In case darkish matter did not appear mysterious sufficient, a new research proposes that it may have arisen earlier than the Large Bang.
Standard considering goes that the Large Bang was the start of the whole lot – matter, darkish matter, area, vitality, all of it. After the occasion itself, the Universe went by a interval of cosmic inflation, which noticed its measurement swell by an element of 10 septillion inside an unfathomable fraction of a second.
However some theories counsel that this inflation interval truly occurred earlier than what we name the Large Bang. And now, physicists on the College of Texas (UT) at Austin have proposed that darkish matter was shaped throughout this temporary window.
The staff calls the brand new mannequin heat inflation through freeze-in, or WIFI. Principally, darkish matter particles can be created from tiny interactions between radiation and particles in a heat ‘thermal tub’ through the inflation interval.
“The thing that’s unique to our model is that dark matter is successfully produced during inflation,” says Katherine Freese, a theoretical astrophysicist at UT Austin.
“In most models, anything that is created during inflation is then ‘inflated away’ by the exponential expansion of the Universe, to the point where there is essentially nothing left.”
It is thought that previous to the Large Bang, the whole thing of the Universe existed in a singularity, some extent of infinite density the place spacetime is infinitely curved. However the identified legal guidelines of physics fully break down there, so some physicists suggest {that a} completely different epoch preceded the Large Bang, as a substitute of a singularity.
This could possibly be the collapse of an earlier universe, as within the Large Bounce mannequin – or it could possibly be cosmic inflation. This section lasted simply nonillionths of a second, and the vitality transferred to matter and light-weight to change into what we confer with because the Large Bang.
From there, the stage is about for the Universe to evolve as described by common relativity.
The authors of the brand new research aren’t the primary to counsel that cosmic inflation predated the Large Bang. They don’t seem to be even the primary to counsel that darkish matter arose throughout this epoch. What’s new is their mechanism for a way the unusual stuff is produced, in portions that align with astronomical observations.
Heat inflation (the ‘WI’ within the new WIFI mannequin) is an current concept that implies that radiation is produced whereas the exponential enlargement is happening. This creates a type of thermal tub, permitting for tiny however necessary interactions to happen.
The motive force of cosmic inflation remains to be unknown, however the stand-in is a discipline of hypothetical particles referred to as inflatons, just like the well-known Higgs boson. Within the heat inflation situation, this inflaton discipline would lose a few of its vitality to radiation within the thermal tub.
From there, the radiation produces darkish matter particles by a course of referred to as UV freeze-in (there’s the ‘FI’ in WIFI). Primarily, the darkish matter by no means reaches equilibrium with the bathtub, and the temperature of that tub stays beneath a sure threshold.
In keeping with the staff’s calculations, this mechanism produces sufficient darkish matter to account for the quantity that astronomical observations inform us is on the market.
This does not imply the thriller is solved, after all. It is only one speculation of many, together with that darkish matter arose in its personal ‘Darkish Large Bang‘ in a while.
For now, the WIFI mannequin cannot be instantly verified, however a minimum of a part of it could possibly be quickly. Upcoming research of the cosmic microwave background, corresponding to CMB-S4, may put the concept of heat inflation to the check.
“If future observations confirm that warm inflation is the correct paradigm, it would significantly strengthen the case for dark matter being produced as described in our framework,” says UT physicist Gabriele Montefalcone, co-author of the research.
The analysis was printed within the journal Bodily Overview Letters.
