From: LARRY KLAES (ljk4_at_msn.com)
Date: Fri Apr 04 2003 - 09:40:34 PST
----- Original Message -----
From: NASA Jet Propulsion Laboratory
Sent: Wednesday, April 02, 2003 8:40 PM
To: ljk4_at_msn.com
Subject: NASA Researchers Put New Spin on Einstein's Relativity Theory
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JET PROPULSION LABORATORY
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Carolina Martinez (818) 354-9382
Jet Propulsion Laboratory, Pasadena, Calif. April 2,
2003
NEWS RELEASE: 2003-047
NASA Researchers Put New Spin on Einstein's Relativity Theory
Albert Einstein might be astonished to learn that NASA physicists have
applied his relativity theory to a concept he introduced but later
disliked namely that two particles that interact could maintain a
connection even if separated by a vast distance. Researchers often
refer to this connection as "entanglement."
Researchers at NASA's Jet Propulsion Laboratory, Pasadena, Calif.,
have discovered that this entanglement is relative, depending on how
fast an observer moves with respect to the particles, and that
entanglement can be created or destroyed just by relative motion. This
might change the way entanglement is used on future spacecraft that
move with respect to Earth or with each other.
"Imagine a particle on Earth entangled with a particle light years
away," said Dr. Christoph Adami, principal scientist in the Quantum
Computing Technologies Group at JPL. "Whatever happens to particle A
on Earth happens to particle B, even if it is on another planet.
Einstein referred to this connection as 'spooky'."
Einstein thought this connection violated the relativity rule that
information can't travel faster than the speed of light. Adami and
Dr. Robert Gingrich, also of JPL, are the first to apply Einstein's
relativity theory to quantum entanglement between particles. They
compared the amount of entanglement when the particles were at rest to
when they were given a boost. Their findings show that while speeding
up ordinary entangled pairs would lead to a loss of the precious
entanglement, certain special pairs can be created whose entanglement
is increased instead. This increases the connection between them.
Understanding how some of the characteristics of a particle can become
entangled through relative motion alone when they seemed to be
unentangled or unconnected when at rest could have many applications.
For example, entangled particles could be used to synchronize atomic
clocks, which are essential for navigating spacecraft in deep space.
"One of the amazing things about entanglement is that it connects
objects over arbitrary distances, so that in principle the two clocks
could be started and stopped simply by acting on only one of them,"
said Adami. "However, no workable protocol has been found to date to
achieve that."
Because the creation of entanglement in the laboratory is usually a
delicate matter, discovering new ways to create entanglement is always
a goal of the quantum technology community.
"If you can create entanglement just by moving with respect to what
you're measuring, then seemingly you've created something from
nothing," said Gingrich.
Another possible application of entanglement is quantum teleportation:
the ability to transfer the precise quantum state of one microscopic
object to another, while using only traditional communications, such
as a phone line. This technique, which has been demonstrated
experimentally, requires that the sender and receiver share pairs of
entangled particles. But until now nobody knew what would happen to
these pairs if the sender and receiver move with respect to each
other, or if an observer moves with respect to them. This new theory
gives researchers a whole new outlook on what happens to particle
pairs when you apply the relativity theory.
The research also has ramifications for ongoing work in the area of
quantum computation, which seeks to use the subtle effects of quantum
mechanics to build faster and more efficient computers.
"Whenever new ground is treaded by theory, new applications are sure
to follow in its wake," said Adami.
Gingrich and Adami's findings appeared in a paper they co-authored
titled, "Quantum Entanglement of Moving Bodies," which appeared in the
December 2002 issue of the journal Physical Review Letters.
The Quantum Computing Technologies Group at JPL investigates the
design and capabilities of hypothetical computing and measurement
devices that use delicate quantum effects for enhanced power and
accuracy for future space missions.
More information is available at http://cs.jpl.nasa.gov/qct/qat.html .
NASA's Office of Earth Science, Washington, D.C. provided funding for
this work. The California Institute of Technology in Pasadena manages
JPL for NASA.
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