Efficient quantum simulation of electron-phonon systems by variational basis state encoder

Li, Weitang; Ren, Jiajun; Huai, Sainan; Cai, Tianqi; Shuai, Zhigang; Zhang, Shengyu

doi:10.1103/physrevresearch.5.023046

Cited by 6 publications

(5 citation statements)

References 43 publications

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“…To demonstrate the superiority of SOAP as a parameter optimizer for real quantum devices, we conducted experiments using a superconducting quantum computer. The superconducting quantum processor is composed of nine transmon qubits, and its details are reported in our previous work . In order to reduce circuit depth, we use a model system of H 8 and employ a (2e, 2o) active space approximation.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Efficient and Robust Parameter Optimization of the Unitary Coupled-Cluster Ansatz

Li,

Ge,

Zhang

et al. 2024

J. Chem. Theory Comput.

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The variational quantum eigensolver (VQE) framework has been instrumental in advancing near-term quantum algorithms. However, parameter optimization remains a significant bottleneck for VQE, requiring a large number of measurements for successful algorithm execution. In this paper, we propose sequential optimization with approximate parabola (SOAP) as an efficient and robust optimizer specifically designed for parameter optimization of the unitary coupled-cluster ansatz on quantum computers. SOAP leverages sequential optimization and approximates the energy landscape as quadratic functions, minimizing the number of energy evaluations required to optimize each parameter. To capture parameter correlations, SOAP incorporates the average direction from previous iterations into the optimization direction set. Numerical benchmark studies on molecular systems demonstrate that SOAP achieves significantly faster convergence and greater robustness to noise compared with traditional optimization methods. Furthermore, numerical simulations of up to 20 qubits reveal that SOAP scales well with the number of parameters in the ansatz. The exceptional performance of SOAP is further validated through experiments on a superconducting quantum computer using a 2-qubit model system.

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Section: Resultsmentioning

confidence: 99%

“…The superconducting quantum processor is composed of nine transmon qubits, and its details are reported in our previous work. 70 In order to reduce circuit depth, we use a model system of H 8 and employ a (2e, 2o) active space approximation. The bond length is set to d = 3.0 Å, which corresponds to the strong correlation regime.…”

Section: Performance Of Soapmentioning

confidence: 99%

Efficient and Robust Parameter Optimization of the Unitary Coupled-Cluster Ansatz

Li,

Ge,

Zhang

et al. 2024

J. Chem. Theory Comput.

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“…We note that an efficient variational encoding scheme requiring only (1) qubits was proposed recently. 70 2.3. Supported Ansaẗze.…”

Section: Electronic Structure Fermionic Creation and Annihilation Ope...mentioning

confidence: 99%

“…TenCirChem supports all of the encoding schemes and, by default, uses binary encoding with Gray codes because of its compact representation. We note that an efficient variational encoding scheme requiring only scriptO ( 1 ) qubits was proposed recently …”

Section: Tencirchem Overview and Theoretical Backgroundsmentioning

confidence: 99%

TenCirChem: An Efficient Quantum Computational Chemistry Package for the NISQ Era

Allcock

Cheng

et al. 2023

J. Chem. Theory Comput.

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TenCirChem is an open-source Python library for simulating variational quantum algorithms for quantum computational chemistry. TenCirChem shows high-performance in the simulation of unitary coupled-cluster circuits, using compact representations of quantum states and excitation operators. Additionally, TenCirChem supports noisy circuit simulation and provides algorithms for variational quantum dynamics. TenCirChem’s capabilities are demonstrated through various examples, such as the calculation of the potential energy curve of H2O with a 6-31G(d) basis set using a 34-qubit quantum circuit, the examination of the impact of quantum gate errors on the variational energy of the H2 molecule, and the exploration of the Marcus inverted region for charge transfer rate based on variational quantum dynamics. Furthermore, TenCirChem is capable of running real quantum hardware experiments, making it a versatile tool for both simulation and experimentation in the field of quantum computational chemistry.

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“…Binary encoding with Gray codes is a variant of the standard binary encoding that involves changing only one bit between consecutive integers, which can be used to facilitate the efficient encoding of operators b † and b. TenCirChem supports all encoding schemes in Table I and by default uses binary encoding with Gray codes because of its compact representation. We note that an efficient variational encoding scheme requiring only O(1) qubits was proposed recently [72].…”

Section: Quantum Dynamicsmentioning

confidence: 99%

TenCirChem: An Efficient Quantum Computational Chemistry Package for the NISQ Era

Li¹,

Allcock²,

Cheng³

et al. 2023

Preprint

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TenCirChem is an open-source Python library for simulating variational quantum algorithms for chemistry, biology, and material science. Its easy-to-use high-level interface enables users to optimize molecular energies or study quantum dynamics in only a few lines of code, while still allowing for a high degree of flexibility and customizability. By making use of compact representations of quantum states and excitation operators, efficient quantum circuits for fermionic excitations, and the powerful TensorCircuit software framework, TenCirChem displays high performance in simulating both noiseless and noisy quantum circuits, even when large numbers of qubits and tunable parameters are involved. As an example, we use it to compute the potential energy surface of H 2 O with 6-31G(d) basis set and (8e, 17o) active space using a quantum circuit ansatz of 34 qubits with 565 independent parameters, and achieve an equilibrium bond length error to 0.01 Å with respect to experiments.

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Efficient quantum simulation of electron-phonon systems by variational basis state encoder

Cited by 6 publications

References 43 publications

Efficient and Robust Parameter Optimization of the Unitary Coupled-Cluster Ansatz

Efficient and Robust Parameter Optimization of the Unitary Coupled-Cluster Ansatz

TenCirChem: An Efficient Quantum Computational Chemistry Package for the NISQ Era

TenCirChem: An Efficient Quantum Computational Chemistry Package for the NISQ Era

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