Field Theory Vacuum and Entropic Dark Energy Models

We investigate the cosmological implications of a novel definition of field theory vacuum energy. The free field Hamiltonian represented as an ensemble of oscillators (in the Fourier space) usually implies the presence of mass scale for these oscillators, which in quantum field theory is of little importance since quantum energy spectrum of oscillator is mass independent. This mass scale, however, may be interesting due to its possible gravitational implications. Since black hole physics puts an upper limit on the total energy within a given region, one obtains constraint on the number of field oscillators. If the mass scale for field oscillators is set by the IR cutoff, then this number saturates the black hole entropy bound. Following this reasoning, one derives various kinds of dark energy models that maybe interesting for further study.