wave-particle duality

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.

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.

Quantum mechanics rests on five foundational principles that explain all atomic and subatomic behavior. This primer covers each principle, its experimental basis, and what it means.

Heisenberg showed that position and momentum cannot both be sharply defined at once. This is not a limit of our instruments. It is built into how quantum states work. Here's why.

Discover how light acts as both particle and wave, fundamentally challenging our understanding of reality