Wave Definition and 999 Threads

  1. S

    I Gravitational wave interactions and the equivalence principle

    According to wikipedia, the strong equivalence principle states “the gravitational motion of a small test body depends only on its initial position in space time and velocity, and not on its constitution, and the outcome of any local experiment (gravitational or not) in a freely falling...
  2. Addez123

    Find Wavelength of Light Wave for Optimal Constructive Interference

    The green ray is moved upwards for clarity, they are all on same x-axis with no y component. Theres a phaseshift at both reflections of the green light because n1 and n3 are > n2. This results in a complete wavelength phaseshift, aka no impact on the wave. That means that only the extra travel...
  3. Haynes Kwon

    I Fourier Transform of the Wave function

    Given that the wave function represented in momentum space is a Fourier transform of the wave function in configuration space, is the conjugate of the wave function in p-space is the conjugate of the whole transformation integral?
  4. olgerm

    I Wave function for a helium atom

    Can you say whether I understood these things correctly? to get condition on wavefunction ##\Psi## for a system that consists of 2 electrons(without taking spin into account) and helium nuclei I can solve schrödinger equation: ##i*\frac{\partial \Psi}{\partial...
  5. J

    I How do waves following a shockwave catch up to the shock wave?

    I was in an argument about a jet engine and I was arguing that since there is a cutoff in terminology what would kill someone approaching a engine is not technically sound, but a shock wave, (I'm probably wrong about this, but that's not the question). That got me wondering how waves can catch...
  6. Haynes Kwon

    I Why does the square of the amplitude of a wave function represent P?

    Born's postulate suggests if a particle is described a wave function ψ(r,t) the probability of finding the particle at a certain point is ψ*ψ. How does this work and why?
  7. T

    Wave motion and two detectors to measure that motion

    Solving for t' by substitution I obtained t' = 7/8. Then I substituted x= 10 and t = 7/8 in the given equation. Is that the right way to do it? My answer key says the answer is 100 but I am getting 78.5.
  8. N

    Vector and scalar potentials for an EM plane wave in a vacuum

    Lorentz gauge: ∇⋅A = -μ0ε0∂V/∂t Gauss's law: -∇2V + μ0ε0∂2V/∂t2 = ρ/ε0 Ampere-Maxwell equation: -∇2A + μ0ε0∂2A/∂t2 = μ0J I started with the hint, E = -∇V - ∂A/∂t and set V = 0, and ended up with E0 ei(kz-ωt) x_hat = - ∂A/∂t mult. both sides by ∂t then integrate to get A = -i(E0/ω)ei(kz-ωt)...
  9. e101101

    Complex representation of a wave

    Homework Statement: Hi there, I'm currently taking an Optics course and the teacher is expecting us to have an understanding of the complex representation of waves. Although, hardly any of us have even heard of this yet. I've tried to google how to convert a cos(obj) and sin(obj) to an...
  10. dRic2

    I Wave function of a scattered particle and cross section

    In Landau-Lifsits's book about non relativistic QM it is said that if I have a particle described by a plane wave ##\phi = e^{ikz}## (I think he choses the ##z## direction for simplicity) the wave function after the scattering event is (far from the scattering event) $$\psi \approx e^{ikz} +...
  11. B

    Shock wave through a liquid metal filled steel tube

    Would an A36 steel tube filled with liquid mercury be able to transmit a shock wave longitudinally through the liquid mercury with a peak pressure higher than the yield strength of the steel tube? My thinking is that since the shock wave is traveling normal to the tube wall, it should not be...
  12. Haorong Wu

    How to calculate a wave function in time t

    I use the equation ##\psi \left ( x, t \right ) = e^{-iEt/\hbar} \psi \left ( x,0 \right )## to calculate ##\psi \left ( x , t \right)##, and the result is ##\psi \left ( x , t \right) = \frac 1 {\sqrt {2 \pi \hbar}} exp \left [ \frac {ip_0 x} {\hbar} - \frac {i p^2 t} {2m \hbar} \right...
  13. T

    Shock Wave Front: How Does Source Movement Create Waves?

    So when the source is not vibrating, it is not setting waves due to vibration? But it is moving so it is still causing disturbance in the medium ... And I happened to read that if the source is moving faster than the speed of sound, a shock wave is set up. How ?
  14. I

    A How can you generate a sine wave using integers only?

    I need to recursively generate a quadrature signal which fits exactly into a grid NxN, where N is a large power of two. After unsuccessful research, I decided to develop my own solution, starting from the waveguide-form oscillator taken from Pete Symons' book 'Digital wave generation, p. 100'...
  15. A

    I Why simultaneous detection of wave and particle nature is not possible

    We have been taught that the there is no experiment designed to detect wave and particle nature of light simultaneously. Also, that light propagates by the virtue of its wave nature and interacts by the virtue of its particle nature. let us take an electron beam passing through two slits...
  16. christang_1023

    Derivation about the wave interference

    Starting from the simple case, there is a single wave ##e=a\cos(2\pi ft+\frac{2\pi}{\lambda}x+\phi_0)##, and integrate in such a way, where ##T_{eye}## stands for the response time of human eyes' response time towards energy change: $$I=\int_{0}^{T_{eye}}e^2dt$$ The calculation includes...
  17. nineteen

    How to find the frequency of the second wave?

    I don’t understand how to approach this. So I couldn’t make an attempt at a solution. Please help me understand better. Thank you in advance.
  18. H

    I How to collapse a water wave through a double slit into particle behaviour?

    Electrons passing through a double slit is in a superposition of passing through the left slit and the right slit, thereby producing an interference pattern on the screen. But when a detector is placed to detect which slit the electrons pass through, the interference pattern is destroyed. How...
  19. J

    I Wave damping on a stretched string

    Is there a simple model I can use to describe the damping of a wave on a string? Is c = 2*mu*sqrt(T/mu) where mu is damping coefficient, mu is linear density and T is tension a valid option? I replaced k and m with T and mu from the simple equation found here. What I am interested in showing is...
  20. jdou86

    Wanting to understand the linearity of wave equations

    dear yall with tranditional wave equation on the gre book it says by the linearity in function f which represents wave. it leads to the principle of superposition. I get an intuition about with a standing wave with cos(x)cos(t) you can break it down to pair of left and right moving waves. i...
  21. H

    I Wave function when there is coupling between spin and position

    Why can't the general state, in the presence of coupling, take the form $$\psi_-(r)\chi_++\psi_+(r)\chi_-$$ where ##\psi_+(r)## and ##\psi_-(r)## are respectively the symmetric and anti-symmetric part of the wave function, and ##\chi_+## and ##\chi_-## are respectively the spinors representing...
  22. Lynch101

    B Entanglement & Wave Function Collapse

    This thread is to look at the notion of wave function collapse and relativity of simultaneity. The other thread I started on QFT has helped to clarify a lot, so hopefully this one can do the same. I may have this all wrong, but I will outline my question and hopefully someone can point out...
  23. michael872940

    Can I determine mass & spring k from graph of wave, t, a, & vectors?

    Classical problems for hookes law generally give either mass or spring constant. What if I have a graph of a wavelike structure that is oscillating which I can use to measure for example: T (period), t (time), Δx (displacement), v (velocity), a (acceleration) and other variables is this...
  24. Jamister

    I How can the photon wave function be described?

    Fermions such as the electron and proton can be described by wave function in momentum and in position, and it is possible to get the momentum wavefunction from space wave function and vice versa by Fourier Transform. what about photons? can photons be described by position wave function? If...
  25. H

    I Does a Gaussian wave packet remain Gaussian?

    Consider a gaussian wave packet whose wave function at a particular instant of time is Its time dependence is implicit in the "constants" A, a, <x> and <p>, which may all be functions of time. But regardless of what functions of time they may be, these constants will take on some values at...
  26. P

    A Real image of a sawtooth standing wave in a musical string?

    Hi there I am teaching resonance and standing waves in stringed instruments at the moment at high school. The theory states that a number of standing waves simultaneously (harmonics) exist in a naturally vibrating musical string, but with varying amplitudes, the 1 st harmonic being loudest...
  27. P

    How to solve this sound problem (minimum sampling rate required)

    Summary: The problem: If one wants to make a digital record of sound such that no audible information is lost, what is the longest interval, Δt, between samples that could be used? ( it gives a hint that humans can hear sound waves in the frequency range 20 Hz to 20 kHz. It should be a very...
  28. A. Neumaier

    I Wave-particle duality revisited: Neither wave nor particle

    Jan Sperling et al., Wave-particle duality revisited: Neither wave nor particle, arXiv:1907.09836 From the abstract:
  29. J

    A Using the 2d wave equation or the Kirchhoff plate equation

    I would like to model the dynamics of a plate. Is it ok to use just the 2d wave equation if the plate will be under tension and fixed at the boundaries? I am a bit confused what the point of the Kirchhoff plate equation is in that case, is it for when the plate is self supporting? Many thanks
  30. novera

    Seemingly simple Physics 2 wave question (third harmonic frequency)

    I cannot find the correct answer anywhere online and the answer I keep getting is 5.4 (incorrect) Please show me the process to get to the answer! Thank you
  31. person123

    MATLAB MATLAB API For Wave Flume Data Analysis

    (As a quick note, 'wave flume' should be taken rather generally. I basically just mean the sort of experiments involved in the flow of water which may use instruments such as pressure gauges, load cells, wave gauges, and ADVs. I know that they're not always done in a flume per say -- the...
  32. L

    I Can we truly ignore the existence of quantum objects between measurements?

    We always think in terms of isolated particles. It's better to analyze it with solids. If wave functions were just calculational tools. Molecules like the following still interact by wave functions, right? So how can it be calculational tool? And if it is, then what model do you use to...
  33. L

    I Objective Wave Function and Non-locality

    In interpretations where the wave function represents something real, like Many worlds, Copenhagen with objective wave function and spontaneous objective collapses. I'd like to understand which of them has true non-locality. First. Is Many Worlds not having true non-locality due to the...
  34. F

    I How to Determine a Photon's Wavefunction After it Collapses?

    Suppose one measures the position of a photon without destroying it. From my understanding, the wavefunction of the photon should collapse, and will return to a more spread out state over time. How would one calculate this, specifically the rate at which the wavefunction spreads out from the center?
  35. Jarvis323

    Noisy Wave Pattern Between Round Objects Behind a Light

    I noticed that if I hold two small rounded quartz stones together in front of my eye, with light shining on them from the other direction, I see what looks like a very distinct, black, noisy waveform between them. Does anyone know the detsals about wy this happens?
  36. Andy_K

    B Quantum Wave & Principle of Least Action

    Dear All, I would like to better understand how the Principle of Least Action applies in observations / measurements in quantum physics. Does the wave function of a particle correspond directly to the principle of least action, as in, the positions with higher probability of detecting the...
  37. B

    I Basic doubt on chain rule in DAlemberts soln to wave equation

    In D Alembert's soln to wave equation two new variables are defined ##\xi## = x - vt ##\eta## = x + vt x is therefore a function of ##\xi## , ##\eta## , v and t. For fixed phase speed, v and given instant of time, x is a function of ##\xi## and ##\eta##. Therefore partial derivative of x w.r.t...
  38. E

    Compute the energy for 2D wave function with discontinuous derivatives

    I have calculated the normalization constant, but I'm struggling with the discontinuities in the derivatives of the wave function. Due to the symmetry, it should suffice to consider the first two cases. The results should be (according to WolframAlpha): \left( \frac{\partial^{2}}{\partial...
  39. MichPod

    A How momentum measurement is defined in Pilot Wave interpretation?

    Considering pilot wave interpretation, a singular particle measurements are fully defined (?) by knowing its wave function (a pilot wave) and the position of the "particle" (some hypotetical point particle riding on the wave). This should provide some sort of "realistic" explanation of how a...
  40. QuasarBoy543298

    I Particle in free space - what happens to the wave function after measurement?

    If I'm trying to solve the problem of a particle in free space (H = P2/2m ). the eigenfunctions of the Hamiltonian cannot be normalized. now assume I have a legitimate wave function expressed in terms of the eigenfunction of H and I want to measure its energy. what will happen to the...
  41. J

    Pinhole Diffraction of a Spherical Wave

    Case (a) is the textbook of a planar incident wavefront and below it in the figure is the known simple formula for the central spot and fringes, or minima and maxima, angular distribution with respect to the optical axis. So, the question here is regarding case (b). The position (usually...
  42. B

    I D'Alembert's solution to the wave equation

    Hi On page 81 of the book "A student's guide to waves by Fleisch and Kinneman a conclusion is made while differentiating D Alembert's solution to the wave equation. Will someone explain this please ? The details are in the attachment TIA
  43. M

    B Double Slit Wave Interference With Single Electrons

    I have heard that wavelike interference patterns are observed in the double slit experiment even when electrons are fired one by one. https://physicsworld.com/a/the-double-slit-experiment/ My knowledge on the experimental setup is very basic. The reason I am posting here is out of curiosity...
  44. dRic2

    I Green's function for the wave equation

    Hi, I'm reading "Wave Physics" by S. Nettel and in chapter 3 he introduces the Green's function for the 1-dimensional wave equation. Using the separation of variables method he restricts his attention to the spatial component only. Let ##u(x)## be the spatial solution to the wave equation and...
  45. B

    Single photon wave packet autointerference

    I've been troubled by this problem for some time now and have received several answers to it none of which I find compelling, so I am posing it again in hopes of getting something more convincing. Here's the problem. Consider one had a large optical interferometer with two siderostats place...
  46. I

    I Instantly reformable wave packets instead of "particles"?

    Hello, I am a high school physics teacher, and I have been thinking about a way to model quantum mechanics in an intuitive way in order to teach it better, but I don't want to lead my students down the wrong path. I am certainly no expert in quantum theory. In looking at the guidelines, I...
  47. J

    I Electron wave funtion harmonic oscillator

    As we see in this Phet simulator, this is only the real part of the wave function, the frequency decreases with the potential, so lose energy as moves away the center. we se this real-imaginary animation in Wikipedia, wave C,D,E,F. Because with less energy, the frequency of quantum wave...
  48. M

    How to find the velocity of a wave in simple harmonic motion given time

    The graph provided is below. The problem asks for the speed of the wave at 0.12s. I used the formula v=w*xmax*cos(wt), provided in our textbook where xmax is the amplitude of 2 cm, w (omega) is 2pi divided by the period of 0.2. However, for some reason this formula doesn't give me the correct...
  49. W

    Derivation of the wave equation on a curved space-time

    I'm confused by this question, from minimal coupling shouldn't the answer simply be ## \nabla^a \nabla_a F_{bc} = 0 ##? Any help would be appreciated. EDIT: I should also point out ##F_{ab}## is the EM tensor.
  50. G

    Calculating the Force of a Sound Wave on an Object

    Hello, I am going to be doing a project in which I'll be looking at how sound waves change the shape of an object. Specifically how sound waves can compress something. My question is, can I approximate a sound wave as a force in this case? I know a sound wave is much more complicated than a...
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