Replicating the benefits of closed timelike curves without breaking causality

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, resolving such paradoxes induce 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 closed timelike curves can still be harnessed, even when causality is preserved. Our results unveil the 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.

6 pages, 5 figures. Comments most welcome

References in corpus (4)

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• Quantum Connectivity of Space-Time and Gravitationally Induced Decorrelation of Entanglement
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• Advanced-Retarded Differential Equations in Quantum Photonic Systems
• Detecting non-decomposability of time evolution via extreme gain of correlations
• Simulations of closed timelike curves
• Asymptotic Properties for Markovian Dynamics in Quantum Theory and General Probabilistic Theories
• Deutschian closed timelike curves can create entanglement
• Light propagation through nanophotonics wormholes
• Bell Correlations and the Common Future
• Entangling superconducting qubits through an analogue wormhole
• Revisiting Integer Factorization using Closed Timelike Curves