A quantum gravity does exist as a biphoton exchange between two neutral particles and biphoton exchange and this provides a simple way of understanding quantum gravity in the context of quantum charge. Just as each pair of charged particles bonds with the exchange of a photon, each pair of neutral particles then bonds with the exchange photon pairs called biphotons. While the exchange of a single photon between charges represents dipole force, the exchange of a biphoton between neutral particles represents a quadrupole force. This simple model of quantum gravity simplifies the complexities of many quantum measurements
The GHZ (Greenberger-Horne-Zeilinger) experiment is a variation of the simple crossed polarizer experiment that illustrates quantum entanglement and nonlocality. However, unless you can read the papers and understand the math, why go there?
By jumping back and forth between quantum and GR logic, Maudlin has managed to befuddle even Tegmark and Davies in a discourse about time. Tegmark and Davies asked Maudlin for a theory to support his back and forth arguments so that they could test it. Maudlin replied that he does not have a math theory, just a feeling and intuition about reality.
A determinate classical photon cannot exist as a superposition of two paths or futures and there is no interference of a single determinate photon with itself. A determinate photon spectrum does not retain any information about the beamsplitter or paths and is just a record of the source matter spectrum. A determinate classical photon therefore has an independent existence from either the source or observer and does not bond the source and observer in any way. Therefore, a determinate classical photon path is already in a future frame of a DVD video that is playing back the prerecorded script of the universe.
Said in other words, the action differential of Einstein’s GR is simply the cosmic action time average of the quantum gravity matter wave action derivative. Both space and interval atomic time emerge from the gravity/charge action derivative, now with respect to the action time of the universe. The cosmic action time of the universe represents a kind of absolute time and is different from the interval time of atomic clocks, which varies over cosmic action time. It is the cosmic action of the universe that defines all force and the progress of interval time represents a second time dimension.
The same dipole photons of quantum charge bonds are the quadrupole biphotons of gravity bonds. While charge bonds have very short correlation lengths on the order of atoms, gravity bonds have very long correlation lengths on the order of the universe. While discrete photon emission and absorption are what bond charge matter, discrete biphoton emission and absorption are what bond neutral matter. The biphoton exchange of gravity defines the motions of sources from gravity, but biphotons are also coupled to charge bonds.
Therefore, charge bonds affect gravity and and gravity affects charge bonds. However, the biphoton nature of gravity means that the gravity wave beamsplitter does not show interference effects. This is because the gravity biphoton exchange between source and observer is much more symmetric than the single photon exchange of dipole charge force. In other words, resonances between source and observer result in cavity modes just like a laser.
Stimulated absorption and emission are only possible with the special conditions of a laser cavity for dipole photons, but stimulated absorption and emission are very common for gravity biphotons. Therefore any interaction between two gravity sources represents a quadrupole cavity mode with the exchange of a very large number of biphotons.