Inflation in de Sitter spacetime and CMB large scale anomaly

The influence of cosmological constant-type dark energy in the early universe is investigated. This is accommodated by a new dispersion relation in de Sitter spacetime. We perform a global fit to explore the cosmological parameter space by using the CosmoMC package with the recently released Planck TT and WMAP polarization datasets. Using the results from the global fit, we compute a new CMB temperature-temperature （TT） spectrum. The obtained TT spectrum has lower power compared with that based on the ACDM model at large scales.