Copenhagen interpretation

Quantum decoherence

Quantum decoherence explains wavefunction collapse through environmental interaction

Measurement in quantum mechanics

Quantum states describe probabilities, not certainties

Relativity of simultaneity

Simultaneity depends on the observer's motion

Physical paradox

Einstein argued entanglement implied either hidden variables or nonlocality

Symmetry (physics)

Symmetry leads to energy conservation

Bell's theorem

Bell's theorem disproves local hidden-variable theories