Dissipative quantum algorithms for excited-state quantum chemistry

TL;DR

This paper introduces a dissipative quantum algorithm that efficiently prepares electronic excited states by transforming the problem into a steady-state of a tailored quantum channel, enhancing quantum simulation capabilities.

Contribution

The authors develop a novel dissipative approach for excited-state preparation, recasting it as a ground-state problem via Lindblad dynamics, with strategies tailored to prior information about the states.

Findings

Successfully simulated atomic and molecular spectra

Demonstrated versatility across different molecular systems

Provided a new pathway for quantum simulation of strongly correlated electrons

Abstract

Electronic excited states are central to a vast array of physical and chemical phenomena, yet accurate and efficient methods for preparing them on quantum devices remain challenging and comparatively underexplored. We introduce a general dissipative algorithm for selectively preparing ab initio electronic excited states. The key idea is to recast excited-state preparation as an effective ground-state problem by suitably modifying the underlying Lindblad dynamics so that the target excited state becomes the unique steady state of a designed quantum channel. We develop three complementary strategies, tailored to different types of prior information about the excited state, such as symmetry and approximate energy. We demonstrate the effectiveness and versatility of these schemes through numerical simulations of atomic and molecular spectra, including valence excitations in prototypical planar conjugated molecules and transition-metal complexes. Taken together, these results provide a new pathway for advancing quantum simulation methods for realistic strongly correlated electronic systems.