From: Glenn Morton (glennmorton@entouch.net)
Date: Fri Jul 04 2003 - 09:25:10 EDT
Hi Howard, happy 4th
you wrote:
>-----Original Message-----
>From: Howard J. Van Till [mailto:hvantill@chartermi.net]
>Sent: Friday, July 04, 2003 7:31 AM
>Glenn1,
I am no longer sure of my identity. Today I feel like Glenn99.
>
>Well, it's been a long time since I played seriously with the quantum
>mechanics once knew and taught, but it would make sense to me to suggest
>that even if two identical systems were in identical quantum states, but
>were also located in different Hubble volumes that did not overlap so that
>mutual interaction was impossible, there would be no problem of their
>maintaining their individual identities. The states Glenn3 and Glenn7 would
>not mix.
I certainly am not a quantum expert, and would have agreed with you years
ago. However, now there is the feature of the world, which you haven't
addressed and that is entanglement. Entangle pairs of particles sent in
different directions and being disjoint causally still know what the other
is doing. Below are a couple of press reports on the phenonmenon which has
been seen in the lab. As you read these, remember that Glenn1 (somewhere in
a gallaxy far, far away) and Glenn99 speaking to you here had a common
causal origin at the Big Bang. The question is, am I an entangled pair or a
99-tuplet?
One other item of interest here is the flatness problem of the universe. At
the big bang there were 10^80 causally separated regions of space in the
Hubble volume we are looking at. They all seem to have had the same
temperature. Guth's inflation theory was a way of handling that problem. Is
entanglement a method as well? in the second extract, note the reference
to MWH.
Posted 18 July 1997, 5 pm PST
Quantum Spookiness Wins in Swiss
Test
A Swiss group has provided the best
demonstration yet for one of quantum theory's
weirdest claims: that two particles or photons
can influence each other no matter how far apart
they are. The new demonstration of quantum
"action at a distance," done with the help of
Swiss Telecom's fiber-optic lines, shows that
these mysterious connections can persist over
distances of up to several kilometers.
. . .
Nicolas Gisin and his group at the University
of Geneva have now demonstrated quantum
action at a distance on a large scale by turning
the countryside around Geneva into a giant
quantum laboratory. Gisin's team generated pairs
of entangled photons using a specially
constructed, suitcase-sized generator in central
Geneva and sent them through fiber-optic lines
to the two small villages of Bellevue and Bernex,
10.9 kilometers apart, where the streams of
photons were analyzed and counted.
Light pulses triggered by the arriving
photons were relayed via another optical fiber
system to Geneva and combined. There they
formed an interference pattern with peaks and
troughs that showed how the number of photons
arriving simultaneously in the two villages varied
over time. The pattern changed as the
investigators adjusted both analyzers to alter the
phase of the photons, the measure of how in
step they are. But the nature of the changes in
the interference pattern showed that, no matter
how the phase was adjusted, each photon knew
the phase of its twin, says Gisin, who presented
the findings earlier this month at a meeting in
Turin, Italy. "Even if you change a phase only
on one end, it has an influence on what happens
on the other end," he says.
. . .
copyright 1997 The American Association for the Advancement of Science
This item is supplied by the AAAS Science News Service
http://www.apnet.com/inscight/07181997/graphb.htm
**
July 22, 1997 NY times
Signal Travels Farther and Faster Than Light
Tracking the Paths of 'Twin' Photons
By MALCOLM W. BROWNE
. . .
"In principle, it should make no difference whether the correlation between
twin particles occurs when they are separated by a few meters or by the
entire universe," he said in an interview.
"This research is interesting not only from a scientific and philosophical
point of view, but because of a very practical consequence: we can now
create a completely secure code. A quantum key, which is now within reach,
would allow banks to carry out transactions with each other over optical
fibers, completely safe from all possible code-breaking methods and from
eavesdropping or interference."
The idea for such a system, he said, originated with Dr. Artur D.
Eckert at Oxford University in England. Details of the Swiss experiment
will be described in a forthcoming technical paper, Gisin said, and he is
working with the Swiss telecommunications agency to develop a cryptographic
system based on entangled particle "twins." Identical random-number
sequences generated simultaneously by pairs of widely separated twins would
serve as cipher keys equivalent to the "one-time pads" used by spies and
governments to encode and decode ultra-secret messages.
The receiver and sender of a secret message based on a one-time pad each
must have a copy of the pad, which contains a random sequence of numbers.
The sequence defines a series of mathematical operations used to encipher
the message, and the reverse sequence is used to decipher it. The key pads
of sender and receiver are used for only one message and then destroyed;
this means that every letter of every message is enciphered by its own
unique key and is therefore completely immune to cryptanalysis.
One of the leading experimentalists in quantum optics, Dr. Raymond Y. Chiao
of the University of California,Berkeley, hailed the Geneva experiment as
"wonderful."
But an underlying enigma of quantum mechanics remains unfathomed.
The connections that persist between distant but entangled particles are
"one of the deep mysteries of quantum mechanics," Chiao said in an
interview. "These connections are a fact of nature proven by experiments,
but to try to explain them philosophically is very difficult," he said.
Quantum events obey the laws of quantum theory, which governs the behavior
of minute objects like atoms and subatomic particles, including photons of
light. By contrast with the laws of "classical" physics (which apply to the
relatively large objects of the everyday world), quantum physics often
exhibits behavior that seems impossible.
...
Physicists call this a "collapse of the wave function." The amazing thing is
that if just one particle in an entangled pair is measured, the wave
function of both particles collapses into a definite state that is the same
for both partners, even separated by great distances.
Among several proposed explanations of all this is the "many worlds"
hypothesis: the notion that for every possible pathway or state open to a
particle, there is a separate universe. For each of 10 possible pathways a
quantum particle might follow, for example, there would exist a separate
universe.
Since the 1970s, Dr. John F. Clauser of the University of California at
Berkeley, Dr. Alain Aspect at the Institut des Optics in Orsay, France, and
others have been experimenting with pairs of entangled particles.
One way to create a pair of entangled twins is to start with a single photon
of ultraviolet radiation and pass it through a peculiar artificial mineral
called a "down-conversion crystal." In the Swiss experiment, the crystal
consisted of potassium niobate. The crystal splits the photon in two,
producing two new photons that continue on in somewhat different directions,
and whose combined energy equals the energy of their parent photon.
The special quality of such pairs, as shown both by theory and experiment,
is that they are entangled quantum mechanically. This means that if
the polarization or energy or timing of one of the particles is measured,
its indefinite state is destroyed and it falls into a definite state.
The astonishing consequence of this is that the particle's distant twin
experiences exactly the same metamorphosis at the same moment, even though
there is no physical link or signal between the two twins.
In 1935 a famous paper by Albert Einstein, Boris Podolsky and Nathan Rosen
challenged the quantum theory prediction that entangled particles could
remain instantly in touch with each other. One of their objections was based
on the speed limit imposed by Einstein's Special Theory of Relativity:
nothing can travel faster than the speed of light.
Einstein and his colleagues preferred a more intuitive explanation of the
simultaneous correlation between entangled particles, based on the idea that
the match between them is ordained by their identical antecedents. The
behavior of each particle, they argued, is the product of hidden "local"
factors, not by spooky long-distance effects.
But again and again in recent years, increasingly sensitive experiments have
decisively proved that Einstein's explanation was wrong and quantum theory
is correct.
In Gisin's experiment, as in earlier ones, no signal of any kind was
transmitted between the photons, but despite this, one of the photons "knew"
what happened to its distant twin, and mimicked the twin's response. This
response took less than one ten-thousandth of the time a light beam would
have needed to carry the news from one photon to the other at a speed of
186,282 miles per second. (In fact, the correlation between the two
particles was presumably instantaneous. The Swiss experiment merely set an
upper limit on the time required for the response as about three
ten-billionths of a second.)
Gisin's experiment made use of a system of paired interferometers developed
by Dr. James D. Franson of Johns Hopkins University, who is also a leading
investigator of quantum effects.
Each interferometer, a device for separating and then recombining beams of
light, consists of a complex arrangement of mirrors and "beam splitters" --
semi-opaque reflectors that randomly reflect some photons in one direction
and transmit others in a different direction. In an interview, Franson
explained the system:
"You start with an ultraviolet photon and split it into two photons.
One goes one way and the other goes another way, both to identical
interferometers. Entering its own interferometer, each photon must make a
random decision as to whether it will travel a long pathway through the
device or a short one. Then you look for a correlation between the pathways
taken by the photons in their respective interferometers."
If the timing between the photons is exactly adjusted, each twin seems to
know what the other is doing and matches its choice of pathway to coincide
with that of its distant partner.
Franson said of the correlation demonstrated over a seven-mile course by the
Swiss experiment, "It's pretty amazing."
Whatever the nature of the connection between entangled particles may be,
nearly all physicists agree that it cannot be used to transmit messages
faster than the speed of light. All it can do is assure that a random choice
by one entangled particle is instantly echoed by its distant partner. This
is not the same thing as transmitting information, the experts say, and
therefore it does not violate relativity theory.
But why is a numerical correlation between two particles different from
information?
"That's a difficult question," Franson said, "and I don't think anyone could
give you a coherent answer. Quantum theory is confirmed by experiments, and
so is relativity theory, which prevents us from sending messages faster than
light. I don't know that there's any intuitive explanation of what that
means."
Another deep quantum mystery for which physicists have no answer has to do
with "tunneling" -- the bizarre ability of particles to sometimes penetrate
impenetrable barriers. This effect is not only well demonstrated; it is the
basis of tunnel diodes and similar devices vital to modern electronic
systems.
Tunneling is based on the fact that quantum theory is statistical in nature
and deals with probabilities rather than specific predictions; there is no
way to know in advance when a single radioactive atom will decay, for
example.
The probabilistic nature of quantum events means that if a stream of
particles encounters an obstacle, most of the particles will be stopped in
their tracks but a few, conveyed by probability alone, will magically appear
on the other side of the barrier. The process is called "tunneling,"
although the word in itself explains nothing.
Chiao's group at Berkeley, Dr. Aephraim M. Steinberg at the University of
Toronto and others are investigating the strange properties of tunneling,
which was one of the subjects explored last month by scientists attending
the Nobel Symposium on quantum physics in Sweden.
"We find," Chiao said, "that a barrier placed in the path of a tunneling
particle does not slow it down. In fact, we detect particles on the other
side of the barrier that have made the trip in less time than it would take
the particle to traverse an equal distance without a barrier -- in other
words, the tunneling speed apparently greatly exceeds the speed of light.
Moreover, if you increase the thickness of the barrier the tunneling speed
increases, as high as you please.
"This is another great mystery of quantum mechanics."
...
GRM99 again: This last paragraph seems to imply a connectedness across
space which we don't understand. Maybe my abslutely identical twin, Glenn
the nerd, not Glenn the genocidal maniac, is me, that is, we are one. But
Tegmark claims that he will eventually diffentiate himself from me in future
choices. But of course, like a hall of mirrors, there will be another
Hubble Volume containing another Glenn the nerd who will remain my twin in
the future.
>
>Meanwhile back at the ranch of earlier issues, do you really want a God who
>predetermines all things? Is the coercive power to predetermine
>all things a
>quality to admire in a Deity?
I see no other way for the Deity to be able to predict the future. How
could the predictions of Christ's advent have occurred without
foreknowledge? Without control, I see no way to have foreknowledge.
Glenn
This archive was generated by hypermail 2.1.4 : Fri Jul 04 2003 - 09:25:22 EDT