Variational Quantum Computation of Molecular Linear Response Properties on a Superconducting Quantum Processor

Simulating response properties of molecules is crucial for interpreting experimental spectroscopies and accelerating materials design. However, it remains a longstanding computational challenge for electronic structure methods on classical computers. While quantum computers hold the promise of solving this problem more efficiently in the long run, existing quantum algorithms requiring deep quantum circuits are infeasible for near term noisy quantum processors. Herein, we introduce a pragmatic variational quantum response (VQR) algorithm for response properties, which circumvents the need for deep quantum circuits. Using this algorithm, we report the first simulation of linear response properties of molecules including dynamic polarizabilities and absorption spectra on a superconducting quantum processor. Our results indicate that a large class of important dynamical properties, such as Green's functions, are within the reach of near-term quantum hardware using this algorithm in combination with suitable error mitigation techniques.

Automated summary

Simulating the response properties of molecules is essential for materials design, but it is a challenging task for classical computers. In this study, a practical variational quantum response (VQR) algorithm is introduced to simulate response properties without the need for deep quantum circuits. By using this algorithm on a superconducting quantum processor, the first simulation of linear response properties of molecules, including dynamic polarizabilities and absorption spectra, is reported. The results suggest that near-term quantum hardware can achieve important dynamical properties with suitable error mitigation techniques.