[Seminar] Doing more with the same using metastable states of trapped ions, Jameson O'Reilly, University of Oregon

Title: Doing more with the same using metastable states of trapped ions

Speaker: Jameson O'Reilly (University of Oregon)

Abstract

Today’s most advanced ion trap quantum computers have at most one qubit per ion, each defined within the ground state manifold. Additional non-qubit ions provide sympathetic cooling to keep the computational ions cold enough to perform many rounds of high-fidelity coherent operations. Typically, the two subsets of ions must be different species to prevent cooling light from disturbing the computation. To bypass this added system complexity, we can instead promote our computational ions to a long-lived excited state that is isolated from the ground-state cooling transitions. This promotion also enables new features including erasure conversion and projective state preparation and cooling. We will discuss two recent efforts to develop this architecture: entangling gates between metastable qubits and mid-circuit sympathetic cooling and readout of a metastable ion by a ground-state ion. Finally, we will take advantage of the larger metastable manifold to explore high-fidelity qudit control.