For Tiny Light Particles, 'Before' and 'After' Mean Nothing
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Beneath the surface of the familiar world is a smaller, quantum world that defies our fundamental ideas of time and space.
In this mini world, the concepts of "before" and "after" dissolve, such that two events can both precede and succeed each other. In other words, event A can occur before event B, and event B can occur before event A, according to a new study published Aug. 31 in the journal Physical Review Letters.
This idea, called a "quantum switch," was first proposed in 2009 by another team and has since been explored both theoretically and experimentally. Previous experiments showed event A could both precede and succeed event B, but the research couldn't say that these two scenarios were happening at the same place, said Cyril Branciard, co-author of this new study and a physicist at the NÉEL Institute in France. [The 9 Biggest Unsolved Mysteries in Physics]
To determine exactly where these violations of causality occurred, the researchers "implemented another quantum switch with a slightly different architecture," Branciard told Live Science. The new design allowed them to demonstrate experimentally that event A was happening both before and after event B not only at the same time, but also in the same place, Branciard told Live Science.
Branciard and his team programmed and observed how a photon — a quantum particle of light — moved its way through a circuit. The photon could take one of two paths: If the photon took one path, they called the occurrence event A, and if it took the other, they called it event B.
Read more ~ livescience.com
Note: There’s no “Are we there yet?” for the photon family. They got there when they left. : )