According to Popular Mechanics,Does reality exist and is it formed as observers measure it?Like the old conundrum of whether a tree falling in a forest makes a sound that no one around can hear, the above question is one of the most exciting in the field of quantum mechanics, a sub-discipline of science. The nature of atomic particles at the microscopic level.

In a field dominated by fascinating and almost mystical phenomena like “quantum superposition” — situations in which a particle can be in two or “all” places at once — some experts say reality exists outside of your own consciousness. The way you can change it. Others argue that “quantum reality” may be some form of “Play-Doh” that can be molded into different shapes through your actions. Now, scientists at the Federal University of ABC (UFABC) in Brazil’s São Paulo metropolitan area are fueling the claim that reality may be “in the eye of the beholder.”

In their AprilCommunication PhysicsIn a new study in the journal, Brazilian scientists attempted to test the principle of complementarity, proposed in 1928 by the famous Danish physicist Niels Bohr. It states that objects have certain complementary properties that cannot be observed or measured simultaneously, such as energy and length or position and momentum. For example, no matter how you set up an experiment involving a pair of electrons, you cannot learn the positions of both quantities at the same time: the test will calculate the position of the first electron, but hide the position at the same time. of the second particle (complementary particle) .

To understand how this principle of complementarity relates to objective reality, we need to go back almost a century. In 1927, at the Fifth Solvay Conference (the most important annual international conference in physics and chemistry), Bohr and the famous German-born theoretical physicist Albert Einstein met in Brussels for a legendary debate.

Before 77 other eminent scientists discussed the emerging quantum theory in the Austrian capital, Einstein insisted that quantum states have their own reality, depending on how scientists operate. Meanwhile, Bohr defended the idea that quantum systems can define their own reality only after scientists have established an experimental design.

“God does not play dice,” said Einstein.

“A system behaves as a wave or as a particle, depending on the environment, but you cannot predict what it will do,” Bohr noted, and the concept of wave-particle duality states that matter can act as a wave at one moment and behave as a wave at another, particle form, French physicist Louis de Broglie The concept was first proposed in 1924.

Shortly after the Solvay Conference in 1927, Bohr publicly articulated his principle of complementarity. In the following decades, the controversial Bohr idea was tested several times. American theoretical physicist John Archibald Wheeler was one of the first to test the complementarity principle.

In 1978, Wheeler attempted to reinterpret Thomas Young’s 1801 double slit experiment as a property of light. The double-slit experiment involves illuminating a wall with two parallel slits. As light passes through each slit, on the other side of the divider, it diverges and overlaps and interferes with light from the other slit. This means that there are no more straight lines: the graphic pattern that appears at the end of the experiment is an interference pattern, meaning that light travels in waves. Basically, light has both particle and wave properties and these two properties are inseparable.

After the light had passed through most of the machine, Wheeler switched his instrument between a “wave meter” and a “particle meter.” In other words, he made a delayed choice as to whether the light propagated as a wave or as a particle, and found that the principle of complementarity was not violated even after the late choice.

However, some recent investigations that have attempted to apply the principle of quantum superposition to delayed choice experiments have found that the two possibilities coexist (like two waves in a lake overlapping). This suggests mixed wave- and particle-like behavior within the same device, contrary to the principle of complementarity.

The reality of quantum control

Scientists in Brazil decided to design a real-world experiment with quantum control.

“We used nuclear magnetic resonance techniques similar to those used in medical imaging,” Roberto M. Serra, a UFABC quantum information science and technology researcher who led the experiment, told Popular Mechanics. Particles such as protons, neutrons, and electrons all have nuclear spin, a magnetism similar to the direction of a needle on a compass. “We use a type of electromagnetic radiation to manipulate these nuclear spins of different atoms in a molecule. In this setup, we create a new interaction tool for proton nuclear spins to study their wave and particle reality in the quantum realm,” Serra explained.

“This new arrangement produces the same observational statistics as the previous quantum delayed choice experiment,” said Pedro Ruas Diegus, now a postdoctoral researcher at the International Center for Theory of Quantum Technology (ICTQT) in Poland, who was part of the study. Popular Mechanics. “However, with the new configuration, we were able to relate the experimental results to the way waves and particles behave, thus validating Bohr’s complementarity,” continued Dieges.

The key takeaway from the April 2022 study is that physical reality in the quantum world is made up of mutually exclusive entities, which, however, are not mutually exclusive but complementary.

That’s a curious result, experts say. “Brazilian researchers have developed a mathematical framework and a corresponding experimental configuration that can test quantum theory and, in particular, understand the nature of complementarity by studying the physical reality of systems,” Stephen Holler, associate professor of physics at Fordham University, told Popular Mechanics. “.

The study highlights a long-standing adage by American quantum physicist and Nobel laureate Richard Feynman: “If you think you understand quantum mechanics, you don’t understand quantum mechanics,” Holler said. “There is still much to learn about the theory, and researchers continue to make progress in understanding the fundamentals, which is especially important as we enter an era where quantum devices and computing begin to proliferate.”

“The fact that matter particles behave like waves and light behaves like particles, depending on the situation, remains one of the most interesting and beautiful mysteries in quantum physics,” said Degas.

Ironically, this inherent “weirdness” of quantum mechanics can prove very useful. “The more quantum mechanics unravels, the more quantum technologies can offer beyond their classical counterparts, including quantum computers, quantum cryptography, quantum sensors and devices including quantum heat,” Serra said.

Both researchers agree that the reality seen by the observer is a very special aspect of physical reality in the quantum realm, and the mystery itself shows no sign of abating.