Quantum computing with neutral atoms (2006.12326v2)

Abstract: The manipulation of neutral atoms by light is at the heart of countless scientific discoveries in the field of quantum physics in the last three decades. The level of control that has been achieved at the single particle level within arrays of optical traps, while preserving the fundamental properties of quantum matter (coherence, entanglement, superposition), makes these technologies prime candidates to implement disruptive computation paradigms. In this paper, we review the main characteristics of these devices from atoms / qubits to application interfaces, and propose a classification of a wide variety of tasks that can already be addressed in a computationally efficient manner in the Noisy Intermediate Scale Quantum era we are in. We illustrate how applications ranging from optimization challenges to simulation of quantum systems can be explored either at the digital level (programming gate-based circuits) or at the analog level (programming Hamiltonian sequences). We give evidence of the intrinsic scalability of neutral atom quantum processors in the 100-1,000 qubits range and introduce prospects for universal fault tolerant quantum computing and applications beyond quantum computing.

• The paper introduces a neutral atom platform that leverages optical traps to achieve scalable quantum processors for both digital and analog computations.
• The study employs high-fidelity Rydberg-mediated entanglement and multi-qubit connectivity to efficiently implement complex quantum circuits.
• The paper outlines future prospects including improved error mitigation and the integration of photonic interfaces to advance modular quantum processor design.

Quantum Computing with Neutral Atoms: Current Capabilities and Future Prospects

The manipulation of neutral atoms by light presents a compelling approach to quantum computing, presenting opportunities in the noisy intermediate-scale quantum (NISQ) era. The neutral atom platform, as discussed in the paper, leverages the control of single atoms in optical traps to implement quantum computing paradigms both at digital and analog levels, potentially addressing a breadth of computational tasks that are challenging for classical systems.

Overview of Neutral Atom Quantum Processors

Neutral atom quantum processors store information in qubits encoded in two electronic states of each atom. The platform utilizes laser-arranged arrays of optical traps to precisely control the position and interaction of atoms. This system is highly scalable, with achievable configurations ranging from hundreds to a few thousand qubits. Uniformity in atomic properties contributes to reduced error rates relative to platforms that rely on manufactured qubits, an inherent advantage of using natural atomic states. A major strength of neutral atoms lies in implementing multi-qubit gates with extensive connectivity, which enables efficient computation and shortens processing times, vital for propelling quantum algorithms within the coherence time frame allowed by current technology.

Digital and Analog Quantum Computation

Neutral atom platforms enable two forms of quantum computation:

1. Digital Quantum Computation: Leveraging sequences of quantum gates, this methodology utilizes universal gate sets for algorithm implementation. The control over single and two-qubit operations achieves compelling fidelity, with capabilities demonstrated for high-fidelity Rydberg-mediated entanglement and fast two-qubit gates. The modular architecture allows large degrees of connectivity which is beneficial for executing complex quantum circuits with minimized gate overhead.
2. Analog Quantum Computation: This exploits the Hamiltonian dynamics of atoms under laser control, allowing the direct simulation of quantum processes. This analog approach is advantageous for many-body simulations, significantly beneficial in exploring quantum magnetism and excitation transport, amongst other phenomena beyond classical computing capabilities.

Application Domains

In the NISQ era, where fully error-corrected quantum computers remain a future goal, neutral atom processors provide a robust platform for several applications:

• Quantum Simulation: Quantum simulators based on neutral atoms play a vital role in understanding many-body physics, crucial for condensed-matter physics, chemistry, and high-energy physics. They offer mechanisms to probe complex quantum systems and topological phenomena.
• Optimization: Neutral atom processors exhibit versatility for near-term applications in solving hard optimization problems, illustrating significant potential for combinatorial optimization tasks by implementing quantum approximation optimization algorithms (QAOA).
• Machine Learning: The architecture supports variational algorithms conducive for quantum-assisted machine learning, promising enhancement in pattern recognition and complex data analysis.

Future Outlook and Challenges

Future developments hinge on enhancing the number of qubits, improving gate fidelities, and incorporating error mitigation strategies. Engaging multi-core architecture and leveraging photonic interfaces potentially marks the pathway towards fault-tolerant quantum computation. Efficient light-matter interfaces facilitate quantum networking and modular scaling of quantum processors, contributing to robust error correction schemes.

The paper outlines the advancements in neutral atom quantum devices and the associated research challenges, underscoring their potential impact on enhancing computational processes and understanding quantum dynamics. These developments can significantly broaden the horizon of quantum technologies, paving the way for myriad applications across scientific and industrial domains. The pursuit of integrating photonic capabilities within neutral atom frameworks is anticipated to unlock further avenues of quantum innovation, reinforcing the momentum towards broader quantum supremacy.