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

Abstract

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.

Toward Chemical Accuracy with Shallow Quantum Circuits: A Clifford-Based Hamiltonian Engineering Approach

“…In this study, all the HEA simulations are performed using the TenCirChem package with inputs computed using the CHEM package (). The molecular integrals and reference energies based on classical computational chemistry are obtained via the PySCF package .…”

“…Code availability: The entire CHEM framework is available on GitHub () with example jupyter notebooks and all the testing results. The example codes to perform HEA simulations are available on TenCirChem () …”

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

“…For the HEA ansatz, we employ LiH and BeH 2 with STO-3G basis, which corresponds to 10 and 12 qubits, respectively, with parity transformation. The numerical simulation of quantum circuits and hardware experiments are conducted via TensorCircuit and TenCirChem . TenCirChem is equipped with an efficient algorithm to simulate UCC circuits that allows a 16-qubit simulation in minutes on a laptop.…”

Editorial: Quantum Computing for Chemistry

“…16 Another paper describes the realization of quantum computers with molecular electronics, 17 and one paper introduces software for emulating quantum algorithms for quantum chemistry. 18 This impressive selection of papers highlights only a small fraction of the cutting-edge research at the interface of theoretical chemistry and quantum computing. Quantum computing has also been applied to solve challenging classical problems that arise in chemistry, such as molecular docking and molecular search in databases.…”

“…Other papers in this Virtual Issue seek to reduce quantum resource requirements using Hamiltonian downfolding − and encoding of operators. − One paper presents an approach to estimating quantum resources needed for practical applications of quantum computation in chemistry . Another paper describes the realization of quantum computers with molecular electronics, and one paper introduces software for emulating quantum algorithms for quantum chemistry . This impressive selection of papers highlights only a small fraction of the cutting-edge research at the interface of theoretical chemistry and quantum computing.…”