PART I - Interference
   This thought experiment (which I'll get after a little "refresher") is
based on the Michealson\Morely interferometer. I used to be an avid hobbyist
in the field of holography (until I got tired of living in a lab with a
bed\couch\TV). During my time as a holographer, I obviously had the perfect
opportunity to build and play with the Michealson\Morely interferometer as
well as Young's famous double-slit interferometer.
   I remember having one of the "arm's" mirrors mounted on a translator
stage (with a micrometer adjuster), and seeing the bullseye pattern fringes
shifting inward or outwards as I lengthened\shortened one of the beam paths.
"Cool" I thought..."this illustrates that as I change the length of one arm,
the crests and troughs of the light waves in each beam are lining up to
add-up or cancel out, hence the moving rings of light and dark." But then I
read something which I found disturbing...The interferometer (no matter what
kind) worked in exactly the same way even if only ONE PHOTON AT A TIME was
passed through it! After a great number of single photons is passed through,
the pattern will reveal itself. This implied that the photons are
interfering with themselves and NOT eachother. This made no sense to me. I
went back to moving the mirror back and forth, and thought to myself..."If
only one photon goes through at a time, and I lengthen this arm of the
interferometer, then the photon would obviously take longer to reach the
target through this arm as opposed to the other!" In other words, if the
photon takes BOTH paths, as the books I've read implied, then the photon
must reach the target at two separate times- given the constancy of the
speed of light in a given medium! I can't help but conclude from this that
interference is the result of a photon's ability to be absorbed at the same
place (ie. an atom) at different times.
   I believe it would be more accurate\less misleading if instead of saying
the photon can take path A or path B, we say it can arrive at the target at
T1 or T2 (depending on the path), and that somehow the "overlapping
possibilities" of the absorbsion occuring at either of those times is what
results in interference. This sounds perfectly logical and at the same time
utterly ridiculous to me and I can't decide which.  So while the geometry of
the paths can affect the coarseness\finesse of the pattern, the actual
interference of a photon with itself (avoiding the dark zones) is a product
of time (when it would get there) and not space (how it would get there).
PART II - The "speed" of light\questionable logic behind the "delayed
choice" experiments.
   I've read about attempts made to choose wether one path (or slit in the
case of Young's interferometer) remains opened or closed AFTER a photon is
emitted. These are known as "delayed choice experiments". If we know which
path the photon took, the interference pattern disappears, because we had to
interact with the photon...If we interact with it, then we have brought it
out of it's quantum state (localized it), that is, it now exists at the
point we have interacted with it, and even if somehow we can send it on it's
merry way after interacting with it, the point in space\time in which we
interacted with it can be considered it's new point of origin
(re-emmission). Therefore, if we detect it at one path\slit, then that path
or slit becomes the new starting point for the photon, thereby eliminating
the possibility of it passing through the other path\slit before hitting the
target. It is only if we leave it alone (leave it in it's quantum state)
until enough time has passed that it could have gone through both
paths\slits that interference can occur.
   Now the logic behind delayed choice experiments, at least as I interpret
them, seems to be as follows: A photon must be a particle since it manifests
itself as a "point" of energy (it is absorbed by a single particle). And yet
it must also be a wave as the interference pattern seems to prove. We can
see a photon behave as a particle (know which path it took), or as a wave
(see the pattern) but never both. The delayed choice experiments seem to be
an attempt to show both properties at the same time- that is, if the photon
is emitted first, then it's already on it's merry way. If it's trajectory
takes it through slit A, and both slits were open at the time of emission,
then maybe if we cover slit B after it sets off on it's merry way, we'll
know which path it took and yet still see a pattern (particle AND wave). We
all know of course that the pattern disapears no matter how much we try to
fool mother nature. I've seen terms such as "psychic photons" used to
describe this phenomenon. My interpretation may be off target, but the next
point should make sense either way...
   Einstein's famous theory of relativity makes some predictions about the
speed of light that, when taken together, actually make sense to me.
1- As one approaches the speed of light, space, to the traveller, contracts
(he\she sees rulers shrink) in the direction of travel until, at the speed
of light, it actually becomes a singularity.
2- As one approaches the speed of light, time, to an outside observer, seems
to stand still for the traveller (his\her clock seems to stop).
   These two points seem to me to complement eachother perfectly: If the
knowable universe shrinks to a singularity for a traveller, then Point A and
Point B clearly overlap for the traveller. If Point A and Point B overlap,
then it obviously takes no time to get from Point A to Point B (from the
traveller's perspective).
   Now since a photon obviously "travels" at the "speed" of light, to it,
the paths\slits, the mirrors in the apparatus, and finally the target (or at
least, the possibility of being absorbed at these points) all exist to the
photon at the same place and time (to a photon "in transit",  it's all a
singularity according to relativity) So are "psychic photons" really
psychic? Is "spooky action at a distance" really spooky? If a photon's
reality (or superposition of realities) exists as a singularity (to the
photon), it seems to me that the "psychicness" or "spookiness" is a product
of our existense in a non-quantum (localized) state, or more accurately, our
inability to perceive our knowable universe (space and time) in the same way
a photon does (singularity).
   To a photon (since it travels at the speed of light), all possible
destinations in our spacetime exist, to it, at the same place and time (a
singularity). So when a photon (passed through an interferometer) is
emitted, it's universe consists of all possible points at T1, and all
possible points at T2 etc... all overlapping in a singularity...that is,
it's knowable universe consists of a narrow cross-section of our spacetime
universe. So if one slit at T1 is covered AFTER emmission, the photon at the
moment of emission "knows" the slit "will be" covered because from it's
frame of reference, A) the universe only has a covered slit, and B) the
covered slit is in the same "place\time" as everything else in the photon's
universe (singularity). The uncovered slit just before T1 (and just after
for that matter) simply does not exist in the photon's knowable universe.
   An interesting spin on this (assuming any of this is accurate) is that
once the photon is emitted at T0 (in the above scenario), your fate has
apparently been sealed- at T1 you WILL cover that slit no matter what. I got
into a mini-debate with one fellow overseas by e-mail who argued that there
is no free will, and I believe his logic was based on a similar train of
thought (though I don't think he realised it- we were discussing paradoxes).
Say, for example, I hold my hand up one evening to shoo away an annoying
fly, and a photon from a star ten million light years away is absorbed by an
atom in the skin of my hand (as opposed to hitting a wall behind me).  One
could say that if spacetime shrinks to a singularity for the photon, then
it's target is known upon emmission (indeed, to the photon the "trip" is
instantaneous), and therefore the moment the photon was emitted- ten million
years ago in spacetime, it was "cast in stone" that I would be standing in a
particular spot on the planet Earth with my hand raised ten million years
later. This is a pretty radical statement, and in our frame of reference it
would seem to be true. However, I'm about to make an even more radical
statement which will serve as an introduction to the next section (the
thought experiment): if you think this is crap so far- just wait!
   Instead of thinking that fate is sealed once a photon is emitted,
possibly eliminating freewill, I prefer to think that I, by raising my hand
of my own free will that fateful night, was the one who sealed that photon's
fate ten million years ago rather than vice-versa.- That is, by raising my
hand at just the right time,  I am having a causal effect on a photon ten
million years in the past! This may sound ridiculous now, but the following
thought experiment will hopefully make you wonder...
Part III - The Thought Experiment- Losing the pattern is a GOOD thing!
   If you are standing in front of a modified  interferometer in which after
the beam is split, both paths are redirected to a separate (recombining)
beamsplitter, and in which one arm is signifigantly longer than the other
(I've done this) , and you block the beam path of the long arm right before
the re-combining beam-splitter, the pattern disappears....but WHEN? This is
something I've asked ...

read more »

PART I - Interference
   This thought experiment (which I'll get after a little "refresher") is
based on the Michealson\Morely interferometer. I used to be an avid hobbyist
in the field of holography (until I got tired of living in a lab with a
bed\couch\TV). During my time as a holographer, I obviously had the perfect
opportunity to build and play with the Michealson\Morely interferometer as
well as Young's famous double-slit interferometer.
   I remember having one of the "arm's" mirrors mounted on a translator
stage (with a micrometer adjuster), and seeing the bullseye pattern fringes
shifting inward or outwards as I lengthened\shortened one of the beam paths.
"Cool" I thought..."this illustrates that as I change the length of one arm,
the crests and troughs of the light waves in each beam are lining up to
add-up or cancel out, hence the moving rings of light and dark." But then I
read something which I found disturbing...The interferometer (no matter what
kind) worked in exactly the same way even if only ONE PHOTON AT A TIME was
passed through it! After a great number of single photons is passed through,
the pattern will reveal itself. This implied that the photons are
interfering with themselves and NOT eachother. This made no sense to me. I
went back to moving the mirror back and forth, and thought to myself..."If
only one photon goes through at a time, and I lengthen this arm of the
interferometer, then the photon would obviously take longer to reach the
target through this arm as opposed to the other!" In other words, if the
photon takes BOTH paths, as the books I've read implied, then the photon
must reach the target at two separate times- given the constancy of the
speed of light in a given medium! I can't help but conclude from this that
interference is the result of a photon's ability to be absorbed at the same
place (ie. an atom) at different times.
   I believe it would be more accurate\less misleading if instead of saying
the photon can take path A or path B, we say it can arrive at the target at
T1 or T2 (depending on the path), and that somehow the "overlapping
possibilities" of the absorbsion occuring at either of those times is what
results in interference. This sounds perfectly logical and at the same time
utterly ridiculous to me and I can't decide which.  So while the geometry of
the paths can affect the coarseness\finesse of the pattern, the actual
interference of a photon with itself (avoiding the dark zones) is a product
of time (when it would get there) and not space (how it would get there).
PART II - The "speed" of light\questionable logic behind the "delayed
choice" experiments.
   I've read about attempts made to choose wether one path (or slit in the
case of Young's interferometer) remains opened or closed AFTER a photon is
emitted. These are known as "delayed choice experiments". If we know which
path the photon took, the interference pattern disappears, because we had to
interact with the photon...If we interact with it, then we have brought it
out of it's quantum state (localized it), that is, it now exists at the
point we have interacted with it, and even if somehow we can send it on it's
merry way after interacting with it, the point in space\time in which we
interacted with it can be considered it's new point of origin
(re-emmission). Therefore, if we detect it at one path\slit, then that path
or slit becomes the new starting point for the photon, thereby eliminating
the possibility of it passing through the other path\slit before hitting the
target. It is only if we leave it alone (leave it in it's quantum state)
until enough time has passed that it could have gone through both
paths\slits that interference can occur.
   Now the logic behind delayed choice experiments, at least as I interpret
them, seems to be as follows: A photon must be a particle since it manifests
itself as a "point" of energy (it is absorbed by a single particle). And yet
it must also be a wave as the interference pattern seems to prove. We can
see a photon behave as a particle (know which path it took), or as a wave
(see the pattern) but never both. The delayed choice experiments seem to be
an attempt to show both properties at the same time- that is, if the photon
is emitted first, then it's already on it's merry way. If it's trajectory
takes it through slit A, and both slits were open at the time of emission,
then maybe if we cover slit B after it sets off on it's merry way, we'll
know which path it took and yet still see a pattern (particle AND wave). We
all know of course that the pattern disapears no matter how much we try to
fool mother nature. I've seen terms such as "psychic photons" used to
describe this phenomenon. My interpretation may be off target, but the next
point should make sense either way...
   Einstein's famous theory of relativity makes some predictions about the
speed of light that, when taken together, actually make sense to me.
1- As one approaches the speed of light, space, to the traveller, contracts
(he\she sees rulers shrink) in the direction of travel until, at the speed
of light, it actually becomes a singularity.
2- As one approaches the speed of light, time, to an outside observer, seems
to stand still for the traveller (his\her clock seems to stop).
   These two points seem to me to complement eachother perfectly: If the
knowable universe shrinks to a singularity for a traveller, then Point A and
Point B clearly overlap for the traveller. If Point A and Point B overlap,
then it obviously takes no time to get from Point A to Point B (from the
traveller's perspective).
   Now since a photon obviously "travels" at the "speed" of light, to it,
the paths\slits, the mirrors in the apparatus, and finally the target (or at
least, the possibility of being absorbed at these points) all exist to the
photon at the same place and time (to a photon "in transit",  it's all a
singularity according to relativity) So are "psychic photons" really
psychic? Is "spooky action at a distance" really spooky? If a photon's
reality (or superposition of realities) exists as a singularity (to the
photon), it seems to me that the "psychicness" or "spookiness" is a product
of our existense in a non-quantum (localized) state, or more accurately, our
inability to perceive our knowable universe (space and time) in the same way
a photon does (singularity).
   To a photon (since it travels at the speed of light), all possible
destinations in our spacetime exist, to it, at the same place and time (a
singularity). So when a photon (passed through an interferometer) is
emitted, it's universe consists of all possible points at T1, and all
possible points at T2 etc... all overlapping in a singularity...that is,
it's knowable universe consists of a narrow cross-section of our spacetime
universe. So if one slit at T1 is covered AFTER emmission, the photon at the
moment of emission "knows" the slit "will be" covered because from it's
frame of reference, A) the universe only has a covered slit, and B) the
covered slit is in the same "place\time" as everything else in the photon's
universe (singularity). The uncovered slit just before T1 (and just after
for that matter) simply does not exist in the photon's knowable universe.
   An interesting spin on this (assuming any of this is accurate) is that
once the photon is emitted at T0 (in the above scenario), your fate has
apparently been sealed- at T1 you WILL cover that slit no matter what. I got
into a mini-debate with one fellow overseas by e-mail who argued that there
is no free will, and I believe his logic was based on a similar train of
thought (though I don't think he realised it- we were discussing paradoxes).
Say, for example, I hold my hand up one evening to shoo away an annoying
fly, and a photon from a star ten million light years away is absorbed by an
atom in the skin of my hand (as opposed to hitting a wall behind me).  One
could say that if spacetime shrinks to a singularity for the photon, then
it's target is known upon emmission (indeed, to the photon the "trip" is
instantaneous), and therefore the moment the photon was emitted- ten million
years ago in spacetime, it was "cast in stone" that I would be standing in a
particular spot on the planet Earth with my hand raised ten million years
later. This is a pretty radical statement, and in our frame of reference it
would seem to be true. However, I'm about to make an even more radical
statement which will serve as an introduction to the next section (the
thought experiment): if you think this is crap so far- just wait!
   Instead of thinking that fate is sealed once a photon is emitted,
possibly eliminating freewill, I prefer to think that I, by raising my hand
of my own free will that fateful night, was the one who sealed that photon's
fate ten million years ago rather than vice-versa.- That is, by raising my
hand at just the right time,  I am having a causal effect on a photon ten
million years in the past! This may sound ridiculous now, but the following
thought experiment will hopefully make you wonder...
Part III - The Thought Experiment- Losing the pattern is a GOOD thing!
   If you are standing in front of a modified  interferometer in which after
the beam is split, both paths are redirected to a separate (recombining)
beamsplitter, and in which one arm is signifigantly longer than the other
(I've done this) , and you block the beam path of the long arm right before
the re-combining beam-splitter, the pattern disappears....but WHEN? This is
something I've asked ...

read more »