Quantum mechanics, the theory that describes matter and energy at atomic and subatomic scales, has long relied on complex numbers that include real and imaginary parts. Those numbers are part of the standard mathematical language used to explain quantum states and their behavior.
But researchers from Heinrich Heine University Düsseldorf and the German Aerospace Center say that may not be the only way to write the theory. In a new study published in Physical Review Letters, the team argues that a less restrictive assumption than the one used in a 2021 analysis opens the door to formulations based entirely on real numbers.
According to the study, the resulting family of theories produces the same experimental predictions as conventional quantum mechanics. Lead researcher Professor Dagmar Brüß said this means imaginary numbers are not fundamentally necessary within that framework and could, in principle, be replaced.
The question matters because quantum mechanics underpins many microscopic phenomena, from the double-slit experiment to quantum tunneling, entanglement and coherence. Those effects also form the basis of emerging technologies such as quantum computing and quantum communication, according to the source material.
