Nuclear Dynamics on a Quantum Chip

Project Overview

Quantum computers have extraordinary potential as a transformative technology with a near-term application in the simulation of quantum mechanical systems, including the collisions of atomic nuclei that power the evolution of stars, create most of the universe's elements, and inform nuclear stockpile stewardship. Emerging prototypes of quantum processing units (QPUs) are providing initial evidence of the viability of quantum computing (QC); however, simulations are limited by the buildup of noise (from uncontrollable physical processes in and around the equipment) and error across multiple quantum logical operations (or, quantum gates).

This project set out to establish an unconventional, noise-resilient protocol for the simulation of nuclear dynamics on quantum chips and demonstrate it on the Lawrence Livermore National Laboratory (LLNL) Quantum Device and Integration Testbed (QuDIT) and other emerging quantum computing testbeds; thus, propelling the application of near-term quantum computing platforms to a broad class of problems. The protocol employs a minimal number of continuous gates customized to realize the desired nuclear dynamic interaction rather than long sequences of ‘elementary' gates typically adopted in quantum computing. Demonstrations of the evolution with time of two interacting neutrons frozen in space implemented on the LLNL QuDIT testbed achieved greater than 99% fidelity and increased by an order of magnitude the simulation time compared to previous quantum simulations of dynamical processes. Through a user project at the Berkeley National Lab. Advanced Quantum Testbed (AQT), the project also demonstrated a hybrid coprocessing scheme for the scattering of two neutrons, where the (currently prohibitive) computational cost incurred from the discretization of the spatial coordinates is offloaded to a classical processor. Classical device-level simulations of (noisy) near-term quantum processors were further used to design noise-resilient algorithms for the quantum simulation of multi-nucleon spin dynamics, and to significantly increase the fidelity of quantum state preparation, thus spring-boarding major performance improvementsfor a broader class of problems.

Mission Impact

This work positioned LLNL at the forefront of custom-gate (pulse-level) controlled and hybrid quantum-analog simulations of the dynamics of quantum systems, influencing the research community and industry in adopting these ideas, and promoting a paradigm shift in near-term quantum computing that is poised to accelerate the leap from classical to quantum computing. This effort thrusted LLNL into a major leadership role in the development of science and technology tools and capabilities to pursue the science grand challenges called for by the 2018 National Strategic Overview for Quantum Information Science (QIS) and to meet future national security challenges. It led to the award of a basic science Department of Energy, Office of Nuclear Physics ‘Quantum Horizons' project to develop near-term quantum simulations for nuclear physics, as well as to a new effort under the Advanced Simulation and Computing (ASC) Program aimed at building the foundations for the application of near-term quantum computing platforms to the simulation of neutron-induced reactions and fission processes relevant to the Stockpile Stewardship Program. Finally, this project trained several postdocs (who have since become staff at LLNL, industry and other national laboratories) and graduate students with a unique blend of skills at the interface of QIS and domain science, a profile that is increasingly in demand but hard to come by.

Publications, Presentations, and Patents

Coello Perez, E. A. 2022. "Quantum State Preparation by Adiabatic Evolution with Customized Gates." Physical Review A 105: 032403. https://journals.aps.org/pra/pdf/10.1103/PhysRevA.105.032403. LLNL-JRNL-829224.

Kravvaris, K. 2020."The Future Ain't What It Used To Be": Current Hardware Challenges And Solutions In Computing Atomic Nuclei." Florida State University (online), November 2020. LLNL-PRES-816205.

Kravvaris K, 2021. "First Principles Calculations Of Atomic Nuclei and their Interactions." Lawrence Livermore National Laboratory, Computing Grand Challenge Seminars (online), May 2021. LLNL-PRES-822625.

Holland, E. T., K. A. Wendt, K. Kravvaris, X. Wu, A. E. Ormand,, J.L. DuBois, S. Quaglioni, and F. Pederiva. 2020. "Optimal Control for the Quantum Simulation of Nuclear Dynamics." Physical Review A 101: 062307. https://doi.org/10.1103/PhysRevA.101.062307. LLNL-JRNL-787600.

Luchi, P. 2021a. "Control Optimization For Parametric Hamiltonians By Pulse Reconstruction." Sixth International Conference for Young Quantum Information Scientists (online), April 2021. LLNL-POST-821157.

Quaglioni, S. 2020. "Computing Nuclear Dynamics." Quantum Simulation for Nuclear Physics (online), August 2020. LLNL-PRES-813397.

Quaglioni, S. 2020. "Recent Developments And Prospects In Low-Energy Nuclear Theory." 2020 APS Fall Meeting of the Division of Nuclear Physics (online), October 2020. LLNL-PRES-815991.

Quaglioni, S. 2021. "Ab initio Calculations of Structure and Reactions in Light Nuclei." Yamada Conference LXXII: The 8th Asia-Pacific Conference on Few-Body Problems in Physics (online). May 2021. LLNL-ABS-819104.

Quaglioni, S. 2021. "Noise-Resilient Quantum Simulation Of Nuclear Dynamics." University of Maryland (online), April 2021; Tohoku University (online), June 2021. LLNL-PRES-822126.

Quaglioni, S. 2021."Ab Initio Calculations Of Atomic Nuclei And Their Interactions." University of Trento, September 2021. LLNL-PRES-826725.

Quaglioni, S. 2021. "Noise-Resilient Quantum Simulation Of Nuclear Dynamics." IQuS: Scientific Quantum Computing and Simulation on Near-Term Devices (online), November 2021. LLNL-PRES-829042.

Quaglioni, S. 2021. "Microscopic Nuclear Simulations Usinig Quantum Technologies", INFN - Laboratori Nazionali di Legnaro (online), November 18, 2021. LLNL-PRES-829255.

Quaglioni, S. 2021. "Noise-Resilient Quantum Simulation Of Nuclear Dynamics." TNPI2021- XVIII Conference on Theoretical Nuclear Physics in Italy (online), November 2021. LLNL-PRES-829254.

Turro, F. 2021. "Imaginary Time Propagation On A Quantum Chip." Sixth International Conference for Young Quantum Information Scientists (online), April 2021. LLNL-POST-821131.

Turro, F. 2022. "Imaginary Time Propagation On A Quantum Chip." Physical Review A 105: 022440. https://journals.aps.org/pra/pdf/10.1103/PhysRevA.105.022440. LLNL-JRNL-819649.

Wendt, K. A. 2020. "Optimal Control for the Quantum Simulation of Nuclear Dynamics." Seminars at The Ohio State University, Fermi National Laboratory, SLAC National Accelerator Laboratory, Lawrence Berkeley National Laboratory, January-February 2020. LLNL-PRES-802166.

Wendt, K. A. 2020. "Quantum Computing: A Cold Bright Future for Computational Low Energy Nuclear Theory." Low-Energy Community Meeting (online), August 2020. LLNL-PRES-813520.

Wendt, K. A. 2020. "Optimal Control for the Quantum Simulation of Nuclear Dynamics." APS Division Nuclear Physics Hawaii Meeting 2020. LLNL-ABS-800822.

Wendt, K. A. 2021. "Hybrid Digital/Analog Quantum Simulations via Optimal Control." 2021 APS April Meeting (online). LLNL-ABS-818148.

Wendt, K. A. 2021. "Hybrid Digital/Analog Quantum Simulations via Optimal Control." 2021 APS April Meeting (online), April 2021. LLNL-PRES-821648.

Wendt, K. A. 2021. "Prospects and Challenges for Realizing Hybrid Digital/Analog Quantum Simulations Through Optimal Control." 2021 Fall Meeting of the APS Division of Nuclear Physics. LLNL-ABS-824001.

Wu, X., Tomarken, S. L., Petersson, N. A., Martinez, L. A., Rosen, Y. J., and DuBois, J. L. 2020. "High-Fidelity Software-Defined Quantum Logic on a Superconducting Qudit." Physical Review Letters 125: 170502. https://doi.org/10.1103/PhysRevLett.125.170502. LLNL-JRNL-810657.