Analyzing the Rydberg-based omg architecture for $^{171}$Yb nuclear spins

TL;DR

This paper explores the control and entanglement of nuclear spins in ytterbium-171 atoms using Rydberg states within an 'omg' architecture, demonstrating high-fidelity quantum gate potential with realistic experimental parameters.

Contribution

It provides a detailed analysis of Rydberg states in $^{171}$Yb for nuclear spin entanglement, identifying optimal configurations and conditions for high-fidelity quantum gates.

Findings

The $F=3/2$ manifold is suitable for nuclear spin entanglement.

High gate fidelities (>0.99) are achievable with modest magnetic fields and laser polarization.

Feasible Rabi frequencies enable effective control of nuclear spin states.

Abstract

Neutral alkaline earth(-like) atoms have recently been employed in atomic arrays with individual readout, control, and high-fidelity Rydberg-mediated entanglement. This emerging platform offers a wide range of new quantum science applications that leverage the unique properties of such atoms: ultra-narrow optical "clock" transitions and isolated nuclear spins. Specifically, these properties offer an optical qubit ("o") as well as ground ("g") and metastable ("m") nuclear spin qubits, all within a single atom. We consider experimentally realistic control of this "omg" architecture and its coupling to Rydberg states for entanglement generation, focusing specifically on ytterbium-171 ($^{171}\text{Yb}$) with nuclear spin $I = 1/2$. We analyze the $S$-series Rydberg states of $^{171}\text{Yb}$, described by the three spin-$1/2$ constituents (two electrons and the nucleus). We confirm that the $F = 3/2$ manifold -- a unique spin configuration -- is well suited for entangling nuclear spin qubits. Further, we analyze the $F = 1/2$ series -- described by two overlapping spin configurations -- using a multichannel quantum defect theory. We study the multilevel dynamics of the nuclear spin states when driving the clock or Rydberg transition with Rabi frequency $\Omega_\text{c} = 2 \pi \times 200$ kHz or $\Omega_\text{R} = 2 \pi \times 6$ MHz, respectively, finding that a modest magnetic field ($\approx200\,\text{G}$) and feasible laser polarization intensity purity ($\lesssim0.99$) are sufficient for gate fidelities exceeding 0.99.