Abstract: A method of performing Kohn-Sham Density Functional Theory, DFT, calculations, for simulation of a material, chemical, or biological system includes: (i) constructing a model Hamiltonian of the system; (ii) inputting an electron density; (iii) constructing a Kohn-Sham potential and (iv) executing a quantum Kohn-Sham DFT algorithm iteration using the electron density and the Kohn-Sham potential to compute an updated electron density and an updated total energy.

Abstract: A method of simulating condensed matter systems on quantum computers includes reducing the Hamiltonian of the system to adapt it to being implementable on a given quantum computer. Part of this adaptation is identifying an active space and associated degrees of freedom within the active space. This effective Hamiltonian is provided a localised representation to assist in reducing the depth of the quantum circuit which used to simulate the system. The quadratic and quartic interaction matrix and coefficients between modes of the localised Hamiltonian are calculated and the modes of the localised Hamiltonian are encoded onto the qubits of the quantum computer. Qubit interactions corresponding to interactions between modes of the localised Hamiltonian are implemented between the qubits and the resulting state is measured to extract a simulation of the active space of the effective Hamiltonian.