Time from the Quantum Entanglement Perspective

There is an article [1] about the internal time concept and external to time perspective which is experimented by quantum entanglement. It is published in 2013 by the scientists from Italy and Russia. It has very important implications and results of the article which I will try to explain and show the results in this article.

The theory states that [1] “Energy entanglement between a “clock” system and the rest of the universe can yield a stationary state for an (hypothetical) external observer that is able to test the entanglement vs. abstract coordinate time.” This is based on Page and Wootters [2] solution which states this.

They wanted to show that “how a static, entangled state of two photons can be seen as evolving by an observer that uses one of the two photons as a clock to gauge the time-evolution of the other photon.” [1]. Authors of this article tried to prove the Page and Wootters solution by creating an experiment. It based on the Page and Wootters (PaW) mechanism [2] which they provide a static entangled state

whose subsystems are evolving according to Schrödinger equation. One subsystem is “Clock” and the rest of the universe “R”. Time and polarization of the photons are changed with the quartz plate and its thickness.

They explained the time, splitting the observation modes to two. First mode is the “observer” mode which observers observe the photon status by looking to the clock photon. This shows evolution from the observer perspective…