MATTER-WAVE INTERFEROMETER FOR LARGE MOLECULES demonstrated

A MATTER-WAVE INTERFEROMETER FOR LARGE
MOLECULES has been devised and demonstrated for the first
time. For many years scientists have studied the proposition that
things we normally think of as particles, such as electrons, should
also have wave properties. Indeed studies of beams of electrons,
neutrons, even whole atoms, have confirmed that particles can be
viewed as a series of traveling waves which diffracted when they
pass through a grating or through slits. These waves could even
interfere with each other, resulting in characteristic patterns
captured by particle detectors.
In this way, in 1999 Anton Zeilinger and his colleagues at the
University of Vienna demonstrated the wave nature of carbon-60
molecules by diffracting them (in their wave manifestation) from a
grating (Update 453). Now the same group, using a full
interferometer consisting of three gratings with wider grating
spacings and a more efficient detector setup, observe a sharp
interference pattern. Moreover, because the beam of particles
used, carbon-70 molecules at a temperature of 900 K, are
themselves in an excited state (undergoing 3 rotational and 204
vibrational modes of internal motion), it should be possible to
study the way in which an atom wave, or in this case a
macromolecular wave, becomes decoherent (that is, loses its
wavelike character) because of thermal motions and other
interactions with its environment. Thus this type of interferometer
experiment will be useful in studying the borderland between the
quantum and classical worlds. The researchers (contact Bjorn
Brezger, bjoernbrezger.de, University of Vienna) are aiming to
study the wave properties of even larger composite objects, mid-
sized proteins. (Brezger et al., Physical Review Letters, 11 March
2002; see also http://www.quantum.univie.ac.at)