Starting from the equation of motion of the quantum operator of a real scalar field φ in de
Sitter space–time, a simple differential equation is derived which describes the evolution of …

The Euclidean or Bunch-Davies O (4, 1) invariant state for quantum fields in global de Sitter
space is shown to be unstable to small perturbations, even for a massive free field with no …

We show that the one-loop effective action of quantum matter in a de Sitter background
induces spontaneous breaking of the O (4, 1) symmetry group of the classical spacetime …

Spatially homogeneous perturbations of a spatially flat de Sitter metric, which arise from the
fluctuations of a free, massive, minimally coupled scalar quantum field about the Bunch …

The asymptotic behavior of the energy–momentum tensor for a free quantized scalar field
with mass m and curvature coupling ξ in de Sitter space is investigated. It is shown that for …

The graviton propagator in a de Sitter background is found to be divergent. We show that as
a consequence of this divergence, de Sitter space is not a solution of the equations of …

We usea field theoretic generalization of the Wigner-Weisskopf method to study the stability
of the Bunch-Davies vacuum state for a massless, conformally coupled interacting test field …

Various interacting field theories in de Sitter spacetime which contain a massless, minimally
coupled scalar field are investigated. It is shown that the vacuum expectation value of the …

The stability properties of Einstein theory with a cosmological constant Λ are investigated.
For Λ> 0, stability is established for small fluctuations, about the de Sitter background …

As an alternative to existing quantization schemes, the self-adjointness of the classical field
equations is employed as the basic principle for the quantization of a scalar field of arbitrary …