Quantum field theory is a theoretical framework in physics that combines the principles of quantum mechanics and special relativity to describe the behavior of particles on a subatomic level. It postulates that all particles are excitations of underlying quantum fields and interactions between particles are mediated by the exchange of virtual particles.
Quantum field theory is used in cosmology to study the behavior of matter and energy in the early universe. It helps explain the formation of large-scale structures, such as galaxies and clusters of galaxies, and the evolution of the universe as a whole.
The Higgs field is an important component of the Standard Model of particle physics, which is a quantum field theory. It is responsible for giving mass to elementary particles, such as quarks and electrons, and is thought to have played a crucial role in the early universe, leading to the formation of the Higgs boson and other particles.
Quantum field theory alone is not sufficient to explain the origin of the universe. However, it is a key component in many theories of the early universe, such as inflationary cosmology, which attempt to explain the rapid expansion of the universe in its first moments.
There are many unanswered questions in quantum field theory and cosmology, such as the nature of dark matter and dark energy, the origin of the universe's large-scale structure, and the unification of quantum mechanics and general relativity. Additionally, there are ongoing efforts to reconcile the seemingly incompatible theories of quantum field theory and gravity.