Conventional charge-4e superconductivity

A quantum state where fermion ‘quartets’ form a superconducting condensate, rather than paradigmatic Cooper pairs, has been theoretically suggested as an explanation for recent experimental observations in different materials. This 'charge-4e' superconducting phase was theoretically proposed as a vestigial order to a pair density wave. Yet, further experimental measurements and microscopic theoretical understanding of this phase are missing. Here, we report progress on the theoretical front by proposing a one-dimensional microscopic Hubbard model, hosting a charge-4e phase as a quantum ground state in some regions of the parameter space. We extensively characterize the model through exact diagonalization and density matrix renormalization group numerical methods, paving the way for future studies in higher dimensions.