Why Does Light Exhibit Both Particle and Wave Properties?

[bhobba]

"electrons and photons always behave as waves, while a particle like behavior corresponds only to a special case"

Did you read the context he gave of what he means by waves 'Instead, such serious textbooks talk only about waves, i.e., wave functions'

Wave functions, except in some special circumstances, behave nothing like waves.

This has been thrashed out time and again on this forum - and our FAQ has an entry on it. A simple search will bring you all the detail you can want about it. Its a common misconception people find hard to shake and you get these long threads that basically go nowhere.

Thanks
Bill

 

[tallal hashmi]

I think that dual nature of light is its nature.

 

[bhobba]

I think that dual nature of light is its nature.

Scratching my head why anyone would believe that after reading this thread.

I could point to all sorts of stuff explaining why it isn't true, in fact I already have done that.

Now I think a different tack is required.

Here is our FAQ:
https://www.physicsforums.com/threads/is-light-a-wave-or-a-particle.511178/

After reading it can you explain, in your own words, not with links elsewhere, quotes from physicists, or popularisations, but your own reasoning why you think its true.

Thanks
Bill

 

[tallal hashmi]

hyperphysics.phy-astr.gsu.edu/hbase/mod1.htmlYou should check this link

 

[bhobba]

You should check this link

I can't understand why, when I asked for a reason in your own words, and not for a link, you did exactly the opposite, and gave me a link.

There was a reason for that - to get you to think about it and give your own reasons, not others views.

Unless you are willing to do that then you will not progress and learn.

This is a common misconception, its hard to break because many beginning texts and links (like the one you gave - it basic beginner stuff) promulgate it. But its still wrong.

Now please can you tell me why you would believe some link you gave, rather than the experts from the site you have decided to come to to discuss physics, and who prepared the FAQ link I gave?

I don't understand that. It happens a lot and you get long threads going though the same stuff over and over.

Thanks
Bill

 

[julcab12]

hyperphysics.phy-astr.gsu.edu/hbase/mod1.htmlYou should check this link

...
"Light is neither a particle nor a wave. Instead it is a quantum field. As a general rule while light is traveling it appears as a wave, but when the light quantum field is exchanging energy with anything it does so in quanta that appear as particles i.e. photons.

You see because light excites electrons in rhodosin molecules in the cells in your retina. Since this is an energy exchange (from the quantum field to the rhodopsin molecule) the interaction looks like absorption of a photon."http://physics.stackexchange.com/questions/46237/is-the-wave-particle-duality-a-real-duality

Ignore Luboš Motl and go down juanrga's answer.. It covers some details and easily for us laymen.

 

[microsansfil]

...
"Light is neither a particle nor a wave. Instead it is a quantum field.

What is the meaning of "is" in your assertion ? An ontological Meaning ?
Or just refer to a useful physical model to do prédiction about measurement outcome ?

Patrick

 

[bhobba]

What is the meaning of "is" in your assertion ?

The usual meaning.

It isn't a particle or a wave - it is a quantum field.

Thanks
Bill

 

[microsansfil]

Hi all,

In the framework of Classical electromagnetism light is represented by a wave : http://en.wikipedia.org/wiki/Classical_electromagnetism#Electromagnetic_waves

In this framework we can do a lot of physical experiment without use quantum field theory in wihch the light is represented by a quantum field.

The question about nature of light is a metaphysical question.

Patrick

 

[bhobba]

The question about nature of light is a metaphysical question.

Its a question of fact. All those other theories are a limiting case of QED, which is a quantum field theory ie Maxwell's equations follow from QED, but not the converse.

Thanks
Bill

 

[julcab12]

What is the meaning of "is" in your assertion ? An ontological Meaning ?


Patrick

BTW. It's not mine. I just find the answer convincing to a degree when you consider what it says about experimental limits, outcomes and details. 'Is' in a sense constrained to experimental limits or observed behavior, that it is how we look, describe and formulate light regardless if there can be or/ perhaps any underlying or more fundamental nature of it. In fact, we can't say much about it except put an approximation or some constraint. In QFT-Max Planck (Analogy --indivisible units/chunks -- not particles or localised particles of spread out fields, 6 fields in total); spreading, diffraction and interference and the rest of observation(which is a function of wave) are explained without any duality.

http://statintquant.net/siq/siqse3.html#x42-60003
http://home.web.cern.ch/about/physics

Or just refer to a useful physical model to do prédiction about measurement outcome ?
Patrick

A more meaningful question is that -- Is it a effective or fundamental? Physical models are descriptions of what has been observed and what we observed are bound by our confidence with experiments. Waves are simply a description to a certain behavior and can be said as well to particle. But what's more evident or natural question is in the interaction part.



..According to Weinberg's viewpoint,



In my opinion. Well not a personal one but i find to be more convincing for some reason and i could be wrong for that matter. I'm more interested in the interactions and structures (relational view) than the description itself -- Loops and spinfoams but this is beyond QM and i won't stretch it out.