Neutral Atom Quantum Computing

Neutral atom quantum computing uses individual atoms—typically alkali metals like Rubidium or Strontium—trapped by laser beams called optical tweezers^[6]D. Barredo et al. (2016). An atom-by-atom assembler of defect-free arbitrary two-dimensional atomic arrays. Science 354, 1021.^[7]M. Endres et al. (2016). Atom-by-atom assembly of defect-free one-dimensional cold atom arrays. Science 354, 1024.. Unlike charged ions used in trapped-ion quantum computers, these atoms are electrically neutral, which provides both advantages and unique challenges^[2]M. Saffman et al. (2010). Quantum information with Rydberg atoms. Rev. Mod. Phys. 82, 2313..

The basic operation involves trapping atoms in arrays of optical tweezers, rearranging them into desired configurations, exciting them to Rydberg states (where electrons orbit far from the nucleus), and letting them interact through van der Waals forces^[1]D. Jaksch et al. (2000). Fast quantum gates for neutral atoms. Phys. Rev. Lett. 85, 2208.^[5]M. D. Lukin et al. (2001). Dipole blockade and quantum information processing in mesoscopic atomic ensembles. Phys. Rev. Lett. 87, 037901.. This creates entanglement and enables quantum gates.

What makes neutral atoms particularly exciting is their scalability. Systems with hundreds of atoms have been demonstrated^[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., far exceeding the qubit counts of early superconducting systems. The atoms can be arranged in arbitrary 2D and even 3D geometries, enabling novel connectivity patterns^[11]D. Bluvstein et al. (2022). A quantum processor based on coherent transport of entangled atom arrays. Nature 604, 451.^[17]D. Bluvstein et al. (2024). Logical quantum processor based on reconfigurable atom arrays. Nature 626, 58..

Key capabilities include:

• •All-to-all connectivity: Any two atoms can interact by being moved close together or excited to Rydberg states simultaneously^[11]D. Bluvstein et al. (2022). A quantum processor based on coherent transport of entangled atom arrays. Nature 604, 451.^[17]D. Bluvstein et al. (2024). Logical quantum processor based on reconfigurable atom arrays. Nature 626, 58..
• •Dynamic reconfiguration: Atoms can be moved mid-computation to optimize connectivity for specific algorithms^[11]D. Bluvstein et al. (2022). A quantum processor based on coherent transport of entangled atom arrays. Nature 604, 451.^[17]D. Bluvstein et al. (2024). Logical quantum processor based on reconfigurable atom arrays. Nature 626, 58..
• •Erasure detection: Lost atoms can be detected without destroying quantum information in remaining atoms^[14]Y. Wu et al. (2022). Erasure conversion for fault-tolerant quantum computing in alkaline earth Rydberg atom arrays. Nat. Commun. 13, 4657.^[15]P. Scholl et al. (2023). Erasure conversion in a high-fidelity Rydberg quantum simulator. Nature 622, 273.^[16]S. Ma et al. (2023). High-fidelity gates and mid-circuit erasure conversion in an atomic qubit. Nature 622, 279..
• •Identical qubits: All atoms of the same isotope are fundamentally identical, eliminating manufacturing variation issues^[2]M. Saffman et al. (2010). Quantum information with Rydberg atoms. Rev. Mod. Phys. 82, 2313..

Neutral atom quantum computing has emerged as one of the most promising platforms for scaling to thousands of 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 field is advancing rapidly, with both commercial ventures and academic groups pushing the boundaries of system size and gate fidelity.

Platform Characteristics

• •Coherence times: Seconds to tens of seconds—orders of magnitude longer than superconducting qubits (microseconds to milliseconds)^[2]M. Saffman et al. (2010). Quantum information with Rydberg atoms. Rev. Mod. Phys. 82, 2313.^[10]H. Levine et al. (2018). High-fidelity control and entanglement of Rydberg-atom qubits. Phys. Rev. Lett. 121, 123603..
• •Gate fidelities: Currently 99%+ for single-qubit gates, 97–99.5% for two-qubit gates—improving rapidly^[10]H. Levine et al. (2018). High-fidelity control and entanglement of Rydberg-atom qubits. Phys. Rev. Lett. 121, 123603.^[13]S. J. Evered et al. (2023). High-fidelity parallel entangling gates on a neutral-atom quantum computer. Nature 622, 268.^[16]S. Ma et al. (2023). High-fidelity gates and mid-circuit erasure conversion in an atomic qubit. Nature 622, 279..
• •Operation modes: Both analog (Hamiltonian simulation) and digital (gate-based) computing possible on the same hardware^[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.^[12]T. M. Graham et al. (2022). Multi-qubit entanglement and algorithms on a neutral-atom quantum computer. Nature 604, 457..
• •Atom loss: Atoms can escape traps—a unique error mode that can be detected as erasures and converted into a correctable error type^[14]Y. Wu et al. (2022). Erasure conversion for fault-tolerant quantum computing in alkaline earth Rydberg atom arrays. Nat. Commun. 13, 4657.^[15]P. Scholl et al. (2023). Erasure conversion in a high-fidelity Rydberg quantum simulator. Nature 622, 273..