MIT uses 10,000 ultracold atoms to settle 98-year debate between Einstein and Bohr

Interesting Engineering ^ | July 28, 2025 | Mrigakshi Dixit

[SunkenCiv]

Scientists have long grappled with a fundamental question: what exactly is light?

Is it a wave, flowing like ripples across water, or is it made up of tiny particles, like miniature paintballs zipping through space?

This fundamental question was at the heart of the double-slit experiment, demonstrating light's dual nature.

Just recently, physicists at MIT conducted an experiment using incredible atomic precision.

Interestingly, it has definitively resolved a long-standing debate between quantum giants Albert Einstein and Niels Bohr about the elusive nature of light...

Einstein believed he could devise an experiment to observe light's particle path and wave interference simultaneously.

Bohr, leveraging the uncertainty principle, argued that any attempt to measure the photon's path would inevitably disturb it and destroy the interference pattern.

Over the decades, many versions of the double-slit experiment have confirmed Bohr's view.

But now, MIT physicists, led by Professor Wolfgang Ketterle, have performed the most "idealized" version yet, taking it to its quantum core.

Instead of physical slits, they used individual ultracold atoms as the "slits."

The team cooled over 10,000 atoms to near absolute zero and arranged them in a precise, crystal-like lattice using lasers. Each atom was effectively an isolated, identical slit.

They then shone a very weak light beam, ensuring that "each atom scattered at most one photon."

The scientists hypothesized that their setup -- using individual atoms precisely arranged -- could serve as a miniature double-slit experiment...

They discovered a clear relationship: the more precisely they determined a photon's path (confirming its particle-like behavior), the more the wave-like interference pattern faded.

[Nateman]

There is also the many world's interpretation of quantum reality. It was put forward by Hugh Everett in 1957. Valid or not it energized Science Fiction with its alternative universe interpretations. Hugh Everett himself left the world of academia after he was not taken seriously. There is a delightful documentary about his son, Mark. Mark Oliver Everett went on to become moderately successful with his own rock band. This documentary is about his search into his dad's life and theory.

[aimhigh]

Question for an expert: How does light maintain its speed? If light bounces off an object, to go another direction, it maintains its original speed? Normally, the impact of any other moving object would slow down the object in motion.

[SunkenCiv]

https://physics.stackexchange.com/questions/66856/is-velocity-of-light-constant

[aimhigh]

Thanks

[Rennes Templar]

Interesting. I have looked at Kabbalah in the past. Fascinated with Ein Sof.