  We describe briefly a novel interpretation of the physical nature of dark
energy (DE), based on the vacuum fluctuations model by Gurzadyan & Xue, and
describe an internally consistent solution for the behavor of DE as a function
of redshift. A key choice is the nature of the upper bound used for the
computation of energy density contributions by vacuum modes. We show that use
of the comoving horizon radius produces a viable model, whereas use of the
proper horizon radius is inconsistent with the observations. After introduction
of a single phenomenological parameter, the model is consistent with all of the
curently available data, and fits them as well as the standard cosmological
constant model, while making testable predictions. While some substantial
interpretative uncertainties remain, future developments of this model may lead
to significant new insights into the physical nature of DE.
