Theoretical physics

Physicists are using quantum math to understand what happens when black holes collide. In a surprise, they’ve shown that a single particle can describe a collision’s entire gravitational wave.

Physicists are reexamining a longstanding assumption: that big stuff consists of smaller stuff.

The strong force holds protons and neutrons together, but the theory behind it is largely inscrutable. Two new approaches show how it works.

If only scientists understood exactly how electrons act in molecules, they’d be able to predict the behavior of everything from experimental drugs to high-temperature superconductors. Following decades of physics-based insights, artificial intelligence systems are taking the next leap.

In a quest to map out a quantum theory of gravity, researchers have used logical rules to calculate how much Einstein’s theory must change. The result matches string theory perfectly.

Physicists have been busy exploring how our universe might emerge like a hologram out of a two-dimensional sheet. New clues have come from the symmetries found on an infinitely distant “celestial sphere.”

Physicists are translating commonsense principles into strict mathematical constraints on how our universe must have behaved at the beginning of time.

Years of conflicting neutrino measurements have led physicists to propose a “dark sector” of invisible particles — one that could simultaneously explain dark matter, the puzzling expansion of the universe, and other mysteries.

Investigations of the simplest possible clocks have revealed their fundamental limitations — as well as insights into the nature of time itself.