In modern physics, the double-slit experiment is a demonstration that light and matter can display characteristics of both classically defined waves and particles; moreover, it displays the fundamentally probabilistic nature of quantum mechanical phenomena. This type of experiment was first performed, using light, by Thomas Young in 1801, as a demonstration of the wave behavior of light. At that time it was thought that light consisted of either waves or particles. With the beginning of modern physics, about a hundred years later, it was realized that light could in fact show behavior characteristic of both waves and particles. In 1927, Davisson and Germer demonstrated that electrons show the same behavior, which was later extended to atoms and molecules. Thomas Young's experiment with light was part of classical physics long before the development of quantum mechanics and the concept of wave-particle duality. He believed it demonstrated that the wave theory of light was correct, and his experiment is sometimes referred to as Young's experiment or Young's slits.
The experiment belongs to a general class of "double path" experiments, in which a wave is split into two separate waves that later combine into a single wave. Changes in the path-lengths of both waves result in a phase shift, creating an interference pattern. Another version is the Mach–Zehnder interferometer, which splits the beam with a beam splitter.In the basic version of this experiment, a coherent light source, such as a laser beam, illuminates a plate pierced by two parallel slits, and the light passing through the slits is observed on a screen behind the plate. The wave nature of light causes the light waves passing through the two slits to interfere, producing bright and dark bands on the screen – a result that would not be expected if light consisted of classical particles. However, the light is always found to be absorbed at the screen at discrete points, as individual particles (not waves); the interference pattern appears via the varying density of these particle hits on the screen. Furthermore, versions of the experiment that include detectors at the slits find that each detected photon passes through one slit (as would a classical particle), and not through both slits (as would a wave). However, such experiments demonstrate that particles do not form the interference pattern if one detects which slit they pass through. These results demonstrate the principle of wave–particle duality.Other atomic-scale entities, such as electrons, are found to exhibit the same behavior when fired towards a double slit. Additionally, the detection of individual discrete impacts is observed to be inherently probabilistic, which is inexplicable using classical mechanics.The experiment can be done with entities much larger than electrons and photons, although it becomes more difficult as size increases. The largest entities for which the double-slit experiment has been performed were molecules that each comprised 2000 atoms (whose total mass was 25,000 atomic mass units).The double-slit experiment (and its variations) has become a classic for its clarity in expressing the central puzzles of quantum mechanics. Because it demonstrates the fundamental limitation of the ability of the observer to predict experimental results, Richard Feynman called it "a phenomenon which is impossible […] to explain in any classical way, and which has in it the heart of quantum mechanics. In reality, it contains the only mystery [of quantum mechanics]."
While reading Feynman's 6 Easy Pieces, I see he talks about bouncing photons off of the electrons that are passing through two slits. According to Feynman, when a photon strikes an electron near one of the slits, it bounces (sometimes back at the observer) and registered as a sharp point of...
http://en.wikipedia.org/wiki/Quantum_entanglement#cite_note-0"
Is there an experiment where bucky balls are entangled?
Many of us have heard about bucky balls showing single particle interference in a double slit experiment. However I have not heard of them being entangled.
I read the...
Hi,
In a double slit experiment, shooting a photon will produce interference pattern on a screen.
Using a detector to detect which slit the photon passed through will destroy the interference pattern. The photon will pass through only 1 slit, and cause slit pattern on the screen.
The...
I am just inhaling "The Grand Design" and am stuck in the chapter on the "buckyballs" double slit experiment.
The authors say that in case of the experiment, a particle may take any possible way ("perhaps to Jupiter and back"), which then Feynman depicts as adding vectors to a result vector...
I'm new to quantum physics and the double slit experiment. If the person running the experiment collects the data but does not look at it, does the result of an interference pattern or no interference pattern on the CCD image sensor decide the future of whither that person decides in the future...
Hi, Is it possible to set up a double slit experiment where the numbers of
particles being emitted can be counted and see if it is equal to the numbers
detected at the screen?
The particles should be Buckyball or other molecules where the energy can be
made large compared to single...
I am confused by an aspect of the infamous double slit experiment. It is said that one way to understand why a succession of single particles can give rise to an interference pattern is that a single particle could be going through both slits simultaneously and interfering with itself. But this...
In the aftermath of the recent Steinberg paper where they reconstruct average photon trajectories in the double-slit experiment, it has been pointed out several times that the reconstructed average trajectories strongly resemble the single-photon trajectories predicted by Bohmina mechanics...
Ok double slit experiment. Two slits send through one photon which passes through both slits due to wave/particle duality.
So really we have two probablity waveforms now don't we? One passing through each slit and creating a wave pattern from the start of each slit. THat's how we get an...
Hi Folks
Regarding the double slit problem, I read recently a theory that suggested that the universe itself split creating effectively two particles, which can interfere.
Personally I think this is imaginative but it simply doesn't sit right, it seems somehow illogical and wasteful for...
Hello!
I have a question?
Does anyone know if scientists have tried to run the electrons through the double slit, record the particles that go through each slit, and before looking at the results, looking at the pattern on the screen. And THEN doing the EXACT OPPOSITE of what the screen...
1. Why are the slits necessary? Do 2 individual light sources of the same frequency without slits or cards create an interference pattern? If not, why not?
2. How do different frequencies of light alter the interference patterns? Any links to experiments of this nature?
3. How about 2...
The path of photons can be (almost) reconstructed in a double slit experiment!
Observing the Average Trajectories of Single Photons in a Two-Slit Interferometer
http://www.sciencemag.org/content/332/6034/1170.abstract
Discussion:
http://physicsworld.com/cws/article/news/46193...
i just don't understand diffraction in a double slit , ? how is it related to interference?? like if i want to find how many bright fringes within the central bright fringe of the diffraction envelope?
or how many bright fringes are found between the bright fringes of the first and second of...
I have a question regarding the double slit experiment. I have been doing a little reading (The Grand Design, to be specific) and I was left with a burning question.
First of all, I am not a physics major. I have taken only one college physics class, and although it is something that...
Homework Statement
Consider a young double slit experiments where the two slits are spaced d = 0.1mm apart. If when the screen is at a distance of l=1m the first bright maximum is displaced y = 2cm from the central maximum, then find the wavelength of the light.
Homework Equations...
Hi, I'm trying to perform a double slit diffraction experiment without using a laser, but instead using a super-bright, white LED. This LED has been placed inside a sealed box with a small pinhole opening (~1/32 inch diameter). This however introduces the problem that the light is incoherent...
I have what I believe is a simple question about the single photon (at a time) double slit experiment. This experiment does not use a coincidence counter correct? I understand that one, or more, is used for entanglement experiments, but is one necessary to determine an interference or lack of...
A single particle can behave like its interfering with itself by means of the following explanation (is it true or can you refute it?):
Ballentine wrote in his 1970 paper "Statistical Interpretations of Quantum Mechanics":
"As in any scattering experiment, quantum theory predicts the...
This little link here:
says that if there is a detection device that observes the electron before it gets to the slits, the observation collapses the wave function. This leads to the electron behaving like a particle rather than a wave as it enters the slit, so two bands are produced on the...
(Hope this is the right forum)
For my Physics EEI (year 12 extended experimental investigation) I'd really like do some sort of variation of the double slit experiment that can deviate into wave like behaviour of matter etc... I've found ways to have the interference patterns shown using a...
Homework Statement
so here i have shown the distances of two dark fringes ...
from here ... fringe width is \frac{\lambda L}{2d}
L is distance of screen ... d is distance b/w 2 fringes.
but fringe width is \frac{\lambda L}{d} , right ?
What mistake am i making?
After looking at the graphs of single slit and double slit interference of intensity vs. angle, it seems that the intensity drops off very steeply with single slit interference but doesn't drop off at all with double slit interference patterns. Why is that?
Even if you send a buckyball molecule in the emitter, does the detector always give you output in terms of electrons? Isn't there a way to actually check the buckyball located in the detector?
Because in normal double slit with electrons. One can argue that the emitter send an electron field...
Quantum objects are particles, not waves. Particles are bundles of energy propagating on a field. It is the properties of the field that seem to give particles wave-like qualities. Thus in the Young's double slit experiment, a given particle goes through one and only one of the slits; it does...
I am trying to calculate how wide of a screen you would need in order to observe an interference pattern produced by Young's original real-life double slit experiment. He cut a single narrow slit (width ds) in a window shade, admitting a narrow sliver of sunlight into a dark room. He inserted...
According to Richard Feynman, the double-slit experiment contains the only mystery of quantum mechanics. After we have unveiled the mystery, we will be able to understand quantum mechanics.
Someone has allegedly solved the double slit mystery and unveiled the secret of Quantum Mechanics...
If a "line" source of visible light is not really a line but has a width of 1mm, how far must it be from a double slit which it illuminates in order for the two slits to be reasonably coherent? Assume the slit separation is .5mm.
I approached this problem the same as finding the distance...
When we want to show quantum behavior (like tunneling or double slit) of a large object like a buckyball molecule, what do we need to watch out for in an experiment?
Is it the following?
a, that all constituents of the object (the single atoms of the buckyball) are described by one coherent...
Double Slit and "The Observer"
Hi! First of all, I am just getting started in Physics, so I apologize if this is a silly question.
I was talking with my boyfriend (who has a degree in physics) about the double slit experiment. Obviously, if you perform the experiment one electron (or...
Sorry for the rambling nature of this post.
Hello,I am not a student or teacher.Just a regular person,browsing Youtube.I came across the delayed choice eraser.
http://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser
I am confused...
Does that mean that anything that will never be...
I tried to do the double slit experiment at home with a green laser (for a science project at school and for fun). I failed but someone succeeded with a red laser. Is it true that a red laser works better because it has a longer wavelength?
I have no idea where to start with these questions. I am pretty sure I have to use these equations
1. theta = tan^-1(x/D)
2. wsintheta = nlambda
3. dsintheta = nlambda
Which order m of in the two-slit interference pattern will give the least uncertainty in the slit spacing, d?
a) m = 1 b)...
Homework Statement
A scientist decides to do the double-slit experiment in a ver-
tical tube, with the slits at the top and a viewing screen at the
bottom as shown. With red light from a HeNe laser (632 nm) a
nice pattern forms on the viewing screen, with the bright spots
1.50 cm apart...
Homework Statement
3 narrow slits with spacing of d and 3d/2 as in picture, the slits are irradiated from left with a plane of monochromatic light with wavelength 2d/5.
If the bottom slit is covered with a filter that introduces a half phase change, how many
principal maxima will be...
In my modern physics course we learned that electrons, when shot through two close together slits, will produce an interference pattern just light light. However, when you set up an experiment to observe which slit the electron goes through, there is no longer an interference pattern. To my...
Homework Statement
If i have the intensity pattern of a double slit experiment and aim to find the wavelength of the monochromatic light incident on the slits with the following information,
- width of each slit
- distance to the screen
- intensity pattern (displacement Vs intensity)...
What if:
1)
we put a swtich gate on the bottom slit. The bottom slit is normally closed, but we time it so we open it just before a photon/electron MAY arrive.
so far this will yeild the same result as traditional experiment?
2)
usually the two slits are close by, but we move it very...
Homework Statement
When a 450-nm light is incident normally on a certain double-slit system, the number of interference maxima within the central diffraction maxima is 5. When 900-nm light is incident on the same slit system, the number of interference maxima within the central diffraction...
Question
Suppose molecules are placed next to the slits that fluoresce when electron passes, emitting a photon that can be imaged. Explain why this is no better than direct illumination, and explain how the two-slit interference pattern is destroyed.
My Answer
In direct illumination, a...
Whilst skulking through Youtube videos for a deeper understanding of quantum mechanics I noticed that vidoes offering accurate, legitimate, remotely-science-based information were few and far between.
The rest seemed to be videos of people saying that we, as thinking beings, create the...
Buckyball Double Slit Experiment
I've been reading old archives here and even the FAQ and still not definite about the answer. It is said that a buckyball composed of 60 carbon atoms can still form interference pattern at the screen. It is not the complexity of the object but the fact...
Homework Statement
(a) In a double-slit system, what value of d/a causes diffraction to eliminate the third bright side fringe? Homework Equations
I(\theta) = I_mcos^2(\beta)(\frac{sin(\alpha)}{\alpha})^2
\beta =\frac{\pi d}{\lambda} sin \theta
\alpha = \frac{\pi a}{\lambda} sin \theta...
Hello, I was wondering if I could get any help with the following question/thing:
Why does a stream of photons (let's say that one is fired every 3 seconds) at a double slit as shown in Young's double slit experiment create an interference pattern although there is no interference because the...
If electrons are strings (in string theory), what happened to the string between emission at the double slit experiment and detection on the screen after it passes thru the 2 slits? Does the string splitted and joined again after the slits?
Before string theory, we just say particle...
A friend of mine pointed out this website to me.
http://www.doubleslitexperiment.com/
The site posts an interesting theory; I'll take a quote from the sites document:
"For some unknown reason that haunts scientists, everything we perceive as having mass is just a wave of information (or...
Homework Statement
See figure attached for problem statement as well as my attempt
Homework Equations
The Attempt at a Solution
I don't know where to go from here. Can someone help me get started?
Homework Statement
See figure attached for problem statement as well as my attempt.
Homework Equations
The Attempt at a Solution
I don't know where to go from here. Can someone help me get started?