quantumdominated

Quantum dominated refers to a phase in the early universe where quantum fluctuations played a dominant role in shaping the large-scale structure observed today. This period is thought to have occurred shortly after the Big Bang, during or immediately following cosmic inflation. Before this era, the universe was incredibly small and dense, and its evolution was governed by quantum mechanics.

During the quantum dominated phase, tiny quantum fluctuations, which are inherent uncertainties in the measurement of physical quantities at the quantum level, were stretched to macroscopic scales by the rapid expansion of inflation. These fluctuations, present in the quantum vacuum, acted as seeds for future structure formation.

As the universe expanded and cooled, these amplified quantum fluctuations became density variations. Regions with slightly higher density attracted more matter due to gravity, while regions with slightly lower density expanded more rapidly. Over vast stretches of cosmic time, these initial density contrasts grew, eventually leading to the formation of galaxies, clusters of galaxies, and the cosmic web we observe.

The concept of a quantum dominated era is crucial for understanding the origin of cosmic structure without invoking pre-existing classical inhomogeneities. It provides a natural mechanism for seeding the universe with the initial conditions necessary for the evolution of all observed cosmic structures. Evidence supporting this phase comes from the patterns of the cosmic microwave background radiation, which show slight temperature variations that are consistent with the predictions of quantum fluctuations being stretched by inflation.