Physicists have built a real-number version of quantum mechanics that makes all the same predictions as the standard theory, resolving a question that's simmered since the field began.

The square root of a negative number could easily be regarded as a curious mathematical construction that has little bearing on real life. Indeed, the French polymath René Descartes gave such numbers ...

To a nonmathematician, having the letter “i” represent a number that does not quite exist and is “imaginary” can be hard to wrap your head around. If you open your mind to this way of thinking, ...

Real and imaginary: The time-dependent Schrödinger equation formulated using complex numbers. (Courtesy: iStock/piranka) Complex numbers are essential to achieve the most accurate quantum-mechanical ...