Researchers from the University of Texas at Austin (UT Austin) have proposed a brand new mannequin to clarify the origin of darkish matter. It means that darkish matter originated in the course of the infinitesimally brief span earlier than the Big Bang when the Universe out of the blue expanded to a big extent.
In 1981, physicist Alan Guth proposed the idea of cosmic inflation. It means that in the course of the earliest moments of the universe, it expanded 1026 occasions inside 10-36 seconds. The universe continues to unfold even after the inflation however not at such an unprecedented fee.
Cosmic inflation was an essential occasion as a result of it eradicated all of the irregularities within the construction of the universe. This is why regardless of a lot vastness and steady enlargement, the universe seems uniform and homogenous.
In their new research, the researchers suggest that inflation additionally performed a job within the formation of darkish matter by way of the freeze-in situation.
“The factor that is distinctive to our mannequin is that darkish matter is efficiently produced throughout inflation. In most (different) fashions, something that’s created throughout inflation is then ‘inflated away’ by the exponential enlargement of the universe, to the purpose the place there’s primarily nothing left,” Katherine Freese, lead researcher and professor of physics at UT Austin, stated.
Did darkish matter freeze out or freeze in?
According to the research authors, darkish matter possible originated from the thermal bathtub throughout heat inflation. Thermal bathtub refers back to the particles (like radiation and matter) that work together with one another whereas sustaining a sure temperature in the course of the formation of the universe.
This thermal vitality was sustained by the inflaton subject (the sphere driving inflation) by way of its interactions, making certain a heat atmosphere throughout inflation (that is why known as heat inflation). However, there are two completely different potentialities for the delivery of darkish matter from the thermal bathtub.
For occasion, it’s doable that within the early universe, darkish matter particles have been in thermal equilibrium with common matter. As the universe expanded and cooled, these particles froze out—-meaning they stopped interacting with common matter, and their density grew to become mounted. This known as the freeze-out situation.
The researchers dominated out this chance as a result of, in a dynamic atmosphere surrounded by intense occasions corresponding to inflation and the Big Bang, thermal equilibrium would possible have been disrupted. This makes it unlikely that darkish matter particles remained in equilibrium lengthy sufficient for freeze-out to happen.
Another chance referred to as the freeze-in, implies that darkish matter particles have been by no means in thermal equilibrium. Instead, they have been produced on account of uncommon high-energy interactions like these involving UV radiation within the early universe.
The researchers recommend that in heat inflation, the quantum subject that triggered the inflation misplaced a piece of its vitality to UV radiation, and this interplay brought on the manufacturing of darkish matter particles that ultimately “froze in” because the universe cooled.
“We demonstrated that in a heat inflation setting the persistent thermal bathtub can supply a large darkish matter abundance through the nonrenormalizable interplay attribute of UV freeze-in,” the research authors notice.
But it was all pre-Big Bang
You might haven’t seen however there’s a twist within the model of freeze-in that the UT Austin workforce proposed.
While many scientists consider inflation and freeze-in occurred after the Big Bang, in accordance with the proposed heat inflation through ultraviolet freeze-in (WIFI) mannequin —- darkish matter manufacturing occurred earlier than the Big Bang within the brief time when the universe exponentially expanded on account of cosmic inflation.
This new perspective on cosmic inflation may affect many present theories that specify the origin of our universe.
Moreover, “WIFI suggests a broader applicability such because the manufacturing of different particles that would play an important function within the early universe’s evolution. This highlights new alternatives for exploration in future analysis,” Barmak Shams, one of many research authors, stated.
However, the present findings nonetheless symbolize a idea. The research authors are required to validate their WIFI mannequin by way of observations which may take a few years.
The research is revealed within the journal Physical Review Letters.
