In quantum field theory, particles are understood as excitations or quanta of the underlying quantum fields. For example, the electron is associated with the electron field, and the atom as a whole can be described in terms of the interactions between various quantum fields, such as the electron field and the electromagnetic field.
The stability of an atom arises from the balance of attractive and repulsive forces between its constituents. In the case of atoms, the electron field interacts with the electromagnetic field, which is responsible for the electromagnetic forces between charged particles.
In quantum mechanics, the behavior of particles and their interactions is described by mathematical equations known as wave functions. The wave function of an atom describes the probability distribution of finding the electrons at different positions around the atomic nucleus. The stability of an atom comes from the fact that certain electron configurations, known as energy levels or orbitals, have lower energy and are more stable than others. Electrons occupy these energy levels in a way that minimizes the overall energy of the system.
The electromagnetic force plays a crucial role in holding the atom together. The negatively charged electrons are attracted to the positively charged atomic nucleus, creating an electric force that keeps them in orbit around the nucleus. The balance between the attractive electric force and the repulsive forces arising from the electromagnetic interactions of the electrons determines the stability and structure of the atom.
It's important to note that the description of atoms and their stability goes beyond the scope of quantum field theory alone. The complete understanding of atomic structure and stability involves the application of quantum mechanics, electromagnetic theory, and other relevant theories such as quantum electrodynamics (QED) to describe the interactions between charged particles and electromagnetic fields.