Quantum physics: reading the evidence

Start with what each apparatus records. Then ask what interpretation is justified, what alternative it constrains, and what remains untested. Compare thermal radiation, photon recoil and atomic excitation; then follow precision spectra into quantum control and Bell tests. Related Labs are linked where their models offer a useful comparison.

1. Blackbody radiation: a whole curve, not one quantum

   How did the long-wavelength evidence force a change in the law of thermal radiation?

2. Atomic spectra: evidence for states, not photographs of orbits

   How did a set of wavelengths become a test of atomic structure?

3. Franck–Hertz: what a falling current can establish

   Why does a loss of collected electrons reveal an atomic excitation energy?

4. Compton scattering: light must balance momentum too

   What does a shifted X-ray wavelength add to the evidence from photoemission?

5. The Stark effect: an electric field changes the spectrum

   What distinguishes a field-induced splitting from an ordinary drift or an unresolved broad line?

6. The Lamb shift: a missing signal reveals a missing correction

   How did a decrease in a metastable-atom signal challenge a successful hydrogen theory?

7. Mössbauer resonance: recoil has not disappeared

   How can a solid restore nuclear resonance without violating momentum conservation?

8. Ramsey and ion traps: make time to measure

   What changes when an atom can evolve longer, or remain available for repeated interrogation?

9. Laser cooling: when the temperature contradicted the model

   How did colder-than-expected atoms reveal what the simplest cooling theory left out?

10. Single quantum systems: what survives a measurement?

    How can a detector learn about one quantum system without simply consuming it?

11. Bell tests: correlations need an experimental contract

    Which assumptions turn a surprising correlation into evidence against a local hidden-variable model?