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Simple Nature - Light and Matter

Simple Nature - Light and Matter

Simple Nature - Light and Matter

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ExercisesExercise 13A: Quantum Versus Classical R<strong>and</strong>omness1. Imagine the classical version of the particle in a one-dimensional box. Suppose you insertthe particle in the box <strong>and</strong> give it a known, predetermined energy, but a r<strong>and</strong>om initial position<strong>and</strong> a r<strong>and</strong>om direction of motion. You then pick a r<strong>and</strong>om later moment in time to see whereit is. Sketch the resulting probability distribution by shading on top of a line segment. Doesthe probability distribution depend on energy?2. Do similar sketches for the first few energy levels of the quantum mechanical particle in abox, <strong>and</strong> compare with 1.3. Do the same thing as in 1, but for a classical hydrogen atom in two dimensions, which actsjust like a miniature solar system. Assume you’re always starting out with the same fixed valuesof energy <strong>and</strong> angular momentum, but a position <strong>and</strong> direction of motion that are otherwiser<strong>and</strong>om. Do this for L = 0, <strong>and</strong> compare with a real L = 0 probability distribution for thehydrogen atom.4. Repeat 3 for a nonzero value of L, say L=.5. Summarize: Are the classical probability distributions accurate? What qualitative featuresare possessed by the classical diagrams but not by the quantum mechanical ones, or vice-versa?904 Chapter 13 Quantum Physics

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