  Over the last ten years interest in the physics of de Sitter spacetime has
been growing very fast. Besides the supposed existence of a "de sitterian
period" in inflation theories, the observational evidence of an acceleration of
the universe expansion (interpreted as a positive cosmological constant or a
"dark energy" or some form of "quintessence") has triggered a lot of attention
in the physics community. A specific de sitterian field called "massless
minimally coupled field" (mmc) plays a fundamental role in inflation models and
in the construction of the de sitterian gravitational field. A covariant
quantization of the mmc field, `a la Krein-Gupta-Bleuler was proposed in [1].
In this talk, we will review this construction and explain the relevance of
such a field in the construction of a massless spin 2 field in de Sitter
space-time.
