An attempt to link gravity
to established theories in quantum mechanics
suggested by American physicist, John Archibald Wheeler (Princeton University
), back in the 1950's. Instead of the nice smooth curved space
predicted by general relativity
), if one looks at the world on the scale of around 10-35
meters, quantum fluctuations become significant enough to affect the geometry of the universe. Space and time become "foamy". This vagueness allows postulation of all kinds of weird behavior in spacetime
such as time travel
Giovanni Amelino-Camelia of the University of Neuchâtel Switzerland, is collaborating with Caltech using an interferometer that takes a beam of laser light, splits it in two and sends it to two distal mirrors about 40 meters away each. These beams of light are then recombined. The overlap of the two beams forms an interference pattern which is affected by the relative phase of the two beams. Fluctuations in this pattern would be sensitive to changes in the path, i.e. the foaminess of space between the laser source and the mirrors.
Other theories do exist for the description of gravity at the quantum level. One of the big contenders is one that incorporates superstring theory.