Quantum information theory

Researchers are getting close to building a quantum computer that can perform tasks a classical computer can’t. Here’s what the milestone will mean.

A recent test has confirmed the predictions of quantum trajectory theory.

Pure, verifiable randomness is hard to come by. Two proposals show how to make quantum computers into randomness factories.

Neven’s law states that quantum computers are improving at a “doubly exponential” rate. If it holds, quantum supremacy is around the corner.

An experiment caught a quantum system in the middle of a jump — something the originators of quantum mechanics assumed was impossible.

The universe of problems that a computer can check has grown. The researchers’ secret ingredient? Quantum entanglement.

Quantum computers can’t selectively forget information. A new algorithm for multiplication shows a way around that problem.

These games combine quantum entanglement, infinity and impossible-to-calculate winning probabilities. But if researchers can crack them, they’ll reveal deep mathematical secrets.

A two-player game can reveal whether the universe has an infinite amount of complexity.