Multidimensional cluster states using a single spin-photon interface coupled strongly to an intrinsic nuclear register

Abstract

Photonic cluster states are a powerful resource for measurement-based quantum computing and loss-tolerant quantum communication. Proposals to generate multi-dimensional lattice cluster states have identified coupled spin-photon interfaces, spin-ancilla systems, and optical feedback mechanisms as potential schemes. Following these, we propose the generation of multi-dimensional lattice cluster states using a single, efficient spin-photon interface coupled strongly to a nuclear register. Our scheme makes use of the contact hyperfine interaction to enable universal quantum gates between the interface spin and a local nuclear register and funnels the resulting entanglement to photons via the spin-photon interface. Among several quantum emitters, we identify the silicon-29 vacancy centre in diamond, coupled to a nanophotonic structure, as possessing the right combination of optical quality and spin coherence for this scheme. We show numerically that using this system a 2×5-sized cluster state with a lower-bound fidelity of 0.5 and repetition rate of 65 kHz is achievable under currently realised experimental performances and with feasible technical overhead. Realistic gate improvements put 100-photon cluster states within experimental reach.

Photonic Indistinguishability of the Tin-Vacancy Center in Nanostructured Diamond

“…Using the two-photon interference presented in this work, in combination with control of the spin degree of freedom [33], one could realize spin-photon entanglement [5,65,66] and entanglement of remote emitters [4,67,68]. Modest improvements in the indistinguishability of the photons would position multi-photon entangled states as the next achievement using the SnV center [69,70].…”

Quantum Control of the Tin-Vacancy Spin Qubit in Diamond

“…Gate fidelities can be improved with technical refinements, and tailored pulse protocols are expected to result in 99.6% gate fidelity for π rotations [70]. An immediate next step toward realizing an efficient quantum memory is extending our all-optical approach to control the intrinsic Sn nuclear spin [71]. Further, integrating the SnV into photonic nanostructures [44,50,51,68] will increase the photon-collection efficiency, and in parallel can strengthen the optical Rabi drive.…”

Performance analysis of quantum repeaters enabled by deterministically generated photonic graph states

“…To overcome this challenge, several groups have proposed schemes for deterministic generation of different types of photonic graph states [14][15][16][17][18][19][20][21][22][23], including the tree graph and repeater graph states that are considered as resource states for quantum repeaters [17,18,22,23]. These schemes employ a single spin-tagged quantum emitter to sequentially emit entangled photons, inspired by the original proposal from Lindner and Rudolph [14].…”