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What do you think?AIP News
In some semiconductor devices, such as
light-emitting diodes, an applied voltage can dislodge electrons
from some atoms, leaving behind a hole which behaves in some
situations as if it were a positively charged particle in its own
right. A "current" of holes can move through the material and the
holes can recombine later with electrons to produce light. In very
loose analogy, James Franson (Johns Hopkins) suggests that photonic
holes might be created; a photon hole, to give one example, would be
a place in an otherwise intense laser-beam wavefront where a photon
had been removed (by passing the laser beam through vapor, for
instance). Not only can there be photon holes, Franson
(443-778-6226, james.franson@jhuapl.edu) suggests, but the holes can
be entangled, meaning that their quantum properties would be
correlated, even if far apart from each other. Such entangled
photon-holes would be able to propagate through optical fibers just
as well as entangled photons, but might be even more robust against
the decoherence (the undoing of the quantum correlations) that
plagues present efforts to establish quantum information schemes.
Franson expects to do put his idea to experimental test in the next
few months. (Physical Review Letters, 10 March 2006)