According to our current understanding of physics, subatomic particles do not interact with each other instantaneously at a distance. Instead, their interactions are mediated by fields.
In quantum field theory, which is the framework that combines quantum mechanics and special relativity, particles are associated with fields that permeate all of space. These fields are not static entities but are dynamic and can exhibit excitations called particles. When particles interact, they do so by exchanging other particles or quanta, which are manifestations of the underlying fields.
For example, in the electromagnetic interaction, particles such as electrons interact through the exchange of photons, which are the quanta of the electromagnetic field. Similarly, in the weak nuclear interaction responsible for processes like radioactive decay, particles interact through the exchange of W and Z bosons.
These exchanged particles mediate the interaction between the particles involved, carrying the forces or information between them. This concept is known as the "force carrier" or "mediator" particle. The interactions occur through the exchange of these virtual particles, and the probabilities of different interactions are described by mathematical calculations based on quantum field theory.
Experimental observations and measurements strongly support the concept of field-mediated interactions rather than instantaneous action at a distance. For example, the precision and agreement of experimental results in particle physics, along with the successful predictions made by quantum field theory, provide substantial evidence for the existence of fields and their mediating role in particle interactions.