March 20, 2019
Multiple Realities Exist At The Quantum Level, Study Says

A new quantum mechanics study pre-published on arXiv suggests that there are two different versions of reality at the quantum level. The field of quantum mechanics aims to describe the world at a scale so small that the standard rules of physics don't apply. As Fox News reports, the team behind the recent study explores how two people can come to different conclusions about the state of the same photon and both be correct in their observations.

"In quantum mechanics, the objectivity of observations is not so clear, most dramatically exposed in Eugene Wigner's eponymous thought experiment where two observers can experience fundamentally different realities," the team wrote in the study. "While observer-independence has long remained inaccessible to empirical investigation, recent no-go-theorems construct an extended Wigner's friend scenario with four entangled observers that allows us to put it to the test."

As Live Science reports, the study marks the first time that researchers have replicated the conditions described in Wigner's thought experiment, confirming that two conflicting realities can be true.

The team used two different laboratories for the experiment, each with one experimenter and one friend. From here, they introduced two pairs of entangled photons to link their fates, which means that the state of one tells you the state of the other. Afterward, they introduced two fictional "people"— "Alice" and "Bob"— that were represented by the experimenters, each of whom was paired with a "friend" that acted as an observer.

The experiment began with the friends measuring one of the photons in the entangled pair and recording the results. Afterward, each person measured the results of the second photon using quantum memory. From here, Alice and Bob — from outside of the laboratories - were allowed to choose between measuring their friend's results in quantum memory storage or conducting their own experiment where they measure the photons by examining their light patterns instead.

The results showed that Alice and Bob could conduct their own experiment and come to conclusions about the photons that were difficult than their friends. However, both observations about each pair were are correct and provable.

Martin Ringbauer, the study's co-author and a postdoctoral researcher with the Department of Experimental Physics at the University of Innsbrück in Austria, spoke to Live Science about the results.

"It seems that, in contrast to classical physics, measurement results cannot be considered absolute truth but must be understood relative to the observer who performed the measurement. The stories we tell about quantum mechanics have to adapt to that."