Physicists continue to wrestle with the mystery of dark matter, the elusive substance that makes up about 80% of the matter in the universe but is impossible to detect. Now, a team of researchers has proposed an innovative model that suggests dark matter may have emerged before the Big Bang, during the inflationary phase when the universe underwent rapid exponential expansion.

The role of inflation and the formation of dark matter

Inflation, a concept developed about 45 years ago, describes a brief period in the early universe when its size increased approximately 10 times.²⁶ Once every 10-36 seconds. This rapid expansion, theorized to have occurred before the orderly Big Bang, provides an explanation for many cosmological mysteries, including the flatness and uniformity of the universe and the origin of its structure.

Despite widespread acceptance among cosmologists, the mechanism driving inflation remains unknown. This is attributed to a hypothetical field called the inflaton, which spans all space-time. During inflation, the universe exists in a supercooled state of expansion where the temperature drops significantly. When inflation ends, a process called reheating occurs, which returns the temperature of the universe to its pre-inflation temperature and initiates the production of standard particles, including photons.

Traditional theories about the formation of dark matter

Current theories suggest that dark matter arises due to the interaction of particles with a heat bath, and its amount is determined by the “freezing” or “freezing” mechanism. In the freezing model, dark matter remains in equilibrium with the thermal bath in the earliest moments, whereas in the freezing model dark matter never reaches equilibrium due to suppressed interactions.

For example, in ultraviolet (UV) freezing the temperature of the thermal bath is always lower than the mass of the particles, which connects dark matter to the Standard Model of particle physics. This scenario is based on the interaction of quantum fields when dark matter is formed under certain energy conditions.

A new mechanism: Dark matter during inflation

A new model called WIFI (Hot Blow by ultraviolet Freezing) offers an alternative perspective. It suggests that dark matter was created in the inflationary phase through rare interactions in a hot energetic environment. Unlike traditional models, which assume that everything formed during inflation was diluted by the rapid expansion of the universe, the WIFI model suggests that dark matter formed during this period could survive and explains the dark matter seen today.

“What is unique about our model is that dark matter is successfully produced during inflation,” said lead author Kathryn Freese, director of the Weinberg Institute for Theoretical Physics at the University of Texas at Austin. “In most other models, everything created during inflation is ‘inflated’ by the exponential expansion of the universe to the point where essentially nothing is left.”

In this scenario, the inflationary field that causes inflation loses some of its energy to radiation, which then forms dark matter particles through the freezing mechanism.

Beyond the Big Bang Singularity

This model is consistent with the idea that inflation arose before the Big Bang and challenges the concept of a singularity with infinite density and curvature. Instead, the universe is thought to have a small but finite size after inflation, around 10-26 meters in diameter. From there, the standard processes of radiation and particle production began, leading to the universe as we know it.

Future Validation and Impacts

The WIFI model has not yet been confirmed by observations, but it could be tested in the next decade with experiments examining the cosmic microwave background (CMB). Hot inflation, an important component of the WIFI model, will be the focus of these studies. If hot inflation is confirmed, the model’s reliability will increase and open avenues for understanding other particles and processes in the early universe.

“We focused on the production of dark matter in our study, but WIFI suggests broader applications, such as the production of other particles that could play an important role in the evolution of the early universe,” said co-author Barmak Shams Es Haghi. . “This opens new avenues for discovery in future studies.”

A new chapter in dark matter research

Although the origin of dark matter remains a mystery, the WIFI model offers a fascinating framework that links its formation to one of the earliest and most dramatic phases of the universe. By exploring this unusual pathway, researchers hope to discover not only the nature of dark matter but also a new understanding of the origin and evolution of the universe.