Neutral Atom Systems

Neutral-atom quantum computers trap individual atoms in arrays of optical tweezers. Each atom is a qubit, and lasers drive transitions between ground and highly excited Rydberg states to perform gates ^[1]D. Jaksch et al. (2000). Fast quantum gates for neutral atoms. Phys. Rev. Lett. 85, 2208. ^[2]M. Saffman et al. (2010). Quantum information with Rydberg atoms. Rev. Mod. Phys. 82, 2313..

Because the atoms are neutral, they can be packed densely and rearranged mid-circuit. Because they are identical, they avoid the manufacturing variation that plagues solid-state qubits ^[3]A. Browaeys & T. Lahaye (2020). Many-body physics with individually controlled Rydberg atoms. Nat. Phys. 16, 132. ^[4]L. Henriet et al. (2020). Quantum computing with neutral atoms. Quantum 4, 327..

The platform has recently achieved high-fidelity entangling gates, mid-circuit erasure detection, and reconfigurable arrays with hundreds of atoms ^[5]M. D. Lukin et al. (2001). Dipole blockade and quantum information processing in mesoscopic atomic ensembles. Phys. Rev. Lett. 87, 037901. ^[6]D. Barredo et al. (2016). An atom-by-atom assembler of defect-free arbitrary two-dimensional atomic arrays. Science 354, 1021..

Key Capabilities

• •All-to-all connectivity within the interaction radius — any two atoms can be coupled through Rydberg states ^[10]H. Levine et al. (2018). High-fidelity control and entanglement of Rydberg-atom qubits. Phys. Rev. Lett. 121, 123603..
• •Dynamic reconfiguration — atoms can be moved between gates to create arbitrary interaction graphs ^[11]D. Bluvstein et al. (2022). A quantum processor based on coherent transport of entangled atom arrays. Nature 604, 451..
• •Erasure detection — missing atoms can be flagged, turning some errors into easier-to-correct erasures ^[14]Y. Wu et al. (2022). Erasure conversion for fault-tolerant quantum computing in alkaline earth Rydberg atom arrays. Nat. Commun. 13, 4657..
• •Identical qubits — every atom is the same species, eliminating frequency spread from fabrication ^[4]L. Henriet et al. (2020). Quantum computing with neutral atoms. Quantum 4, 327..

Neutral atoms have moved from many-body physics experiments to competitive quantum computing platforms in under a decade ^[4]L. Henriet et al. (2020). Quantum computing with neutral atoms. Quantum 4, 327. ^[8]S. Ebadi et al. (2021). Quantum phases of matter on a 256-atom programmable quantum simulator. Nature 595, 227..

Platform Characteristics

• •Long coherence times — hyperfine ground states can remain coherent for many seconds ^[2]M. Saffman et al. (2010). Quantum information with Rydberg atoms. Rev. Mod. Phys. 82, 2313..
• •High-fidelity gates — two-qubit entangling gates have reached above 99% fidelity ^[13]S. J. Evered et al. (2023). High-fidelity parallel entangling gates on a neutral-atom quantum computer. Nature 622, 268..
• •Analog and digital modes — useful for both quantum simulation and gate-based computation ^[8]S. Ebadi et al. (2021). Quantum phases of matter on a 256-atom programmable quantum simulator. Nature 595, 227. ^[9]P. Scholl et al. (2021). Quantum simulation of 2D antiferromagnets with hundreds of Rydberg atoms. Nature 595, 233..
• •Atom loss — the dominant error is losing atoms, which can often be detected and converted to erasures ^[14]Y. Wu et al. (2022). Erasure conversion for fault-tolerant quantum computing in alkaline earth Rydberg atom arrays. Nat. Commun. 13, 4657..