Nature of Light

[morp]

By the hypothesis of Maxwell,Light is an E.M. wave, every optical phenomenon can be explained.

Most optical phenomena,e.g. the Rainbow,,cannot be explained bij quantum physics.

Why that preference for quanta.

 

Fashion?

 

 

Morp

[Klaynos]

I'm actually an active researcher in optical physics.

 

We use maxwell's equations every day. They are used for macroscopic effects where the QM is tied up in the origin of the permittivity and permeability. It becomes phenomenally difficult to use maxwells equations for microscopic work because you have to take into account every charge, and the quantum mechanical effects on it.

 

Maxwell's equations are amazing, they are truely amazing, but they do not give you the full story. We need quantum mechanics to understand the systems more fully.

 

Quantum electrodynamics is a continuation of maxwell's equations, it is both relativistic and quantum mechanical it describes more complicated systems than can be used with maxwell's equations.

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You can calculate diffraction effects (rainbows) by just considering simple wave physics, does that mean we should ignore maxwell's equations?

[morp]

I know no atomic phenomenon that cannot be explained simply by Maxwell laws.

But I know several lies told about Maxwell laws

For example in books it is written,and attributed to Rutherford, the hydrogen atom , a rotating electric dipole, should radiate energy.

This lly comes from people who do not know the Maxwell laws or dont understand them.;

 

An electric or magnetic dipole, with a given magnetic or electric dipole moment, will not radiate even wen accelerating., not in reality and not by Maxwell laws.

Proof:the stability of the hydrogen atom.

 

Mawell did not know either about Mikroskopic or Makroskopic worlds.

There is only one physical world.

 

 

Morp

 

 

 

 

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[Klaynos]

I know no atomic phenomenon that cannot be explained simply by Maxwell laws.

 

Optical light scattering around non-spheroid nanoparticles are an example where maxwell's equations cannot be solved to find the solution.

 

But I know several lies told about Maxwell laws

For example in books it is written,and attributed to Rutherford, the hydrogen atom , a rotating electric dipole, should radiate energy.

 

If the electron was actually orbiting it would radiate energy. Fortunately it is.

 

This lly comes from people who do not know the Maxwell laws or dont understand them.;

 

An electric or magnetic dipole, with a given magnetic or electric dipole moment, will not radiate even wen accelerating., not in reality and not by Maxwell laws.

 

Dipoles will radiate, the cone of radiation is quite well understood and a relatively simple solution to the equations. If you would wish to argue with this can you reference a solution to the dipole that shows no radiation?

 

Proof:the stability of the hydrogen atom.

 

Mawell did not know either about Mikroskopic or Makroskopic worlds.

There is only one physical world.

 

As it may be one physical world, as we probe it more deeply and and with more precision we find that our early models do not fit well and we have to find new ones. That is what science is about, testing and adapting....

[swansont]

Photon antibunching is tough to explain classically. Atoms don't radiate continuously — they emit the energy in quantized amounts.

 

Kimble, Dagenais, and Mandel. Phys. Rev. Lett. 39, 691 - 695 (1977)

 

The phenomenon of antibunching of photoelectric counts has been observed in resonance fluorescence experiments in which sodium atoms are continuously excited by a dye-laser beam. It is pointed out that, unlike photoelectric bunching, which can be given a semiclassical interpretation, antibunching is understandable only in terms of a quantized electromagnetic field. The measurement also provides rather direct evidence for an atom undergoing a quantum jump.

[John Cuthber]

Quite a lot of things are difficult to explain in classical physics (ie without QM).

The spectra of atoms and molecules, black body radiation, superfluidity and superconductivity spring to mind, but there are plenty of other examples.

 

I'd like to see a solution to Maxwell's equations for an oscilating dipole that doesn't emit EM radiation.

As far as I can see this thread should be in the "speculation" section of the site.

[Sisyphus]

How about:

 

http://en.wikipedia.org/wiki/Ultraviolet_catastrophe

 

(One of my favorite physics terms/great band names ever.)

[swansont]

One of the underlying points here is that there are phenomena that can be explained (semi)classically, but are a whole lot simpler once you move to quantum physics. "I can explain that phenomenon with classical physics" is insufficient, and not the same as "classical physics gives the best explanation of that phenomenon" (where "best" has some tie-on with Occam)

[granpa]

I've never really understood the ultraviolet catastophe. isnt it readily explained by the fact that matter is made of finite sized atoms that vibrate producing the heat radiation?

[swansont]

I've never really understood the ultraviolet catastophe. isnt it readily explained by the fact that matter is made of finite sized atoms that vibrate producing the heat radiation?

 

As I recall, it was the modes of a cavity with perfect reflectors that shows this: equipartition of energy doesn't hold — mode density varies with frequency and there are an infinite number of them, but the energy radiated is finite.

[morp]

There too many posts to reply at once. Most posst suppose some misunderstaning.

E.g. the ULTRAVIOLETCATASTROFE is based on the hypothesis molecules are similar to steel or marble spheres. When the elastcity of molecules is taken into account,solids ,liquids and gases are mechanically low-pass filters that do not transmit high frequencies.

I must point out that molecules or atoms do not radiate, only Charges radiate , in this case the electrons.

Dipoles radiate when the dipole moment is changed A dipole does not radiate when it is moved or rotated. A general belief is that a rotating dipole radiates but by E.M laws it should not.

It is said also that the hydrogen atom contradicts the Maxwell laws.I should like to hear or to see a more precise accusation.

The hydrogen spectrum is derived simply from old classical principles or laws, the photon hypothesis requires other improbable hypotheses such as the quantisation of orbits. The consequence of this hypothesis is that only lines can be radiated in a discontinuous spectrum .A continous spectrum as radiated in reality and iexplained by classical physics cannot be explained logically by QM.

The hydrogen spectrum is explained by improbable hypotheses that cannot be used for other elements. By classical physics thermal radiation and atomic spectra are explained by the same old laws. If the temperature of any element is lowered to reduce thermal radiation, the atomic spectrum of that element is radiated, showing the radiation laws are all the same.

By classical physics you need only pre-Einstein laws and principles Why the difficult QM -way?

 

Morp

 

Morp

[Klaynos]

But hydrogen atoms don't radiate continuous spectra in reality!

 

You need the difficult QM way to understand many different experiments for both light and other phenomena.

[swansont]

I must point out that molecules or atoms do not radiate, only Charges radiate , in this case the electrons.

 

What of neutrons? Can't their states be excited within a nucleus? You get a discrete spectrum of gammas when a neutron is captured.

 

The hydrogen spectrum is derived simply from old classical principles or laws

 

Where might one see such a derivation?

[morp]

In many textbooks we read Rutherford said a rotating dipole should radiate energy by the Maxwell laws. The hydrogen atom being an rotating electric dipole must therefor radiate energy. But the Poynting Vector of the field of a rotating electric dipole is null,showing there is no energy radiation . My question is:: Iis it possible Rutherford was wrong or did he not make that mistake abd are those, who cite him,lying?

 

Morp

[swansont]

But the Poynting Vector of the field of a rotating electric dipole is null

 

What?

[Klaynos]

An electron in an orbit around a nucleus as classical mechanics requires is an accelerating charge, which radiates.

 

Dipoles radiate, this is well known, if they did not all of my research would not work, and it does.

 

Shockingly we don't just take what people say for granted, science is all about testing, this has been tested experimentally and the theoretical work rederived many many times.