Abstract
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.
Highlights
In this work we study the interaction between quantum emitters (QEs) and graphene wrapped nanoparticle, and explore the possibility to realize tunable multi-qubit quantum gates with ultrahigh fidelity
Based on such a property, tunable three-qubit quantum phase gates (QPGs) can be constructed, if the transition frequencies of the QEs are taken as ωA=276THz, which corresponds to the n=2 eigenmode of the graphene wrapped dielectric sphere when the Fermi level Ef =0.2eV, in this case we can obtain Γ3 ≈ 0 and Γ4(5) ≈ 3Γ/2
Based on the Green’s function approach, we have investigated the coupling of QEs to the plasmonic excited modes of the graphene wrapped dielectric particle
Summary
Quantum logic operation is one of the key steps in quantum information processing.[1,2,3] In the past two decades, two-qubit[4,5,6,7,8,9,10,11] and multi-qubit[12,13,14,15,16,17] quantum logic operations have been investigated widely in many systems like ion trap,[4] cavity QED,[5,6,14,15] optical resonantor,[7] NMR,[8,9] optical systems,[10,16] superconductor[11,17] and multiple levels interacting systems.[12,13] Recently, quantum logic operations based on plamonic systems[18,19] are perceived to have good development prospects due to the low cost and easy implementation. Graphene as a new two-dimensional material has greatly attracted people’s attention due to the novel optical and electronic properties.[20,21] In recent several years, after graphene monolayer can be produced in the experiment, which has been widely used in fabricating various optoelectronics components[21,22,23,24,25,26] and tunable plasmonic devices[27,28,29,30] on the basis of surface plasmon excitations in graphene Apart from these applications, graphene plasmons[31,32,33] could couple individual emitters to realize biosensing,[34,35] energy transfer[36,37] and superradiance.[38,39]. In this work we study the interaction between quantum emitters (QEs) and graphene wrapped nanoparticle, and explore the possibility to realize tunable multi-qubit quantum gates with ultrahigh fidelity
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