Hybrid Quantum-Classical Boson Sampling Algorithm for Molecular Vibrationally Resolved Electronic Spectroscopy with Duschinsky Rotation and Anharmonicity

Abstract

Using a photonic quantum computer for boson sampling has demonstrated a tremendous advantage over classical supercomputers. It is highly desirable to develop boson sampling algorithms for realistic scientific problems. In this work, we propose a hybrid quantum-classical sampling (HQCS) algorithm to calculate the optical spectrum for complex molecules considering Duschinsky rotation effects and anharmonicity. The classical sum-over-states method for this problem has a computational complexity that exponentially increases with system size. The HQCS algorithm creates an intermediate harmonic potential energy surface (PES) to bridge the initial and final PESs. The magnitude and sign of the overlap between the initial and the intermediate state are estimated by boson sampling and classical algorithms, respectively. The overlap between the intermediate and the final state is efficiently evaluated by classical algorithms. The feasibility of HQCS is demonstrated in calculations of the emission spectrum of a Morse model as well as the pyridine molecule.

Excited‐State THz Vibrations in Aggregates of PtII Complexes Contribute to the Enhancement of Near‐Infrared Emission Efficiencies**

“…For high‐frequency vibrations, previous experiments show that deuterium substitutions can reduce nonradiative rates of aggregate Pt II complexes by half, revealing that high‐frequency C−H vibrations also contribute to the nonradiative deactivation processes [4d] . For anharmonicity, previous theoretical studies show that anharmonic potential energy surface gives rise to 30–40 % increase of nonradiative rates comparing to the rates under harmonic approximation [21] . As a result, to improve the NIR emission efficiency, suppressing the above two effects on nonradiative rates is also an issue worth for further investigation.…”