Quantum Phases of Matter on a 256-Atom Programmable Quantum Simulator (2012.12281v1)

Abstract: Motivated by far-reaching applications ranging from quantum simulations of complex processes in physics and chemistry to quantum information processing, a broad effort is currently underway to build large-scale programmable quantum systems. Such systems provide unique insights into strongly correlated quantum matter, while at the same time enabling new methods for computation and metrology. Here, we demonstrate a programmable quantum simulator based on deterministically prepared two-dimensional arrays of neutral atoms, featuring strong interactions controlled via coherent atomic excitation into Rydberg states. Using this approach, we realize a quantum spin model with tunable interactions for system sizes ranging from 64 to 256 qubits. We benchmark the system by creating and characterizing high-fidelity antiferromagnetically ordered states, and demonstrate the universal properties of an Ising quantum phase transition in (2+1) dimensions. We then create and study several new quantum phases that arise from the interplay between interactions and coherent laser excitation, experimentally map the phase diagram, and investigate the role of quantum fluctuations. Offering a new lens into the study of complex quantum matter, these observations pave the way for investigations of exotic quantum phases, non-equilibrium entanglement dynamics, and hardware-efficient realization of quantum algorithms.

• The paper implements a scalable quantum spin model on a 256-atom system using deterministic atom array preparation and Rydberg excitations.
• The paper showcases high-fidelity preparation of antiferromagnetic states and measures (2+1)-dimensional Ising phase transitions with extended correlation lengths.
• The paper maps out the quantum phase diagram, revealing striated and star configurations that validate universal scaling via the Kibble-Zurek mechanism.

Quantum Phases of Matter on a 256-Atom Programmable Quantum Simulator

This paper introduces a programmable quantum simulator utilizing a two-dimensional array of neutral atoms, central to exploring quantum phases of matter. The experimental setup allows for the creation of a 256-atom system, demonstrating a pivotal advancement in probing quantum dynamics in large systems. The experiment employs Rydberg states to induce tunable interactions between atoms, enabling the paper of the many-body phenomena associated with quantum phase transitions and the emergence of novel quantum phases.

Key Contributions

1. Quantum Spin Model Realization: The research implements a quantum spin model across varying system sizes from 64 to 256 qubits. Through deterministic preparation of atom arrays, interactions between qubits are controlled coherently. This control is realized via Rydberg excitations, allowing users to explore different regimes of quantum interactions.
2. Benchmarking and Phase Transitions: The researchers have showcased high-fidelity preparation of antiferromagnetically ordered states, employing a novel measurement of correlation lengths within these quantum phases. By characterizing Ising quantum phase transitions in (2+1) dimensions, the research underscores the universal properties of quantum critical phenomena.
3. Exploration of Quantum Phases: The paper experimentally maps the phase diagram, revealing several quantum phases that emerge due to the interplay of interactions and coherent laser excitation. The striated and star configurations are particularly intriguing, providing a deeper understanding of quantum fluctuation roles.

Numerical Results and Theoretical Implications

• The paper achieves long-range antiferromagnetic correlations over an entire 144 atom array, with correlation lengths far surpassing earlier reports in analogous quantum systems.
• Universality is established through the Kibble-Zurek mechanism's prediction, manifesting in rescaled correlation data collapse onto a single universal curve. The critical exponent extracted corroborates theoretical predictions for the Ising class in (2+1) dimensions.
• By surveying the quantum many-body landscape, the research maps out the phase diagram of Rydberg systems. The highlighted striated and star phases offer insight into quantum systems constrained by second-nearest and third-nearest neighbor interactions.

Practical Implications and Future Directions

The ability to simulate large quantum systems with high precision is foundational for both quantum information sciences and the paper of complex quantum matter. Practical applications extend to the implementation of more efficient quantum algorithms and understanding entanglement dynamics in non-equilibrium states. The system's versatility and control demonstrate a significant step towards simulating phenomena that are otherwise intractable for classical computing.

The future trajectory of such research could involve:

• Enhancing system sizes and coherence times, potentially leveraging different species of qubits, such as molecular assemblies or varying atomic species.
• Further adapting quantum protocols for large-scale quantum operations within these architectures.
• Exploring quantum computing applications including but not limited to error correction schemes, fault-tolerant operations, and optimization tasks in quantum algorithms like Quantum Approximate Optimization Algorithm (QAOA).

In summary, the paper provides an extensive exploration of quantum matter phases, leveraging a pioneering experimental platform. The presented results lay a groundwork towards transcending classical limitations in simulating complex quantum systems, opening new avenues for theoretical and practical advancements in quantum science.