Thought experiment, and proposed experiment of a scenario where either information travels faster than light, rendering relativity as incomplete, or the Copenhagen interpretation as incomplete.
Canonical Copenhagen QED (KQED) predicts that substantive information cannot be communicated faster than light (FTL) or backwards in time. KQED is essentially just the combination of three assumptions used together to make predictions: (1) the assumption that the wave function ψ(t) evolves according to the time-symmetric system ∂tψ=iHψ where is H is the normal product form of the Maxwell-Dirac Hamiltonian; (2) the classical Copenhagen measurement formalism, including metaphysical observers and collapse of the wave function; (3) Fermi’s Golden Rule for spontaneous emission. MQED, published in 2015, replaces the measurement part with a new measurement formalism without observers based on what (1) actually predicts. MQED is not a local realistic theory, but (unlike KQED) it might be derived as a good statistical approximation to one. The 2015 paper proposed a decisive experiment to test which is right, KQED or MQED. This paper proposes a simpler if messier decisive experiment, to demonstrate FTL communication, more details of MQED and the possibility in principle of an underlying local realistic theory of physics.
A protocol using cross‐entangled independent Einstein‐Podolsky‐Rosen (EPR) beams is developed as a means of sending information faster than light (FTL) by taking advantage of quantum nonlocality and indistinguishable particle statistics. Two observers bracket a central midpoint transmitter that contains dual EPR sources from which bits are encoded in packets of photon pairs. FTL communication occurs between the observers in a simplex mode. A reformulation of quantum mechanics is proposed that permits such communications, as well as wave function collapse, to be relativistically consistent, while also resolving the problem of causal ordering normally associated with spacelike connections. The issue of temporal paradox is handled separately at both the quantum and classical levels. Spacelike causal connections lead to closed loops in spacetime and causal self‐reference. It is shown that such self‐reference leads to nonlinearities in the evolution of the wave function that may be sufficient to lead to wave function collapse.