Wave packet Definition and 111 Threads

  1. cepheid

    Understanding Gaussian Wave Packets: Momentum, Width, and Amplitude Explained

    Hi, I've got the right answer in this problem, but I'm not sure if I've got the correct reasoning Homework Statement A Gaussian wave packet travels through free space. Which of the following statements about the packet are correct for all such wave packets? I. The average momentum...
  2. X

    Wave packet vs relative probability

    For a free particle,the one dimensional Schrodinger's equation gives a solution of the form Ae^i(kx - wt).This solution does not meet the normalisation requirement.According to Bransden-Joachain's texr,there are 2 ways out of this difficulty.One is to superpose and form localised wave...
  3. M

    Proof that wave packet moves with the group velocity

    I’m currently taking a class in fluids in which we are studying different types of wave propagation. We discussed how for certain types of waves (such as deep-water ocean waves), the frequency (and phase speed) of each sinusoidal component is a functions of the wave number. This makes the...
  4. K

    Wave packet propagating in one dimension

    I am working on a problem that goes "Show that for a wave packet propagating in one dimension, for a free particle Hamiltonian" m d<x^2>/dt = <xp> + <px> What I think I want to do. Use d<A>/dt = i/hbar * <[H,A]> Which leads me to d<x^2>/dt = i/hbar * <[H,x^2]> For the free...
  5. F

    How Does Quantum Mechanics Combine Particle and Wave Descriptions?

    "The particle and the wave picture are both simplified forms of the wave packet description, a localized wave consisting of a combination of plane waves with different wavelength." it's confusing. Can somebody explain it? particle is an object, it seems wave is also an object.How to combine...
  6. S

    Solving Wave Packet Propagation: Analyzing Group and Phase Velocities

    Consider a wave packet represented by \Psi (x,t) = \int_{k-\Delta k}^{k+\Delta k} A \cos\left[k'(x-ct)\right] dk' A constant and ck' is the dispersion relation SOlve th integral and describe teh propogation properties of this wave packet. Assume this means that the phase and group...
  7. L

    Group velocity of relativistic wave packet

    Hi, I'm trying to figure out what the group and phase velocities of a wave packet describing a particle are in the relativistic case. I started with the relationship between energy and impulse : E squared = p squared X c squared + rest mass squared X c to the fourth. In this, I input the...
  8. quasar987

    Physical Interpretation of a Wave Packet: Single Beat Wavepacket

    In my wave final there was a quetion that went "Write the most general expression for a wave paquet in terms of a Fourier integral and explain what this integral corresponds to physically." What would have you answered to the second part of the question?
  9. D

    Is a photon an EM wave packet?

    The similarities between the classical wave packet and the QM photon are striking. They both move at the group velocity. They both are subjected to an uncertainty principle. A classical wave packet is like a photon a region of concentrated energy, ... So is a photon something like the...
  10. T

    Solving Wave Packet Problem: Tips & Guide

    I was wondering if anyone can give me some assistance on a homework problem. Here it is, Consider a wave packet defined by \begin{equation} \vec{A}(\vec{r},t)=\int \hat{\mathcal{A}}(\vec{k}-\vec{k_0}) \frac{e^{i(\vec{k}\cdot\vec{r}-\omega(k)t)}}{(2\pi)^{3/2}}d\vec{k} \end{equation}...
  11. J

    Understanding Wave Packets and their Role in Particle Physics

    I read that a wave packet is really some superposition of some waves with different wave number k (just slightly different k's). While the wave packet represents the particle, is there any meaning to the individual wave? How does physicists know what to superpose?
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