The development of quantum theory began with Max Planck’s solution to the black‑body radiation problem in 1900, followed by Einstein’s explanation of the photoelectric effect in 1905. The formalism was later refined by Schrödinger, Heisenberg, Dirac, and many others, leading to the modern framework used in chemistry, condensed matter, particle physics, and quantum information science.
Introduction
Quantum mechanics is the fundamental theory describing the behavior of matter and energy at the smallest scales—atoms, electrons, photons, and beyond. It departs from classical physics by introducing concepts such as wave‑particle duality, quantization, and uncertainty.
Key Principles
Particles exhibit both wave‑like and particle‑like properties. The de Broglie wavelength λ = h/p relates a particle’s momentum p to its wavelength.
It is impossible to simultaneously know a particle’s exact position and momentum. Δx·Δp ≥ ħ/2.
A system can exist in multiple states simultaneously until measured. This principle underlies quantum computing.
Two or more particles become linked such that the state of one instantly influences the other, regardless of distance.
Famous Experiments
- Double‑slit experiment – demonstrates wave‑particle duality.
- Einstein‑Podolsky‑Rosen (EPR) paradox – challenges local realism.
- Bell’s inequality tests – confirm entanglement.
- Quantum teleportation – transfers quantum states.
Interactive Quiz
Test your knowledge: