The nature of gravitational waves and their relationship to gravitons is a topic of ongoing research and debate in the field of theoretical physics. Gravitational waves are ripples in the fabric of spacetime that propagate outward from sources with accelerating masses, such as merging black holes or neutron stars. They were predicted by Albert Einstein's theory of general relativity and were directly detected for the first time in 2015.
In the framework of general relativity, gravitational waves are described as disturbances in the curvature of spacetime. They do not require a particle-based interpretation like electromagnetic waves, which are composed of photons. Gravitational waves can be thought of as a propagating wave-like distortion of the geometry of spacetime itself.
Gravitons, on the other hand, are hypothetical particles that are postulated in the framework of quantum gravity. Gravitons are the quanta, or discrete packets, of gravitational fields in a hypothetical quantum theory of gravity. Just as photons are the quanta of the electromagnetic field in quantum electrodynamics, gravitons would be the elementary particles associated with gravitational interactions in a fully developed theory of quantum gravity.
While the existence of gravitons is predicted in some theories of quantum gravity, such as string theory, their precise properties and behavior are still subjects of ongoing research and exploration. It is not yet clear how gravitons, if they exist, manifest in the context of gravitational waves and how they relate to the classical description of spacetime curvature.
Therefore, the relationship between gravitational waves and gravitons is not yet fully understood, and further progress in the development of a theory of quantum gravity is necessary to provide a comprehensive understanding of this connection.