We use finite-temperature strong coupling expansions to calculate thermodynamic properties of the honeycomb-lattice SU(4) Hubbard model. We present numerical results for various properties including chemical potential, compressibility, entropy and specific heat as a function of temperature and density at several $U/t$ values. We study the onset of charge incompressibility and Mott gaps as the temperature is lowered at integer densities. In the incompressible Mott regime, the expansions are recast into a high-temperature expansion for a generalized spin model with SU(4) symmetry, which is then used to study the convergence of strong coupling expansions in $t/U$. We discuss lessons that can be drawn from high-temperature properties of a simple Hubbard model regarding twisted bilayer graphene and other magic-angle flat-band systems.

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• Cold atoms & matter waves
• Cold gases in optical lattices
• Electronic transitions
• Phase diagrams
• Phase transitions
• Specific phase transitions
• Twisted bilayer graphene