Sarunas Verner

In the first moments, the universe expanded at an unimaginable rate — a phase called inflation. It is thought that particles of dark matter, the invisible substance that holds galaxies together, could have been born from the vacuum during this time. But what determines exactly how many are produced? The authors considered a model with two fields.

In the first fractions of a second after the Big Bang, the Universe underwent inflation — a monstrously rapid expansion that smoothed out all irregularities. But amid this cosmic smoothness, one "wrong" note could have been hidden: quantum fluctuations of the axion field.