Applications of quantum annealers in chemistry and materials science

The promise of quantum computing is to provide new methods to unveil the physics of correlated many-body systems. Over the past few years, quantum annealers have grown in complexity to the point that useful applications are feasible. Whilst typical approaches use a quantum annealer to extract the solution of an optimization problem from the ground state of the Ising Hamiltonian, we pursue the application as a generator of structural models for disordered materials, where disorder appears from the competition between the different degrees of freedom. Starting from the representation of the crystal in terms of a network, we map the relevant interactions into Ising Hamiltonians and encode the disordered phases in the excited-state spectrum of the target Ising Hamiltonian. The quantum annealer is thus used to explore the energy surfaces and to identify stable and metastable phases of prototypical disordered materials. Furthermore, the electronic structure problem can be mapped onto a quantum annealer, as an alternative to the widespread variational quantum eigensolver. We illustrate examples and discuss the possibility of including solvent effects in the molecular electronic structure.