Wave/Particle Duality: Observing Reality Differently?

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In summary, when a photon is observed as a wave or a particle, the observation itself determines its state. This means that if two observers observe the same particle differently, it will only appear as a particle to both of them. The reality is the same for all observers and the wave and particle states cannot be observed simultaneously. However, it is possible to have a partial wave or particle state for a very short period of time. Additionally, in ultrafast laser spectroscopy, a single photon can exhibit wave-like behavior due to interference effects, but it is still fundamentally a particle.
  • #1
beatlemaniacj
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If a photon can be observed as a wave or a particle, and that observation decides whether it is in fact a wave or a particle, what happens when to observers observe the same particle differently? Is it both? Is reality different for each observer?
 
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  • #2
beatlemaniacj said:
If a photon can be observed as a wave or a particle, and that observation decides whether it is in fact a wave or a particle, what happens when to observers observe the same particle differently? Is it both? Is reality different for each observer?

measurement/detection by any observer forces/converts the photon into the "particle state"

thus all other observers will only see the particle face/side, no matter how they choose to observe

the reality is same for all observers

particle and wave states cannot be observed at the same time, even if we have more than one observer and they are using different observation methods..

to be more precise/technical -- wave state can never be observed...it can only be inferred...based on the effect of the wave on the behavior of the photon...

it's not about the observer, its about the photon...it can either be in wave state or particle state...and every observer will see the same state at any given instance of time

though, i think, a partial wave state and partial particle state might be possible...for at least infinitesimally small periods of time
 
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  • #3
So a wave/particle in an observer tank appears. In Sweden a researcher observes it as a wave. In America, a researcher observes it as a particle. Lease give a slution where time is negligible and where it is not.
 
  • #4
The smallest portion you can observe is a single photon. And a single photon is always observed as a particle! If you observe a wave-like phenomenon (e.g. an interference pattern) this is always created by interference of many photons (you can have a single photon interfering with itself, but it never creates an interference pattern, it always creates a single, point-like spot or something like that).
 
  • #5
I thought I had this sorted out years ago but now thinking about it, I'm not so sure.

Lets take ultrafast laser spectroscopy. A "flash" of light is a wavetrain. As the wavetrain gets shorter and shorter, eventually it will be just 1 peak; you can't have less light than 1 peak.

this is a wave description of the light.

now, this 1 peak can still suffer destructive and constructive interference like a wave if we had another ultrafast laser aimed the right way, very hard practically of course. this ultrashort "wavetrain" could also be diffracted by a 2 slit experiment.

How would this work out?
 
  • #6
I am not an expert in laser spectroscopy and quantum optics but as long as you have a large number of photons in that ultrashort peak you would observe interference (for a very short time). No problemn with that theoretically.
 
  • #7
beatlemaniacj said:
If a photon can be observed as a wave or a particle, and that observation decides whether it is in fact a wave or a particle, what happens when to observers observe the same particle differently? Is it both? Is reality different for each observer?

It is not a wave - it is a particle - simple as that. However it is a particle that obeys the rules of QM and has interference effects etc like a wave - but in reality it is a particle pure and simple.

Thanks
Bill
 
  • #8
tom.stoer said:
The smallest portion you can observe is a single photon. And a single photon is always observed as a particle! If you observe a wave-like phenomenon (e.g. an interference pattern) this is always created by interference of many photons (you can have a single photon interfering with itself, but it never creates an interference pattern, it always creates a single, point-like spot or something like that).

True - a single photon can not create an interference pattern but it will give away that it is interfering with itself by never being detected at certain points.

Thanks
Bill
 
  • #9
bhobba said:
True - a single photon can not create an interference pattern but it will give away that it is interfering with itself by never being detected at certain points.
That's correct, but you are not able to check this experimentatlly by just using one single photon; you always need multiple photons, either in a beam or single photons in many identical experiments. So in a sense we claim theoretically that a photon can (and does) interfer with itself, but we know that we can never check this directly. The best we can do is to look at the interference pattern created by many individual photons where we make sure that for a certain time interval T=L/c only one single photon does exist inside the experimental setup (with a typical size L).
 

1. What is wave/particle duality?

Wave/particle duality is a concept in quantum mechanics that states that particles, such as electrons or photons, can exhibit both wave-like and particle-like properties depending on how they are observed or measured.

2. How does wave/particle duality challenge our understanding of reality?

Wave/particle duality challenges the classical, Newtonian view of the world that states that objects can only possess one set of properties at a time. It suggests that the behavior of particles cannot be fully explained by classical physics and that our understanding of reality may be limited.

3. What experiments have been conducted to demonstrate wave/particle duality?

The double-slit experiment and the delayed-choice quantum eraser experiment are two of the most well-known experiments that demonstrate wave/particle duality. These experiments show that particles can behave like waves or particles depending on how they are observed or measured.

4. How does the observer affect the behavior of particles in wave/particle duality?

In wave/particle duality, the act of observation or measurement can influence the behavior of particles. This is known as the observer effect, where the act of observing a system can change its behavior. This suggests that the observer plays a vital role in shaping our understanding of reality.

5. What are the implications of wave/particle duality on the field of science?

Wave/particle duality has significant implications in the field of science, particularly in quantum mechanics. It challenges our traditional understanding of the behavior of particles and requires us to rethink our models and theories. It also has practical applications, such as in quantum computing and cryptography, that rely on the principles of wave/particle duality.

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