Quantum experiment revisits wave-particle debate

A recent experiment in quantum physics has reignited an old debate about whether particles behave like waves or follow precise paths. The study, published in Nature, challenges a theory that suggests particles are guided by waves, known as the Broglie-Bohm theory.

Origins of quantum theory

Quantum mechanics, developed over a century ago, has led to major technological advances like lasers and MRI machines. However, scientists still argue about how to interpret its principles, especially the nature of reality at the smallest scales.

Einstein versus the Copenhagen school

At the fifth Solvay Congress in Brussels, physicists debated two contrasting views. The Copenhagen school, led by Niels Bohr and Werner Heisenberg, argued that the universe is inherently random. Albert Einstein opposed this, believing that particles follow precise paths determined by their initial conditions.

Alternative quantum theory

Louis de Broglie proposed an alternative idea, called the pilot wave theory, in which particles are guided by waves. Though initially dismissed, the theory was later revived by David Bohm and is now known as the Broglie-Bohm or dBB theory. It was seen as an outdated idea by supporters of the Copenhagen interpretation.

New experiment challenges dBB theory

A recent experiment involving photons and a microbarrier aimed to test the dBB theory. Researchers claimed they observed evidence that contradicted the theory, suggesting particles could not cross the barrier as the theory predicted. This raised questions about the validity of the dBB model.

Reanalysis supports dBB theory

Further analysis by scientists from the Technion showed that the initial experiment had overlooked the optical properties of the barrier. When these factors were considered, the dBB theory no longer predicted zero velocity inside the barrier, and the observed particle movement aligned with its predictions. This suggests the theory remains valid.