Author Topic: Was Albert Einstein Wrong on This? (Read 403 times)

MikeLigalig.com · « **on:** August 12, 2025, 02:33:34 PM »

MIT physicists proved Einstein wrong in 100-year-old wave-particle dispute with Niels Bohr.

The 100-year-old quantum debate was solved using single atoms and single photons.

MIT physicists have performed an idealized version of the double-slit experiment. Their findings demonstrate, with atomic-level precision, the dual yet evasive nature of light. They also happen to confirm that Albert Einstein was wrong about this particular quantum scenario.

The double-slit experiment is now known for its surprisingly simple demonstration of a head-scratching reality: that light exists as both a particle and a wave. Stranger still, this duality cannot be simultaneously observed. Seeing light in the form of particles instantly obscures its wave-like nature, and vice versa.

The original experiment involved shining a beam of light through two parallel slits in a screen and observing the pattern that formed on a second, faraway screen. One might expect to see two overlapping spots of light, which would imply that light exists as particles, a.k.a. photons, like paintballs that follow a direct path. But instead, the light produces alternating bright and dark stripes on the screen, in an interference pattern similar to what happens when two ripples in a pond meet. This suggests light behaves as a wave. Even weirder, when one tries to measure which slit the light is traveling through, the light suddenly behaves as particles and the interference pattern disappears.

Nearly a century ago, the experiment was at the center of a friendly debate between physicists Albert Einstein and Niels Bohr. In 1927, Einstein argued that a photon particle should pass through just one of the two slits and in the process generate a slight force on that slit, like a bird rustling a leaf as it flies by. He proposed that one could detect such a force while also observing an interference pattern, thereby catching light’s particle and wave nature at the same time. In response, Bohr applied the quantum mechanical uncertainty principle and showed that the detection of the photon’s path would wash out the interference pattern.

Now, MIT physicists have performed the most “idealized” version of the double-slit experiment to date. Their version strips down the experiment to its quantum essentials. They used individual atoms as slits, and used weak beams of light so that each atom scattered at most one photon. By preparing the atoms in different quantum states, they were able to modify what information the atoms obtained about the path of the photons. The researchers thus confirmed the predictions of quantum theory: The more information was obtained about the path (i.e. the particle nature) of light, the lower the visibility of the interference pattern was.

They demonstrated what Einstein got wrong. Whenever an atom is “rustled” by a passing photon, the wave interference is diminished.

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.

By directing a faint light beam at the atoms, they could study how single photons interacted with two neighboring atoms, revealing whether the light behaved as a wave or a particle.

In the new variant to the double-slit experiment. These single atoms are like the smallest slits you could possibly build.

The team was able to precisely tune the “fuzziness” of these atomic slits by adjusting the laser light holding them.

The fuzziness of these atoms affected how much information was obtained about a photon’s path.

Their results fully agreed with quantum theory and revealed that any attempt to detect a photon’s path — even at the tiniest scale — diminishes the wave interference pattern. The findings also disproved a key prediction from Albert Einstein, validating Niels Bohr’s century-old argument in their famous debate.

By stripping away all but the essential quantum components — even removing the “spring-like” mechanism many past experiments used — the researchers showed that what matters is not the mechanical setup, but the quantum correlation between photons and atoms. The breakthrough, published in Physical Review Letters. Lead researcher Wolfgang Ketterle called the work “an idealized Gedanken experiment,” one that Einstein and Bohr could scarcely have imagined possible in their time.

Source:
https://news.mit.edu/2025/famous-double-slit-experiment-holds-when-stripped-to-quantum-essentials-0728

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MikeLigalig.com

Author Topic: Was Albert Einstein Wrong on This? (Read 403 times)

MikeLigalig.com

Was Albert Einstein Wrong on This?