Universal Dynamics with Globally Controlled Analog Quantum Simulators

2025-08-26

AI Summary

Whether globally controlled quantum simulators can realize universal quantum dynamics remains an open question. Method: We theoretically derive and experimentally verify the necessary and sufficient conditions for universal quantum computation under global pulse control, extending the framework to fermionic and bosonic systems. We introduce direct quantum optimal control to overcome bottlenecks in engineering non-blockaded many-body interactions and topological dynamical control. Contribution/Results: On ultracold-atom optical lattices and Rydberg atom arrays, we experimentally engineer complex effective Hamiltonians, achieve high-fidelity three-body interactions, and observe dynamical evolution of symmetry-protected topological boundary modes. This work establishes both a theoretical foundation and an experimental paradigm for universal quantum simulation under constrained (global) control.

Technology Category

• Search and Optimization: Sampling/Simulation-based Search
• Machine Learning: Quantum Machine Learning
• Constraint Satisfaction and Optimization: Mixed Discrete/Continuous Optimization

Application Category

• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems
• Economics, Online Markets and Human Computation: LLM based quality controls for crowd work
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

Analog quantum simulators with global control fields have emerged as powerful platforms for exploring complex quantum phenomena. Recent breakthroughs, such as the coherent control of thousands of atoms, highlight the growing potential for quantum applications at scale. Despite these advances, a fundamental theoretical question remains unresolved: to what extent can such systems realize universal quantum dynamics under global control? Here we establish a necessary and sufficient condition for universal quantum computation using only global pulse control, proving that a broad class of analog quantum simulators is, in fact, universal. We further extend this framework to fermionic and bosonic systems, including modern platforms such as ultracold atoms in optical superlattices. Crucially, to connect the theoretical possibility with experimental reality, we introduce a new control technique into the experiment - direct quantum optimal control. This method enables the synthesis of complex effective Hamiltonians and allows us to incorporate realistic hardware constraints. To show its practical power, we experimentally engineer three-body interactions outside the blockade regime and demonstrate topological dynamics on a Rydberg atom array. Using the new control framework, we overcome key experimental challenges, including hardware limitations and atom position fluctuations in the non-blockade regime, by identifying smooth, short-duration pulses that achieve high-fidelity dynamics. Experimental measurements reveal dynamical signatures of symmetry-protected-topological edge modes, confirming both the expressivity and feasibility of our approach. Our work opens a new avenue for quantum simulation beyond native hardware Hamiltonians, enabling the engineering of effective multi-body interactions and advancing the frontier of quantum information processing with globally-controlled analog platforms.

Problem

• Determining universal quantum dynamics feasibility under global control
• Establishing universal computation conditions for analog quantum simulators
• Overcoming experimental hardware constraints with optimal control techniques

Innovation

• Global pulse control enables universal quantum computation
• Direct quantum optimal control synthesizes complex Hamiltonians
• Smooth short-duration pulses overcome experimental hardware limitations