The theory of general relativity, as it was originally formulated by Albert Einstein, is a classical theory of gravity. It describes the gravitational interactions between massive objects and the curvature of space-time they produce. However, it does not explicitly incorporate quantum mechanics, which is the framework used to describe the behavior of subatomic particles.
When it comes to understanding how gravity affects quantum particles, such as atoms, a complete and universally accepted theory that unifies general relativity and quantum mechanics has not yet been achieved. This quest is one of the ongoing pursuits in theoretical physics and is often referred to as the theory of quantum gravity.
The challenge arises because general relativity and quantum mechanics have different mathematical frameworks and conceptual foundations. General relativity is a theory of continuous space-time curvature, while quantum mechanics deals with discrete quantities, probabilistic behavior, and wave-particle duality.
Efforts to reconcile general relativity with quantum mechanics have led to various proposed theories of quantum gravity, such as string theory, loop quantum gravity, and others. These theories attempt to provide a framework that unifies both quantum mechanics and general relativity, allowing for a description of gravity at the quantum level. However, these theories are still under active research and development, and their definitive experimental verification remains a challenge.
In summary, while general relativity and quantum mechanics are both highly successful theories in their respective domains, a comprehensive theory that fully explains how gravity affects quantum particles is yet to be established.