Abstract: The physical origin of the observed acceleration of the universe has not been well understood. Within the framework of general relativity, dark energy is commonly introduced as being independent of other cosmic components, but such models have certain arbitrariness. In this paper, we consider a low-temperature system for dark energy based on the standard model of particle physics. This system consists of a charged boson condensate, a degenerate fermion gas, and a non-electromagnetic U(1) gauge field that couples both components and is constrained by charge conservation. The charged boson condensate has negative pressure and acts as dark energy, while the degenerate Fermi gas with opposite charge is a secondary component. With this boson-fermion system, we find that the accelerating cosmic expansion occurs for a broad range of model parameters. The dust component decreases with the expansion, the energy density of the boson-fermion component remains nearly constant, and the acceleration occurs at a redshift z ~0.7. Within the reasonable parameter space, this model provides a good explanation for the observational data of type Ia supernova and baryon acoustic oscillations.

Key words: cosmology, dark energy, accelerating expansion, charged boson-fermion system