Feelgood Theosophy
Welcome to the Feelgood
Lodge
The Quantum Principle
of
Superposition
Superposition
is a principle of quantum theory that describes a challenging concept about the
nature and behavior of matter and forces at the atomic level. The principle of
superposition claims that while we do not know what the state of any object is,
it is actually in all possible states simultaneously, as long as we don't look
to check. It is the measurement itself that causes the object to be limited to
a single possibility.
In 1935, Erwin Schrodinger proposed an analogy to show how superposition
would operate in the every day world: the somewhat cruel analogy of Schrodinger's cat. Here's Schrödinger's (theoretical)
experiment: We place a living cat into a steel chamber, along with a device
containing a vial of hydrocyanic acid. There is, in the chamber, a very small amount
of a radioactive substance. If even a single atom of the substance decays
during the test period, a relay mechanism will trip a hammer, which will, in
turn, break the vial and kill the cat. The observer cannot know whether or not
an atom of the substance has decayed, and consequently, cannot know whether the
vial has been broken, the hydrocyanic acid released, and the cat killed. Since
we cannot know, the cat is both dead and alive according to quantum law, in a
superposition of states. It is only when we break open the box and learn the
condition of the cat that the superposition is lost, and the cat becomes one or
the other (dead or alive).
This situation
is sometimes called quantum indeterminacy or the observer's paradox: the
observation or measurement itself affects an outcome, so that the outcome as
such does not exist unless the measurement is made. (That is, there is no
single outcome unless it is observed.)
Superposition
is well illustrated by Thomas Young's double-slit experiment, developed in the
early nineteenth century to prove that light consisted of waves. In fact, the
noted physicist Richard Feynman claimed that the essentials of quantum
mechanics could be grasped by an exploration of the implications of Young's
experiment.
The Double-Slit
Experiment
For this
experiment, a beam of light is aimed at a barrier with two vertical slits. The
light passes through the slits and the resulting pattern is recorded on a
photographic plate. If one slit is covered, the pattern is what would be
expected: a single line of light, aligned with whichever slit is open.
Intuitively, one would expect that if both slits are open, the pattern of light
will reflect that fact: two lines of light, aligned with the slits. In fact,
however, what happens is that the photographic plate is entirely separated into
multiple lines of lightness and darkness in varying degrees. What is being
illustrated by this result is that interference is taking place between the
waves/particles going through the slits, in what, seemingly, should be two
non-crossing trajectories.
We would expect
that if the beam of light particles or photons is slowed enough to ensure that
individual photons are hitting the plate, there could be no interference and
the pattern of light would be two lines of light, aligned with the slits. In
fact, however, the resulting pattern still indicates interference, which means
that, somehow, the single particles are interfering with themselves. This seems
impossible: we expect that a single photon will go through one slit or the
other, and will end up in one of two possible light line areas. But that is not
what happens. As Feynman concluded, each photon not only goes through both
slits, but simultaneously takes every possible trajectory en route to the
target, not just in theory, but in fact.
In order to see
how this might possibly occur, experiments have focused on tracking the paths
of individual photons. What happens in this case is that the measurement in
some way disrupts the photons' trajectories (in accordance with the uncertainty
principle), and somehow, the results of the experiment become what would be
predicted by classical physics: two bright lines on the photographic plate, aligned
with the slits in the barrier. Cease the attempt to measure, however, and the
pattern will again become multiple lines in varying degrees of lightness and
darkness. Each photon moves simultaneously in a superposition of possible
trajectories, and, furthermore, measurement of the trajectory causes the
superposition of states to collapse to a single position.
Feelgood Theosophy
Thankyou for visiting the Feelgood Lodge
______________________
An
independent Theosophical Republic
Worldwide
links to FREE online
Courses,
Writings, Commentaries,