Black Holes Pose Threat to Quantum States, Say Researchers

Researchers at the University of Chicago and Princeton University have found that the presence of a black hole is enough to turn a particle's hazy "superposition" into a well-defined reality, suggesting that black holes are observing the universe. The effect is one of many uncovered in the past decade by physicists studying what happens when quantum theory is combined with gravity at low energies. The authors argue that there is something uniquely "insidious" about this kind of decoherence, which will occur anywhere there is a horizon that only allows information to travel in one direction, creating the potential for causality paradoxes.