Interference pattern built up photon by photon

What people said

Strong rec CaffeinatedPerson · 2015-03 · Physics Stack Exchange · on “Can only one electron or photon produce interference pattern?”

Short answer: no. The interference pattern is formed only after many electrons are shot through the slits. The "natural" conclusion of this experiment is that we cannot predict where an electron will be detected, only the probability of the electron being detected in particular locations, as indicated by the interference pattern. Another remarkable aspect of this outcome is that it is indicative of wave-particle duality. The single point of detection when shooting a single electron suggests particle-like properties, whereas the interference pattern suggests wave-like properties. [this video] (an excellent real-life video showing the build-up of the interference pattern)

Recommends anna v · 2013-06 · Physics Stack Exchange · on “Are the Maxwell equations a correct description of the wave character of photons?”

The photon is an elementary particle. Elementary particles [LINK] are described by their rest mass, spin and quantum numbers as seen in the table. They then have attributes that are variable, like energy and momentum, which are states measured with the corresponding quantum mechanical operator. The photon has spin 1, zero mass and zero charge. Its energy is given by E=h*nu, where nu is the frequency characterizing it . The frequency is the one common point with the classical electromagnetic light description. This is verified with the double slit experiment [LINK] which displays the probabilistic nature from quantum mechanics when the photons are projected one by one and the interference pat

Recommends anna v · 2013-07 · Physics Stack Exchange · on “Double Slit experiment with just one photon or electron”

Yes, several people have done the experiment, and the photons/ [LINK] electrons are not split, you can get one hit at a time. Here is a second video [this video] . The wikipedia two slit article has a build up of the electron interference pattern one at a time. It is a probability pattern that shows the interference. The electrons and photons either go through one of the slits or the other, whole. Nothing mysterious is happening. There have been experiments recently where one can detect which the slit the particle went through [LINK] and still the interference pattern appears.

Recommends anna v · 2014-01 · Physics Stack Exchange · on “How fast does the collapse travel in a multiple slit experiment?”

I assume we are talking quantum mechanics here. In quantum mechanic "collapse" is a fancy terminology for "measurement." A measurement in quantum mechanics picks one out of the probable values of a variable, where the probability is given by the square of the wavefunction describing the system. If we have a kilometer long million slit light source and make an observation on a slit at one of the ends, will the interference pattern fully collapse or partially collapse? is there any delay in the propagation of the collapse or is the collapse instant? The measurement of an interference pattern needs a lot of statistics, i.e. a lot of photons hitting the screen ( individual measurements/dots on t

Recommends anna v · 2014-11 · Physics Stack Exchange · on “What happens to the energy when waves perfectly cancel each other?”

I had prepared this answer for a question that was made duplicate [LINK] , so here it comes, because I found an instructive MIT video. (the second link) This answer is for electromagnetic waves mainly Have a look at this video [this video] to get an intuition how interference appears photon by photon in a two slit experiment. It comes because the probability distribution for the photons, as accumulated on the screen, has destructive and and constructive patterns, ruled by the underlying quantum mechanical solution of "photon + two slits". The classical electromagnetic wave emerges from a great plethora [LINK] of photons which have phases and such that they build up the electric and magnetic field

Recommends bright magus · 2015-02 · Physics Stack Exchange · on “Can light emit light?”

@Paul: Are you aware of the fact, that particles sent through the double slit are detected to be arriving as particles - be they electrons or photons? You might want to read this answer to Is the wave-particle duality a real duality? [LINK] question. It refers to photons as well - watch this video by Leiden University [this video] . So, single particles do not produce any wave pattern - the pattern that looks like interference is only statistical.

Recommends Punk_Physicist · 2019-07 · Physics Stack Exchange · on “Is it possible to see individual photons impressioning film?”

There are a number of videos online of optical interference patterns being built up at the level of single photons. For instance there is this [this video] short YouTube video taken in 2008 at Leiden University using an intensified CCD or ICCD camera [LINK] (essentially a CCD with a phospher screen that is sensitive at the single photon level). As described in the details on the YouTube page: This movie has been captured with an intensified CCD camera. The movie consists of 200 frames, with exposure times ranging between 0,025 milliseconds and 6,000 milliseconds. It shows how individual photons, transmitted through a double slit, form an interference pattern. It shows wave-particle duality of lig

Cites anna v · 2013-07 · Physics Stack Exchange · on “How does optical phase modulation produce photons with different frequencies?”

A photon is an elementary particle , a building block of the Standard Model [LINK] . Elementary particles follow quantum mechanics and not classical physics trajectories, once one has been able to isolate one of them and follow it course. A light beam which optics works with, microscopically emerges from the congruence of zillions of photons, each moving at the velocity of light and with point dimensions within the Heisenberg uncertainty principle, HUP [LINK] . An individual photon cannot be chopped, it is either there or it is not. Lubos Motl, who contributes here, has an article [LINK] in his blog on how classical electromagnetic fields emerge out of an ensemble of photons. One could in pr

Cites anna v · 2013-07 · Physics Stack Exchange · on “Photons-Wave/particle duality”

The two resulting rays are said to constructively interfere, which is confusing to me. The two rays are clearly parallel, but not coinciding, so how do the two interfere at all? You are actually confusing three different physics representations of the behavior of light, each framework self consistent and smoothly transitioning to the other in the region of validity. There is the classical electromagnetic wave framework, where light is an electromagnetic wave whose amplitude are changing electric and magnetic fields as the wavefront progresses. Rays are a geometric representation of the way the classical wavefront [LINK] progresses and transmits its energy and are useful for construction of o

Cites anna v · 2013-12 · Physics Stack Exchange · on “Matter Waves Interference”

The confusion comes because you are thinking of probability waves, which is what the interference pattern from elementary particles through the double slit experiment are, as if they are classical waves. Current day physics accepts that the fundamental framework of nature is quantum mechanical. Classical mechanics, classical electromagnetism are emergent theories from the quantum mechanical foundations, in an analogous way that thermodynamics is an emergent theory on the substratum of statistical mechanics. The electromagnetic wave is a special case because the classical wave as given by Maxwell's equations emerges from the coherent synergy of a huge number of photons, i.e. elementary partic