Photons as bullets at 10 trillion FPS (frames per second)

  • Context: High School 
  • Thread starter Thread starter EPR
  • Start date Start date
  • Tags Tags
    Fps Per Photons
Click For Summary

Discussion Overview

The discussion revolves around the behavior of photons as they travel through a medium, particularly in the context of a recent experiment from Caltech. Participants explore the classical and quantum characteristics of photons, their measurement, and the implications of viewing them as analogous to classical objects like bullets.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants suggest that photons behave similarly to classical objects when measured, highlighting the relationship between theory and practice.
  • Others argue that while photons can exhibit particle-like behavior, they are fundamentally quantum objects and do not conform to classical definitions of particles.
  • A participant points out that the experiment does not provide new insights, as the behavior of light has been established since Einstein's work in 1905.
  • There is a contention regarding the visibility of photons, with some asserting that what is seen are not the photons traveling through the medium, but rather those reflected off the medium.
  • Another participant challenges the notion of "not seeing photons," suggesting that this statement is both true and false, depending on the context of the discussion.
  • Some participants express concern over the terminology used, arguing that the definition of "seeing photons" is complex and may not align with the experimental observations.
  • There is a discussion about the implications of using classical analogies, such as comparing photons to bullets, and whether such comparisons are valid.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the nature of photons and their visibility. Multiple competing views remain regarding the interpretation of the experiment and the terminology used to describe the observations.

Contextual Notes

Participants note the limitations of the discussion, including the dependence on definitions of terms like "photon" and "seeing," as well as the unresolved nuances in the interpretation of experimental results.

EPR
Messages
440
Reaction score
105
The following extraordinary experiment from Caltech highlights the 'classical' behaviour of light(photons) traveling through medium. It vindicates the notion that photons(at least from our limiting human perspective) do behave the same way as other quanta(much like ordinary 'matter' - chairs, cars, cups and walls) in the presence of measuring equipment. Nice to see the relationship between theory and practice in a previously unexplored domain(C). Between fields and 'objects'.
And viewing photons as bullets.

 
Last edited:
  • Like
  • Skeptical
Likes   Reactions: OmCheeto and weirdoguy
Physics news on Phys.org
EPR said:
It vindicates the notion that photons(at least from our limiting human perspective) do behave the same way as other quanta(much like ordinary 'matter' - chairs, cars, cups and walls) in the presence of measuring equipment.
Not too exciting since Einstein showed this in 1905. The thing to keep in mind is that this does NOT mean that they are "particles" in the classical sense of that term. They are quantum objects and will indeed exhibit particle-like behavior if you measure for that. They will also exhibit wave-like behavior if you measure for that.
 
EPR said:
The following extraordinary experiment from Caltech highlights the 'classical' behaviour of light(photons) traveling through medium. It vindicates the notion that photons(at least from our limiting human perspective) do behave the same way as other quanta(much like ordinary 'matter' - chairs, cars, cups and walls) in the presence of measuring equipment. Nice to see the relationship between theory and practice in a previously unexplored domain(C). Between fields and 'objects'.
And viewing photons as bullets.

Actually, photons are not at all like bullets or other classical objects. Photons are localized quanta in momentum space, not in physical position space.

This means that a quantum of light (a photon) has a sharp value of momentum (and thus energy), not a sharp value of position. A photon is completely delocalized in position space. Roughly, think uncertainty principle.

The right superposition of light quanta (phtotons) can result in light pulses that have some of the properties of classical objects.
 
  • Like
Likes   Reactions: vanhees71
So these are pictures not of "photons" but of "photon torpedoes" ?...
 
  • Haha
Likes   Reactions: DrClaude
I don't think one is seeing 'photons' here anyway. Also the pulse bouncing in the cavity is is already a macroscopic wavefront made presumably of trillions of photons, many of which must be scattered by the medium, otherwise one wouldn't see anything. From the physics there isn't much news here, but what I found interesting is how it resembles Finite-Difference-Time-Domain (FDTD) numerical simulations that employ classical Maxwell's equations for light propagation in optical media (no quantum physics involved).
 
I find the concept of " not seeing photons" to be problematic. What, in fact, are we "seeing"?
 
hutchphd said:
I find the concept of " not seeing photons" to be problematic. What, in fact, are we "seeing"?
You are seeing photons, but not the ones traveling through the medium, rather the ones that are reflected off of the medium and directed to the camera.

If you want to get REALLY technical, you are seeing photons created by a computer (or phone) screen which were created from an image of the photons reflected off of the medium through which the laser pulse was traveling.
 
Actually it is more remote than that because the camera technique involves tomography using what are essentially streak images as I understand it.
Your point is well said but my problem is more doctrinal.
It just seems to me the statement "you are not seeing photons" is equivalent to saying "I am not eating a cow" while devouring a cheeseburger. It is both true and not true and I grow weary of the polemical.
 
hutchphd said:
Actually it is more remote than that because the camera technique involves tomography using what are essentially streak images as I understand it.
Your point is well said but my problem is more doctrinal.
It just seems to me the statement "you are not seeing photons" is equivalent to saying "I am not eating a cow" while devouring a cheeseburger. It is both true and not true and I grow weary of the polemical.
ALL "seeing" for humans is the impinging of photons on the retina, so I understand your point but I disagree that it is polemical. The point is that you are not seeing the photons that move through the medium.
 
  • Like
Likes   Reactions: hutchphd
  • #10
But this is true if I say "I see the baseball". Really by this definition I guess you should say "I see the milky substrate in the phial" (but not for very long!)
 
  • #11
hutchphd said:
It just seems to me the statement "you are not seeing photons" is equivalent to saying "I am not eating a cow" while devouring a cheeseburger. It is both true and not true and I grow weary of the polemical.

I think the problem is only that of nomenclature and the precise meaning of words. In a certain sense "seeing photons" is an everyday experience. Just look at an object that reflects light, turn on the light, look at the sun, etc., then you are "seeing photons". But, if by the term 'photon' we indicate a light particle, a single corpuscle flying around, then this experiment does not at all show that. You don't "see a photon" here, like one does not see H2O molecules looking at a water wave. We can only say that one sees an electromagnetic perturbation that is propagating throughout an optical medium. But to describe what is seen one does not need any reference to particles, photons or quantum mechanics, it is just good old classical electromagnetism.
 
  • #12
Aidyan said:
then you are "seeing photons".
Not really, this reasoning is due to a photochemical reaction in the retina. If you see a thing you get an impression about it but you can't get an impression about a photon itself.
 
  • #13
timmdeeg said:
Not really, this reasoning is due to a photochemical reaction in the retina. If you see a thing you get an impression about it but you can't get an impression about a photon itself.
That's getting too far down into the weeds.
 
  • #14
hutchphd said:
But this is true if I say "I see the baseball". Really by this definition I guess you should say "I see the milky substrate in the phial" (but not for very long!)
But the surface of the baseball is not made of photons so your analogy is false. This thread is talking about photons moving through a medium and whether you can see THEM or not.
 
  • #15
As I said you are "seeing" the medium by the usual definition so I was agreeing with you.
I guess my attempt to be polemical about folks being polemical was not well received...
 
  • Haha
Likes   Reactions: phinds

Similar threads

High School Delayed choice experiment and FTL communication
  • · Replies 15 ·
Replies
15
Views
4K