Your April 2025 Issue of Physics Today Is Now Available

Physics Today, the flagship publication of the American Institute of Physics (AIP), is the most influential and closely followed physics magazine in the world. With authoritative features, full news coverage and analysis, and fresh perspectives on technological advances and groundbreaking research, Physics Today informs readers about science and its role in society. Members of the AAS, an AIP Member Society, automatically receive free print and online subscriptions to the magazine. Physics Today Online, the magazine’s internet home, presents an enhanced digital edition and provides a valuable online archive.

Highlights from the April 2025 Issue

Earth’s Magnetic Dipole Collapses, and Life Explodes
The present-day magnetic field protects life, but an ancient phase when it nearly collapsed corresponded with a key step in evolution. Changes in the planet’s deep interior may have started it all. — John A. Tarduno

Demythologizing Quantum History
Celebrating the 100th anniversary of quantum mechanics in 2025 without providing appropriate context risks reinforcing a long legacy of hagiography and hero worship. — Ryan Dahn

Peter Shor on the Genesis of Shor’s Algorithm
The theoretical computer scientist describes his path to the factoring algorithm that helped spark interest in quantum computing. — David Zierler and Ryan Dahn

Dense Crowds Follow Their Own Rules
When thousands of people are packed into a confined space, collective dynamics takes over. The phenomenon can be described with a physical model. — Johanna L. Miller

Plasma Channel Guides Electrons to 10 GeV
Femtosecond-scale laser pulses make a plasma waveguide that helps wakefield-surfing electron bunches keep their energy focused. — Laura Fattaruso

See the Complete Table of Contents