we know that according to quantum mechanics electron behaves as dual (wave and particle)...now i accelerate electron in a lab or in a particle accelerator ....under the condition of electron is a wave, does it radiate or lost energy?
Well any accelerated subatomic particle will radiate energy as it gains momentum.
https://www.researchgate.net/publication/271960900_Everything_is_Physics_book_3_Particle_physics_and_the_quarks_revealed
Book Everything is Physics book 3. Particle physics and the quarks revealed
@ Andrew Worsley
my dear Andrew Worsley i am asking a question if any any accelerated subatomic particle is a wave will radiate energy?
@ C. Y. Lo
my dear C. Y. Lo quantum mechanics introduced wave nature of electron to study atomic structure....
@ Adrian Sfarti
my dear Adrian Sfarti quantum mechanics introduced wave nature of electron to study atomic structure so that an electron occupy fixed energy state though it is accelerating around a nucleus .....
An acelerated charged particle will radiate.
The electron can be considered a charged particle. It also has wave properties.
@ Juan Weisz
my dear Juan Weisz of course you are right....but when electron goes around nucleus it has to to radiate and atom would have not exist..to overcome this problem we introduced wave nature... in wave nature of an electron it occupy fixed energy states so it wont radiate energy right? in analogous to this i am saying in lab also electron wont radiate energy under the condition of wave !!!! i
Dear shs
Well for an atom is does not radiate, in a lab condition over some
finite distance it does.
The difference is a Classical situation(lab) and a Quantum situation.(atom)
This difference of behaviour is probably not entirely understood yet. There is some coherence length which exceded converts quantum to classical behaviour. A noisy environment with particle collisions, photon interections etc. converts a quantum situation into a classical situation. This is my mode of understanding.
A quantum situation requires strict energy conservation...with integral number of wavelength in each orbit in the Bohr model of the atom.
For an atom to radiate requires a jump between quantum states, this is a different process altogether.
The radiation of accelerated particles comes from the Maxwell equations, they are wave equations. We can describe electric current by classical function j=j(r,t) or by j=ecψ†αψ. When elementary particle moves in homogeneous field or similar or in a field of electromagnetic wave its energy can take every value. Then it can absorb and emit electromagnetic field in continuous way. In an atom energy of electron can not take every value. That is why it can absorb or emit field only in portions, i.e. quantums. This is the general idea.
@ Janusz Szcząchor;;\
my dear Janusz Szcząchor its valid information you have given ..thank you..
Depends on the details-if it's bound to the nucleus, for instance, it won't, since it will be in an eigenstate of the full Hamiltonian and, therefore, it will stay in such a state.
You should first consider the very term 'acceleration'. If a cloud changes its shape, is it accelerated? In quantum theory, the concept 'wave' stands for a complex wave function, which is not the same as an ordinary wave. What is actually observed in the atom in measurements with scattering probe particles or spectra obserwations, is probability, i.e. the absolute value of this function squared. In the stationary states of the atom, this 'wave' is NOT accelerated, and the eigenfunction depends on time only exponentially, this dependence disappearing in the probability function; therefore the atom is 'accelerated', hence radiates, only in transitions if excited. However, charged wave packets do radiate if accelerated.
One should be attentive with respect to basic concepts. In more details this topic is discussed in the book entitled 'Irony of the Method' published in the journal 'Progress in physics' vol.12. issue2 (2016).
@ Felix Tselnik...
my dear Felix Tselnik thank you for your valuable information.. plz give better clarification for us about wave' is NOT accelerated which you said and wave packets do radiate if accelerated...
of course here we are not talking about cloud changes its shape but we are talking about cloud changes its direction ....
1) though electron (cloud) changes its shape does it not orbiting about the nucleus?
2) orbiting (of course cloud changes shape) about the nucleus does not mean acceleration?
3) if wave is not accelerated in stationary states of atom, from where electromagnetic force came in between nucleus and electron?
of course we are all scholars know and yes its true that complex wave function and its absolute value of this function squared gives constant energy ..that is; it maintains constant energy for any electron orbiting about nucleus...
finally you said wave packets do radiate if accelerated.....if it is a wave pocket, it should maintain constant energy due to absolute value of complex wave function squared ..and so it wont radiate....
according to what mechanism you claimed wave packets do radiate if accelerated?
plz give your valuable clarification....
1) Wave eigenfunction of the electron in the atom is formed by the attracting nucleus 1/r potential, and it is therefore confined within a finite size region. As I said, the quantum mechanical solution provides this particular eigenfunction with the corresponding potential levels. In general, the Shroedinger equation defines evolution of the wave function, and no orbits are present in this theory. So, the orbite of the electron around nucleus is just a visualization: rigorous solution doesn't impliy this picture. No radiation is possible here in stationary states.. The attracting static Coulomb potential has nothing to do with electromagnetic radiation, and it enters the Shroedinger equation directly.
2) For my example with cloud, what direction do you mean in the just shape distortion. If a displacement of the cloud is much larger than than its size, then any of its points might be taken in a trajectory description. I regret your underestimation of this simple but example that exactly to the point.
3) Particle-like wavepackets are moving as a whole, and this picture is reasonable when the range of their displacement is large as compared to the de Broiile wave length. Then thei radiation consists of very soft photons, and the total energy of radiation is big as compared to that of single photons. Rigorous result in quantum electrodynamics, involving related multibranch Feynman diagrams, gives in this case the same formula for radiation as the classical field theory.
There are two types of electrons which you need to consider. (1) Free electrons have continuous energy spectrum whereas (2) bound electrons inside a nucleus have usually a discrete energy spectrum. In quantum mechanics an electron can jump from one eigenstate to another one, the energy difference is either radiated away or absorbed from radiation. So, you see, the radiation emitted in the first case will have continuous spectrum, whereas in second case it will contain discrete lines. And of-course, as you are working with quantum mechanics, here electron has a dual role, namely particle as well as wave.
@ Felix Tselnik...
my dear Felix Tselnik thank you very much ....before claiming something you should give proper proofs ...do you give proofs about your claim regarding underestimation?
we should respect with each other here...this is the stage to discuss subject, convince subject etc.....we are talking absurd here does not mean that we don't know anything and underestimation but it is the inquisitiveness of unlocking many angles of subject...
from where you got this sentence Particle-like wavepackets? i have never came across this sentence in quantum mechanics will you plz give reference for this sentence? or you mistakenly written this sentence? so your third explanation is completely wrong ..plz go through once and reformat mistake you have done....
i am requesting you to read my question again "If an electron is accelerated in a lab and that electron is a wave, does it radiate energy"? and give your valuable answer...
thank you very much....
Dear shs
The notion of a wave packet can be constructed from
Fourier Analysis, where a wide spectrum of waves with different
wave length combine together to form a rather localized structure.
In particular the amplitude of finding the particle in real space is a Fourier transform of the amplitude of finding it in k space. Usually you find this discussion in some of the more advanced texts of QM. It leads to a good way to understand the uncertainty principle., and to bridge the gap between particles and waves.
Heisenbergs book on QM gives a good discussion.
@ Felix Tselnik... Juan Weisz
my dear scholars how can you decide electron is a wave with wave length without accelerating about the nucleus?
@Juan Weisz. There is no bridge as there are no corpuscles, nor "corpuscular aspects", nor "duality". Only in the fairy tales told by the sect.
@C. Y. Lo . Please feel free to prove your point. If an electron, according to you, ceases to be its de-Broglie-Dirac wave, with four components, please explain the Ramsauer-Townsend transparency effect, known for 1921.
If the electron can be well treated classically, then it will radiate, as it can be treated using the usual Maxwell's equations.
If the electron is essentially quantum, it may or may not radiate, depending in circumstances, and you need a better knowledge of the details. As Stam says, if it is in the ground state of an atom, it can be shown that it will not radiate.
Finally, how do you tell whether an electron is classical or quantum? A good test is to look at the characteristic scales of momentum and position, take the product and compare to hbar.If the product is large, in a good approximation you will have classical behaviour. If it is small or of order one, you should use QM.
Thus an electron in an X-ray machine will have a quite large value, hence the remark that Bremsstrahlung electrons radiate is correct and appropriate. On the other hand, an electron in an tom is definitely quantum by the criterion I gave, and thus may or may not radiate.
Finally, your question is a bit ambiguous: an electron is *never* a wave. Occasionally it may be correctly described as a particle (in the classical limit) otherwise it must be described as a *quantum system* which is definitely not either a wave o a particle.
Best wishes.
An electron is *never* another thing than an electronic wave.
Proved in 1921 by the Ramsauer-Townsend transparency effect. And thousands of other experimental facts, for instance in radiocrystallography. Etc.
@ F. Leyvraz ;;;;
my dear F. Leyvraz if an electron is *never* a wave, from where we developed Quantum mechanics? so do we discovered the QM without a wave notion of an electron (ambiguous)? if there is no wave what is the use of Quantum mechanics....
Jaques
Even Feierabend would not deny everything, he is just in favour
of democratizing science. Are you one of his followers?
Please let Paul Feyarebend rest in peace.
But please explain the Ramsauer-Townsend transparency effect, known for 1921.
And lots of other proved experimental facts, that the standard teachers of QM carefully hide to their students.
``from where we developed Quantum mechanics?''
At the very beginning, a long, long time ago, several exceedingly brilliant physicists were trying to make sense of the atomic world. In that attempt they coined several phrases, one of which is the so-called ``wave-particle dualism''. It presumably was useful, for a time, to think in those terms. It definitely is not so any more.
Quantum mechanics is now a mature theory, and ``from where'' we have developed it, is merely of historical interest. For classical mechanics, you might ask about the connections of the principle of inertia to Aristotle's physics, but it is useless for present day classical mechanics.
It is similar for QM. We do not need its history.
In its present state, QM claims that a system is described by a complex valued function defined on the set of all possible configurations of the system. In the peculiar case of a one-particle system, the wave interpretation is not *always* totally wrong, and that is why its followers keep on talking. For any kind of many particle system, the wave interpretation is completely meaningless. Since we cannot measure a system without bringing it into contact with a (very) large number of particles, the wave picture is altogether incomplete.
So indeed, an electron is never a wave (though in some contexts, when strictly kept away from any measurement, it may behave rather similarly). Admittedly, it is also never a particle, but in the semiclassical limit, there is a well-defined sense in which it behaves like one.
@ F. Leyvraz ;;;;
my dear F. Leyvraz ,,,,,you may said to me directly i am anti to particle is a wave..why are you wasting time by giving lengthy answers unnecessarily to the question which i posed....
In your question you state: "that electron is a wave" and in condition it is a wave
You get the right answer from dr Leyvraz and then you are angry that you are wrong
@ Harry ten Brink;;
my dear Harry ten Brink i am also saying, in condition electron is a wave and is accelerated in a lab, does it radiate energy?
my dear Harry ten Brink why to feel angry in learning something? i never feel angry in learning subject and in creating absurd or new angles of physics.....
You are stubborn
in condition? what does this mean? the electron is NOT a wave
@ F. Leyvraz. Your believing depends on what you call "time".
In the hegemonic QM teaching, time is a parameter at hand, ubiquitous and universal. The time of the god of Isaac Newton.
However, experiments show that nothing is true in this believing.
You have extrapolated to microphysics the macro-time of the laboratory, which is a statistical emergence, exactly as temperature and entropy are, too. This statistical emergence has no causal power at the microphysical scale.
The Dirac-de-Broglie noise does not lie in any macro-time.
@ harry..
my dear Harry ten Brink if electron is not a wave ...why de Debroglie awarded by noble prize...
Louis de Broglie kept the believing in corpuscles, he believed that his wave only drove the corpuscle. So he remained for the remaining of his life with the two feet in the same concrete sock. The tragedy of a life.
I think what Levraz is trying to say is that the wave in not a physical entitiy, only a probability amplitude. And that is standard stuff.
@Juan Weisz ;;
my dear Juan Weisz do that probability amplitude have no physical meaning?
The real physical and individual wave has one emitter and one absorber.
But we cannot predict which emitter nor which absorber, nor when.
husainsha
de Broglie was BEFORE quantum mechanics: 1922 vesus 1925?!
@ Harry ten Brink;;;
oh! my dear Harry ten Brink there is no use of de Broglie in QM? do you mean QM is without wavefunction?
De Broglie : sept. 1923 (note at Académie des Sciences) and thesis in 1924.
Schrödinger was defeated in Copenhaguen in december 1926, by sheer violence by his host Niels Bohr.
De Broglie was defeated in Brussels in october 1927, by sheer violence, again by Niels Bohr.
Physicists are territorial animals like the others.
hussain
The "wave" in QM is not a classical wave! This has been explained to you before here
A wave function is NOT a classical wave but a STATE function on which operators work
@Harry ten Brink. We all know that.
You ignore that the hegemonic fairy tale from the Göttingen-København sect is not the ultimate answer, and that it fails in front of so many experimental facts.
"Classical" is a rhetoric term of the newspeak of this sect. They use it because they are unable to discern the microphysics scale from their "observer", a big and slow animal.
@Harry ten Brink;;
my dear Harry ten Brink every scholar knows that A wave function is NOT a classical wave but a STATE function on which operators work....i asked question in this language only.....
The wave function is not a real classical wave. It gives only
information, probability density.if you square modulus the complex function psi
Probability has its subjective and objective aspect. The predicted
or a priori part is what the Quantum theory gives through the wave function. Then the empirical or objective data allows one to check this.
But is an electron the wave function that the copenhaguists say on it ?
But why the Dirac's wave equation of the electron (1928) is so heavily censured, and so frantically forgotten ? Our most sommital leading figures are like a hen who has found a knife, in front of the Zitterbewegung.
In geometrical terms:
It is necessary for radiation that E and H were in phase. Otherwise, the Pointing vector merely oscillates and no far propagating wave can exist. Required phase shift, coming from the retarded (Lienard-Wiechert) potential, for the field of moving electron needs its acceleration.
In quantum mechanics, the related experiment consists in “infinitely’ many measurements, carried out on a single electron at a time, to be averaged further on to form the “wave function”. (Just fancy that in a wave similar to ordinary waves but electrically charged, its parts would repel each other!).
Hence, radiation can occur only in individual acts. In such an act, the electron (particle) moves over a one-dimensional continuous though not differentiable line (not at all a trajectory in classical meaning!), the absence of a derivative resulting from measurements. They are just these that distort the collection of the necessary for radiation phase shift. Only for a large (as compared to quantum jumps range) wavelength, radiation (classical) is being formed due to averaged over jumps acceleration.
In quantum electrodynamical interactions, emitted photons might have energies up to the full initial electron energy, though with low probability, while soft photons are emitted with high probability, the cross section even diverging as photon energy goes to 0: the so-called “infrared catastrophy”, which was solved using multibranching Feynman diagrams to yield in the limit just classical formulae for radiation.
On the other hand, in (e.g., hydrogen) atom, its geometrical size is of the order of Heisenberg uncertainty limit, hence momentum must be jumping at random, and the electron orbit exists only as something in short fragments: Just consider a real orbit (In what direction?) that would have an angular (not only spin) magnetic momentum! It is just uncertain momentum quantum jumps that prevent phase shift collection, so cancelling radiation in the ground state.
@C. Y. Lo. What is the purpose of the Dirac's wave equation of the electron (1928) ?
The Dirac wave equantion is to do relativistic QM, in the sense
of the special theory. It leads to negative energy levels of the electron
and to electron spin.
Dear C.. Y. Lo, quantum mechanics as well as the classical mechanics might be formulated in a different form. See:
http://www.ptep-online.com/complete/PiP-2016-02.pdf
@Juan Weisz. Any relativistic theory gives "negative energy", or more precisely, negative frequencies. For the electrons, there are two retrochronous components with negative frequency.
An accelerated elementary particle tends to give off energy- because it behaves and is a wave.
Macroscopic particles do not..
Jacques
A negative frequency is the frequency of a wave that goes
backward in time?
Andrew
If it is charged? Because it behaves well?
The particle is a wave
in the same sentence-
Bakward in micro-time.
Our macro-time is a statistical emergence, as the entropy. It has no causal power in microphysics.
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