55417521
Evolution of semilocal string networks: large-scale properties
We report on a detailed numerical study of the evolution of semilocal string networks, based on the largest and most accurate field theory simulations of these objects to date. We focus on the large-scale network properties, confirming earlier indications (coming from smaller simulations) that linear scaling is the attractor solution for the entire parameter space of initial conditions that we are able to probe. We also provide a brief comparison of our numerical results with the predictions of a previously developed one-scale model for the overall evolution of these networks. Two subsequent papers will discuss in more detail the analytic modeling of the semilocal segment populations as well as optimized numerical diagnostics.
118474758
Analytic models for the evolution of semilocal string networks
We revisit previously developed analytic models for defect evolution and adapt them appropriately for the study of semilocal string networks. We thus confirm the expectation (based on numerical simulations) that linear scaling evolution is the attractor solution for a broad range of model parameters. We discuss in detail the evolution of individual semilocal segments, focusing on the phenomenology of segment growth, and also provide a preliminary comparison with existing numerical simulations.
117951510
Parametric resonance with multi‐frequencies in preheating
We present here an extended abstract of the results derived in [1], We study the decay of the inflaton field to another scalar field χ in the parametric resonance preheating mechanism. We consider the presence of several simultaneous couplings between the fields. We show that the contribution for the χ field energy density of the higher harmonic is a small fraction of that of the fundamental frequency, and so the presence of a finite number of higher harmonics has limited cosmological implications
115768541
How general is inflation in the presence of a non-minimal coupling?
Abstract The qualitative analysis of a Robertson-Walker geometry non-minimally coupled to a scalar field is summarized. It is claimed that a divergenceless effective energy-momentum tensor should be used. In this case, the conformal coupling (ξ= 1 6 ) corresponds to the minimum value of the x -coordinate of a singular line in phase space. To analyse the generality of the occurrence of inflation we calculate the measure of the set of the initial conditions of the solutions leading to a final dust state. We conclude that there is inflation for a wide range of values of ξ.
18454632
Scaling solutions from interacting fluids
We examine the dynamical implications of an interaction between some of the fluid components of the universe. We consider the combination of three matter components, one of which is a perfect fluid and the other two are interacting. The interaction term generalizes the cases found in scalar field cosmologies with an exponential potential. We find that attracting scaling solutions are obtained in several regions of parameter space, that oscillating behaviour is possible, and that new curvature scaling solutions exist. We also discuss the inflationary behaviour of the solutions and present some of the constraints on the strength of the coupling, namely those arising from nucleosynthesis.
119519761
SCALAR FIELD PHASE DYNAMICS IN PREHEATING
We study the model of a massive inflaton field $\phi$ coupled to another scalar filed $\chi$ with interaction term $g^2\phi^2\chi^2$ for the first stage of preheating. We obtain the the behavior of the phase in terms of the iteration of a simple family of circle maps. When expansion of the universe is taken into account the qualitative behavior of the phase and growth number evolution is reminiscent of the behavior found in the case without expansion.
118523307
Scaling Behavior in Warm Inflation
We analyze the dynamics of warm inflation models with general viscous effects. We characterize the situations yielding asymptotic scaling behavior.