Can something be in 2 places at the same time?

Originally posted by Andrew Hamilton

I know that it is common scientific wisdom in quantum physics that the outcome of the slit experiment is influenced by the observer but I think that is bases on flawed logic for you cannot safely conclude that from the premises you just pointed out.
The only thing that can safely be concluded from the premises you just pointed out is that the out ...[text shortened]... ere although I am sure there are many physicists that would very strongly disagree with me here.

it would be a disagreement of only semantics i think

Originally posted by Andrew Hamilton
[b]…It is extraordinary that the observer can influence the outcome of the experiment...…

I know that it is common scientific wisdom in quantum physics that the outcome of the slit experiment is influenced by the observer but I think that is bases on flawed logic for you cannot safely conclude that from the premises you just pointed out.
The ...[text shortened]... ere although I am sure there are many physicists that would very strongly disagree with me here.[/b]

I'm sure almost every physicist would disagree. I'm not sure how familiar you are with Bell's inequality, but it's very relevant to this issue, and settles it.

Originally posted by KazetNagorra
I'm sure almost every physicist would disagree. I'm not sure how familiar you are with Bell's inequality, but it's very relevant to this issue, and settles it.

How does it settle it? I looked it up:

http://en.wikipedia.org/wiki/Bell_inequality

I could be wrong but I don’t see in what way this contradicts my assertion but I could just be reading it wrong.

I was traught that anything traveling at greater than the speed of light would be "everywhere at once, yet nowhere at the same time."

Originally posted by PinkFloyd
I was traught that anything traveling at greater than the speed of light would be "everywhere at once, yet nowhere at the same time."

What happens beyond the speed of light are only speculations. I don't think there are any science behind these speculations. No observations of superluminal particles have been made, so we know nothing about any of them, if they exist at all.

No physical laws, however, forbid superluminal velocities. But their mass must have an imaginary part in its value. Like I would weigh (60+2i) kg in some superluminal velocity.

Originally posted by Andrew Hamilton
How does it settle it? I looked it up:

http://en.wikipedia.org/wiki/Bell_inequality

I could be wrong but I don’t see in what way this contradicts my assertion but I could just be reading it wrong.

Bell's inequality implies that the collapse of the wavefunction is fundamental in physics, and not simply an artifact of the experimentation.

To answer the original question when I am at work I am frequently required to be in two places at the same time.

Originally posted by deriver69
To answer the original question when I am at work I am frequently required to be in two places at the same time.

That I can identify with!

Originally posted by KazetNagorra
Light is subject to the laws of time and space. The laws of time and space as we currently know them imply that you cannot simultaneously measure position and momentum (which in the case of photons, is proportional to energy) of any particle.

Is it though. Then how does it achieve the speed it travels at? Does a photon have any mass at all? Surely not, if it travels at that speed it must be free of mass, or how else would it be able to accelerate to that speed? And light doesn't actually accelerate does it, I believe it is just 'the speed of light' -- incredible. So if it is free of mass is it pure energy? And if pure energy does that explain why it can be in more than one place at once?

Before you physics dudes stone me for what are probably silly questions, please note that i live in the word not the number!

Originally posted by divegeester
Is it though. Then how does it achieve the speed it travels at? Does a photon have any mass at all? Surely not, if it travels at that speed it must be free of mass, or how else would it be able to accelerate to that speed? And light doesn't actually accelerate does it, I believe it is just 'the speed of light' -- incredible. So if it is free of ma ...[text shortened]... me for what are probably silly questions, please note that i live in the word not the number!

1. Yes, photons have no mass, which means they can attain the speed of light and indeed can only travel at the speed of light. This applies to all particles with no mass (yes, there are more).

2. The "being able to be in more than one place" applies to all particles, not just massless ones. To understand this you need to stop thinking of particles as a dot somewhere in space, but as a wave somewhere in space. The reason the wave character of particles is not always apparent is that the wave can be confined to (or at least have a very large probability density in - but let's not get into details) a certain area of space.

Originally posted by KazetNagorra
Bell's inequality implies that the collapse of the wavefunction is fundamental in physics, and not simply an artifact of the experimentation.

Yes, and I don’t have a problem with that, but how does that relate to the observer in my original assertion?

Originally posted by Andrew Hamilton
Yes, and I don’t have a problem with that, but how does that relate to the observer in my original assertion?

If information can somehow be recovered, this influences the nature of the particle. The act of "observing" changes the particle because Heisenberg's uncertainty principle cannot be violated.

Originally posted by KazetNagorra
If information can somehow be recovered, this influences the nature of the particle. The act of "observing" changes the particle because Heisenberg's uncertainty principle cannot be violated.

…The act of "observing" changes the particle because Heisenberg's uncertainty principle cannot be violated...…

I can accept that Heisenberg's uncertainty principle cannot be violated but I don’t see why this should mean that “The act of "observing" changes the particle” for the process of a sapient "observing" is actually extremely complex process and consists of a long chain of causally linked events (such as light entering the eyes and then being detected by retina cells that respond by firing electrical signals etc) and I fail to see what is so special about this "observing" process as a whole that would make “change” in the particle.
-I mean, why cannot any kind of process do? Such as just the physical process of light entering your eyes (which, by itself, is not “observing” because it is just part of the process of observing) or even a simple interaction with another particle?
This is why I think it isn’t true that “The act of "observing" changes the particle” but rather “the physical interaction with anything changes the particle” -let me try and elaborate on that:

I understand that in quantum physics, the Heisenberg uncertainty principle basically says that, the greater the precise you know the position of a particle, the less precisely you can know the momentum of the particle and visa versa. This is not a statement about the limitations of an observers ability to measure these particular quantities, but rather about the nature of the particles themselves -and I understand and accept this.

But what if neither the position or the momentum of a particle is known nor observed by an observer? (perhaps because the existence of a particular particle is unknown to any observer) -the particle may still physically interact with something as if it has either a momentum within a certain range or a position that is “fuzzy” but it still can have a rough “position” or “momentum” -right? -that is what I am trying to say; I am trying to say that only a physical interaction is required to make “changes in the particle” and no particular “observation” is necessary to have a directly relevant effect here and nor what is “known” by us can directly “cause” any change in the particle.

"Observing" does not necessarily involve humans. Observing, in a quantum mechanical sense, means a process in which information can be recovered.

Originally posted by KazetNagorra
"Observing" does not necessarily involve humans. Observing, in a quantum mechanical sense, means a process in which information can be recovered.

I didn’t know that! This is the first I have heard of this. -if that is really the case then I don’t have any disagreement with this conventional wisdom in quantum physics 🙂

But I seem to distinctly remember from my university courses that the usual interpretation is that a conscious observer is required which I intuitively always thought was extremely erroneous -is this interpretation that a conscious observer is required simply a common fallacy in quantum physics?