Yet physicists today still search for a gravity force, such as gravity waves.

The other three fundemental forces of interaction in Quantum Physics are: the strong nuclear force, weak nuclear force and electromagnetism. All of these forces interact with particles with their own particles specifically called 'guage bosons' which mediate those forces. Namely; Gluons, W&Z Bosons and the Photon. These particles have all been observed and interact with all kinds of other classification of particles (Hadrons, Leptons etc). However, gravity as we know it thanks to Einstein is expressed as geometry, the curving of spacetime due to mass (as in dimensions, as in shapes (geometry)).

This does not fit with the other three fundemental forces of interaction in Quantum Physics because it doesn't require a mediating particle

*however*, it does have a mediating

*wave*. This is because a wave in order to be a wave has to have time in which it is observed, in which case pertains to geometry, however a particle; doesn't.

In quantum physics there is a well known behaviour called 'Wave/Particle duality'. Which means that particles can exihibit both wave and particle like properties. Photons for example can be expressed as a wave (a wave of light) and a packet of energy called a photon (particle). However, you can only observe one type of behaviour at the same time. This is known as the uncertainty principle, and there are many examples of this effect as wave/particle duality that tried to solve it, however they often end up facing difficulties when applying to the macro, or 'real world' scale if you will. One particular example is Schrodinger's Cat.

The main point of all of this is that the three fundemental forces of interaction that can be quantized, gravity isn't one. And that is because wave/particle like behaviour is on the atomic scale (Micro Scale). Gravity as we know it has to be impossibly more larger to be observed because the force of gravity compared to the other 3 is impossibly weak, so much that to observe the gravity within an atom becomes an impossible task. The only thing close to observing and quantizing gravity, its the discovery of the Higgs Boson, which gives particles mass. The discovery of this particle will help teach us the circumstances in which gravity can exist and how it will have an effect on all particles, which in turn might help us quantize it and help find the graviton, gravity's gauge boson.

In a nutshell, gravity cannot be quantized because its effects are too large to be observed as a particle, and can only be observed at best, as a wave. For the time being at least.