  Inspired by the unique nonclassical character of two-photon interactions
induced by entangled photons, we develop a new comprehensive F\"orster-type
formulation for entangled two-photon resonance energy transfer (E2P-RET)
mediated by inhomogeneous, dispersive and absorptive media with any
space-dependent and frequency-dependent dielectric function and with any size
of donor/acceptor. In our theoretical framework, two uncoupled particles are
jointly excited by the temporally entangled field associated with two virtual
photons that are produced by three-level radiative cascade decay in a donor
particle. The temporal entanglement leads to frequency anticorrelation in the
virtual photon's field, and vanishing of one of the time-ordered excitation
pathways. The underlying mechanism leads to more than three orders of magnitude
enhancement in the E2P-RET rate compared with the uncorrelated photon case.
With the power of our new formulation, we propose a way to characterize E2P-RET
through an effective rate coefficient $K_{E2P}$, introduced here. This
coefficient shows how energy transfer can be enhanced or suppressed depending
on rate parameters in the radiative cascade, and by varying the donor-acceptor
frequency differences.
