The challenge of accurately modelling the behaviour of atomic nuclei, particularly those of medium mass, represents a significant hurdle in nuclear physics. Sota Yoshida from Utsunomiya University and RIKEN, alongside Takeshi Sato and Takumi Ogata from The University of Tokyo, and Masaaki Kimura from RIKEN, now demonstrate a powerful new approach using quantum computation. The team successfully models the ground state energies of nuclei including oxygen, calcium and nickel on a trapped-ion quantum computer with unprecedented accuracy, achieving errors below one percent. This achievement establishes a new benchmark for simulating complex nuclear systems on real quantum hardware and highlights the potential of trapped-ion technology to unlock deeper understanding of nuclear structure.
Nuclear Hamiltonian And Hard-Core Treatment
This research details a method for calculating the binding energies of nuclei using Variational Quantum Eigensolver (VQE) with the pUCCD ansatz, demonstrating the feasibility of using near-term quantum computers to solve problems in nuclear physics. The work addresses the complexities of accurately modeling nuclear interactions and achieving reliable results with limited quantum resources. The team derived a Hamiltonian suitable for the hard-core boson approximation, transforming a fermionic Hamiltonian describing nucleon behavior into a form involving pairwise interactions between bosons within the zero-seniority space. This derivation justifies the chosen approximation and the form of the Hamiltonian used in the VQE algorithm.
To quantify uncertainty in VQE results, the team used a Monte Carlo approach to generate random circuits, varying initial qubit configurations and rotation orderings, and approximated resulting energy distributions with Gamma distributions. These fitted distributions were then used to construct uncertainty bands, providing a rigorous justification for the reported estimates. The team investigated the performance of the pUCCD ansatz on IBM’s noisy simulator, comparing three measurement strategies: direct expectation-value evaluation, a Hadamard gate method, and a basis-rotation strategy. The basis-rotation strategy consistently provided more stable results, demonstrating that the pUCCD ansatz can be implemented on realistic quantum hardware and yields reasonably accurate results, even in the presence of noise.
Nuclear Structure Simulation with Trapped Ions
Scientists achieved a breakthrough in simulating the structure of medium-mass nuclei, including oxygen, calcium, and nickel, using the RIKEN-Quantinuum Reimei trapped-ion computer, attaining sub-percent accuracy. The study pioneered a novel approach combining a hard-core-boson mapping with the pair-unitary coupled-cluster doubles (pUCCD) ansatz, efficiently capturing strong pairing correlations between nucleons. The team implemented the pUCCD ansatz on the Reimei processor, a high-fidelity trapped-ion system with all-to-all connectivity, using the Nexus cloud-based quantum computing platform. Calculations focused on even-neutron isotopes of oxygen, calcium, and nickel, spanning light to medium-mass ranges and providing benchmarks for nuclear structure calculations. To address non-diagonal interaction terms, scientists employed two measurement strategies, “Hadamard” and “Basis rotations”. This innovative combination enabled the team to achieve ground-state energies for oxygen, calcium, and nickel isotopes that agree with noise-free statevector simulations within sub-percent relative error, establishing a new benchmark for quantum simulations of strongly correlated nuclear systems.
Nuclear Structure Simulations with Quantum Computing
Scientists have achieved highly accurate quantum simulations of medium-mass atomic nuclei, including oxygen, calcium, and nickel, on the RIKEN, Quantinuum Reimei trapped-ion quantum computer, attaining sub-percent accuracy in their calculations. The work introduces a novel approach combining a hard-core-boson mapping with the pair-unitary coupled-cluster doubles (pUCCD) ansatz, effectively capturing the strong pairing correlations between nucleons within the nucleus. Experiments reveal that the calculated ground-state energies for the studied isotopes agree with noise-free statevector simulations to within 0. 1% relative error, representing a new benchmark for quantum simulations of strongly correlated nuclear systems.
The team successfully implemented the pUCCD ansatz on the high-fidelity Reimei processor, leveraging symmetry-aware techniques and post-selection methods to minimize errors and enhance reliability. Data shows that the combination of the hard-core-boson mapping and the pUCCD ansatz efficiently captures the intricate correlations arising from nuclear forces, offering a pathway towards more accurate and scalable simulations of nuclear structure. This breakthrough delivers a significant step forward in utilizing trapped-ion platforms for tackling complex problems in nuclear physics.
Accurate Nuclear Energy Calculations with Quantum Hardware
Scientists have achieved highly accurate calculations of the ground-state energies of medium-mass atomic nuclei, including oxygen, calcium, and nickel, using the RIKEN-Quantinuum Reimei trapped-ion computer. Employing a sophisticated symmetry-aware computational method, the team attained sub-percent accuracy in these calculations, demonstrating a significant advancement in the field of nuclear structure physics. The results closely match those obtained from traditional, noise-free simulations, confirming the accuracy and reliability of the quantum computing approach. This achievement represents a significant step towards utilizing quantum computers for solving complex problems in nuclear physics and beyond. This research demonstrates the potential of trapped-ion quantum computers to provide accurate and reliable simulations of nuclear structure, paving the way for future investigations of heavier nuclei and more realistic nuclear models.
👉 More information
🗞 Bridging Quantum Computing and Nuclear Structure: Atomic Nuclei on a Trapped-Ion Quantum Computer
🧠 ArXiv: https://arxiv.org/abs/2509.20642