3 June 1998
 
 

1-DOWSING FOR SILICON
"Dowsers" claim to detect underground water without digging, using a
magical forked tree branch. In the 1 June PRL, a team demonstrates the
atomic-scale equivalent by imaging the nuances of a silicon surface
buried deep under a layer of lead. Using a scanning tunneling
microscope (STM), they obtained a surprisingly clear view of the buried
interface, suggesting that the many physicists who make atomic-scale
layered structures could benefit from the technique.
(Phys. Rev. Lett. 80, 4895; posted 29 May 1998.)
 

9 June 1998
 

1-OCEAN CURRENTS IN A NEUTRON STAR
After a star explodes in a supernova, it usually leaves behind an
extremely dense, hot, spinning ember--a neutron star. But according
to calculations in the 1 June PRL, the excitement doesn't end with
the supernova. Many neutron stars, say the researchers, slow from
1000 revolutions per second at birth to perhaps one tenth that spin
rate in their first year of life, losing the energy by radiating
gravitational waves. The radiation comes from the oscillatory motion
of the star's fluid in a sort of giant "ocean circulation" pattern,
driven by the star's rotation. The results suggest not only a
revision in the theory of neutron stars, but also an unexpected
source of gravitational radiation--the waves Einstein predicted that
have yet to be observed directly. (Phys. Rev. Lett. 80, 4843;
posted 5 June 1998.)

2-WAVES WILL BE WAVES
Nature sometimes adds a twist to the familiar type of diffusion where
molecules simply wander along through a medium, ignoring one
another most of the time. In reaction-diffusion systems, molecules
react chemically with each other when they collide, so a chemical
wave can propagate as the concentrations of the components change.
These chemical waves, claims a report in the 8 June issue of PRL,
conform to Snell's law--the simple rule that dictates the angles of
reflection and refraction when light waves hit an interface. The
authors mathematically derive the phenomenon, which was observed by
others, and show with computer simulations that their formulation
agrees with experiments. (Phys. Rev. Lett. 80, 5216; posted 8 June 1998.)
 

24 June 1998
 
 

1-QUANTUM STATES MADE TO ORDER
Humans have always tried to tame nature, and for many atomic
physicists, the dream is to completely control the quantum state of
an atom or molecule. By manipulating atomic and molecular states
researchers could prepare them for a wide range of physics
experiments and perhaps even chemical reactions. In the 22 June PRL a
team reports "sculpting" the quantum state of an atomic electron and
then completely determining its wave function--the "probability wave"
that describes the state. They specified the state with unprecedented
detail using new laser technology and measured the wave function more
completely and directly than previous experimenters.
(Phys. Rev. Lett. 80, 5508; posted 23 June 1998.)
 
 
 

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