Closed timelike curves via post-selection: theory and experimental demonstration

TL;DR

This paper introduces a new quantum theory of closed timelike curves based on teleportation and post-selection, which is experimentally testable and offers an alternative to Deutsch's approach.

Contribution

It proposes a novel quantum formulation of CTCs using teleportation and post-selection, differing from Deutsch's theory, and provides experimental validation.

Findings

Experimental demonstration of resolving the grandfather paradox

Evidence supporting the new quantum CTC theory

Comparison showing physical inequivalence to Deutsch's model

Abstract

Closed timelike curves (CTCs) are trajectories in spacetime that effectively travel backwards in time: a test particle following a CTC can in principle interact with its former self in the past. CTCs appear in many solutions of Einstein's field equations and any future quantum version of general relativity will have to reconcile them with the requirements of quantum mechanics and of quantum field theory. A widely accepted quantum theory of CTCs was proposed by Deutsch. Here we explore an alternative quantum formulation of CTCs and show that it is physically inequivalent to Deutsch's. Because it is based on combining quantum teleportation with post-selection, the predictions/retrodictions of our theory are experimentally testable: we report the results of an experiment demonstrating our theory's resolution of the well-known `grandfather paradox.