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theoretical physics

theoretical physics

In Fake Universes, Evidence for String Theory

If string theorists can show that their framework is the only consistent theory of quantum gravity, does that make it true even without tangible evidence?

Reaching for the Multiverse
Infinity and Beyond: The Ultimate Test

Multiverse Collisions May Dot the Sky

Early in cosmic history, our universe may have bumped into another — a primordial clash that could have left traces in the Big Bang’s afterglow.

Infinity and Beyond: The Ultimate Test

In a Multiverse, What Are the Odds?

Testing the multiverse hypothesis requires measuring whether our universe is statistically typical among the infinite variety of universes. But infinity does a number on statistics.

particle physics

Quark Quartet Fuels Quantum Feud

Newly discovered particles are forcing physicists to extend their simple picture of subatomic interactions or replace it with a more nuanced understanding.

theoretical physics

At Multiverse Impasse, a New Theory of Scale

Physicists have begun to explore the idea that mass and length may not be fundamental properties of nature. The hypothesis could help to avoid the conclusion that our world is just a weird bubble in an endlessly foaming multiverse.

Katherine Freese

In Search of Dark Stars

Katherine Freese, a physicist who will soon lead the Nordic Institute for Theoretical Physics, reflects on the hunt for dark matter and how dark matter heating may have produced the first stars.

Boucing droplet
quantum mechanics

Fluid Tests Hint at Concrete Quantum Reality

Surprising oil drop experiments suggest that the quantum world may not be as strange as advertised.

The arrow of time.

Time’s Arrow Traced to Quantum Source

A new theory explains the seemingly irreversible arrow of time while yielding insights into entropy, quantum computers, black holes, and the past-future divide.


A ‘Rebel’ Without a Ph.D.

A conversation with the mathematical physicist Freeman Dyson on quantum electrodynamics, climate change and his latest pet project.