Which component of light is a photon?

Click For Summary

Discussion Overview

The discussion centers around the nature of photons in relation to light, exploring the relationship between wave and particle descriptions of light. Participants examine whether photons are components of light or if they exist only during interactions with matter, delving into theoretical implications and interpretations within quantum mechanics.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory
  • Technical explanation

Main Points Raised

  • Some participants propose that light consists of two perpendicular wave components, questioning where the photon fits into this framework.
  • Others argue that there is no separate photon and wave component, suggesting that light behaves as either a wave or a particle depending on measurement circumstances.
  • A participant challenges the concept of "real nature," stating that scientific theories are based on their ability to explain and predict behavior rather than on metaphysical interpretations.
  • It is noted that while classical electrodynamics describes light as electromagnetic waves, the interactions with matter occur in discrete steps, referred to as photons.
  • Some participants suggest that photons may be viewed as probability waves until they interact with matter, while others clarify that they are fluctuations in an electromagnetic field.
  • There is a discussion about the discrete energy transitions of electrons and how this relates to the particle-like behavior of light, emphasizing that not all photons can excite all electrons, depending on frequency.
  • One participant compares the observation of photons to the act of throwing dice, highlighting the probabilistic nature of quantum mechanics and the role of observation in determining outcomes.
  • It is mentioned that photons do not have a wave-function in the traditional sense, but this concept is often simplified in introductory texts.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the nature of photons and their relationship to light, with no consensus reached on whether photons are components of light or exist only during interactions.

Contextual Notes

Limitations include the dependence on definitions of "photon" and "wave," as well as the unresolved nature of how these concepts interact within quantum mechanics. The discussion reflects various interpretations and assumptions that are not universally accepted.

LSMOG
Messages
62
Reaction score
0
Light is an electromagnetic radiation with two wave components that are perpendicular. Between these two perpendicular waves, where is the photon in this system.
 
Physics news on Phys.org
There is no separate photon and wave component.

Light can behave like a wave or it can behave like a particle depending on the circumstances being measured.

https://en.wikipedia.org/wiki/Photon
 
  • Like
Likes   Reactions: bhobba
Okay thanks. It behaves like! What is its real nature.
 
LSMOG said:
Between these two perpendicular waves, where is the photon in this system.
When I strike a block of stone with a heavy steel hammer, there are sparks. Between the hammer and the stone, where is the spark in this system?
LSMOG said:
Okay thanks. It behaves like! What is its real nature.
"Real nature" is not a meaningful concept in science. If a theory explains and accurately predicts the behavior of a system, we go with that theory until and unless we find something better.

The best theory we have for explaining and predicting the behavior of light is classical electrodynamics, discovered by Maxwell in 1861. The explanation is that light is the electromagnetic waves predicted by Maxwell's equations, and it pretty much always works.

However, Maxwell's equations do not completely describe the way that electromagnetic fields exchange energy and momentum with charged particles. It turns out that these interactions always transfer energy and momentum in discrete steps, and we call these steps "photons". That doesn't mean that photons are a "component" of light, or that light is "made up" of photons, or that the photon is even there except when the light is interacting with matter.
 
Last edited:
  • Like
Likes   Reactions: vanhees71 and jedishrfu
Nugatory said:
That doesn't mean that photons are a "component" of light, or that light is "made up" of photons, or that the photon is even there except when the light is interacting with matter.

What does that mean, that the photon is just a probability wave until it interacts with something?
 
GhostLoveScore said:
What does that mean, that the photon is just a probability wave until it interacts with something?
Not a 'probability wave', just fluctuations (waves) in an electromagnetic field.
'Interacting with something' generally means that the something has absorbed some energy of the wave.
This results in some electrons gaining energy, however electrons can only transition to a more excited state in discrete steps, (quanta).
The number of such steps occurring is countable by an appropriate measuring device, so from that perspective light is behaving more like a bunch of particles than a continuous wave.
 
Last edited:
rootone said:
Not a 'probability wave', just fluctuations (waves) in an electromagnetic field.
'Interacting with something' generally means that the something has absorbed some energy of the wave.
This results in some electrons gaining energy, however electrons can only transition to a more excited state in discrete steps, (quanta).
The number of such steps occurring is countable by an appropriate measuring device, so from that perspective light is behaving more like a bunch of particles than a continuous wave.
And to extend this just a bit for the OP, what's also true is that not just any "photon" can excite just any electron. That ability depends on the frequency of the wave that causes the excitation so details of the "photon nature" side of a beam of light is a directly affected by the frequency of the light wave.

Photons are not "particles" in the classical view of particles, they are instead more accurately referred to as "quantum particles" or better still, "quantum objects".
 
GhostLoveScore said:
What does that mean, that the photon is just a probability wave until it interacts with something?

The same as when you throw a dice. You know a side will come come up with a probability of 1/6 but nothing happens until you throw the dice.

QM is a theory about observations that appear here in a common sense classical world. We can predict probabilities of those observations but nothing happens until an observation actually occurs.

With light we can predict the probabilities of observing a photon, and that is done with the wave-function (also called a probability wave) but nothing happens until it is actually observed.

Note: What I said above isn't quite true because photons don't really have a wave-function in a usual sense. But liberties with the truth about photons is often taken in beginner texts.

Thanks
Bill
 
  • Like
Likes   Reactions: GhostLoveScore and vanhees71

Similar threads

  • · Replies 8 ·
Replies
8
Views
808
  • · Replies 20 ·
Replies
20
Views
4K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 28 ·
Replies
28
Views
3K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 3 ·
Replies
3
Views
1K