# Archive

## Latest Articles

### How Our Reality May Be a Sum of All Possible Realities

Richard Feynman’s path integral is both a powerful prediction machine and a philosophy about how the world is. But physicists are still struggling to figure out how to use it, and what it means.

### Mathematicians Eliminate Long-Standing Threat to Knot Conjecture

A new proof shows that a knot some thought would contradict the famed slice-ribbon conjecture doesn’t.

### Machines Learn Better if We Teach Them the Basics

A wave of research improves reinforcement learning algorithms by pre-training them as if they were human.

### When Does the Brain Operate at Peak Performance?

The critical brain hypothesis suggests that neural networks do their best work when connections are not too weak or too strong.

### Astronomers Say They Have Spotted the Universe’s First Stars

Theory has it that “Population III” stars brought light to the cosmos. The James Webb Space Telescope may have just glimpsed them.

### How Quantum Physicists ‘Flipped Time’ (and How They Didn’t)

Two teams have made photons act as if time were simultaneously flowing in two directions. The experiments demonstrate a way to potentially boost the performance of quantum devices.

### The Cause of Depression Is Probably Not What You Think

Depression has often been blamed on low levels of serotonin in the brain. That answer is insufficient, but alternatives are coming into view and changing our understanding of the disease.

### The Computer Scientist Who Finds Life Lessons in Games

In Shang-Hua Teng’s work, theoretical and practical questions have long been intertwined. Now he’s turning his focus to the impractical.

### Mathematicians Find an Infinity of Possible Black Hole Shapes

In three-dimensional space, the surface of a black hole must be a sphere. But a new result shows that in higher dimensions, an infinite number of configurations are possible.