Controlled-SWAP gates by tuning of interfering transition pathways in neutral atom arrays

• URL: http://arxiv.org/abs/2511.22214v1
• Date: Thu, 27 Nov 2025 08:34:41 GMT
• Title: Controlled-SWAP gates by tuning of interfering transition pathways in neutral atom arrays
• Authors: Mohammadsadegh Khazali, Klaus Mølmer,
• Abstract summary: By lifting the degeneracy between interfering transition pathways, a single Rydberg-excited atom can control state exchange between pairs of atoms.<n>We realize a direct controlled-SWAP operation with more than 99% fidelity and an order-of-magnitude reduction in circuit depth.<n>Our work provides multiqubit gates that enable higher-order state-verification protocols, occupation-dependent simulations, and conditional routing across optical lattices.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Neutral-atom quantum processors employ Rydberg blockade for multiqubit phase operations but lack similar native exchange and conditional exchange gates, which are essential primitives for state verification, fermionic and XY-model simulation, and efficient routing in large qubit arrays. We demonstrate that by lifting the degeneracy between interfering transition pathways, a single Rydberg-excited atom can control state exchange between pairs of atoms. Using this mechanism, we realize a direct controlled-SWAP (Fredkin) operation with more than 99\% fidelity and an order-of-magnitude reduction in circuit depth and reduced exposure to decay and decoherence of Rydberg state components compared with decomposed implementations. The mechanism operates robustly under Doppler broadening at ~150 $μ$K and realistic laser-intensity noise and extends naturally to an entire family of useful gates, including multi-control conditional exchanges (C$_k$-SWAP) and conditional multiplexed SWAP gates. By incorporating controlled exchange operations as native physical operations on neutral atoms, our work provides multiqubit gates that enable higher-order state-verification protocols, occupation-dependent simulations, and conditional routing across optical lattices.

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