# Questions tagged [plane-wave]

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### Plane waves, angular momentum, and the 2D Schrödinger equation

I've been thinking about the 2D Schrödinger equation for a free particle, particularly in polar coordinates, and the particular solution $$\Psi(r, \phi) = J_1(r)e^{i\phi}.$$ This solution has an ...
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### Dispersion Relations in a Cold, Unmagnetized, Collision-less Plasma

Currently I am trying to understand the physics of waves in cold plasmas. So in a cold, collison-less, unmagnetized plasma you can derive two different different dispersion relations: one for ...
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### Plane Wave in a Periodic Lattice

From Introduction to Superconductivity; Second Edition; A.C. Rose-Innes and E. H. Rhoderick; Page 3 Electrons have, of course, a wave-like nature, and an electron travelling through a metal can be ...
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### Calculating in-duct sound intensities from sound pressure measurements with mean mass flow

In the time domain and in free field condition the sound intensity can be calculated as $\vec I(t)=p(t) \cdot \vec v(t)$ with $p(t)$ being the sound pressure and $\vec v(t)$ being the sound velocity. ...
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### How to formulate the expression of this EM wave? [closed]

Consider a plane EM wave polarised parallel to the $(Oz)$ axis, this wave propagate in empty space with direction $\overrightarrow{OD}$ in the $(Oxy)$ plane with an angle $\theta$ from the $(Oz)$ ...
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### What is meant by "bases" not belonging to state space and how are they possible?

Section A3 of Chapter II on mathematical basis of QM in Cohen-Tannoudji’s "Quantum Mechanics" book has me a bit confused. The section is named ...
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### What is the graphical representation of a wave plane of the form $e^{i(\vec{k}.\vec{r}-\omega t)}$ or $e^{i(k.x-\omega t)}$?

Let's consider a plane wave of the form $e^{i(\vec{k}.\vec{r}-\omega t)}$ Is the graphical representation the following or the following ? I'm wondering what is now the graphical representation for ...
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### How and why the state of free particle in quantum physics is represented by plane wave packet? [closed]

In Quantum Mechanics (Cohen Tannoudji) Topic: "Asymptotic Form Of Stationary Scattering States" It is written that for large negative values of $t$, the incident particle is free and it's ...
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### What is the propagation direction of plane wave?

As far I know, plane wave equation is given by: $$\vec{E}(\vec{r},t)=\vec{E_0} \cdot e^{i(\vec{k}\cdot \vec{r}-\omega t)} \hspace{2cm} \tag{1}$$ In some textbook propagation direction of $(1)$ is ...
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### Finding helicity eigenstates

Question: Give the mode expansion of the $A_i$ in terms of plane wave \epsilon^{\pm}_i(p)e^{-ip \cdot x} \ \ \ \ \ \text{ and } \ \ \ \ \ \epsilon^{*\pm}_i(p)e^{-ip \cdot x} \...
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### What Plane Waves Make a Gaussian Beam?

When I think of a light beam, what first comes to mind is this: Black lines are axes (both spatial axes, at a snapshot in time), and blue lines represent the surfaces of constant phase of a plane ...
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### Determining plane wave polarization given the magnetic-field vector phasor

Given the following magnetic-field vector phasor: $$\vec H(\vec r)=\left[\hat x - j\hat y\right]H_o e^{jkz}$$ I need to find the associated E-field vector phasor so that I can determine the ...
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Assume we have a step potential $$V(x)=\left\{\begin{array}{ll} 0, & x<0 \\ V_{0}, & x \geq 0 \end{array}\right.$$ and we fire particles from a distance $s$ towards the barrier from the ...