Improved algorithms of quantum imaginary time evolution for ground and excited states of molecular systems
arXiv:2205.01983 · doi:10.1021/acs.jctc.2c00906
Abstract
Quantum imaginary time evolution (QITE) is a recently proposed quantum-classical hybrid algorithm that is guaranteed to reach the lowest state of system. In this study, we present several improvements on QITE, mainly focusing on molecular applications. We analyze the derivation of the underlying QITE equation order-by-order, and suggest a modification that is theoretically well founded. Our results clearly indicate the soundness of the here-derived equation, enabling a better approximation of the imaginary time propagation by a unitary. We also discuss how to accurately estimate the norm of an imaginary-time-evolved state, and applied it to excited state calculations using the quantum Lanczos algorithm. Finally, we propose the folded-spectrum QITE scheme as a straightforward extension of QITE for general excited state simulations. The effectiveness of all these developments is illustrated by noiseless simulations, offering the further insights into quantum algorithms for imaginary time evolution.
10 pages, 5 figures, 1 table
References in corpus (14)
- Qulacs: a fast and versatile quantum circuit simulator for research purpose
- Hardware-efficient variational quantum algorithms for time evolution
- Filtering variational quantum algorithms for combinatorial optimization
- Quantum Computation of Finite-Temperature Static and Dynamical Properties of Spin Systems Using Quantum Imaginary Time Evolution
- Simultaneous Perturbation Stochastic Approximation of the Quantum Fisher Information
- Adaptive Variational Quantum Imaginary Time Evolution Approach for Ground State Preparation
- Efficient step-merged quantum imaginary time evolution algorithm for quantum chemistry
- Adaptive variational quantum eigensolvers for highly excited states
- Variational Quantum Simulation for Periodic Materials
- Benchmarking adaptive variational quantum eigensolvers
- A Quantum Algorithm to Calculate Band Structure at the EOM Level of Theory
- Scattering in the Ising Model Using Quantum Lanczos Algorithm
- Quantum computation of silicon electronic band structure
- Adaptive construction of shallower quantum circuits with quantum spin projection for fermionic systems
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- Cheaper and more noise-resilient quantum state preparation using eigenvector continuation
- Adaptive time Compressed QITE (ACQ) and its geometrical interpretation
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- Hybrid Quantum-Classical Clustering for Preparing a Prior Distribution of Eigenspectrum