Quantum gravity

Even empty space bubbles with energy, according to quantum mechanics — and that fact affects almost every facet of physical reality. The theoretical physicist Isabel Garcia Garcia explains to Steven Strogatz why it’s so important in modern physics to understand what a true vacuum is.

For decades, physicists have struggled to develop a quantum theory of gravity. But what if gravity — and space-time — are fundamentally classical?

Physicists finally know where at least some of these high-energy particles come from, which helps make the neutrinos useful for exploring fundamental physics.

The puzzling behavior of black hole interiors has led researchers to propose a new physical law: the second law of quantum complexity.

Renate Loll has helped pioneer a radically new approach to quantum gravity. She assumes that the fabric of space-time is a blend of all possible fabrics, and she has developed the computational tools needed to calculate the far-reaching implications of that assumption.

Last fall, a team of physicists announced that they had teleported a qubit through a holographic wormhole in a quantum computer. Now another group suggests that’s not quite what happened.

New calculations suggest that the event horizons around black holes will ‘decohere’ quantum possibilities — even those that are far away.

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.

In a year filled with sweet new observations in astronomy and tantalizing breakthroughs in condensed matter physics, the brand-new space telescope takes the cake.