LAUSR

With the steady-state assumption we approximately solve the simplified reaction-diffusion equation together with isothermal boundary conditions via the boundary perturbation approach and obtain the possible negative (dimensionless) temperatures (around the order of magnitude of \(10^{14}\)) for some selection of fine-tuned physical parameters and a fixed geometric parameter (considering a wavy-rough microannuli). Our numerical evidences will be useful to the understanding of two possible scenarios (i) spontaneous symmetry breaking with negative temperature and broken Lorentz symmetry occurs due to higher order curvature corrections similar to the beginning of the universe in a lattice (ii) dark energy in cosmology (in which a negative-pressure state is necessary to explain the accelerating expansion of the universe) as well as the application for a laboratory dark energy analogue.