Timetanglement: Ruickbie excerpt #29

Psychologist Leo Ruickbie writes in “The Ghost in the Time Machine,” his essay in a competition sponsored by the Bigelow Institute for Consciousness Studies:   

In 1983, Don Page and William Wootters showed how the quantum phenomenon of entanglement – where two particles can remain in apparent contact even though separated (non-locality), Einstein’s famous “spooky action at a distance” – can be used to measure time. They argued that the way in which entangled particles evolve can be seen as a kind of clock, allowing the measurement of change. An observer within the system could compare this evolution against the rest of the system – the system being the physical universe. In doing so, the observer would be able to measure the passage of time as a relative difference of change between two things. 

However, an observer outside the system using an external clock to measure change would see no change in the entangled particles, meaning that time does not exist. This leads to the conclusion that time is an emergent property of quantum entanglement. 

Ingenious though it was, because it was impossible to have an observer outside the universe, the theory could never be tested. That is, until a team of researchers led by Ekaterina Moreva at the Instituto Nazionale di Ricerca Metrologica (INRIM) in Turin, Italy, built their own universe to test it out.

Using two entangled photons in a deceptively simple setup, the experimenters were able to position internal and external “observers” to their mini-universe. In the first condition, the internal observer becomes entangled with the system by measuring it. In the second condition, the external observer remains outside the system and uses an independent measure of time. They discovered that within the universe they could measure change, whilst outside the universe there was no change. Page and Wootters had been right: time is an emergent property of entanglement.

To make this clearer let us try a metaphor. A river appears to be there in all its entirety to an external observer at a sufficient altitude. He can see its source, its in-between points and its mouth; but push him into the river and his observation changes dramatically, suddenly there is flow (passage of time) and the experience of the river is reduced to the point (the present) at which the observer is bobbing about in it. It is only a metaphor, but it gives us a more tangible idea of time as an emergent property of entanglement within a system, “timetanglement.” 

Leo Ruickbie, “The Ghost in the Time Machine,” his 2021 prize winning essay in a competition sponsored by the Bigelow Institute for Consciousness Studies. Ruickbie teaches psychology at Kings College and the University of Northamptom in the United Kingdom. Footnotes have been deleted from these online excerpts from his essay. The entire essay may be downloaded at the Bigelow site https://bigelowinstitute.org/contest_winners3.php.