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LaNiGa$_2$ is superconductor that breaks time-reversal symmetry in the superconducting state without any known nearby magnetism. Recently, single crystals of LaNiGa$_2$ have been synthesized, revealing a nonsymmorphic Cmcm space group. Here, we report measurements of the electronic structure of LaNiGa$_2$ throughout the three-dimensional Brillouin zone (BZ) using angle-resolved photoemission spectroscopy (ARPES). Our findings show broad consistency with density functional theory (DFT) calculations and provide evidence for degeneracies in the electronic structure that are predicted from the space group. The calculations also predict four Fermi surfaces which cross the purported nodal plane and should therefore form two degenerate pairs. We report evidence for those predicted symmetry enforced degeneracies as well as accidental near degeneracies throughout the BZ. These degeneracies and near-degeneracies may play a role in the pairing mechanism of LaNiGa$_2$. Our results provide insight into the interplay between structure, Fermiology, and superconductivity in unconventional superconductors with nonsymmorphic space group., Comment: Main: 8 pages, 6 figures. SI: 6 pages, 8 figures

Integrated photonics has been a promising platform for analog quantum simulation of condensed matter phenomena in strongly correlated systems. To that end, we explore the implementation of all-photonic quantum simulators in coupled cavity arrays with integrated ensembles of spectrally disordered emitters. Our model is reflective of color center ensembles integrated into photonic crystal cavity arrays. Using the Quantum Master Equation and the Effective Hamiltonian approaches, we study energy band formation and wavefunction properties in the open quantum Tavis-Cummings-Hubbard framework. We find conditions for polariton creation and (de)localization under experimentally relevant values of disorder in emitter frequencies, cavity resonance frequencies, and emitter-cavity coupling rates. To quantify these properties, we introduce two metrics, the polaritonic and nodal participation ratios, that characterize the light-matter hybridization and the node delocalization of the wavefunction, respectively. These new metrics combined with the Effective Hamiltonian approach prove to be a powerful toolbox for cavity quantum electrodynamical engineering of solid-state systems.