Quantum information theory

Today Google announced that it achieved “quantum supremacy.” Its chief quantum computing rival, IBM, said it hasn’t. The disagreement hinges on what the term really means.

Researchers finally seem to have a quantum computer that can outperform a classical computer. But what does that really mean?

Fifty years after the current internet was born, the physicist and computer scientist Stephanie Wehner is planning and designing the next internet — a quantum one.

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.