The causal problem of entanglement

Ryuhei ISHIBASHI

The tension between quantum entanglement and relativistic causality has persisted fornearly a century. Bell inequality violations demonstrate correlations inexplicable by localhidden variables, yet relativity prohibits faster-than-light causal inuences. We dissolvethis tension through causal eliminativism: causation does not exist in fundamental physics.Three results follow: (1) Bell correlations are derivable as atemporal relational constraintswithout causation; (2) relativity prohibits superluminal causation, which does not exist,not superluminal correlation, which does; (3) the measurement problem disappears whenreconceived as constraint activation rather than causal collapse. The 90-year problem wasan artifact of imposing causal categories onto an acausal world. We survey the neo-Russelliantradition supporting this move, address the measurement problem's standard formulation(Maudlin 1995), and demonstrate concrete applications to the Wigner's friend scenario andBell's theorem premises.

Bob Coecke

Xiao Yuan, Syed M. Assad, Jayne Thompson +6 more

Abstract In general relativity, closed timelike curves can break causality with remarkable and unsettling consequences. At the classical level, they induce causal paradoxes disturbing enough to motivate conjectures that explicitly prevent their existence. At the quantum level such problems can be resolved through the Deutschian formalism, however this induces radical benefits—from cloning unknown quantum states to solving problems intractable to quantum computers. Instinctively, one expects these benefits to vanish if causality is respected. Here we show that in harnessing entanglement, we can efficiently solve NP-complete problems and clone arbitrary quantum states—even when all time-travelling systems are completely isolated from the past. Thus, the many defining benefits of Deutschian closed timelike curves can still be harnessed, even when causality is preserved. Our results unveil a subtle interplay between entanglement and general relativity, and significantly improve the potential of probing the radical effects that may exist at the interface between relativity and quantum theory.

Shantilal Gangadas Goradia

John W. Moffat

A possible causal solution to the problem of providing a spacetime description of the transmission of signals in quantum entangled states is described using a `bimetric' spacetime structure, in which the quantum entanglement measurements alter the structure of spacetime. Possible experimental tests to verify the suggested spacetime interpretation of quantum entangled states are proposed.