Cosmic inflation and dark energy from the electroweak phase transition

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Konstantinos Dimopoulos (University of Lancaster)

21 November 2018

Cosmic inflation is a period of accelerated expansion in the early universe. Inflation is the most compelling proposal for the formation of of the observed structures in the universe like galaxies and galactic clusters. It also makes the universe uniform and spatially flat in agreement with observations.

To drive inflation an exotic substance is needed, with pressure negative enough to cause the expansion of the universe to accelerate, when this substance is dominant. Observations suggest that the late universe is also undergoing accelerated expansion, which is assumed to be due to another exotic substance called dark energy. Can this be the one and the same with the substance behind inflation?

In this talk I present a novel idea, in which inflation leaves behind a minute potential density, which can become the dark energy observed today. The field responsible for inflation (scalaron), is trapped in a local minimum of its scalar potential until the electroweak phase transition.

The transition releases the field and allows it to vary slowly down a shallow potential tail, becoming dark energy. This behaviour is facilitated by a suitable coupling between the scalaron field and the electroweak Higgs field. The model is successful without fine-tuning, because it makes use of the curious fact that the electroweak energy scale is roughly the geometric mean of the Planck scale and the dark energy scale.