Theoretical Studies On A Slow-Roll Inflation Model In Standard Cosmology

In recent years,a large number of cosmological observations have been analyzed by researchers all over the world,showing that the universe is in a period of accelerated expansion.The theory of the deceleration expansion universe proposed by traditional Cosmology has been gradually abandoned by scholars all over the world.The inflation theory can well explain the accelerated expansion of the early universe,and provides a good explanation for the three classic problems caused by the standard model: the flatness problem,the horizon problem and the magnetic monopole problem.Besides solving the original classical problems,the Inflation theory also predicts some properties of cosmic microwave background radiation and large-scale structure.The theory of inflation shows that there is a period of rapid expansion before the radiation-dominated period,when the Friedman-Robertson-Walker scale factor a(t)increases exponentially.Exponential inflation smoothed out the initial inhomogeneity and resulted in a nearly isotropic,flat universe.The inflation process also leads to a dramatic reduction in the contribution of magnetic monopoles to the mass density of the universe,which explains the problem that magnetic monopoles can not be observed in particle physics.The inflation model proposed by the inflation theory is generally driven by a scalar field,but only by a scalar field.The contribution of other fields in the process of inflation can be neglected,which is called single scalar field inflation.In this paper we first present a review on the standard cosmology as well as inflation theory.Then we introduces the slow-rolling condition and slow-roll parameters which are frequently used in model analysis.we also and the general treatment on perturbation in the inflation theory.We propose single-field inflationary model that agrees with the PLANCK2015 and WAMP observations.The from the model The feature of this particular model is that it can make the inflation field roll slowly from the potential energy hill to the local minimum of the potential.Moreover,at the very low point of the potential energy,the model no longer satisfies the condition of slow roll,so it terminates naturally.We give a detailed study of the slow rolling parameters of the model,and prove that the slow rolling parameters really meet the requirements of the slow rolling inflation in the inflation stage.Then,using the BINGO program,we give the power spectrum of the scalar perturbation of the model.Using the BINGO program,we calculate the non-Gaussian parameters of the model and compare the results with the cosmological observations of Planck satellite and WMAP working group.It is proved that the new model is indeed supported by cosmological observations.In the fourth chapter of this paper,we will analyze this model in detail.