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Physics World October 2025

Physics World October 2025

Causal chaos: what happens when cause and effect are in a quantum superposition

In the latest of our series of articles about weird quantum effects, Hamish Johnston examines the notion of “indefinite causal order”, which is challenging our understanding of cause and effect. Also this month, there’s an interview with Nobel-prize-winning physicist William Phillips, along with a panel discussion on how quantum technology is boosting quantum fundamentals. Finally, don’t miss our look at careers for physicists in intelligence and cyber security at GCHQ.

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computer graphic of human skull superimposed with colourful representation of quantum physics feature

Why quantum technology is driving quantum fundamentals

GCHQ spelt out in Scrabble pieces on a chess board careers

What it means to have a career in intelligence and cyber security

William Phillips interview

A passion for quantum physics

Traffic lights showing amber opinion

AI needs good data

Illustration of clock faces distorted feature

How quantum physics is challenging causality

a kingfisher under water with a small fish in its beak review

More physics than birds

Photo of ESA astronaut Rosemary Coogan interview

Training for the stars

Students struggling in an exam news

Concern over A-level physics exams

Abstract illustration of two people in a cityscape with machine cogs opinion

Physics for presidents

Graphic showing a red laser beam illuminating a pair of atoms. A screen behind the atoms shows red and black interference fringes research update

Famous double-slit experiment gets its cleanest test yet

Stefano Mensa interview

Taking the risk out of quantum computing

Abstract visualization of two entangled particles connected by a glowing beam of light opinion

Quantum physics is at a crossroads

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