Quantum-inspired classical algorithm for molecular vibronic spectra

We have recently seen the first plausible claims for quantum advantage using Gaussian boson sampling. The obvious next step is to channel the potential quantum advantage to solve practical problems rather than conducting proof-of-principle experiments. An interesting proposal of using a boson sampler is to generate molecular vibronic spectra, which is essentially an estimation of the sum of output probabilities of a boson sampler and is an important problem in chemistry. Also, it has been thought to be difficult for a classical computer to efficiently solve. In this talk, we provide a quantum-inspired classical algorithm to solve the problem as accurately as running a boson sampling. In particular, the classical algorithm enables us to achieve the same accuracy efficiently for the case of Fock-state boson sampling and Gaussian boson sampling. Finally, we provide a different type of molecular vibronic spectra problem for which we might be able to take advantage of boson sampling to solve a classically hard problem, which is also chemically well-motivated. The details can be found in Ref. [1]

[1] Changhun Oh, Youngrong Lim, Yat Wong, Bill Fefferman, Liang Jiang, arXiv:2202.01861 (2022)