a) State the problems of the Hot Big Bang model in cosmology, and briefly explain how infla tion solves these problems. b) The Klein-Gordon equation at background level for a scalar field is given by 4 +3H + V' = 0, where H is the Hubble parameter, V the potential of the scalar field, and V' = dv/dy. Assume a flat Friedmann-Robertson-Walker universe, dominated by the scalar field.

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a) State the problems of the Hot Big Bang model in cosmology, and briefly explain how infla-
tion solves these problems.
b) The Klein-Gordon equation at background level for a scalar field is given by
+3H +V' = 0,
where H is the Hubble parameter, V the potential of the scalar field, and V' = dV/dp.
Assume a flat Friedmann-Robertson-Walker universe, dominated by the scalar field.
i) State the conditions for slow-roll inflation. Write down the Friedmann equation and the
Klein-Gordon equation valid for slow-roll inflation.
ii) For a scalar field potential V = m²p2, where m is the mass of the field, calculate the
time evolution of the field in the case of slow-roll inflation.
c) The inflationary slow-roll parameters (p) and n(y) are given by
2
1
<(x) = 2/₁² (2) ².
€
a²
* ( ).
V
n(x) =
where a is a constant.
i) Calculate (4) and n(y) for the scalar field potential V= / m² p².
ii) Inflation ends when €(p) = 1. Calculate the value of the field at the end of inflation.
Transcribed Image Text:a) State the problems of the Hot Big Bang model in cosmology, and briefly explain how infla- tion solves these problems. b) The Klein-Gordon equation at background level for a scalar field is given by +3H +V' = 0, where H is the Hubble parameter, V the potential of the scalar field, and V' = dV/dp. Assume a flat Friedmann-Robertson-Walker universe, dominated by the scalar field. i) State the conditions for slow-roll inflation. Write down the Friedmann equation and the Klein-Gordon equation valid for slow-roll inflation. ii) For a scalar field potential V = m²p2, where m is the mass of the field, calculate the time evolution of the field in the case of slow-roll inflation. c) The inflationary slow-roll parameters (p) and n(y) are given by 2 1 <(x) = 2/₁² (2) ². € a² * ( ). V n(x) = where a is a constant. i) Calculate (4) and n(y) for the scalar field potential V= / m² p². ii) Inflation ends when €(p) = 1. Calculate the value of the field at the end of inflation.
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