Towards Chemically Accurate and Scalable Quantum Simulations on IQM Quantum Hardware: A Quantum-HPC Hybrid Approach

• URL: http://arxiv.org/abs/2604.01983v1
• Date: Thu, 02 Apr 2026 12:43:43 GMT
• Title: Towards Chemically Accurate and Scalable Quantum Simulations on IQM Quantum Hardware: A Quantum-HPC Hybrid Approach
• Abstract summary: We present a large-scale experimental study of quantum-computing-based molecular simulation carried out on IQM's Sirius 24-qubit superconducting processor.<n>The work employs Sample-based Quantum Diagonalization (SQD) together with the Local Unitary Cluster Jastrow (LUCJ) ansatz to estimate ground-state energies.<n>To move beyond small benchmark systems, we combine SQD(LUCJ) with Density Matrix Embedding Theory (DMET) to compute active-space energies.
• Score: 0.37475012732344193
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: We present a large-scale experimental study of quantum-computing-based molecular simulation carried out on IQM's Sirius 24-qubit superconducting processor, utilizing up to 16 operational qubits. The work employs Sample-based Quantum Diagonalization (SQD) together with the Local Unitary Cluster Jastrow (LUCJ) ansatz to estimate ground-state energies for a set of benchmark molecules, including H$_2$, LiH, BeH$_2$, H$_2$O, and NH$_3$. In addition, we introduce a Linear-CNOT variant of the Unitary Coupled-Cluster Singles and Doubles (LCNot-UCCSD) ansatz within the SQD workflow, trading higher circuit depth for reduced classical preprocessing. A comparison between these ansätze is provided, clarifying their respective strengths, limitations, and suitability for near-term quantum hardware. We further explore potential energy landscapes through 1D scans for H$_2$ and HeH$^+$ using both STO-3G and 6-31G basis sets, and for LiH and BeH$_2$ in STO-3G. Extending beyond this, we demonstrate the experimental construction of a full 2D potential energy surface for the water molecule on quantum hardware, mapped over a 32 $\times$ 32 grid in bond length and bond angle. To move beyond small benchmark systems, we combine SQD(LUCJ) with Density Matrix Embedding Theory (DMET) to compute active-space energies for a set of ligand-like molecules, as well as the pharmacologically relevant amantadine system. Across all studies, the majority of quantum-computed energies agree with reference FCI results, as well as with DMET-CASCI energies for embedded systems, to within chemical accuracy for the chosen basis sets. These results demonstrate the reliability of sample-based diagonalization approaches and underscore the potential of hybrid embedding strategies for extending quantum simulations to increasingly complex molecular systems, while also highlighting their practicality on current IQM quantum hardware.

Related papers

• Bridging the NISQ and Fault-Tolerant Regimes: Generative-ML-Assisted Quantum Selected CI for Molecular Simulations [0.0]
  This report presents a hybrid quantum-classical workflow performed on the Fujitsu FX700.<n>It addresses two structural inefficiencies in quantum-based diagonalization.<n>It enables more efficient and economical drug discovery simulations for the industry.
  arXiv  Detail & Related papers  (2026-06-29T16:48:44Z)
• Transformer refined quantum sampling for strongly correlated electronic structure [28.783585072184867]
  QiankunNet-QSCI is a hybrid quantum-classical framework for system simulation.<n>USCI ansatz is proposed to identify the most chemically significant electronic configurations on the Zuchongzhi 3.1 quantum processor.<n>Transformer model QiankunNet learns from sparse yet critical quantum data to infer and reconstruct the complete electronic wavefunction.
  arXiv  Detail & Related papers  (2026-05-23T15:00:59Z)
• Quantum Simulation of Ligand-like Molecules through Sample-based Quantum Diagonalization in Density Matrix Embedding Framework [0.0]
  This work combines Density Matrix Embedding Theory (DMET) with Sample-based Quantum Diagonalization (SQD) to compute ground-state energies of a set of natural ligand-like molecules.<n>The resulting embedded Hamiltonians are solved on IBM's Eagle R3 superconducting quantum hardware.<n>Results demonstrate that sample-based quantum methods, when integrated with a robust embedding framework, can reliably extend quantum computation towards simulation of chemically relevant molecular systems.
  arXiv  Detail & Related papers  (2025-11-27T06:50:52Z)
• Quantum Computing Approach to Atomic and Molecular Three-Body Systems [0.0]
  We present high-precision quantum computing simulations of three-body atoms and molecules.<n>Results make three-body atoms and molecules excellent candidates for benchmarking and testing on current Noisy Intermediate-Scale Quantum (NISQ) devices.
  arXiv  Detail & Related papers  (2025-10-20T18:39:32Z)
• Qumode-Based Variational Quantum Eigensolver for Molecular Excited States [43.148034499498586]
  We introduce the Qumode Subspace Variational Quantum Eigensolver (QSS-VQE), a hybrid quantum-classical algorithm for computing molecular excited states.<n>We demonstrate the performance of QSS-VQE through simulations of molecular excited states, including dihydrogen and a conical intersection in cytosine.
  arXiv  Detail & Related papers  (2025-09-05T00:53:51Z)
• Quantum-centric computation of molecular excited states with extended sample-based quantum diagonalization [0.0]
  The simulation of molecular electronic structure is an important application of quantum devices. We extend the sample-based quantum diagonalization (SQD) algorithm to determine low-lying molecular excited states.
  arXiv  Detail & Related papers  (2024-11-01T09:33:08Z)
• Non-unitary Coupled Cluster Enabled by Mid-circuit Measurements on Quantum Computers [37.69303106863453]
  We propose a state preparation method based on coupled cluster (CC) theory, which is a pillar of quantum chemistry on classical computers. Our approach leads to a reduction of the classical computation overhead, and the number of CNOT and T gates by 28% and 57% on average.
  arXiv  Detail & Related papers  (2024-06-17T14:10:10Z)
• Relativistic VQE calculations of molecular electric dipole moments on trapped ion quantum hardware [0.4074484551332309]
  This work presents high-precision 18-qubit relativistic VQE simulations for calculating the permanent electric dipole moments (PDMs) of BeH to RaH molecules on traditional computers.<n>We apply various resource reduction methods, including Reinforcement Learning and causal flow preserving ZX-Calculus routines, along with error mitigation and post-selection techniques.<n>Our approach reduces the two-qubit gate count in our 12-qubit circuit by 99.71%, with only a 2.35% trade-off in precision for PDM when evaluated classically.
  arXiv  Detail & Related papers  (2024-06-07T15:04:28Z)
• Shortcut to Chemically Accurate Quantum Computing via Density-based Basis-set Correction [0.4909687476363595]
  We embed a quantum computing ansatz into density-functional theory via density-based basis-set corrections (DBBSC) We provide a shortcut towards chemically accurate quantum computations by approaching the complete-basis-set limit. The resulting approach self-consistently accelerates the basis-set convergence, improving electronic densities, ground-state energies, and first-order properties.
  arXiv  Detail & Related papers  (2024-05-19T14:31:01Z)
• Simulating electronic structure on bosonic quantum computers [34.84696943963362]
  We propose an approach to map the electronic Hamiltonian into a qumode bosonic problem that can be solved on bosonic quantum devices.<n>This work establishes a new pathway for simulating many-fermion systems, highlighting the potential of hybrid qubit-qumode quantum devices.
  arXiv  Detail & Related papers  (2024-04-16T02:04:11Z)
• A qubit-ADAPT Implementation for H$_2$ Molecules using an Explicitly Correlated Basis [28.279056210896716]
  In the era of non-fault tolerant quantum devices, ADAPT algorithms are considered to be a promising approach for assisting classical machines with finding solution on computationally hard problems. In this work, the ADAPT algorithm has been combined with a first-quantized formulation for the hydrogen molecule in Born-Oppenheimer approximation.
  arXiv  Detail & Related papers  (2023-08-14T16:44:29Z)
• Experimental quantum computational chemistry with optimised unitary coupled cluster ansatz [23.6818896497932]
  Experimental realisation of scalable and high-precision quantum chemistry simulation remains elusive. We push forward the limit of experimental quantum computational chemistry and successfully scale up the implementation of VQE with an optimised unitary coupled-cluster ansatz to 12 qubits.
  arXiv  Detail & Related papers  (2022-12-15T18:04:28Z)
• Quantum simulation of topological zero modes on a 41-qubit superconducting processor [22.990199532365097]
  We develop a one-dimensional 43-qubit superconducting quantum processor named as Chuang-tzu. By engineering diagonal Aubry-Andr$acutemathrme$-Harper (AAH) models, we experimentally demonstrate the Hofstadter butterfly energy spectrum. Using Floquet engineering, we verify the existence of the topological zero modes in the commensurate off-diagonal AAH models.
  arXiv  Detail & Related papers  (2022-11-10T04:56:37Z)
• Towards the simulation of transition-metal oxides of the cathode battery materials using VQE methods [0.0]
  Variational quantum eigensolver (VQE) is a hybrid quantum-classical technique that leverages noisy intermediate scale quantum hardware to obtain minimum eigenvalue of a model Hamiltonian. In this work, we employ VQE methods to obtain the ground-state energy of LiCoO$$, a candidate transition metal oxide used for battery cathodes.
  arXiv  Detail & Related papers  (2022-08-16T22:30:54Z)
• Computing molecular excited states on a D-Wave quantum annealer [52.5289706853773]
  We demonstrate the use of a D-Wave quantum annealer for the calculation of excited electronic states of molecular systems. These simulations play an important role in a number of areas, such as photovoltaics, semiconductor technology and nanoscience.
  arXiv  Detail & Related papers  (2021-07-01T01:02:17Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.