The concept of gravitons arises when attempting to reconcile general relativity with quantum mechanics, particularly in the context of a theory of quantum gravity. In general relativity, gravity is not described as a force in the traditional sense, but rather as the curvature of spacetime caused by mass and energy. However, when trying to incorporate quantum mechanics into the framework of gravity, the idea of gravitons emerges.
In quantum field theory, particles are described as excitations of their respective fields. For example, photons are the quanta of the electromagnetic field. Similarly, in the context of quantum gravity, gravitons are hypothesized as the quanta of the gravitational field. They would be the carriers of gravitational interactions, analogous to how photons mediate the electromagnetic interactions between charged particles.
Gravitons would be the particles associated with the quantum description of gravitational waves, which are ripples in the fabric of spacetime. Just as photons are considered to be the quanta of electromagnetic waves, gravitons would be the quanta of gravitational waves.
It's important to note that while the concept of gravitons is an intriguing idea, their existence has not been experimentally confirmed, and a complete theory of quantum gravity is still an active area of research. The inclusion of gravitons in the framework of quantum gravity is an attempt to extend our understanding of how gravity may behave at the quantum level, but their precise nature and properties remain speculative until experimental evidence or a more comprehensive theory emerges.