Quantum Gates for Neutral Atoms Separated by a Few Tens of Micrometers

We present theoretical schemes for a family of fast and high-fidelity two-qubit gates between neutral atoms separated by more than 20 um. We first show that, by using resonant dipole–dipole spin-exchange interactions between Rydberg states, it is possible to harness coherent excitation–exchange–deexcitation dynamics between the qubit and Rydberg states within a single, smooth laser pulse to produce the desired gate. Furthermore, we propose a second protocol that aims to realize a quantum gate between two distant atoms via a chain of ancillary atoms that mediate the interaction. We employ optimal control methods to achieve theoretical gate fidelities and durations comparable to those of blockade-based gates in the presence of relevant noise sources, while extending the effective interaction range by an order of magnitude. This enables entanglement well beyond the blockade radius, offering a route toward fast, high-connectivity quantum processors.