Abstract In the twin paradox of special relativity, an observer that travels along an accelerated trajectory at a high velocity will experience a smaller amount of elapsed time than an observer that remains at rest. This illustrates the fact that time is relative unlike the situation in classical physics where time is absolute. In a recent paper, Bushev et al (2016 New J. Phys. 18 093050 ) showed that the twin paradox can also be demonstrated using a single electron that functions as a quantum-mechanical clock. The wave function of the electron can travel along two different paths simultaneously, which allows a measurement of the difference in proper times along the two trajectories using a single particle. Quantum interference effects show that time cannot be thought of as a classical parameter even when associated with a single clock or observer.
We propose a novel framework for understanding quantum entanglement as a phenomenon fundamentally dependent on the proper-time histories of entangled particles. Drawing an analogy to the classical twin paradox of special relativity, we hypothesize that entanglement persists only when particle worldlines remain synchronized in their accumulated proper time. When differential aging occurs due to relative velocity or gravitational time dilation, quantum correlations degrade in a predictable, oscillatory manner. This “Entangled Twin Paradox” makes testable predictions that distinguish it from standard quantum mechanics, which treats entanglement as independent of relativistic effects.