Math just proved we'll never actually know if the universe is built out of 'imaginary' numbers or the regular ones we know.
March 20, 2026
Original Paper
Quantum theory based on real numbers cannot be experimentally falsified
arXiv · 2603.19208
The Takeaway
Quantum mechanics usually requires 'imaginary' numbers (like the square root of -1) to describe the world, and many scientists thought this was a physical necessity. This paper proves that a version of physics using only 'real' numbers can perfectly mimic every quantum experiment we could ever perform. This means the mathematical language we use to describe the universe is a matter of human choice rather than a discoverable physical truth.
From the abstract
Whether the complex numbers of standard quantum theory are experimentally indispensable has remained open for decades. Real quantum theory (RQT), obtained by replacing complex amplitudes with real ones while retaining the usual Kronecker-product composition rule, reproduces all single-party and bipartite Bell correlations of quantum theory (QT), but its lack of local tomography suggested that the two theories might diverge in more general local experiments. This possibility appeared to be confir