Quantum gravity

A decades-old method called the “bootstrap” is enabling new discoveries about the geometry underlying all quantum theories.

The effort to unify quantum mechanics and general relativity means reconciling totally different notions of time.

Can a fluid analogue of a black hole point physicists toward the theory of quantum gravity, or is it a red herring?

The story of the universe’s birth — and evidence for string theory — could be found in triangles and myriad other shapes in the sky.

At 86, Britain’s preeminent mathematical matchmaker is still tackling the big questions and dreaming of a union between the quantum and the gravitational forces.

Bizarre quantum bonds connect distinct moments in time, suggesting that quantum links — not space-time — constitute the fundamental structure of the universe.

Two leading candidates for a “theory of everything,” long thought to be incompatible, may be two sides of the same coin.

If a theory can’t be tested, is it still science?

Explore the deepest mysteries at the frontier of fundamental physics, and the most promising ideas put forth to solve them.