A graphene wrapped dielectric particle has been proposed theoretically to realize tunable multi-qubit quantum phase gates (QPGs) with ultrahigh fidelity. By using a first-principles Green’s function technique, the interactions between quantum emitters mediated by graphene plasmons have been investigated. We find that the spontaneous decay rates of these emitters can be strongly enhanced and controlled by means of the efficient excitations of eigenmodes in graphene. The collective subradiance and superradiance resulting from the graphene-mediated interactions have been predicted. Based on these phenomena, we propose the tunable multi-qubit QPGs. These phase gates have the advantage of sensitive adjustability by changing the Fermi level or the electrostatic gating in graphene, at the same time they possess very high fidelities due to the small dissipation in the graphene monolayer.
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