Transcription de l'émission à:
http://www.pbs.org/wgbh/nova/transcripts/2612time.html
Invités:
Carl Sagan
Kip Thorne
Stephen Hawking
Matt Visser
Raymond Chiao
John Wheeler
Steve Lamoreaux
Igor Novikov
Guenter Nimtz
David Deutsch
Ken Ziet
Un avant-goût ?
squeezing energy out of a vacuum:
NARRATOR: All ordinary matter has positive
energy. But exotic matter can be made by
squeezing energy out of a vacuum created in a
tiny gap between two metal plates.
STEVE LAMOREAUX: Now when you bring two
plates close together photons of long
wavelengths can't exist between the plates, so it
excludes some of this energy from the system
and when you do so, the energy between the
plates is lower than the energy outside and so
there's a force between these two plates.
MATT VISSER: The force actually pulls the
plates together and that's critical because that
tells you that the energy density between the
plates has to be negative and that is the key to
it actually being exotic matter.
STEVE LAMOREAUX: We just did it for fun and
it's built with this junk we found around the lab
here, and in fact we can measure an extremely
tiny force with it.
MATT VISSER: The experiments from our point
of view are a proof in principle that at least
small amounts of exotic matter effectively
negative energy do exist in the real world.
Mais surtout allez lire David Deutsch et Ken Ziet !!!!
NARRATOR: This is a radical interpretation of
quantum mechanics. But David Deutsch finds
the evidence he needs for parallel universes in
a well known physics experiment.
DAVID DEUTSCH: I first saw this experiment
demonstrated when I was an undergraduate. In
fact it's a very old experiment. It was first done
in 1909.
KEN ZIET: This is our light source for the
experiment. The light is being steered by these
mirrors onto the slits here. There's two slits in
this slide and that produces the young slit's
interference pattern which we see on the
camera.
NARRATOR: The interference pattern is the set
of faint, vertical stripes at the center of the red
spot. These only appear when two slits are
open.
KEN ZIET: One slit, two slits. One slit, two slits.
NARRATOR: With two slits open, the single
beam of light is split into two beams which
overlap like ripples on a pond. In some places
the ripples reinforce each other, while in
others, they cancel each other out - creating
the pattern of stripes on the screen. But what
happens if the intensity of the beam is reduced
by a filter so that only one photon at a time
could reach the slits?
KEN ZIET: Now you can't see the beam at the
moment, but if I introduce some liquid nitrogen
you should be able to pick that up, so now you
can see the beam scattered by the nitrogen, but
you see nothing after the filter. The filter
essentially stops everything we can see, but the
camera can pick up the few photons that are
arriving.
NARRATOR: The photons arrive at the slits
one at a time, so those that get through and
reach the screen on the other side should form
just two bright lines. They shouldn't interfere
and produce the full pattern of stripes, but they
do. And this is how the stripes appear on a
computer screen.
DAVID DEUTSCH: When one does the
experiment with individual photons, the pattern
that builds up after one has passed many
photons through the apparatus is exactly the
same as it was in strong light.
KEN ZIET: And that's something we just don't
understand.
DAVID DEUTSCH: As an undergraduate we
were told oh, this is because the photon
behaves partly as a particle and partly as a
wave. Now that just doesn't make sense, it's
gibberish, it's saying that the photon is both in
one place and spread out at the same time.
NARRATOR: Deutsch believes that the single
photons are producing the full pattern of stripes
by interacting with other photons that we can't
see.
DAVID DEUTSCH: The photon that we can't
see is a photon in a parallel universe which - a
nearby parallel universe which is interacting
with the photon in our universe and causing it to
change its direction. The result of these single
photon inference experiment is the strangest
thing I know. It is conclusive evidence that
reality does not consist of just a single universe
because that result could not come about
unless there were another nearby universe
interacting with ours.
NARRATOR: If true, this idea has profound
implications for time travel.
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