  Tho-photon Rabi oscillations hold potential for quantum computing and quantum
information processing, because during a Rabi cycle a pair of entangled photons
may be created. We theoretically investigate the onset of this phenomenon in a
heterodimer comprising a semiconductor quantum dot strongly coupled to a metal
nanoparticle. Two-photon Rabi oscillations in this system occur due to a
coherent two-photon process involving the ground-to-biexciton transition in the
quantum dot. The presence of a metal nanoparticle nearby the quantum dot
results in a self-action of the quantum dot via the metal nanoparticle, because
the polatization state of the latter depends on the quantum state of the
former. The interparticle interaction gives rise to two principal effects: (i)
- enhancement of the external field amplitude and (ii) - renormalization of the
quantum dot's resonance frequencies and relaxation rates of the off-diagonal
density matrix elements, both depending on the populations of the quantum dot's
levels. Here, we focus on the first effect, which results in interesting new
features, in particular, in an increased number of Rabi cycles per pulse as
compared to an isolated quantum dot and subsequent growth of the number of
entangled photon pairs per pulse. We also discuss the destructive role of
radiative decay of the excitonic states on two-photon Rabi oscillations for
both an isolated quantum dot and a heterodimer.
