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Projective Measurement-Based Quantum Phase Difference Estimation Algorithm for the Direct Computation of Eigenenergy
Kenji Sugisaki1,2,3
1Graduate School of Science and Technology, Keio University, 7-1 Shinkawasaki, Saiwai-ku, Kawasaki, Kanagawa 212-0032, Japan.
Journal of Chemical Theory and Computation
|October 24, 2023
Summary
This study introduces an improved quantum phase difference estimation (QPDE) algorithm using inverse quantum Fourier transformation. This method enhances accuracy for calculating electronic energy differences, crucial for quantum chemistry simulations.
Area of Science:
- Quantum computing
- Computational chemistry
- Quantum algorithms
Background:
- Quantum computers can calculate electronic energy differences via the quantum phase difference estimation (QPDE) algorithm.
- Previous Bayesian inference-based QPDE methods showed dependency on input wave function quality.
Purpose of the Study:
- To develop an improved QPDE algorithm for accurate eigenenergy difference computation.
- To overcome the limitations of existing Bayesian inference-based QPDE approaches.
Main Methods:
- Implementation of an inverse quantum Fourier transformation-based QPDE algorithm.
- Utilizing ancillary qubits (Na) for enhanced computation.
- Employing single-shot projective measurement for eigenenergy difference determination.
Main Results:
- Successful computation of singlet-triplet energy difference for the hydrogen molecule.
- Accurate calculation of vertical excitation energies for halogen-substituted methylenes (CHF, CHCl, CF2, CFCl, CCl2) and formaldehyde (HCHO).
Conclusions:
- The inverse quantum Fourier transformation-based QPDE offers a robust method for calculating electronic energy differences.
- This approach provides accurate results independent of input wave function quality, demonstrated through various molecular systems.
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