Physicists just proved that light beams can actually break Newton’s first law of motion and change direction on their own.
April 2, 2026
Original Paper
Characterization of non-classical particle propagation using superpositions of position and momentum
arXiv · 2604.00417
The Takeaway
Classical physics dictates that objects in motion must travel in a straight line unless acted upon by a force, but quantum interference can force individual particles of light to swerve and cluster in narrow intervals. This experiment proves that at the quantum level, even 'free' particles don't follow the simple rules of motion taught in every classroom.
From the abstract
The uncertainty principle suggests a quantitative trade-off between the control of position and the control of momentum in particle propagation. However, a superposition of two states with very different uncertainty trade-offs introduces an interference term that seems to combine precise statements about position and about momentum, allowing us to study how quantum mechanics describes the propagation of individual particles in free space. Here, we present a detailed experimental study of photons