With the single slit one pattern is seen using a single particle. Why is it a wave just because a wave like distribution is seen.^ That is to say, when both slits are open we no longer have a particle but a wave because?..ìWhy? Just because a wave distribution is seen the particle must now be a wave? Perhaps the particle remains a particle and gives this distribution not becase it is a wave but because the particle interacts with the geometrical pattern of two open slits and gives this new pattern as a particle. Just because you have a wave pattern does not prove the particle is now itself a wave. The possibility of a particle being in two places at the same time is impossiblehilbert2 said:They don't need a material medium, just like light doesn't need a "luminiferous ether" to move in, as the Michelson-Morley experiment proved. The electrons, and their antiparticles positrons, are excitations of the Dirac fermion field, just as light quanta (photons) are excitations of the electromagnetic field. Both fields permeate all space and are not made of any material, but they differ in the sense that electrons are fermions (particles of half-integer spin) and photons are bosons (particles of integer spin).
That's not far off of what's really going on, although you wouldn't know it if you've trying to understand QM from pop-sci sources. (Everything you've been told about how we have a wave with interference when two slits are open and a particle with no interference when one slit is open is somewhere between seriously misleading and just plain wrong. Try to unlearn it).Bruce Barron said:For instance, the photon may be simply interacting with a different geometrical pattern when both slits are open.
They are neither particles or waves. They are quantum objects whose behavior is described by the laws of quantum mechanics (actually, quantum electrodynamics). "Wave/particle duality", the idea that sometimes photons are particles and sometimes they are waves, is not part of the modern understanding of quantum mechanics. It's something that was conjectured early last century when physicists first encountered quantum phenomena, and was abandoned when the modern form of the theory was discovered.SWB123 said:I had wondered if it is possible, that photons are indeed waves from the start, and throughout their travel, UNTIL they encounter something with physical mass! At that instant, their electromagnetic field interacts with an opposite polar field/spin within the mass. At that instant, the photon's energy is imparted to the mass, and 'THAT INTERACTION' is felt by the mass, as though it had been hit by a particle.
The size and position of the slits definitely matters. Generally it will be towards the end of the second year of a bachelor's degree program that you'll learn how to calculate what pattern is built up on the screen when you have slits of a given size and position, and there's a fair amount of mathematical heavy lifting involved. However, Feynman's fun and layman-friendly math-free book "QED: The strange theory of light and matter" will give you a pretty good feel for how it works.I do have some questions myself about the double slit experiment:
1) Is there a physical size to, or distance between the slits, which alters/eliminates the findings, which we all find so amazing?
2) If so, how exactly do those factors change the behaviour of the photon?
3) Can knowing the results of those variations help in figuring out the original iteration of the experimant?
Nugatory said:However, something interesting happens: the pattern formed by the dots is not the tight clump behind each slit you'd expect if we were shooting bullets through the slits.
OK, maybe should have said "charged bullets"... although this thread is about photons, which have no charge...ueit said:Why would you expect the particles to behave like bullets? An electron is a charged particle and it interacts with a barrier composed of many charged particles in motion (electrons and nuclei). It is a difficult problem to solve in classical electrodynamics and it is not obvious to me why do you find the "tight clump" solution an obvious one.
If you really like the "bullets" analogy try to use charged bullets (having the enormous charge/mass ratio of an electron) and a barrier formed by an array of dipoles. Again I'm not sure what pattern to expect, but I bet it's not a "tight clump".
Andrei
here the particles are electronsNugatory said:Here's what we observe when we do the double slit experiment with individual photons:
... This article reports an experiment that successfully recorded the actual buildup process of the interference pattern with a series of incoming single electrons in the form of a movie.
Nugatory said:OK, maybe should have said "charged bullets"... although this thread is about photons, which have no charge...
However, the key point for purposes of this thread is that the pattern you get is not the pattern that would be produced by small solid objects (which is how most non-specialists understand the word "particle") moving under the influence of any force or combination of forces. You get the pattern that is produced by a wave interacting with the entire surface of the barrier, slits and all.
This is simply personal speculation and goes against mainstream physics.ueit said:It seems to me possible that the EM interaction between the incoming electrons and the electrons and nuclei in the barrier could in principle account for the observed pattern.
The double-slit experiment is a classic physics experiment that involves sending particles (such as photons or electrons) through two parallel slits and observing the resulting interference pattern on a screen behind the slits.
The double-slit experiment is important because it demonstrates the wave-particle duality of matter and energy. It shows that particles can behave like waves and exhibit interference patterns, challenging our previous understanding of the nature of matter.
The implications of the double-slit experiment are far-reaching and have led to the development of quantum mechanics, which has revolutionized our understanding of the microscopic world. It also has implications for fields such as optics and electronics, as well as for our understanding of the fundamental laws of nature.
The outcome of the double-slit experiment is affected by several factors, including the size of the slits, the distance between the slits and the screen, and the type of particles used. Additionally, the act of observation itself can also affect the outcome, as particles can behave differently when they are being observed.
The double-slit experiment is often used to explain the concept of superposition, which is the idea that a particle can exist in multiple states at the same time. In the experiment, the particle passes through both slits simultaneously, creating an interference pattern. This demonstrates how a particle can exist in multiple states until it is observed and its wave function collapses into a single state.