Gravitons are hypothetical particles that are predicted by certain theories in physics, particularly in the framework of quantum gravity. Gravitons are postulated to be the force-carrying particles associated with the gravitational force, similar to how photons are associated with the electromagnetic force.
However, it is important to note that the existence of gravitons has not been experimentally confirmed yet, and the current understanding of gravity is described by general relativity, which does not incorporate quantum mechanics. The successful unification of general relativity and quantum mechanics into a consistent theory of quantum gravity is still an ongoing area of research and remains a challenge.
As for the state in which gravitons exist, if they were to exist, they would be expected to exist in a quantum state. In quantum field theory, particles are described as excitations of their respective quantum fields. Gravitons would be associated with the gravitational field and would exist as quanta of that field, similar to how photons are quanta of the electromagnetic field.
In quantum field theory, particles are described as both particles and waves, exhibiting both particle-like and wave-like behavior. This duality means that gravitons, if they exist, would not be confined to a particular state in the same sense as, for example, an electron in an atom. Rather, they would exist as quantum superpositions of different possible states until they are observed or interact with other particles.
It is important to emphasize that the nature and properties of gravitons are still highly speculative, and further theoretical and experimental advancements are needed to provide a more definitive understanding of their existence and the nature of quantum gravity.