Are Photons Real? New Study Challenges Assumptions

[log0]

Recently I've stumbled across a preprint in which the author describes a photon is a wave packet and even suggests a transverse extent.

I find it strange, as my understanding so far has been that a photon (and the EM field as such) is a construct used to model certain observed interactions between particles of matter.

Yes, I am assuming matter to be real, as something that interacts with each other. While force fields are mathematical models of those interactions.

https://arxiv.org/ftp/arxiv/papers/1706/1706.04475.pdf

 

[martinbn]

Why wouldn't light be real?

 

[weirdoguy]

Yes, I am assuming matter to be real, as something that interacts with each other. While force fields are mathematical models of those interactions.

But matter also interact with the force fields (eg. Compton scattering).

 

[vanhees71]

Many fields are real, among them the electromagnetic one. For me "real" means it's an observable entity of Nature, and indeed electromagnetic fields are observable. E.g., light and thus literally all we see is just a manifestation of the electromagnetic field. Another manifestation are the forces on objects you observe due to the presence of electrostatically charged bodies or the force between a permanent magnet and the door of your fridge etc. etc. In fact according to the most precise theory ever, the Standard Model of particle physics, all matter is also the manifestation of various (quantum) fields, and since you can observe this matter also these fields are "real".

 

[malawi_glenn]

Are forces real? Or are they just a mathematical concept "invented" to model how we describe natural phenomena?

 

[Vanadium 50]

What does it mean to be real? That's the Philosophy Department, two doors down. How do we know anything is real? How do we know we're not just brains in vats?

This is not physics. In physics, "just a model" is all you get.

 

[DrClaude]

Recently I've stumbled across a preprint in which the author describes a photon is a wave packet and even suggests a transverse extent.

I find it strange, as my understanding so far has been that a photon (and the EM field as such) is a construct used to model certain observed interactions between particles of matter.

Yes, I am assuming matter to be real, as something that interacts with each other. While force fields are mathematical models of those interactions.

https://arxiv.org/ftp/arxiv/papers/1706/1706.04475.pdf

That paper looks very iffy.

 

[vanhees71]

What does it mean to be real? That's the Philosophy Department, two doors down. How do we know anything is real? How do we know we're not just brains in vats?

This is not physics. In physics, "just a model" is all you get.

Physics is an empirical science, and "real" in the sense of the natural sciences is what can be reproducibly and objectively observed. Models and theories are the way to organize the empirically found knowledge in an efficient way.

 

[martinbn]

He gave the definition of "real" he uses. Things that interact with other things are real. Photons do, so they are real.

 

[Vanadium 50]

I don't think he did - he would seem to exclude a magnetic field as real. But in any event, this is not physics. It's just not something physics concerns itself with. Is a Lagrangian real? Are image charges real? Wavefunctions? This is a fast way to get tied up in knots. Unproductive knots.

 

[martinbn]

I don't think he did - he would seem to exclude a magnetic field as real.

He would but he shouldn't. It is real.

But in any event, this is not physics.

No, it is not. But that doesn't mean in it doesn't matter for physics. Mathematics is not physics but is usually not dismissed.

It's just not something physics concerns itself with. Is a Lagrangian real? Are image charges real? Wavefunctions? This is a fast way to get tied up in knots. Unproductive knots.

These are not real. They are mathematical objects (dont know what the image charges are).

 

[hutchphd]

He gave the definition of "real" he uses. Things that interact with other things are real. Photons do, so they are real.

What if the object with which they interact is not "real"? This is a fundamentally circular definition whose utility eludes me. I guess it proves self -consistency which I think was the extent of @vanhees71 argument

 

[martinbn]

What if the object with which they interact is not "real"? This is a fundamentally circular definition whose utility eludes me. I guess it proves self -consistency which I think was the extent of @vanhees71 argument

By this definition it cannot be not real. If it interacts it is real. It is symmetric not circular.

 

[hutchphd]

By this definition it cannot be not real. If it interacts it is real. It is symmetric not circular.

This is foundationalism instead of coherentism..... but remember

What does it mean to be real? That's the Philosophy Department, two doors down. How do we know anything is real? How do we know we're not just brains in vats?

This is not physics. In physics, "just a model" is all you get.

.

 

[Demystifier]

That paper looks very iffy.

When a not so old paper uses ##h## rather than ##\hbar##, it's usually wrong.

 

[fresh_42]

What does it mean to be real? That's the Philosophy Department, two doors down. ...

... This is not physics. In physics, "just a model" is all you get.

But it set the ground for great pieces of art:

Lem, The Futuorological Congress,1971
Wachowski, The Matrix, 1999

 

[Vanadium 50]

Don't forget M. Williams, The Velveteen Rabbit.

 

[Dale]

Questions on QM philosophy and interpretations belong in the dedicated section: https://www.physicsforums.com/forums/quantum-interpretations-and-foundations.292/

Thread closed