Physicists from Heinrich Heine University Düsseldorf (HHU) and the German Aerospace Center (DLR) have explored a core idea in quantum mechanics. They found that this theory might not always need imaginary numbers. Instead, real numbers could also be used.
Their findings were published in Physical Review Letters. The American Physical Society also highlighted this work in its Physics Magazine.
Quantum mechanics explains how matter and energy act at very small scales, like atoms. It was developed in the early 1900s by scientists such as Max Planck and Erwin Schrödinger. It is one of the most successful scientific theories ever.
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Start Your News DetoxThe theory accurately describes many tiny events. This includes the double-slit experiment, where particles act like waves. It also covers quantum tunneling, where particles can pass through barriers without enough energy.
Other quantum effects, like entanglement, are now key to new technologies. These include quantum computing and quantum communication.
Are Complex Numbers Truly Needed?
For many years, quantum mechanics has relied on complex numbers. These numbers combine a real part with an imaginary part. In quantum math, the real part shows the amplitude, and the imaginary part shows the phase. This setup was thought to be vital for describing quantum processes.
Still, physicists have wondered if complex numbers are truly part of nature. Or are they just a useful math tool? This question led to another: Could quantum mechanics work with only real numbers?
Re-examining a Quantum Idea
A 2021 study suggested that complex numbers were essential. This was based on the usual rules of quantum mechanics. Experiments also seemed to back this up.
However, researchers from HHU and DLR, led by Professor Dr. Dagmar Bruß and Pedro Barrios Hita, looked again at the earlier study's assumptions.
Their new study in Physical Review Letters found that one rule from the 2021 analysis was too strict. They replaced it with a different, more physical way to describe how quantum systems combine. They found a group of theories that use only real numbers. These theories are also impossible to tell apart from standard quantum mechanics in experiments.
Professor Bruß explained that both ways of thinking give the same results for any experiment. She noted that imaginary numbers are not fundamentally needed in quantum mechanics. They can be replaced by other ways using real numbers.
Deep Dive & References
Quantum Mechanics Based on Real Numbers: A Consistent Description - Physical Review Letters, 2026
