Contextual Subspace Variational Quantum Eigensolver Calculation of the Dissociation Curve of Molecular Nitrogen on a Superconducting Quantum Computer

Abstract

In this work we present an experimental demonstration of the Contextual Subspace Variational Quantum Eigensolver on superconducting quantum hardware. In particular, we compute the potential energy curve for molecular nitrogen, where a dominance of static correlation in the dissociation limit proves challenging for many conventional quantum chemistry techniques. Our quantum simulations retain good agreement with the full configuration interaction energy in the chosen STO-3G basis, outperforming all benchmarked single-reference wavefunction techniques in capturing the bond-breaking appropriately. Moreover, our methodology is competitive with several multiconfigurational approaches, but at a considerable saving of quantum resource, meaning larger active spaces can be treated for a fixed qubit allowance. To achieve this result we deploy an error mitigation/suppression strategy comprised of dynamical decoupling, measurement-error mitigation and zero-noise extrapolation, in addition to circuit parallelization that not only provides passive averaging of noise but improves the effective shot-yield to reduce the measurement overhead. Furthermore, we introduce a modification to previous adaptive ansatz construction algorithms that incorporates hardware-awareness into our variational circuits to minimize the transpilation cost for the target qubit topology.

22 pages, 12 figures

References in corpus (11)

• Simulated Quantum Computation of Molecular Energies
• Negativity and contextuality are equivalent notions of nonclassicality
• Is there evidence for exponential quantum advantage in quantum chemistry?
• Hartree-Fock Critical Nuclear Charge in Two-Electron Atoms
• Synergetic quantum error mitigation by randomized compiling and zero-noise extrapolation for the variational quantum eigensolver
• A stabilizer framework for Contextual Subspace VQE and the noncontextual projection ansatz
• Benchmarking Noisy Intermediate Scale Quantum Error Mitigation Strategies for Ground State Preparation of the HCl Molecule
• Unitary Partitioning and the Contextual Subspace Variational Quantum Eigensolver
• Stabilization of Discrete Time-Crystaline Response on a Superconducting Quantum Computer by increasing the Interaction Range
• Error mitigation, optimization, and extrapolation on a trapped ion testbed
• SpacePulse: Combining Parameterized Pulses and Contextual Subspace for More Practical VQE

Cited by in corpus (8)

• Quantum-machine-assisted Drug Discovery
• Extending Quantum Computing through Subspace, Embedding and Classical Molecular Dynamics Techniques
• Ladder Operator Block-Encoding
• Accurately Simulating the Time Evolution of an Ising Model with Echo Verified Clifford Data Regression on a Superconducting Quantum Computer
• Assessing Projected Quantum Kernels for the Classification of IoT Data
• Photonic variational quantum eigensolver for NISQ-compatible quantum technology
• Towards Compact Wavefunctions from Quantum-Selected Configuration Interaction
• Noncontextual Pauli Hamiltonians