Optimized Low-Depth Quantum Circuits for Molecular Electronic Structure using a Separable Pair Approximation

Abstract

We present a classically solvable model that leads to optimized low-depth quantum circuits leveraging separable pair approximations. The obtained circuits are well suited as a baseline circuit for emerging quantum hardware and can, in the long term, provide significantly improved initial states for quantum algorithms. The associated wavefunctions can be represented with linear memory requirement which allows classical optimization of the circuits and naturally defines a minimum benchmark for quantum algorithms. In this work, we employ directly determined pair-natural orbitals within a basis-set-free approach. This leads to an accurate representation of the one- and many-body parts for weakly correlated systems and we explicitly illustrate how the model can be integrated into variational and projective quantum algorithms for stronger correlated systems.

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• Synergy Between Quantum Circuits and Tensor Networks: Short-cutting the Race to Practical Quantum Advantage
• Improving the Accuracy of the Variational Quantum Eigensolver for Molecular Systems by the Explicitly-Correlated Perturbative [2]-R12-Correction
• AGP-based unitary coupled cluster theory for quantum computers
• Molecular Quantum Circuit Design: A Graph-Based Approach
• State Preparation Boosters for Early Fault-Tolerant Quantum Computation
• Chemically Aware Unitary Coupled Cluster with ab initio Calculations on System Model H1: A Refrigerant Chemicals Application
• Partitioning Quantum Chemistry Simulations with Clifford Circuits
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• State preparation of AGP on a quantum computer without number projection
• A Quantum Algorithmic Approach to Multiconfigurational Valence Bond Theory: Insights from Interpretable Circuit Design
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