De Marco, JeannetteTolle, LuisaHalati, Catalin-MihaiSheikhan, AmenehLäuchli Herzig, M.Kollath, Corinna2022-09-292022-09-292022-09-292022-08-1110.1103/PhysRevResearch.4.033119https://infoscience.epfl.ch/handle/20.500.14299/191119In this paper we analyze the spectral level statistics of the one-dimensional ionic Hubbard model, the Hubbard model with an alternating on-site potential. In particular, we focus on the statistics of the gap ratios between consecutive energy levels. This quantity is often used in order to signal whether a many-body system is integrable or chaotic. A chaotic system has typically the statistics of a Gaussian ensemble of random matrices while the spectral properties of the integrable system follow a Poisson statistics. We find that whereas the Hubbard model without alternating potential is known to be integrable and its spectral properties follow a Poissonian statistics, the presence of an alternating potential causes a drastic change in the spectral properties, which resemble the one of a Gaussian ensemble of random matrices. However, to uncover this behavior one has to separately consider the blocks of all symmetries of the ionic Hubbard model.text::journal::journal article::research article