This Is How Quantum Physics Creates The Largest Cosmic Structures Of All
How can physics on the smallest scales affect what the Universe does on its largest ones? Cosmic inflation holds the answer.
On a macroscopic level, the Universe appears to be entirely classical. Gravity can be described by the curvature of space according to the rules of General Relativity; electromagnetic effects are perfectly well-described by Maxwell’s equations. Only on ultra-tiny scales do quantum effects begin to come into play, showing themselves in features like atomic transitions, absorption and emission lines, the polarization of light, and vacuum birefringence.
And yet, if we extrapolate back to the earliest stages of the Universe, every relevant interaction that occurred was purely quantum in nature. Individual quantum particles and fields interacted on short scales and at enormous energies, leading to many observables today that have a quantum legacy imprinted on them. In particular, the largest galactic and supergalactic structures owe their origins to quantum physics, too. Here’s how.