We are aware of how skewed our perception of reality is. How we see the world is shaped by our senses, our societies, and our knowledge.

And you may want to rethink your belief that science will always provide you with objective reality.

Physicists can now verify a hypothesis that Nobel Prize winner Eugen Wigner initially put out in 1961.

The setting of the experiment, dubbed “Wigner’s Friend,” is not too difficult. You begin with a quantum system that is in superposition, which implies that both of its states exist concurrently up to the point of measurement. In this example, the polarisation (the axis on which a photon spins) is both horizontal and vertical.

When they measure it, the system will collapse and the photon will be stuck into one of those two states. Wigner’s buddy is in the lab doing the experiment. However, the quantum system—which, crucially, also includes the lab—remains in superposition for Wigner, who is outside the lab and uninformed of the outcome of the experiment.

Despite having different outcomes, they are both accurate. So, two objective realities, Wigner’s and Wigner’s friend’s seem to coexist. (This is comparable to Schrödinger’s cat, a thought experiment also involving superposition, assuming Schrödinger and his cat-in-a-box were both in a box.) And that’s a problem.

It has been impossible to test this theory for a very long time. Wigner finds it difficult to calculate the quantum mechanics formula after seeing his buddy do an experiment. However, owing to recent advances, scientists were able to create a quantum mechanics experiment that would precisely replicate that.

A cutting-edge six-photon experiment and the system’s four entangled observers demonstrated that while one component of the system generated a measurement, the other revealed that the measurement had not been made.

At once, two realities were measured. According to the study, this supports the claim made by quantum theories whose framework already takes observer dependence into account.

“This calls into question the objective status of the facts established by the two observers,” the scientists write in their paper, which is available to read on ArXiv.

Can their disparate records be reconciled, or are they fundamentally incompatible—making it impossible for them to be regarded as objective, observer-independent “facts of the world”?

The influence and limits of the observers are well understood, despite the fact that science is the finest instrument we have for understanding reality. Observers may not see simultaneous occurrences at the same time, according to relativity.

We learn from quantum physics that observers have an impact on their experiments. Now it seems that two worlds may exist simultaneously, at least at the quantum level.

Reference(s): MIT Technology Review