Scientists have simulated the primordial quantum structure of our universe


Look enough in the skies and the Universe begins to look like a city at night. Galaxies take on the characteristics of street lamps that crowd neighborhoods of dark matter, linked by roads of gas that run along the shores of intergalactic nothingness.

This map of the Universe was predetermined, laid out in the slightest chills of quantum physics moments after the Big Bang launched into an expansion of space and time some 13.8 billion years ago.

However, exactly what those fluctuations were, and how they set in motion the physics that would see atoms clumping together in the massive cosmic structures we see today, is still unclear.

A new mathematical analysis of the moments after a period called the inflationary epoch reveals that some kind of structure could have existed even within the boiling quantum furnace that filled the infant universe, and could help us better understand its current distribution.

Astrophysicists at the University of Göttingen in Germany and the University of Auckland in New Zealand used a combination of particle motion simulations and a kind of quantum / gravitational modeling to predict how structures might form in particle condensation after the occurrence. inflation.

The scale of this type of modeling is a bit mind-boggling. We are talking about masses of up to 20 kilograms compressed in a space of just 10-twenty meters wide, at a time when the Universe was only 10-24 seconds old.

“The physical space represented by our simulation would fit into a single proton a million times,” says astrophysicist Jens Niemeyer of the University of Göttingen.

“It is probably the largest simulation of the smallest area of ​​the Universe that has been carried out so far.”

Most of what we know about this early stage in the existence of the Universe is based precisely on this kind of mathematical research. The oldest light that we can still see flickering through the Universe is Cosmic Background Radiation (CMB), and the entire show had already been on the road for some 300,000 years by then.

But within that faint echo of ancient radiation are some clues as to what was happening.

Light from the CMB was emitted as basic particles combined into atoms from the dense, hot soup of energy, in what is known as the age of recombination.

A map of this background radiation across the sky shows that our Universe already had some kind of structure for a few hundred thousand years of age. There were slightly cooler parts and slightly warmer parts that could push matter into areas that would eventually see stars light up, spiral galaxies, and clustered masses in the cosmic city we see today.

This raises a question.

The space that makes up our Universe is expanding, which means that the Universe must once have been much smaller. So it stands to reason that everything we see around us now was once crammed into too confined a volume for such warm and cold patches to emerge.

Like a cup of coffee in an oven, there was no way for any part to cool down before reheating.

The inflationary period was proposed as a way to solve this problem. In a trillionth of a second into the Big Bang, our Universe jumped in size by an incredible amount, essentially freezing any quantum scale variation in place.

Saying this happened in the blink of an eye still wouldn’t do it justice. It would have started around 1036 seconds after the Big Bang, and ended at 1032 seconds. But it was long enough for the space to take on proportions that would prevent small variations in temperature from smoothing out again.

The researchers’ calculations focus on this brief instant after inflation, demonstrating how elementary particles freezing from the quantum-wave foam at that time could have generated brief halos of matter dense enough to crinkle space. -weather.

“The formation of such structures, as well as their movements and interactions, must have generated a background noise of gravitational waves”, says the astrophysicist of the University of Göttingen Benedikt Eggemeier, first author of the study.

“With the help of our simulations, we can calculate the strength of this gravitational wave signal, which could be measured in the future.”

In some cases, the intense masses of such objects could have drawn matter into primordial black holes, objects believed to contribute to the mysterious attraction of dark matter.

The fact that the behavior of these structures mimics the large-scale agglomeration of our Universe today does not necessarily mean that it is directly responsible for the current distribution of stars, gas, and galaxies.

But the complex physics that unfold between those freshly baked particles might still be visible in the sky, amid that wavy landscape of flickering lights and dark voids that we call the Universe.

This research was published in Physical review D.

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