Boson Sampling for Molecular Vibronic Spectra

The first proposal for quantum supremacy—boson sampling—was developed in 2011 by Scott Aaronson and Alex Arkhipov.  The proposal showed that a near term quantum device could outperform a classical computer in a well-defined sampling task. However, such an experiment had no practical use. This paper proposes for the first time a practical application of a sampling algorithm in the context of molecular chemistry, more specifically for the computation of molecular vibronic spectra.


Quantum computers are expected to be more efficient in performing certain computations than any classical machine. Unfortunately, the technological challenges associated with building a full- scale quantum computer have not yet allowed the experimental verification of such an expectation. Recently, boson sampling has emerged as a problem that is suspected to be intractable on any classical computer, but efficiently implementable with a linear quantum optical setup. Therefore, boson sampling may offer an experimentally realizable challenge to the Extended Church-Turing thesis and this remarkable possibility motivated much of the interest around boson sampling, at least in relation to complexity-theoretic questions. In this work, we show that the successful development of a boson sampling apparatus would not only answer such inquiries, but also yield a practical tool for difficult molecular computations. Specifically, we show that a boson sampling device with a modified input state can be used to generate molecular vibronic spectra, including complicated effects such as Duschinsky rotations.