The most powerful formula in physics starts with a slender S, the symbol for a sort of sum known as an integral. Further along comes a second S, representing a quantity known as action. Together, ...
Quantum mechanics replaced the clockwork certainty of classical physics with something far stranger: a framework in which particles do not follow single, predictable paths but instead exist as clouds ...
image: There are two sound velocities in a Bose-Einstein condensate. In addition to the normal sound propagation there is second sound, which is a quantum phenomenon. Scientists around Ludwig Mathey ...