Why do we need wave-particle duality?

[ukgazzer]

Light is emitted from processes that (as far as I know) involve a rapid reorganization of charged particles and this light is emitted into an environment that is full of other charged particles that will adapt to any changes in EM fields and by adapting will also cause 2y adaptations etc etc. Taking into account the speed of light,a reaction that would`ve lasted perhaps a picosecond would take a lot longer to be registered by an observer as i/it would take time for the particles in any detector to move in response to the field ii/ it would be impossible to separate the effect of the surroundings from the localized effects from the actual reaction.As the rest of the universe is more substantial than the few participants in a reaction,wouldn`t any adaptation by the environment disguise the observed effects from the reactants?Wouldn`t the observed effects from reactants and environment appear as waves?I don`t know where the flaw is in this logic!

 

Do (Could?) all processes that produce light involve a reorganization of charged particles?

Would surrounding matter be affected by very rapid positional changes in charged particles?

Light is an EM field and will effect charged fundamental particles,won`t it?

Could environmental effects disguise the effects from the process itself?

Does the concept of the speed of light allow alternative interpretations for the nature of light?

Does the speed limit of c mean that any sudden process would appear as waves ,as 'seen' by groups of particles?

Can any detector (since they are all made of matter and there is a speed limit of c)react instantly to a stimulus?

Would environmental effects cause apparent wave/particle behavior? (Wouldn`t individual particles react differently depending on their positions relative to neighbors and collectively cause waves?)

Are we trying to attribute wave particle effects to a carrier when it could just as easily be attributed to the medium in which the processes occur?

 

If this is right(!!) why do we need photons and light waves?

[pantheory]

Light is emitted from processes that (as far as I know) involve a rapid reorganization of charged particles and this light is emitted into an environment that is full of other charged particles that will adapt to any changes in EM fields and by adapting will also cause 2y adaptations etc etc. Taking into account the speed of light,a reaction that would`ve lasted perhaps a picosecond would take a lot longer to be registered by an observer as i/it would take time for the particles in any detector to move in response to the field ii/ it would be impossible to separate the effect of the surroundings from the localized effects from the actual reaction.As the rest of the universe is more substantial than the few participants in a reaction,wouldn`t any adaptation by the environment disguise the observed effects from the reactants?Wouldn`t the observed effects from reactants and environment appear as waves?I don`t know where the flaw is in this logic!

 

Do (Could?) all processes that produce light involve a reorganization of charged particles?

Would surrounding matter be affected by very rapid positional changes in charged particles?

Light is an EM field and will effect charged fundamental particles,won`t it?

Could environmental effects disguise the effects from the process itself?

Does the concept of the speed of light allow alternative interpretations for the nature of light?

Does the speed limit of c mean that any sudden process would appear as waves ,as 'seen' by groups of particles?

Can any detector (since they are all made of matter and there is a speed limit of c)react instantly to a stimulus?

Would environmental effects cause apparent wave/particle behavior? (Wouldn`t individual particles react differently depending on their positions relative to neighbors and collectively cause waves?)

Are we trying to attribute wave particle effects to a carrier when it could just as easily be attributed to the medium in which the processes occur?

 

If this is right(!!) why do we need photons and light waves?

In the 17th century Newton proposed light as being particles based upon his corpuscular theory and model. Huygens then followed with his wave theory of light toward the end of the century. Although Newton's model prevailed for about 100 years eventually the bulk of theorists eventually adopted Hoygen's model because the corpuscular model failed to adequately explain the diffraction, interference and polarization of light, and because of new evidence concerning the wave nature of light revealed by Tomas Young concerning his double slit experiment and other experimenters of the 18th and 19th century. It wasn't until the late 19th century and the early 20th century that the idea of light as a particle was again postulated by Max Planck which he called quanta (as in Quantum Mechanics) and Alberta Einstein who called the same proposed particles photons.

 

The idea was that since they could not find an aether to carry the waves of EM radiation, they proposed the idea of waves of pure energy having no medium at all. To explain the particles/ quanta/ photons they proposed particles moving through generally empty space between stars, and later between galaxies. Theory evolved that depending on the observers point of view, light could be considered a particle or a wave, but not both at the same time. This is the present view which is based upon interpretations in Quantum Mechanics with the realization that atomic and other quantum particles also have a wave nature to them as shown by De Broglie. So present theory is based upon the evolution of Quantum Mechanics of which this assertion of the duality of EM radiation is one of its foundation pillars.

 

Although there are many new and modern aether theories, most theorists still are not interested believing that the aether was long ago disproved. If we ever discover an aether as "the medium in which the process occurs" (in your words) then at that time we might consider that EM radiation is both a particle and a wave at the same time. Maybe ideas like the particles/ photons are produced by the waves and are surfers within them, or that light particles as they move in groups at a given frequency, push up the waves, or other such ideas. But presently such ideas are not ever considered by mainstream theorists is Quantum Mechanics since there seemingly is no present reason for such speculation.

 

Based upon your doubting statement, I too also think there are flaws in present logic of Quantum Mechanics concerning this and other interpretations, and so did a great many other theorists such as Einstein, De Broglie, Schrodinger, etc. The formulations were not in question by them, only the logic concerning why the formulations should be valid. Einstein believed QM was merely a predictive system of statistics and equations formulated to match observations. Heisenberg, Born, Wheeler, and others believed the system represented a fundamental character of nature at the quantum level proposing such things as probability waves concerning no actual exact physical location or momentum of particles in motion, as well as wave particle duality of EM radiation, etc.

 

The answer to most of your questions can be found in QM theory (whether present interpretation may or may not seem to have logic to it), and other questions you have asked have various possible QM mainstream answers or interpretations.

 

http://en.wikipedia....antum_mechanics

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Edited April 19, 2012 by pantheory

[Klaynos]

Why do we need wave particle duality. Two experiments.

 

The Young's double split experiment. This clearly shows that light is wavelike.

 

Photoelectric effect. If you start with a frequency so that there is no measured photoelectric effect increasing the intensity does not result in an effect being measured. Increasing the frequency results in a step function, this can only happen if the light is in particles.

 

Wave particle duality has been observed in very large objects such as Bucky balls. It is an inescapable observational finding.

 

This is NOT an interpretation of quantum mechanics.

[ukgazzer]

Thanks for the replies.

I`m not sure what to believe.The history of science has a lot of revolutions in it!

What I mean by a medium is not the classical aether but merely ordinary matter.How can ordinary matter not be affected by,and alter the appearance of light,if light is an EM field? Charged elementary particles in an observer surely must be deflected if,say +ve charges in products are closer to the observer than they were in the reactants- The observer sees a sudden change in EM potential in that direction-That must do something!Surely?And thus ordinary matter must surely be considered as a medium-even if it did not lie directly in the path from the source to the observer it would have to have an effect on the light perceived by the observer.

I`ve looked up the two experiments.

Youngs Double Slit:I would be convinced if the material either side of the slits wasn`t susceptible to electromagnetic forces,wasn`t in a state of continuous motion at the atomic level,and thus didn`t have a potential to deflect electrons/photons by varying amounts(but perhaps maybe not to the extent or in the pattern we observe.)Surely atoms will defect electrons,and surely(classically at least) the positions of charges in an atom will vary over time and so the field an electron(or photon) has to pass through will also vary over time? Or has this been taken into account by the experimenters,and the effect discarded from the results?

Photoelectric Effect:If light was neither a wave nor a particle but merely a signal then the intensity of light would merely represent the number of individual reactions that caused the light,each signal from each reaction would arrive almost together and with a strength proportional to the frequency of the light-the violence of the reaction.I can`t see how this signal would produce different results from photons.

[pantheory]

...Youngs Double Slit:I would be convinced if the material either side of the slits wasn`t susceptible to electromagnetic forces,wasn`t in a state of continuous motion at the atomic level,and thus didn`t have a potential to deflect electrons/photons by varying amounts(but perhaps maybe not to the extent or in the pattern we observe.)Surely atoms will defect electrons,and surely(classically at least) the positions of charges in an atom will vary over time and so the field an electron(or photon) has to pass through will also vary over time? Or has this been taken into account by the experimenters,and the effect discarded from the results?

The size of the slits are huge compared to an electron. The beam of electrons or photons passing through the slits are directed toward its center. It is thought that no atomic interference can occur. I would expect the material being used is non-magnetic and maybe nonmetallic materials involving no net charge. General Influences of the sidewalls of slits for these reasons, are thought to be non-existent or negligible.

 

De Broglie believed that both waves and particles have a physical reality. He explained that he saw no mystery at all in the double-slit experiment and was surprised that others considered it a mystery. When two slits are open but an electron goes through just one slit, the physical waves produced would go through both slits and interfere with each other and the particle producing the observed patterns. The same explanation would apply to photons. Most did not accept his very simple explanation since physical waves would seemingly involve an aether.

 

Photoelectric Effect:If light was neither a wave nor a particle but merely a signal then the intensity of light would merely represent the number of individual reactions that caused the light,each signal from each reaction would arrive almost together and with a strength proportional to the frequency of the light-the violence of the reaction.I can`t see how this signal would produce different results from photons.

In today's physics there is no such thing as a signal without a wave or particle being involved. The idea of pure radiated energy involves waves. I agree that either a particle or wave, or both could seemingly cause the photo-electric effect, but in present theory photons alone can do this based upon Einstein's related equations which propose discrete light particles (photons), that accordingly predict the observed results.

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Edited April 20, 2012 by pantheory

[ukgazzer]

Thank you.

This is one of the questions that made me study chemistry,rather than physics at university-Seriously!

Maybe textbooks don`t give enough answers,or explain how conclusions were reached with sufficient clarity,or maybe there is genuinely room for an element of doubt in modern theories.

To a chemist like me some of this QM wave-particle stuff sounds like magic,although maybe I simply don`t understand the maths!

[pantheory]

ukgasser,

 

.....To a chemist like me some of this QM wave-particle stuff sounds like magic,although maybe I simply don`t understand the maths!

Some of the explanations of quantum mechanics seem counter-intuitive to most people that first study them. Most criticisms of QM do not involve the phenomena or experiment involved, or the maths/ equations being used, only the explanations being offered. Concerning quantum-entanglement explanations of QM, Einstein called this interpretation "spooky actions at a distance," where "magic" would be a similar description

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Edited April 20, 2012 by pantheory

[Zvonko]

Although I am keeping an open mind, one problem I have with QM is not scientific. I am ok witht QM being able to explain every known experiment but isn't that just because it has given up on deduction proper, and instead implying averaging things out is close enough? It just seems to me that statistics permeates the whole QM model too strongly i.e. Me thinkest thou protesteth too much! To me, this approach may have its merits in being able to encompass more laws of physics toward a sought after GUT, but it is zooming further away from what is actually going on in order to do this. If I'm explicitly wrong, please let me know why. Until then, I can't help but feel that there was a competition between the statistics (telescopic) and analytical (microscopic) methods, and stats are behind QM.

BTW, don't get me started on why there seems to be so much alignment between QM and what religions have been saying for a long time..

 

How about this? Maybe a paradigm was developed early to mid last century based on the level of technology and if we redid some of those today with modern equipment, a breakthrough could be made that the paradigm of the past could not measure.

[swansont]

QM is probabilistic in nature. That necessarily leads to statistics, even before you get to experiment.