Particle PhysicsParticle Physicsand Cosmologyand Cosmology

InflationInflation

Friedman Universe :Friedman Universe :horizon grows with timehorizon grows with time

flatness problemflatness problem

ΩΩ=1 : unstable fixed =1 : unstable fixed pointpoint

inflationary kinematicsinflationary kinematics

exponential inflationexponential inflation

end of inflationend of inflation

when when νν gets < 1 gets < 1

e - foldingse - foldings

inflationary cosmologyinflationary cosmologywith scalar fieldwith scalar field

energy density and energy density and pressurepressure

crucial ingredient : shape of scalar potential Vcrucial ingredient : shape of scalar potential V

field equationsfield equations

flat region in potentialflat region in potential

change of scalar change of scalar is small effect ,is small effect ,V,H essentially constantV,H essentially constant

slow roll parametersslow roll parameters

single field inflation single field inflation

ifif

slow roll approximationslow roll approximation

slow roll approximationslow roll approximation

νν ≈≈ - - εε

chaotic inflationchaotic inflation

slow roll conditionslow roll condition

scales of fluctuationsscales of fluctuations

first out last infirst out last in

e - foldingse - foldings