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More Than One Reality Exists (in Quantum Physics) (livescience.com)
Zorro (Slashdot reader #15,797) quotes Live Science:
Can two versions of reality exist at the same time? Physicists say they can -- at the quantum level, that is.
Researchers recently conducted experiments to answer a decades-old theoretical physics question about dueling realities. This tricky thought experiment proposed that two individuals observing the same photon could arrive at different conclusions about that photon's state -- and yet both of their observations would be correct.
For the first time, scientists have replicated conditions described in the thought experiment. Their results, published Feb. 13 in the preprint journal arXiv, confirmed that even when observers described different states in the same photon, the two conflicting realities could both be true. "You can verify both of them," study co-author Martin Ringbauer, a postdoctoral researcher with the Department of Experimental Physics at the University of Innsbruck in Austria, told Live Science.
Researchers recently conducted experiments to answer a decades-old theoretical physics question about dueling realities. This tricky thought experiment proposed that two individuals observing the same photon could arrive at different conclusions about that photon's state -- and yet both of their observations would be correct.
For the first time, scientists have replicated conditions described in the thought experiment. Their results, published Feb. 13 in the preprint journal arXiv, confirmed that even when observers described different states in the same photon, the two conflicting realities could both be true. "You can verify both of them," study co-author Martin Ringbauer, a postdoctoral researcher with the Department of Experimental Physics at the University of Innsbruck in Austria, told Live Science.
...we knew it for long time
For a little more clarity on the subject, this is a physical realization of the "Wigners Friend" experiment. The "state" referred to in the summary is "superposition/collapsed waveform", and not the specific information about the photon such as its spin.
In the experiment, one scientist ("Wigner's friend") observes a photon in a superposition of states, which collapses the state, while a second scientist observes the first scientist. This uses entangled photons, so that observing the first photon collapses the state of the second.
The first scientist observes one photon, thereby collapsing its state to reveal information. Does the second scientist see his photon in a superposition or collapsed state? The first scientist might even tell the 2nd that he has observed the photon, collapsing its state - but not sating what state information was seen.
According to the experiment, the 2nd scientist still sees his photon in a superposition of states even though he knows that the first scientist has observed the photon and that the first scientist knows what the collapsed state is.