The principle of superposition is characteristic in that it is found in many branches of physics. This is some provision that applies in a number of cases. This is one of the general physical laws on which physics, as a science, is built. This is why it is noteworthy for scientists who use it in different situations.
If we consider the principle of superposition in the most general sense, then according to it, the sum of the effects of external forces acting on the particle will be composed of the individual values of each of them.
This principle applies to various linear systems, i.e. such systems whose behavior can be described by linear relationships. An example is a simple situation where a linear wave propagates in a particular medium, in which case its properties will be preserved even under the influence of perturbations arising from the wave itself. These properties are defined as the concrete sum of the effects of each of the harmonious components.
Fields of application
As already mentioned, the principle of superposition has a fairly wide scope. Most clearly, its action can be seen in electrodynamics. However, it is important to remember that when considering the principle of superposition, physics does not consider it a concrete postulate, namely, a consequence of the theory of electrodynamics.
For example, in electrostatics, this principle applies to the study of the electrostatic field. The system of charges at a specific point creates tension, which will be the sum of the field intensities of each charge. This conclusion is used in practice, because it can be used to calculate the potential energy of electrostatic interaction. In this case, it will be necessary to calculate the potential energy of each individual charge.
This is confirmed by the Maxwell equation, which is linear in vacuum. This also implies the fact that light does not scatter, but spreads linearly, so individual rays do not interact with each other. In physics, this phenomenon is often called the principle of superposition in optics.
It is also worth noting that in classical physics the principle of superposition follows from the linearity of the equations of individual moving linear systems, therefore it is approximate. It is based on deep dynamic principles, but proximity makes it neither universal nor fundamental.
In particular, a strong gravitational field is described by other equations, nonlinear, therefore, the principle cannot be applied in these situations. A macroscopic electromagnetic field also does not obey this principle, since it depends on the influence of external fields.
However, the principle of superposition of forces is fundamental in quantum physics. If in other sections it is used with some errors, then it works quite accurately at the quantum level. Any quantum-mechanical system is depicted from wave functions and vectors of linear space, and if it obeys linear functions, then its state is determined by the principle of superposition, i.e. consists of a superposition of each state and wave function.
The boundaries of application are rather arbitrary. The equations of classical electrodynamics are linear, but this is not the basic rule. Most fundamental theories of physics are based on nonlinear equations. This means that in them the principle of superposition will not be fulfilled, here we can include the general theory of relativity, quantum chromodynamics, as well as the Yang-Mills theory.
In some systems where the principles of linearity are only partially applicable, the principle of superposition can be applied conditionally, for example, weak gravitational interactions. In addition, when considering the interaction of atoms and molecules, the principle of superposition is also not preserved, this explains the variety of physical and chemical properties of materials.