Modern cosmological models suppose that the very early universe undergoes a period of accelerated expansion, known as inflation. This phase sets the initial conditions for the subsequent evolution of the universe and many of its key predictions have been confirmed since the idea was introduced in the early 1980s.

In most scenarios inflation occurs within 10^-30 seconds of the big bang. Inflation is often followed by a matter dominated phase, in which the pressure is close to zero and the contents of the universe can undergo gravitational collapse. The physics of this era is analogous to galaxy formation in the current epoch but operates at length scales far smaller than present-day atoms.

This period lasts less than a trillion of a second but the universe can grow by a factor of as much as 10¹⁵ during this phase. The pace of gravitational collapse is set by the “doubling time” of the universe so this early phase can be extraordinarily complex. Moreover, nonlinear interactions of the inflaton field itself can lead to additional complex phenomena.

Understanding this era and its consequences – including the formation of primordial black holes and the generation of gravitational waves – is a key area of activity here at Auckland.

[Research content below. For an introduction to inflation and early universe cosmology see e.g. Baumann or Kinney‘s TASI lectures.]