Schrödinger's cat of Light

Factual Questions
1

You may think that I know more of the subject - but sorry that is not the case. I don’t even have any background in Physics. I changed the end of the title from Photon to Light, because I’m not sure if nuclear decay is due to photons. And I don’t belive that photons even exist - only waves.

But, what I mean with this OP is that does anybody know where one photon propagates, before you see it. And I don’t mean a bunch of waves collimated to a direction, but an occurrence when one formerly exited electron emits light. My theory is that it can be seen anywhere until it is “consumed” by the observer (or a wall or whatever).

2

The way I would put it is that its position is ill-defined before it’s detected, just like an electron’s position is ill-defined in an atomic orbital. If we prepare an atom in a particular excited state, and it emits a photon, then we can only tell probabilistically the direction in which the photon will be emitted. Depending on the properties of the excited state and the ground state, there will be some directions of travel that are more likely than others. But each individual atom shows up as a “point of light” when it is observed, and it’s only if we repeat the same experiment many, many times that we can see that some directions of travel are more or less likely.

3

I’m not sure I understand your question, and possibly the problem is in the set of assumptions either you or I have.

In the first place, nuclear decay isn’t “due to photons”. Many forms of nuclear decay don’t involve photons at all. Alpha emission results when an alpha particle (two protons and two neutrons, a helium-4 nucleus) is emitted. There are several forms of beta decay, but your classical form involves emitting an electron and an electron antineutrino. Nuclear fission results in the emission of several particles, and of gamma rays, which are high-energy photons. so nuclear decay can involve and require photons, but it isn’t “due to them” as a cause.

To say that photons don’t exist, “only waves” gets to the heart of wave-particle duality. Photons (and electrons, and other particles) have properties of both particles and waves. That’s kind of hard to get away from. Just when you think you’ve pinned down the identity to one type – light reflects, refracts, and diffracts the same way waves do, but it’s hard to see how particles would do that – you get other features that suggest the other type, such as the quantization of energy that suggests particle nature.

I suspect part of the confusion is the concept of a particle existing only at a specific point in space, which I think you hold, based on your phrasing (“where one photon propagates”) But electrons and protons have sizes (or at least characteristic lengths), despite their wave nature. How big is a photon? I can make a good argument that a photon isn’t a point particle, nor even a hard sphere, but more like a fuzzy ball that trails off gradually, much like the true shape of atomic orbitals.

Consider the single-slit experiment. People get hung up on a false dilemma with the double-slit experiment - “Which slit does the photon go through?” But consider the single slit-- there’s a characteristic diffraction pattern for a single slit. The narrower the slit, the broader the pattern. You can do an experiment where you can be certain that the flux rate is so low that only single photons are pasing through the slit, yet the same characteristic diffraction pattern results. It’s always dangerous to try to visualize quantum events with human-sized models, but I think it’s fair to say that the photon effectively “senses” the full width of the diffraction slit, which is evidence that the full extent of the photon must extend out to pretty macroscopic distances, since the individual photons contributing to the pattern aren’t communicating with each other – the information must be there, sensed by each photon. It’s like a dust bunny from under your bed with tendrils that extend to a great many times what you think its size ought to be.
Physicist view wave packets not as single-frequency waves nor as tightly-defined sharp-edged balls. Your photon (and electron, and other particles) shares not only wave and particle characteristics, but also acts like a wave packet made up of many components of differing wavelength.

Finally, "My theory is that it can be seen anywhere until it is “consumed” by the observer (or a wall or whatever). " doesn’t make a lot of sense. The photon can’t be seen anywhere until it is “consumed”. And onced you consume it with your detector, that’s it.By my mental picture, the trailing off “wings” of the photon extend very, very far from where the photon probably is, and in that sense it is “anywhere”, but all locations are not equally probable. In that sense, the beam of light can be said to propagate through a certain, well-defined region, even if there is enough of a beam outside that area to allow for diffraction effects. A lowest-order laser beam is demonstrably a well-defined and confined beam, with 99% of its energy lying within a radius of three sigmas of the center, even if 1% might lie outside that region.

4

Isn’t frequency a function of time? If so, should not the photon appear at least twice on a sensor?

5

The the inverse of frequency is a wave and does appear–ie manifests itself as a physical reality–by definition, on a sensor of appropriate size, in enough repetitions–call it twice at a minimum–such that you can actually see that it is, well, frequent and, repeatable, enough for it to be identified or investigated as such.
,
And photons don’t do that (have to do that), even in worked out real-observation, and by definition and pioneering worked-out math and experiment from the early 20th century, and a single dab’ll do ya.

But with light they both are operant, depending on the needs of the analysis of the observer.

Weird shit.

6

That’s a consequence of the wave/particle duality of light. Monochromatic light can be shown experimentally to consist only of photons of one specific energy, and even single photons behave in a wave-like matter, such as refracting and reflecting.

There’s no way to describe how the frequency of a light beam arises other than it being a property of the individual photons.

7

The verb “see” doesn’t really apply at this scale. You can’t see a photon the way you can see a tree or a house. Seeing is when photons that have traveled from somewhere interact with atoms inside your eyes and cause an electric reaction. So the only photons you can “see” are the ones inside your eyes.

One photon doesn’t convey a meaningful amount of information. But a large group of photons can cause a pattern which the mind can interpret and draw information from - like where the photons are coming from.

8

I’ve never understood why wave-particle duality should be considered so weird, when there are plenty of similar dualities in our everyday familiar life. For instance, a son, a brother, and an uncle are different things, but the same entity can be all of them, depending on context. Ask my mother, and she’ll tell you that I’m a son. Ask my sister, and she’ll tell you I’m a brother. Ask my nieces or nephew, and they’ll tell you I’m an uncle. Which one is right? All of them, of course.

Ask a photomultiplier tube or a solar cell what light is, and it’ll tell you that it’s a particle. Ask a diffraction grating what light is, and it’ll tell you that it’s a wave. Which one is right?

9

Yes, frequency is the reciprocal of time. If a wave crest passes you once every 3 seconds, the frequency is 1/3 Hertz. If you see a wave every 1/100 second, the frequency is 100 Hertz.

No. I can’t see any relation between this question and the fact that frequency is a function of time.

10

Me: “But with light they both are operant, depending on the needs of the analysis of the observer.”

You: Damn. Game, set, and match.

Next thing you’re going to tell me you teach physics outside of GQ to all sorts of students including noobs like me.

[Actually, I believe you have told me that.]

11

I think Chronos was a little vague - maybe he is sick? Another effort?

12

Technically under more modern models a photon (as a particle) takes all possible paths to the point where it is absorbed, this idea is called Feynman’s Paths.

His interpretation does explain some observable effects like diffraction and airy disks.

13

Feynman’s sum over histories is a perfectly valid interpretation of quantum mechanics. But there are dozens of other interpretations of quantum mechanics which are just as valid. If some interpretation or other makes it easier to guide you in figuring out how to set up your calculations, great, use it, but that’s largely a matter of personal taste, and none of them are wrong.

14

Photons are not very much like little balls that fly around bouncing off stuff, but they can sometimes be compared to a little ball flying around, which helps us understand them.

But this comparison can also lead us to misunderstand them, because despite sometimes acting in ways analogous to a little ball, many of the ways they act are very much unlike a little ball.

Similarly, we observe waves in an ocean, and in some ways photons can be compared to ocean waves. But in a lot of ways photons are wholly unlike ocean waves.

It turns out that there is nothing in the macroscopic world that is a particularly good model for how photons and other subatomic particles behave. And why should there be?

Once we get down to fundamental forces and fundamental particles, those things and forces act like nothing else than themselves, because they are what makes up the things we’re trying to analogize to them.

Try this video of Feynman answering the question of how magnets work. They work because magnetic forces attract and repel, and things we could use as analogies to magnets, like rubber bands or whatever, act that way because of the very same electromagnetic forces that we’re trying to use to explain magnets.

Photons act the way they do, not because they’re like little rubber balls or ducks floating on a wavy pond. They’re like nothing else except photons, and they act like that because that’s the fundamental nature of photons. We’re down to the fundamental forces that control the universe, and the reason those forces act the way they do is because that’s the way the universe works.

15

There’s a couple of important differences between the two cases, though. First of all, the properties of being an uncle, son, or brother can occur simultaneously without problem—say, at a family gathering. The reason for that is that there’s no conflict between them: being a brother does not preclude being an uncle (indeed, the former is a precondition for the latter). Waves and particles have opposing properties: extendedness vs. localization, definite trajectories vs. wavelike propagation, and so on. Being a wave and a particle thus means being both localized and not localized, while being both a brother and an uncle doesn’t incur any such problems.

More importantly, brotherhood, unclehood, and sonhood are relational properties: they’re conferred upon you not by what you are, but by the relations you stand in to others. No experiment done on you can tell us whether you are an uncle; an exact duplicate of you that is not an uncle could exist. If your sister, thousands of miles away, has a child, you instantly become an uncle, without any worries for relativity, because this doesn’t change anything about you (indeed, you don’t even necessarily know it), but merely about the web of relations you stand in. Particlehood or wavehood, however, appear to tell us something about the nature of the thing we’re considering—they seem at least candidates for intrinsic properties. And really, the only reason some people deny this is quantum mechanics—in a Newtonian world, that would be just obvious, which tells you something about how strange the matter is perceived to be.

16

Some physicist seem to use the word Photon for as a synonym for “I know, but the leymen can’t, because it is too mathematical”. Actually when they ponder something they don’t comprehend, they take this “photon is the carrier” -sentence so they look wise among other physicist. Nothing mathematical there.

Ok - a bit negative, but the positive thing is that I’m not drunk (right now).

17

I’m like the Schrödinger’s Cat myself. You never know when I’m drunk. My wifey says I am. I am not (or am I?). Sorry physicists, sorry Chronos.

18

But nobody is ever both an uncle and a brother to the same person (well, OK, sometimes, but let’s ignore those cases). Just as whether the wave properties or particle properties of something are relevant depends on the context, so too does the brotherness or uncleness of a person depend on context.

It’s not a perfect analogy, of course, but then, it’s not even a perfect analogy for the sister-aunt duality. It’s still, I think, a good enough analogy.

19

“I am your father’s, brother’s, nephew’s, cousin’s, former roommate.”

20

No they don’t. Unless of course you can present a number of relevant cites.