Fundamentals of Physics, II - Audio

Ramamurti Shankar

This is a continuation of the introductory course on the principles and methods of physics for students who have good preparation in physics and mathematics. This course covers electricity, magnetism, optics and quantum mechanics.

  1. 2011-04-01

    25 - Quantum Mechanics VII: Summary of postulates and special topics

    The various postulates of quantum mechanics treated in previous lectures are reviewed and summarized. The uncertainty principle is again discussed and a new one between energy and time is introduced. The quantum mechanical behavior of an electron in a hydrogen atom is described. The principles of quantum mechanics are then generalized to describe two or more quantum particles. It is shown that identical particles have to be bosons or fermions, the latter obeying the Pauli exclusion principle, which in turn is key to explaining the periodic table.

    3 sek

  2. 2011-04-01

    24 - Quantum Mechanics VI: Time-dependent Schrödinger Equation

    The time-dependent Schrödinger Equation is introduced as a powerful analog of Newton's second law of motion that describes quantum dynamics. It is shown how given an initial wave function, one can predict the future behavior using Schrödinger's Equation. The special role of stationary states (states of definite energy) is discussed.

    4 sek

  3. 2011-04-01

    23 - Quantum Mechanics V: Particle in a Box

    The allowed energy states of a free particle on a ring and a particle in a box are revisited. A scattering problem is studied to expose more quantum wonders: a particle can tunnel into the classically forbidden regions where kinetic energy is negative and a particle incident on a barrier with enough kinetic energy to go over it has a nonzero probability to bounce back.

    4 sek

  4. 2011-04-01

    22 - Quantum Mechanics IV: Measurement Theory, states of definite energy

    It is shown how to extract the odds for getting different values of momentum from a generic wave function by writing it as a sum over functions of definite momentum. A recipe is given for finding states of definite energy, which requires solving a differential equation that depends on what potential the particle is experiencing. The particle in a box is considered and the allowed energies derived.

    4 sek

  5. 2011-04-01

    21 - Quantum Mechanics III

    The fact that the wave function provides the complete description of a particle's location and momentum is emphasized. Measurement collapses the wave function into a spike located at the measured value. The quantization of momentum for a particle on a ring is deduced.

    4 sek

  6. 2011-04-01

    20 - Quantum Mechanics II

    Lecture begins with a detailed review of the double slit experiment with electrons. The fate of an electron traversing the double slit is determined by a wave putting an end to Newtonian mechanics. The momentum and position of an electron cannot both be totally known simultaneously. The wave function is used to describe a probability density function for an electron. Heuristic arguments are given for the wave function describing a particle of definite momentum.

    4 sek

  7. 2011-04-01

    19 - Quantum Mechanics I: Key Experiments and Wave-particle duality

    The double slit experiment, which implies the end of Newtonian Mechanics is described. The de Broglie relation between wavelength and momentum is deduced from experiment for photons and electrons. The photoelectric effect and Compton scattering, which provided experimental support for Einstein's photon theory of light are reviewed. The wave function is introduced along with the probability interpretation. The uncertainty principle is shown arise from the fact that the particle's location is determined by a wave and that waves diffract when passing a narrow opening.

    4 sek

  8. 2011-04-01

    18 - Wave Theory of Light

    Young's double slit experiment shows clearly that light is a wave. (In order to observe the wave behavior of light, the slit size and separation should be comparable or smaller than the wavelength of light.) Interference is described using real and complex numbers (in anticipation of quantum mechanics). Grating and crystal diffraction are analyzed.

    4 sek
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Om

This is a continuation of the introductory course on the principles and methods of physics for students who have good preparation in physics and mathematics. This course covers electricity, magnetism, optics and quantum mechanics.

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Mer från Yale University