Pulser: An open-source package for the design of pulse sequences in programmable neutral-atom arrays (2104.15044v3)

Abstract: Programmable arrays of hundreds of Rydberg atoms have recently enabled the exploration of remarkable phenomena in many-body quantum physics. In addition, the development of high-fidelity quantum gates are making them promising architectures for the implementation of quantum circuits. We present here \textit{Pulser}, an open-source Python library for programming neutral-atom devices at the pulse level. The low-level nature of Pulser makes it a versatile framework for quantum control both in the digital and analog settings. The library also contains simulation routines for studying and exploring the outcome of pulse sequences for small systems.

• The paper introduces Pulser as a tool for low-level design and simulation of pulse sequences in programmable neutral-atom arrays.
• It details a modular architecture with registers, channels, waveforms, pulses, and sequences that facilitates flexible quantum operations.
• The study demonstrates Pulser's utility in both digital and analog quantum computing, including applications like QAOA and many-body state simulations.

Pulser: An Open-Source Package for Designing Pulse Sequences in Neutral-Atom Quantum Computers

The manuscript introduces "Pulser," an open-source Python library created to facilitate the programming and simulation of quantum operations in neutral-atom arrays—a promising architecture for quantum information processing. This package allows researchers to design pulse sequences at a low level, providing them with precise control over neutral-atom quantum processing units (QPUs).

Technical Contributions and Software Architecture

Pulser is engineered to work with neutral atom arrays, where individual atoms can be trapped using optical tweezers. The platform exploits Rydberg states to enable robust, long-range interactions critical for quantum computation. Unlike traditional hardware, the connectivity in a neutral-atom QPU can be dynamically reprogrammed between runs. The flexibility of such a system presents a stark contrast to fixed qubit arrangements found in other hardware options like superconducting qubits or trapped ions.

The software architecture of Pulser is modular and includes several interconnected components: Registers manage the spatial arrangement and identification of qubits, Channels define laser actions, Waveforms shape the transitions, Pulses execute quantum gates, and Sequences orchestrate quantum operations across qubits. Additionally, Pulser incorporates a Simulation module, leveraging QuTiP for emulating quantum behavior in small systems.

Use Cases and Implications

Pulser supports both digital and analog quantum computation. Digital computation with Pulser involves directly programming quantum circuits using standard gates like single-qubit and two-qubit (controlled-Z) gates. Analog computation can smoothly transition quantum states to explore phenomena in many-body physics, such as the Ising model.

The paper underscores Pulser's utility through two applications:

1. Quantum Approximate Optimization Algorithm (QAOA): Pulser facilitates the design of variational algorithms by allowing parametrized sequences, making it efficient for classical-quantum hybrid optimization tasks.
2. State Preparation and Correlation Analysis: In simulating the adiabatic preparation of an antiferromagnetic state, Pulser demonstrated its utility in setting up and testing quantum simulations of complex many-body interactions.

Future Directions and Developments

Pulser aims to be more than a tool for prototyping. Its open-source nature and adaptability make it a crucial element for future extensions, which may include more realistic error models and handling processes like atom assembly and state readout. Additionally, collaborative efforts with higher-level quantum frameworks like Qiskit or Cirq could expand Pulser's reach, integrating it as a backend in versatile quantum development ecosystems.

Pulser's development corresponds with the broader goals of enhancing the programmability and efficiency of quantum computation platforms based on atom arrays. Its adaptability and precise control at the pulse level position it as a pioneer in the field of open-source quantum software, potentially influencing both theoretical research and experimental practices.