Simulating Energy Transfer in Molecular Systems with Digital Quantum Computers

Lee, Chee‐Kong; Lau, Jonathan Wei Zhong; Shi, Liang; Kwek, Leong Chuan

doi:10.48550/arxiv.2101.06879

Cited by 5 publications

(6 citation statements)

References 48 publications

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“…The solver can be combined with adaptive strategies to reduce the complexity of the Ansatz circuit (Yao et al, 2020c;Zhang et al, 2020c). VQS has been applied on the IBM quantum processor to simulate energy transfer in molecules (Lee et al, 2021) as well as to simulate a time-dependent Hamiltonian (Lau et al, 2021). A straightforward extension of the variational quantum simulator can be applied to solve the Schrödinger equation in imaginary time (McArdle et al, 2019a), for time-dependent problems (Yuan et al, 2019) or for general linear differential equations (Endo et al, 2020c;Kubo et al, 2020).…”

Section: Variational Quantum Simulatormentioning

confidence: 99%

Noisy intermediate-scale quantum algorithms

et al. 2022

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Section: Variational Quantum Simulatormentioning

confidence: 99%

Noisy intermediate-scale quantum algorithms

et al. 2022

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“…While we only consider systems in Cartesian coordinates in this work, the DVR framework is also applicable in polar and radial coordinates, useful for systems with rotational degree of freedom. Measurement cost is a major concern for many VQAs, particularly for quantum dynamics simulations [44][45][46][47]. Indeed we show that direct application of the real-time VQA would require a large number of circuit evaluations for two reasons: (1) a very small time step is needed in solving the differential equation in Eq.…”

Section: Discussionmentioning

confidence: 99%

Variational Quantum Simulation of Chemical Dynamics with Quantum Computers

Lee¹,

Hsieh²,

Zhang³

et al. 2021

Preprint

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Classical simulation of real-space quantum dynamics is challenging due to the exponential scaling of computational cost with system dimensions. Quantum computer offers the potential to simulate quantum dynamics with polynomial complexity; however, existing quantum algorithms based on the split-operator techniques require large-scale fault-tolerant quantum computers that remain elusive in the near future. Here we present variational simulations of real-space quantum dynamics suitable for implementation in Noisy Intermediate-Scale Quantum (NISQ) devices. The Hamiltonian is first encoded onto qubits using a discrete variable representation (DVR) and binary encoding scheme. We show that direct application of real-time variational quantum algorithm based on the McLachlan's principle is inefficient as the measurement cost grows exponentially with the qubit number for general potential energy and extremely small time-step size is required to achieve accurate results. Motivated by the insights that most chemical dynamics occur in the low energy subspace, we propose a subspace expansion method by projecting the total Hamiltonian, including the time-dependent driving field, onto the system low-energy eigenstate subspace using quantum computers, the exact quantum dynamics within the subspace can then be solved classically. We show that the measurement cost of the subspace approach grows polynomially with dimensionality for general potential energy. Our numerical examples demonstrate the capability of our approach, even under intense laser fields. Our work opens the possibility of simulating chemical dynamics with NISQ hardware.

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“…[30,31] It has recently been experimentally demonstrated in superconducting quantum devices to simulate adiabatic quantum computing [32] and energy transfer. [33] We demonstrate the feasibility of quantum computer in simulating condensed-phase spectroscopy by studying the UV-Vis absorption spectrum of bi-thiophene (T2), a widely used organic semiconducting molecules. The setup of the workflow in this paper is depicted in Fig.…”

Section: Previous Work On Quantum Simulations Of Spectroscopy Include...mentioning

confidence: 99%

Simulation of Condensed-Phase Spectroscopy with Near-term Digital Quantum Computer

Lee,

Hsieh,

Zhang

et al. 2021

Preprint

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Spectroscopy is an indispensable tool in understanding the structures and dynamics of molecular systems. However computational modelling of spectroscopy is challenging due to the exponential scaling of computational complexity with system sizes unless drastic approximations are made.Quantum computer could potentially overcome these classically intractable computational tasks, but existing approaches using quantum computers to simulate spectroscopy can only handle isolated and static molecules. In this work we develop a workflow that combines multi-scale modeling and time-dependent variational quantum algorithm to compute the linear spectroscopy of systems interacting with their condensed-phase environment via the relevant time correlation function.We demonstrate the feasibility of our approach by numerically simulating the UV-Vis absorption spectra of organic semiconductors. We show that our dynamical approach captures several spectral features that are otherwise overlooked by static methods. Our method can be directly used for other linear condensed-phase spectroscopy and could potentially be extended to nonlinear multidimensional spectroscopy.

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Simulating Energy Transfer in Molecular Systems with Digital Quantum Computers

Cited by 5 publications

References 48 publications

Noisy intermediate-scale quantum algorithms

Noisy intermediate-scale quantum algorithms

Variational Quantum Simulation of Chemical Dynamics with Quantum Computers

Simulation of Condensed-Phase Spectroscopy with Near-term Digital Quantum Computer

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