What is De broglie: Definition and 272 Discussions

Louis Victor Pierre Raymond, 7th Duc de Broglie (, also US: , French: [də bʁɔj] or [də bʁœj] (listen); 15 August 1892 – 19 March 1987) was a French physicist and aristocrat who made groundbreaking contributions to quantum theory. In his 1924 PhD thesis, he postulated the wave nature of electrons and suggested that all matter has wave properties. This concept is known as the de Broglie hypothesis, an example of wave–particle duality, and forms a central part of the theory of quantum mechanics.
De Broglie won the Nobel Prize for Physics in 1929, after the wave-like behaviour of matter was first experimentally demonstrated in 1927.
The 1925 pilot-wave model, and the wave-like behaviour of particles discovered by de Broglie was used by Erwin Schrödinger in his formulation of wave mechanics. The pilot-wave model and interpretation was then abandoned, in favor of the quantum formalism, until 1952 when it was rediscovered and enhanced by David Bohm.Louis de Broglie was the sixteenth member elected to occupy seat 1 of the Académie française in 1944, and served as Perpetual Secretary of the French Academy of Sciences. De Broglie became the first high-level scientist to call for establishment of a multi-national laboratory, a proposal that led to the establishment of the European Organization for Nuclear Research (CERN).

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  1. weezy

    Doubt regarding derivation of De Broglie relation

    For someone who's familiar with the de Broglie relation it's easy to say that for k=0 we have p=0 but how would we know that before deriving the result? In this image the author derives de Broglie relation by considering a wave packet in motion. As you can see where I have star-marked the author...
  2. Phynos

    De Broglie Wavelength for 1Mev electron

    Homework Statement Calculate the de Broglie Wavelength of a 1 MeV electron. Express your answer in femptometers. Homework Equations ## λ = h/p ## ## p = (2mT + T^2/c^2)^{1/2} ## The Attempt at a Solution basically just plugged everything in. ## λ = \frac{h}{(2mT + T^2/c^2)^{1/2}} ## ## λ...
  3. C

    De Broglie wavelength of a train

    Homework Statement Imagine you are traveling in a train, and see in the distance how the train path splits into two parallel tracks separated by a distance d.1) Obtain an analytical expression of the de Broglie wavelength of the train. 2) What condition would you use to determine at what point...
  4. A

    De Broglie Bohm interpretation with virtual particles....

    Hi all, This question is similar to a question asked previously, but slightly different. I understand that there have now been attempts to extend the Broglie-Bohm, or Pilot Wave, interpretation of QM to QFT. I'm a layman, but if I understand correctly, the standard method for computing the...
  5. W

    De broglie wavelength for helium and distance between atoms

    Homework Statement Consider a balloon filled with helium gas at room temperature (T = 294 K) and atmospheric pressure. Calculate (a) the average de Broglie wavelength of the helium atoms and (b) the average distance between atoms under these conditions. The average kinetic energy of an atom is...
  6. O

    De Broglie wave length, average electron energy and momentum calculation

    Homework Statement Calculate the average electron energy of an electron in an electron gas at thermal equilibrium. Temperature is 315K. Calculate the average electron momentum. Calculate the de Broglie wave length of the electron Homework Equations 3*kT/2 The Attempt at a Solution [/B] Part...
  7. Safinaz

    Calculating the De Broglie Wavelength of an Accelerated Particle

    Homework Statement A particle of mass m and charge q is accelerated across a potential dierence V to a non-relativistic velocity. What is the de Broglie wavelength of this particle? Homework Equations Is it The Attempt at a Solution I think it's ## \frac{h}{\sqrt{2mqV}} ##, because ##...
  8. F

    Show change in de Broglie wavelength from change in speed

    Homework Statement Show that for a nonrelativistic particle, a small change in speed leads to a change in de Broglie wavelength given from The Attempt at a Solution I have tried to expand the left hand side of the equation, but found that it gave the answer of v0/delta v. My definition of...
  9. Molar

    De Broglie wavelength of an atom

    In my book it is says, DeBroglie wavelength of a particle at temp T is, λ = h/√(2mKT) and DeBroglie wavelength of He atom is, λ = h/√(3mKT) Well, λ = h/ mv and mv2/2 = (3/2) KT and so , λ = h/√(3mKT) How to prove the first one..?? and why they are different...??
  10. F

    Nonrelativistic de Broglie energy Threshold of 1%

    Homework Statement Determine at what energy, in electron volts, the Nonrelativistic expression for the de Broglie wavelength will be in error of 1% for an electron. 2. The attempt at a solution For the error to be 1%, that means that the classical wavelength/relativistic wavelength will be...
  11. J

    What Is the True Nature of Electrons According to de Broglie's Theory?

    This is going to seem like it should be an educational question, and perhaps it should, but please bear with me, because I think that it has theoretical content. A nice quote that I recently heard someplace went something like: "We used to argue about whether electrons [etc] were particles or...
  12. K

    De Broglie wavelength of nitrogen molecules

    Homework Statement According to statistical mechanics, the average kinetic energy of a particle at temperature T is 3kT/2, where k is the Boltzmann constant. What is the average de Broglie wavelength of nitrogen molecules at room temperature? Homework Equations KE = 3kt/2 = p2/2m λ = h / p...
  13. K

    1-D standing de Broglie wave

    Homework Statement A free proton moves back and forth between rigid walls separated by a distance L = 0.01 nm. a) If the proton is represented by a one-dimensional standing de Broglie wave with a node at each wall, show that the allowed values of the de Broglie wavelength are given by λ = 2L/n...
  14. davidbenari

    Question about the De Broglie Hypothesis

    I'm having a hard time understanding the De Broglie hypothesis in a mathematical form. So my book says that Individual matter waves have a frequency ##f=E/h## and a wavelength ##\lambda=h/p##. This is said as if the individual component sine waves of my complete wave packet have these frequency...
  15. D

    De Broglie wavelength of an ant

    An ant of mass m = 1.80×10−6 kg goes through a hole of diameter D = 5.00 mm in a window screen which has thickness L = 0.600 mm. (a) What should be the approximate wavelength and speed of the ant for it to show wave behavior as it goes through the hole? I am not sure what should the...
  16. C

    What is the relationship between De Broglie frequency and energy in QM and QFT?

    As we know de broglie wavelength is λ = h/p and f = E/h λ = h/p v/f = h/mv as f*λ=v then f = mv^2/h but it should f = E/h and E=1/2*mv^2
  17. A

    Calculating energy from de Broglie wavelength

    Given the relationships: \lambda = \frac{h}{p} = \frac{h}{mv} and E = hf for wavelike non-relativistic matter, and v = \lambda f for a general wave, one can obtain the result: E = \frac{h^2}{m \lambda^2}. Whilst for particulate matter, we have E = \frac{1}{2}mv^2, which when combined with the...
  18. predaylight

    De Broglie wavelength and ideal gas entropy derivation

    When the ideal gas entropy is derived, we consider N atoms in a box of volume=Lx*Ly*Lz. Then, we make the assumption that Lx,Ly,Lz >>de Broglie wavelength of atoms. I am not sure why we need to make this assumption? Thanks!
  19. Avatrin

    De Broglie Wavelength at Relativistic velocity

    Homework Statement A particle has charge e and masse m0. It is accelerated by a charge V to a relativistic velocity. Show that its de Broglie wavelength is: \lambda = \frac{h}{\sqrt{2m_0eV}} (1+\frac{eV}{2m_0c^2})^{-\frac{1}{2}} Homework Equations \lambda = \frac{h}{p} Conservation of...
  20. C

    Physical meaning of a wave packet w/ respect to HUP&duality

    I'm a QM noob/newb trying to understand the physical implication of a wave packet, in my mind it is something like this: On the x-axis there is displacement (vibration), probability on the y. I Imagine stretching and compressing the wave packet. When I stretch it out, the amplitude must...
  21. Akash Pardasani

    Propagation of de Broglie waves

    I had a doubt regarding the propagation of de Broglie waves. How do we know the speed of propagation of these waves and also do there characteristics( speed and amplitude and frequency) depend on the source particle ( or they depend only on the motion(momentum) of the source and no whatsoever...
  22. D

    De Broglie wavelength of a tennis ball

    This is a multiple choice question. The de Broglie wavelength of a moving tennis ball is calculated as 1x10^-33. This means that the moving tennis ball A)Diffracts through a narrow slit. B)Does not behave as a particle C)Does not display wave properties D)Is traveling at the speed of light The...
  23. J

    De Broglie Wavelength of an electron

    1. The velocity of the electron in the ground state of the hydrogen atom is 2.6 x 10^8 m/s. What is the wavelength of this electron in meters?2. De Broglie's equation: lamda = h/p p=mvThe Attempt at a Solution ... (6.626 x 10^-34) / (2.6 x 10^8 x 9.11 x 10^-31) = 2.798 x 10^-12 meters This...
  24. L

    What waves in wave-particle duality according to de Broglie

    NON-LINEAR WAVE MECHANICS A CAUSAL INTERPRETATION by LOUIS DE BROGLIE "Since 1954, when this passage was written, I have come to support wholeheartedly an hypothesis proposed by Bohm and Vigier. According to this hypothesis, the random perturbations to which the particle would be constantly...
  25. L

    De Broglie wavelength of helium atoms

    Homework Statement a) In the double slit interference pattern for helium atoms, the kinetic energy of a beam of atoms is 0.020 eV. What is the de Broglie wavelength of a helium atom with this kinetic energy? b) Also, estimate the de Broglie wavelength of the atoms from the fringe spacing...
  26. H

    De Broglie wavelength - model for comparing photons and electrons

    Hello, I'm thinking about the wavelength of a freely propagating photon vs. a freely propagating electron. For the photon, we have the classical picture of oscillating E and B fields perpendicular to the direction of propagation, and we call the wavelength of the photon, which can be...
  27. A

    What's the Flaw in De Broglie's Derivation of Wave-Particle Duality?

    Hi all, De Broglie had proposed the theory of wave particle duality. But I don't understand how the relation λ=h/(mu) holds true. I will tell you why: De Broglie's derivation: E=mc2 and E=hv So mc2=hv Thus, λ=h/(mc) and for particles its h/(mu). I have a problem in the last line...
  28. P

    De Broglie theory and relativity

    After suitable study I'd have to say that it is a misnomer to state that de Broglie's theory is not relativistic. But it does express relativity in such a unique way that it becomes a replacement for Newtonian mechanics within any chosen single inertial frame. The most basic expression is...
  29. xortdsc

    De Broglie wavelength computable by just fixing speed of light ?

    Hi, I was wondering if it is possible to compute e.g. bohr radii for a metric system whose correspondence to real units is unknown and only the speed of light is known. Let's say the only thing I know is that lightwaves travel x spaceunits in t timeunits, therefore defining the speed of...
  30. A

    Mechanistic explanation of de Broglie wavelength

    I am not proposing a particular explanation and just in case you suspect I have something in mind, I must tell you that I don't. I was wondering if anybody here has some ideas. I understand that you may have objections to my question. One of them might be that a mechanistic model would not work...
  31. F

    De Broglie Wavelength Thought Problem

    Homework Statement A) Find the wavelength of an Ewok that has a mass of 50kg and is Running on Edor where 'h' id 1000Js at a velocity of 0.5m/s Yes the value of h to be used is 1000. B) What would the implications of him running be?Homework Equations \lambda=\frac{h}{p}The Attempt at a...
  32. S

    Question regarding the de Broglie wavelength of a particle.

    Homework Statement A particle with charge e and mass m_0 is accelerated by a potential V to a relativistic speed. Show that the de Broglie wavelength is: λ = h / √(2 m_0 eV ) √(1+( eV / 2 m_0 c^2 )) Homework Equations E = qV λ = h/p E = √(p^2 * c^2 + m^2 * c^4 ) p = (m_0 * v) / (1 -...
  33. S

    De Broglie Waves: Exploring Probability & Wave Nature of Particles

    I have a hard time understanding some very fundamental things about matter waves. To start with, the basic question is what are these De Broglie waves? Is it just a pure mathematical concept that describes probability of the particle to be in a certain place or is it some property of space? As I...
  34. R

    Units of the Thermal de Broglie wavelength?

    1. Units of the Thermal de Broglie wavelength? 2. λ = h / (2*pi*mkT)^(.5) 3. through dimensional analysis i get S (J / kg)^.5 can you even have .5 of a unit?
  35. G

    How Do Electrons Exhibit Standing Wave Behavior in Atomic Orbits?

    Could anyone please push to the right direction... Bohr's model of Atom. Energy quantized. Angular momentum. - I understand that Standing waves - know what it is. But, when it come to the question why electrons being always accelerated don't radiate, I have a problem. It says that, the...
  36. M

    How does de Broglie postulate enter into the Schroedinger theory?

    How does de Broglie postulate enter into the Schroedinger theory?
  37. bohm2

    De Broglie dynamics fine/Bohmian dynamics untenable?

    An interesting paper within the pilot-wave camp by Colin/Valentini arguing in favour of de Broglie dynamics over Bohmian mechanics: Instability of quantum equilibrium in Bohm's dynamics http://lanl.arxiv.org/pdf/1306.1576.pdf
  38. T

    Issue with mass in de Broglie wave

    I was looking for a frequency by calculating the wavelength, and I found the answer. However, I have no idea where I came up with one of the values! my notes say: wavelength = Planck Constant / (proton mass * velocity) My values: 1.9078e-21 m = 6.63e-034 / (2.81e-8 * 1.236e-5) The...
  39. G

    The correct pronounciation of de Broglie

    Is this correct? http://upload.wikimedia.org/wikipedia/commons/3/34/De_Broglie.ogg
  40. W

    De Broglie Equations: Exploring Matter Waves

    The de Broglie equations describing matter waves are $$\lambda = \frac{h}{p} , f = \frac{E}{h} .$$ When these are substituted into ##v = \lambda f## the result is $$v = \frac{E}{p} .$$ Now, when ##E = \frac{1}{2} m v^2## and ##p = m v## are substituted into this equation the result is $$v...
  41. P

    What is the radius of the de broglie circular orbit with n=1?

    What is the radius of the de broglie circular orbit with n=1?
  42. D

    De Broglie Wavelength: What Is It and How Does It Affect Us?

    Before i understood that the de Broglie wavelength gets smaller as the momentum increases of an object, so my think was that because our (human body) momentum is so large that the de Broglie wavelength would be so small for there to be any effect on us, i know that we are also to large to...
  43. N

    Understanding de Broglie Wavelengths

    I understand the derivation and calculation of de Broglie wavelengths. What I don't understand is what exactly they are. What does the wavelength of a particle mean? Does it mean the wavelength of its probability wave, or some other kind of wave? The idea of wave-particle duality for EMR...
  44. S

    Can a Football Behave Like a Wave at the Same Speed as an Electron?

    i've just learned de broglie wave equation in chemistry which tells that matter can act as wave. if an electron is moving at a certain speed(v) at which its wavelength is comparably in meters. If a football is made to move at the same speed (v),will it behave as a wave? Since Football also has...
  45. V

    De Broglie wavelength in terms of accelerated potential difference

    Problem: Derive a formula expressing the de Broglie wavelength (in Å) of an electron in terms of the potential difference V (in volts) through which it is accelerated. Solution (so far): The textbook's answer is the following, \lambda=12.27[V(\frac{eV}{2m_{0}c^{2}}+1)]^{-\frac{1}{2}} I'm...
  46. V

    How Do You Calculate the Energy of Particles Using De Broglie's Equation?

    Problem: a. Calculate the energy in eV of an electron with a wavelength of 1 fm. b. Make the same calculation for a neutron. Solution (so far): a. λ=h/p=(hc)/(pc)=(1240 MeV fm)/(pc)=1fm so, pc=1240 MeV E=√[(pc)^2+E_0^2] =√[(1240 MeV)^2+(.511MeV)^2] ∴E=1.24 GeV This is the same answer...
  47. Roodles01

    Understanding the de Broglie Wave Function - Need a Little Help?

    Just starting QM & am looking at TISE & how it builds from start & need a little help understanding. OK, for a free particle the de Broglie wave function is ψdB(x,t) = Aei(kx-ωt) where A is a complex constant this corresponds t a free particle with momentum magnitude p = h/λ = hbar k...
  48. D

    Question about de broglie wavelengths

    Homework Statement Assume that the total energy E of an electron greatly exceeds its rest energy E0. If a photon has a wavelength equal to the de Broglie wavelength of the electron, what is the photon’s energy? Repeat the prob- lem assuming E = 2E0 for the electron. I need help with the first...
  49. jaumzaum

    Why the electron orbit is a integer multiple of De Broglie wavelength?

    I cannot understand why the electron orbit should be an integer multiple of De Broglie wavelength. Why should the wave path "fit" the electron orbit for it to be stationary?
  50. J

    De Broglie Bohm interpretation & virtual particles

    I sincerely apologise if this has been asked previously, I searched via Google and have been unable to find an answer I understand. How does the de Broglie-Bohm, or Pilot Wave, interpretation, well interpret virtual particles. The beauty of the deBB interpretation seems to be the unity of the...
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