Hybrid quantum-classical algorithm for computing imaginary-time correlation functions

Quantitative descriptions of strongly correlated materials pose a considerable challenge in condensed matter physics and chemistry. A promising approach to address this problem is quantum embedding methods. In particular, the dynamical mean-field theory (DMFT) maps original system an effective impurity model comprising orbitals embedded electron bath. The biggest bottleneck DMFT calculations numerically solving model, i.e., computing Green's function. Past studies have proposed theoretical methods compute function polynomial time using computer. So far, however, efficient for imaginary-time functions not been established despite advantages formulation. We propose quantum-classical hybrid algorithm on devices with limited hardware resources by applying variational simulation. Using circuit simulator, we verified dimer as well four-site obtained single-band Hubbard although our method can be applied general correlation functions.