Objective Reality May Not Exist At All, Quantum Physicists Say

Long-time Slashdot reader waspleg shares a thought-provoking article from Popular Mechanics:
Does reality exist, or does it take shape when an observer measures it? Akin to the age-old conundrum of whether a tree makes a sound if it falls in a forest with no one around to hear it, the above question remains one of the most tantalizing in the field of quantum mechanics, the branch of science dealing with the behavior of subatomic particles on the microscopic level.... Now, scientists from the Federal University of ABC (UFABC) in the São Paulo metropolitan area in Brazil are adding fuel to the suggestion that reality might be 'in the eye of the observer.'

In their new research, published in the journal Communications Physics in April, the scientists in Brazil attempted to verify the 'complementarity principle' the famous Danish physicist Niels Bohr proposed in 1928. It states that objects come with certain pairs of complementary properties, which are impossible to observe or measure at the same time, like energy and duration, or position and momentum. For example, no matter how you set up an experiment involving a pair of electrons, there's no way you can study the position of both quantities at the same time: the test will illustrate the position of the first electron, but obscure the position of the second particle (the complementary particle) at the same time....

'We used nuclear magnetic resonance techniques similar to those used in medical imaging,' Roberto M. Serra, a quantum information science and technology researcher at UFABC, who led the experiment, tells Popular Mechanics. Particles like protons, neutrons, and electrons all have a nuclear spin, which is a magnetic property analogous to the orientation of a needle in a compass. 'We manipulated these nuclear spins of different atoms in a molecule employing a type of electromagnetic radiation. In this setup, we created a new interference device for a proton nuclear spin to investigate its wave and particle reality in the quantum realm,' Serra explains. 'This new arrangement produced exactly the same observed statistics as previous quantum delayed-choice experiments,' Pedro Ruas Dieguez, now a postdoctoral research fellow at the International Centre for Theory of Quantum Technologies (ICTQT) in Poland, who was part of the study, tells Popular Mechanics. 'However, in the new configuration, we were able to connect the result of the experiment with the way waves and particles behave in a way that verifies Bohr's complementarity principle,' Dieguez continues.

The main takeaway from the April 2022 study is that physical reality in the quantum world is made of mutually exclusive entities that, nonetheless, do not contradict but complete each other.
Stephen Holler, an associate professor of physics at Fordham University, tells Popular Mechanics that the study underscores a famous observation by Richard Feynman: 'If you think you understand quantum mechanics, you don't understand quantum mechanics.'

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