Heralded high-fidelity quantum hyper-CNOT gates assisted by charged quantum dots inside single-sided optical microcavities

Abstract

Photonic hyper-parallel quantum information processing (QIP) can simplify the quantum circuit and improve the information-processing speed, as well as reduce the quantum resource consumption and suppress the photonic dissipation noise. Here, utilizing the singly charged semiconductor quantum dot (QD) inside single-sided optical microcavity as the potentially experimental platform, we propose five schemes for heralded four-qubit hyper-controlled-not (hyper-CNOT) gates, covering all cases of four-qubit hyper-CNOT gates operated on both the polarization and spatial-mode degrees of freedom (DoFs) of a two-photon system. The novel heralding mechanism improves the fidelity of each hyper-CNOT gate to unity in principle without the strict restriction of strong coupling. The adaptability and scalability of the schemes make the hyper-CNOT gates more accessible under current experimental technologies. These heralded high-fidelity photonic hyper-CNOT gates can therefore have immense utilization potentials in high-capacity quantum communication and fast quantum computing, which are of far-reaching significance for QIP.

Complete Hyperentangled Bell States Analysis For Polarization‐Spatial‐Time‐Bin Degrees of Freedom with Unity Fidelity

“…Such two schemes were further improved to the error-detected ones by Wang et al, [57] Zheng et al, [58] and Cao et al [59] QDs, named as artificial atom, have been recognized as the promising candidates for QIP. [63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78] Nowadays, schemes for implementing quantum gates have been proposed in hybrid photon-QD systems, [63][64][65] solid-QD systems, [66,67] and flying photon systems, [68,69] respectively. Quantum entanglements between a QD spin and a single photon [70] and between two distance QD hole spins [71] have been experimentally demonstrated.…”

Error-detected three-photon hyperparallel Toffoli gate with state-selective reflection

“…Less resources required from quantum gates is crucial in quantum computation, originating from two strategies. One is to exploit a system with additional qudit [31][32][33], the other one is to encode the quantum information in multiple degrees of freedom (DoFs) of a system in universal computational tasks, i.e., hyperparallel quantum gates [34][35][36][37][38][39][40] simultaneously operating more than one independent operations. The hyper-parallel quantum computing can simplify the quantum circuit, improve the information-processing speed, reduce the quantum resource consumption, and suppress the photonic dissipation noise.…”

“…The hyper-parallel quantum computing can simplify the quantum circuit, improve the information-processing speed, reduce the quantum resource consumption, and suppress the photonic dissipation noise. Recently, implementing hyperparallel photon-based controlled-NOT (CNOT) gate [34][35][36][37], hyper-parallel photon-matter-based universal CNOT gate [38], and hyper-parallel photon-based Toffoli gate [39] have been proposed. Ru et al [40] have realized a deterministic quantum Toffoli gate on one photon in orbital-angular-momentum and polarization DoFs.…”

Complete hyperentangled Bell states analysis for polarization-spatial-time-bin degrees of freedom with unity fidelity

“…Such two schemes were further improved to the error-detected ones by Wang et al, [57] Zheng et al, [58] and Cao et al [59] QDs, named as artificial atom, have been recognized as the promising candidates for QIP. [63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78] Nowadays, schemes for implementing quantum gates have been proposed in hybrid photon-QD systems, [63][64][65] solid-QD systems, [66,67] and flying photon systems, [68,69] respectively. Quantum entanglements between a QD spin and a single photon [70] and between two distance QD hole spins [71] have been experimentally demonstrated.…”