Abstract
The exact evaluation of the molecular ground state in quantum chemistry requires an exponentially increasing computational cost. Quantum computation is a promising way to overcome the exponential problem using polynomial-time quantum algorithms. A quantum-classical hybrid optimization scheme known as the variational quantum eigensolver is preferred for noisy intermediate-scale quantum devices. However, the circuit depth becomes one of the bottlenecks of its application to large molecules of more than 20 qubits. In this work, we employ point-group symmetry to reduce the number of operators in constructing ansatz so as to achieve a more compact quantum circuit. We illustrate this methodology with a series of molecules ranging from LiH (12 qubits) to (28 qubits). A significant reduction of up to 82% of the operator numbers is reached on . This also sheds light onto further work in this direction to construct even shallower ansatz with enough expressive power and simulate even larger scale systems.
2 More- Received 27 October 2021
- Revised 16 March 2022
- Accepted 7 June 2022
DOI:https://doi.org/10.1103/PhysRevA.105.062452
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