Use this tag for questions relating to the "wave-nature of particles" or the "particle-nature of waves" as they are often discussed in quantum mechanics, where a single object has properties of both classical particles and classical waves.
Questions tagged [wave-particle-duality]
873 questions
76
votes
12 answers
Is the wave-particle duality a real duality?
I often hear about the wave-particle duality, and how particles exhibit properties of both particles and waves. However, I wonder, is this actually a duality? At the most fundamental level, we 'know' that everything is made up out of particles,…
user14445
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64
votes
11 answers
How does light 'choose' between wave and particle behaviour?
Light exhibits wave behaviour in phenomenon such as interference but particle behaviour in the photoelectric effect. How does light 'choose' where to be a wave and where to be a particle?
d_g
- 722
48
votes
5 answers
What is a phonon?
I am trying to understand intuitively what a phonon is, but for the moment I find it quite difficult (having a limited background in quantum mechanics, an undergraduate course in non-relativistic QM). In fact, I find it hard to formulate good…
doetoe
- 9,484
46
votes
4 answers
How does the light source fire a single photon in the double-slit experiment
All the youtube videos I have seen on the double slit experiment broadly fall into one of the following three categories:
Documentaries and fan made videos heavy on animation which 'admire' the wave-particle duality of light rather than…
user58110
42
votes
5 answers
In the double-slit experiment, why is it never shown that particles may hit the space between or outside the slits?
In depictions of the double-slit experiment that model the photon or electron as a particle, i.e. when attempting to measure which slit the particle passes through, it always shows the particle entering one of the two slits. Why is it that the…
Andrew Cheong
- 679
37
votes
4 answers
Why do photons follow specific path after reflection from a mirror surface if they can be emitted in any direction by electrons of mirror surface?
The electron absorbs the energy of photon(with specific frequency)and re-emits the photon.The photon can be emitted in any direction. So why do they get re-emitted in a specific direction after reflection? On hitting normal to surface the photons…
Karan Bhatia
- 511
37
votes
5 answers
What do we see while watching light? Waves or particles?
I'm trying to understand quantum physics. I'm pretty familiar with it but I can't decide what counts as observing to cause particle behave (at least when it's about lights). So the question is what do we see with our eye-balls?
We point a laser (or…
martintrapp
- 505
37
votes
3 answers
Do photons occupy space?
Total noob here.
I realize that photons do not have a mass. However, they must somehow occupy space, as I've read that light waves can collide with one another.
Do photons occupy space? and if so, does that mean there is a theoretically maximum…
LanceLafontaine
- 799
32
votes
4 answers
$\lambda=\frac{2h}{p}$ instead of $\lambda=\frac{h}{p}$?
I am studying quantum physics and there is something I don't understand:
I know that for any particle $E=hf$ (Einstein relation) and
$v=\lambda f$ ($v$ is the speed of the particle).
I also know that the kinetic energy is $E_k=\frac{mv^2}{2}$.…
snickers
- 527
30
votes
7 answers
Why does observation collapse the wave function?
In one of the first lectures on QM we are always taught about Young's experiment and how particles behave either as waves or as particles depending on whether or not they are being observed. I want to know what about observation causes this change?
Alex Voinescu
- 497
28
votes
4 answers
What does a de Broglie wave look like?
What does a de Broglie wave look like?
Are de Broglie waves transverse or longitudinal?
Can they be polarized?
What about the de Broglie wave of a ground state neutral spin-zero Helium 4 atom?
What experimental evidence do we have that…
Jim Graber
- 5,817
27
votes
4 answers
Why is the force exerted by a light beam on a spherical object independent of the amount of light reflected or absorbed?
When a sphere of radius $r$ is placed in the path of a parallel beam of light of intensity $I$, the force exerted by the beam on the sphere is given by:
$$F=\frac{\pi r^2 I}{c}$$
I derived the above result by assuming the sphere to be perfectly…
Vishnu
- 5,336
26
votes
6 answers
What actually is white light?
I was studying spectra and suddenly a question popped up relating to the absorption spectra.
When we say that the electron absorbs certain wavelengths(photons) so we are implying that white light is a collection of infinite photons of many many…
26
votes
7 answers
'Why' is the Schrödinger equation non-relativistic?
The transition amplitude for a particle currently in one spacetime point to appear up in another point doesn't respect causality which becomes one of the main reasons to abandon non-relativistic quantum mechanics. We impose the relativistic…
Manas Dogra
- 1,108
26
votes
4 answers
Why would Pilot-Wave be wrong?
If this question has already been asked or is super basic, apologies. I'm a physics novice and this is my first question on this side of the site.
In classical physics, waves and particles are mutually exclusive, but in quantum theory subatomic…
Mercutio
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