quantum mechanics

Particles can penetrate energy barriers that classical physics says they cannot cross. This quantum phenomenon, first observed in radioactive decay, powers nuclear fusion in stars and modern electronics.

In 1932, Carl Anderson photographed a positron in a cloud chamber — the first antiparticle ever detected, confirming Dirac's 1928 relativistic quantum theory and opening the field of antimatter physics.

In 1923, Arthur Compton showed that X-rays scatter off electrons like billiard balls — shifting wavelength in a way only particles explain. The Compton effect settled the wave-particle debate and won the 1927 Nobel Prize.

Schrödinger's cat was designed in 1935 to mock quantum mechanics, not celebrate it. Here's what Schrödinger actually argued and what modern physics says now.

Alain Aspect's 1982 Bell test used entangled photons to close the locality loophole, violating Bell inequalities and ending Einstein's hidden-variable debate.

Einstein spent years designing thought experiments to break quantum mechanics. Bohr defeated every one. The Bohr-Einstein debates, from Solvay 1927 to the EPR paradox.

In 1927, Davisson and Germer fired electrons at a nickel crystal and found a diffraction pattern — direct proof of wave-particle duality. Here is how the experiment worked and what it confirmed.

The double-slit experiment shows light and matter interfering like waves until which-path information exists, from Thomas Young to single electrons and atoms.

The delayed-choice quantum eraser seems to show the future changing the past. It does not. Here is what Kim et al. 2000 actually demonstrated, and why it matters.

In 1911, Ernest Rutherford interpreted Geiger and Marsden's alpha scattering data and concluded that the atom has a tiny, dense nucleus. Here is how the experiment worked and what the results proved.

In 1922, Stern and Gerlach fired silver atoms through a magnetic field and watched the beam split in two. Here is exactly what they saw and why it rewrote physics.

In 1801, Thomas Young passed light through two slits and saw stripes on a screen that only waves can produce. The same experiment later revealed the quantum nature of matter.