From: Roddy Young (email@example.com)
Date: Mon Sep 25 2000 - 15:17:38 PDT
From: Food for Thought
Sent: Monday, September 25, 2000 4:00 PM
Subject: ENTANGLED PHOTONS COULD PROMISE LIGHTNING-SPEED COMPUTERS
> Donald Savage
> Heaquarters, Washington, DC September 25, 2000
> (Phone: 202/358-1547)
> Gia Scafidi
> Jet Propulsion Laboratory, Pasadena, CA
> (Phone: 818/354-0372)
> RELEASE: 00-149
> ENTANGLED PHOTONS COULD PROMISE LIGHTNING-SPEED COMPUTERS
> Defying traditional laws of physics, researchers may have
> found a way to blast through imminent roadblocks on the highway to
> faster and smaller computers.
> Using modern quantum physics, a research team from NASA's Jet
> Propulsion Laboratory (JPL), Pasadena, CA, and the University of
> Wales in the United Kingdom has discovered that entangled pairs of
> light particles, called photons, can act as a single unit, but
> perform with twice the efficiency.
> Using a process called "entanglement," the research team proposes
> that existing sources of laser light could be used to produce
> smaller and faster computer chips than current technology allows.
> Their paper appears in the today's issue of the journal Physical
> Review Letters.
> "Our economy constantly depends on faster and faster computers,"
> said JPL researcher Dr. Jonathan Dowling, a co-author of the
> paper. "This research potentially could enable us to continue
> upgrading computers even after traditional manufacturing
> procedures have been exhausted."
> Currently, in a process known as optical lithography,
> manufacturers use a stream of light particles to sculpt computer
> chips. A chip is basically a grid of interconnected on-off
> switches, called transistors, through which electric current flows
> and enables computers to calculate. As companies crowd millions of
> transistors into tinier chips, electric current travels shorter
> distances, resulting in speedier processes.
> Chipmakers shine a laser light onto photosensitive material to
> create a stencil-like mask, which is used to carve silicon into
> the components of transistors. However, the producers can only
> provide transistors with dimensions as small as those of the
> Today's state-of-the-art chips have transistors measuring between
> 180 and 220 nanometers, approximately 400 times narrower than the
> width of a human hair. While traditional computers have the
> ability to perform with transistors as small as 25 nanometers, or
> 3,000 times narrower than a human hair, this presents
> manufacturing obstacles.
> The light manufacturers use to produce today's transistors has a
> wavelength of 248 nanometers. It becomes increasingly difficult to
> use light with shorter wavelengths to produce transistors with
> smaller dimensions. In fact, according to a central principle of
> optics called the "Rayleigh criterion," 248-nanometer light can't
> create features smaller than 124 nanometers.
> However, this new research, still in its theoretical stage, could
> provide a bypass of the Rayleigh criterion. The research team
> proposes that entanglement would allow the use of existing sources
> of laser light of 248 nanometers to produce computer chips with
> dimensions of a fourth of the wavelength (62 nanometers) or
> smaller compared to today's limits (124 nanometers).
> Entanglement would allow researchers to use the intermingled
> properties of two or more photons to obtain subwavelength spatial
> resolutions. Albert Einstein called this intermingling of photons
> process "spooky action at a distance" because the particles can
> immediately influence each other over huge distances, even halfway
> across the galaxy.
> Here on Earth, entangled photons can be produced by passing a
> light beam through a special crystal. In this quantum lithography
> proposal, a pair of entangled photons enters a setup with two
> paths. While the two particles travel together and act as a single
> unit, it is impossible to determine which of the two paths the
> pair has taken. In a strange effect of quantum mechanics, however,
> each photon actually travels down both paths.
> On each path, the photons act like a rippling wave with peaks and
> valleys. After traveling on their own path for a while, the two
> photons converge on a surface. Because the light particles making
> up each wave were originally entangled, the result of adding the
> photon waves together is to create patterns on the surface
> equivalent to those made by a single photon with half the
> This process, in essence, enables the entangled photon pair to
> produce patterns twice as small on each side of a chip's surface
> as can be created by the single photons in the conventional
> optical lithography procedures. Entangling more than two photons
> would improve results even further.
> While a number of technical challenges remain, researchers are
> already working on developing materials that would be required for
> quantum lithography.
> This research is part of the Revolutionary Computing Technology
> project in the NASA/JPL Center for Integrated Space Microsystems
> (CISM). CISM is supported by the Deep Space Systems Program in
> NASA's Office of Space Science. JPL is managed for NASA by the
> California Institute of Technology in Pasadena.
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