Nonlinear Dynamics of Preheating after Multifield Inflation with Nonminimal Couplings

Nguyen, Rachel; Vis, Jorinde van de; Sfakianakis, Evangelos I.; Giblin, John T.; Kaiser, David

doi:10.1103/physrevlett.123.171301

Cited by 49 publications

(48 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This family of models has been shown to possess strong single-field attractors for large values of ξ I , both during [40] and after inflation [43,44]. Within such an attractor, the fields evolve along a straight trajectory in field-space.…”

Section: A Structure Of the Modelsmentioning

confidence: 99%

“…In this subsection we introduce the equations of motion for the linearized perturbations. Although these equations break down in the later stages of reheating due to strong nonlinear effects [43], they are useful for understanding the initial parametric resonance as well as for setting initial conditions for our lattice simulations. As noted above, in our lattice simulations we neglect perturbations of the spacetime metric.…”

Section: B Fluctuations and Parameter Choicesmentioning

confidence: 99%

“…Yet it is critical to understand the time-scales over which distinct processes during the post-inflation reheating phase unfold, such as the onset of a radiation-dominated equation of state and the emergence of thermal equilibrium at an appropriately high temperature. In this family of models in particular, one must also track the evolution of the single-field attractor [37,[40][41][42] beyond the end of inflation in order to understand whether any post-inflation effects could significantly affect the predictions for primordial observables [43].…”

Section: Introductionmentioning

confidence: 99%

“…We build upon Ref. [43] to identify several distinct nonlinear effects, characteristic of the preheating dynamics, which can unfold on different time-scales. To explore the nonlinear dynamics of this family of models, we focus on several distinct processes and consider how the associated time-scales change as one varies the relevant parameters.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Time scales for nonlinear processes in preheating after multifield inflation with nonminimal couplings

Vis¹,

Nguyen

Sfakianakis

et al. 2020

Phys. Rev. D

Self Cite

View full text Add to dashboard Cite

We have conducted extensive lattice simulations to study the post-inflation dynamics of multifield models involving nonminimal couplings. We explore the parameter dependence of preheating in these models and describe the various timescales that control such nonlinear processes as energy transfer, re-scattering, and the approach to radiation-domination and thermalization. In the limit of large nonminimal couplings (ξ I ∼ 100), we find that efficient transfer of energy from the inflaton condensate to radiative degrees of freedom, emergence of a radiation-dominated equation of state, and the onset of thermalization each consistently occur within N reh 3 e-folds after the end of inflation, largely independent of the values of the other couplings in the models. The exception is the case of negative ellipticity, in which there is a misalignment between the dominant direction in field-space along which the system evolves and the larger of the nonminimal couplings ξ I. In those cases, the field-space-driven parametric resonance is effectively shut off. More generally, the competition between the scalar fields' potential and the field-space manifold structure can yield interesting phenomena such as two-stage resonances. Across many regions of parameter space, we find efficient rescattering between the distinct fields, leading to a partial memory loss of the shape of the initial fluctuation spectrum. Despite the explosive particle production, which can lead to a quick depletion of the background energy density, the nonlinear processes do not induce any super-horizon correlations after the end of inflation in these models, which keeps predictions for CMB observables unaffected by the late-time amplification of isocurvature fluctuations. Hence the excellent agreement between primordial observables and recent observations is preserved for this class of models, even when we consider post-inflation dynamics.

show abstract

Section: A Structure Of the Modelsmentioning

confidence: 99%

Section: B Fluctuations and Parameter Choicesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Time scales for nonlinear processes in preheating after multifield inflation with nonminimal couplings

Vis¹,

Nguyen

Sfakianakis

et al. 2020

Phys. Rev. D

Self Cite

View full text Add to dashboard Cite

show abstract

“…The largest possible excursion occurs for gravitational reheating, but we focus on instant preheating for simplicity, which can occurs quite generically for single-field and multifield models induced by non-minimal couplings, roughly 2-2.5 e-foldings after the end of inflation[66].…”

mentioning

confidence: 99%

Beyond the poles in attractor models of inflation

Karamitsos

2019

J. Cosmol. Astropart. Phys.

View full text Add to dashboard Cite

We offer a geometric interpretation of attractor theories with singular kinetic terms as a union of multiple canonical models. We demonstrate that different domains (separated by poles) can drastically differ in their phenomenology. We illustrate this with the help of a "master model" that leads to distinct predictions depending on which side of the pole the field evolves before examining the more realistic example of α-attractor models. Such models lead to quintessential inflation within the poles when featuring an exponential potential. However, beyond the poles, we discover a novel behaviour: the scalar field responsible for the early-time acceleration of the Universe may reach the boundary of the field-space manifold, indicating that the theory is incomplete and that a boundary condition must be imposed in order to determine its late-time behaviour. If the evolution of the field is arrested before this happens, however, we discover that quintessence can be achieved without a potential offset. Turning to multifield models with singular kinetic terms, we see that poles generalise straightforwardly to singular curves, which act as "model walls" between distinct pole-free inflationary models. As an example, we study a simple two-field α-attractor-inspired model, whose evolution of isocurvature perturbations is sensitive to where the non-canonical field begins its trajectory. We finally discuss initial conditions in attractor theories, where the existence of multiple disconnected canonical models implies that we must make a fundamental choice: in which domain we impose a distribution for the inflaton in order to then determine the likelihood of inflation.

show abstract

On Preheating after Inflation in Scalar‐Tensor Theories of Gravity

Koad

Channuie

2023

Fortschritte der Physik

View full text Add to dashboard Cite

In this work, the preheating mechanism is investigated after inflation in general scalar‐tensor theories of gravity. In the present scenario, two‐field scenario is considered and then derived the potential of exponential and hyperbolic tangent forms. The evolution of the background system is studied when the back reaction on the background field is neglected. The particle production due to parametric resonances in both models is examined. It is found that in Minkowski space the stage of parametric resonances can be described by the Mathieu equation. Finally, parametric resonances in the models are sufficiently broad possible for the exponential growth of the number of particles are demonstrated. The case in which the expansion of space is taken into account is also discussed.

show abstract

Nonlinear Dynamics of Preheating after Multifield Inflation with Nonminimal Couplings

Cited by 49 publications

References 42 publications

Time scales for nonlinear processes in preheating after multifield inflation with nonminimal couplings

Time scales for nonlinear processes in preheating after multifield inflation with nonminimal couplings

Beyond the poles in attractor models of inflation

On Preheating after Inflation in Scalar‐Tensor Theories of Gravity

Contact Info

Product

Resources

About