Quantum mechanics and the general theory of relativity are two pillars of modern physics. However, a coherent unified framework of the two theories still remains an open problem. Attempts to quantize general relativity have led to many rival models of quantum gravity, which, however, generally lack experimental foundations.
The research team reports a quantum optical experimental test of event formalism of quantum fields, a theory which attempts to present a coherent description of quantum fields in exotic spacetimes containing closed time-like curves and ordinary spacetime. They experimentally test a prediction of the theory with the quantum satellite Micius that a pair of time-energy entangled particles probabilistically decorrelate passing through different regions of the gravitational potential of Earth. Their measurement results are consistent with the standard quantum theory and hence do not support the prediction of event formalism.