Caption: "Results of a doubleslit experiment
performed by
Akira Tonomura (19422012) showing
the buildup of a
diffraction pattern
from single electrons.
The counts of electrons
are 10 (a), 200 (b), 6000 (c), 40000 (d), 140000 (e)."
(Slightly edited.)
Features:

Electrons like
photons are subject to the
waveparticle duality of
quantum mechanicsall microscopic
particles are.
 The diagram illustrates
the doubleslit experiment
with electrons
and the waveparticle duality.
 Each electron is in a continuum
superposition of positions described by
a wave functionwhose common
symbol is the
capital Greek Psi = Ψ.
The wave function of each
electron passes through
both of two slits on a screen.
Which means each electron passes through
both of two slits on a screen.
The intensity of the
electron beam in the
experiment is so low that
there is only one electron
at a time passing through the
two slits.
 The wave function
then interferes with itself and creates a
diffraction pattern
which is the
probability distribution
for an absorption of the
electron at one point on an absorption screen.
When an absorption occurs, we say there has been a
wave function collapse to a point.
 The electrons,
via
probability distribution
(essentially the
diffraction pattern)
of wave function,
gradually create an quasicontinuous absorption
diffraction pattern as the number
of electrons having passed
through the two slits increases.
 Eventually,
the individual electron behavior is washed out.
 The doubleslit experiment can be done with
photons with the same results qualitatively speakinglight
propagates like a wave and is absorbed like a particle.
 The photon version actually
does NOT prove
photons existalthought
the point can be debatedbut
it is consistent with
their existence. Given that photons exist,
it does prove that each one goes through both slits and interferes with itself.
Final proof that photons are
indispensable entities in physics
was finally obtained only in the 1970s
(e.g.,
Greenstein & Zajonc, 2005, p. 3234).
 Remarkably, the photon version was done
first in 1909
by
Geoffrey I. Taylor (18861975)
(see Wikipedia: G.I. Taylor: Biography).
Credit/Permission: ©
Akira Tonomura (19422012),
before or circa 2006
(uploaded to Wikipedia by
User:Belsazar, 2006) /
Creative Commons
CC BYSA 3.0.
Image link: Wikipedia:
File:Doubleslit experiment results Tanamura 2.jpg.
Local file: local link: qm_double_slit.html.
File: Quantum file:
qm_double_slit.html.