Tag: quantum mechanics

• Physics in Everyday Life: The Quantum Mechanics and Relativity Running Your Phone, GPS and MRIWorks out the numbers behind three everyday machines: the band gap that sets an LED's color, the 38 microseconds a day GPS clocks gain, and the 5 ppm spin polarization MRI detects.PhysicsPhysics ColumnsHigh school / generalsemiconductorsrelativitynuclear magnetic resonancequantum mechanicsband gap~26 min
• Schrödinger's Cat: Where Does Superposition Stop?Unpacks the thought experiment of a cat in a box suspended between life and death using polarizer experiments and elementary vector algebra, up to the differences between the Copenhagen interpretation, many-worlds, and decoherence.PhysicsPhysics ColumnsHigh school / generalquantum mechanicssuperpositionmeasurement problemthought experimentdecoherence~21 min
• Operators and Observables: From Hermitian Operators and Commutators to the Uncertainty RelationWhy observables are represented by Hermitian operators, derived from the reality of expectation values; the meaning of the canonical commutation relation, a proof of Heisenberg's principle via Robertson's inequality, and measurement as projection.PhysicsQuantum MechanicsUndergraduatequantum mechanicsHermitian operatorscommutation relationsuncertainty principlemeasurement~33 min
• The Schrödinger Equation and the Wave Function: From the Born Rule to the Evolution of Expectation ValuesWe introduce the time-dependent and time-independent Schrödinger equations and prove the Born rule, the conservation of probability, the momentum operator and Ehrenfest's theorem.PhysicsQuantum MechanicsUndergraduatequantum mechanicsSchrödinger equationwave functionBorn ruleexpectation values~22 min