Solid state superatoms: Rydberg excitons in cuprous oxide

Abstract

Creating isolated, two-level quantum systems (qubits) that can be coupled to perform gate operations or study many-body quantum systems is one of the outstanding goals in quantum information science. In cold-atom systems, Rydberg states have been used to create and coherently control non-classical states of light and atoms. Is there a way of combining the proven successes in cold-atom systems with the benefits of solid-state scalability? Rydberg excitons in cuprous oxide provide a potential route towards a new hybrid quantum technology. A major breakthrough by the Dortmund physics group in 2014 showed that robust high principal quantum number excitons could be realised in cuprous oxide, and the same group provided the first evidence of Rydberg blockade in this material. We have recently observed high principal quantum number excitons in cuprous oxide with N = 14, and our measurements are comparable to the state-of-the-art result achieved by the Dortmund group with white light excitation.