# Sergei Winitzki

# Quantum field theory in inflationary cosmology

** Abstract: **

I review some of the important applications that quantum field theory in curved spacetime (QFTCS) has had in theoretical cosmology. I give a broad overview of today's cosmological knowledge, in terms of observations and theory. The major application of QFTCS is in predicting the spectrum of density fluctuations resulting from an era of cosmological inflation. The predictions of theory are in good agreement with observations. However, a detailed description of the decoherence of quantum fluctuations into classical perturbations is still missing. Other applications of QFTCS in cosmology include the theory of eternal inflation, the use of scalar fields with effective Lagrangians derived from supergravity, and an attempt to explain dark energy as a Casimir-like effect due to vacuum polarization.