against previously proposed schemes and find an order magnitude reduction in gate count complexity with a slight increase in the number of parameters. Our work represents a significant step towards constructing compact quantum circuits with good trainability and convergence properties and applications in solving chemistry and physics problems.

Duke Scholars

Author Kenneth R Brown Pierre R. Lamond Department of Electrical and Computer Engin ...