PHYSICS NEWS UPDATE
The American Institute of Physics Bulletin of Physics News
Number 711 December 1, 2004
by Phillip F. Schewe, Ben Stein
                        
THE TOP PHYSICS STORY FOR 2004.  For us it was the detection of spin at the
single-electron level using a cantilever device---a combination of MRI and
AFM technologies---known as a magnetic resonance force microscope
(http://www.aip.org/pnu/2004/split/692-1.html).  Other top physics stories
included the following: the detection of large galaxies located at a very
early period in the history of the universe
(http://www.aip.org/pnu/2004/split/668-1.html); reports of a
"supersolid," a superfluid in solid form
(http://www.aip.org/pnu/2004/split/669-1.html;
http://www.aip.org/pnu/2004/split/699-2.html); progress in the pursuit of
quark-gluon plasma in heavy-ion collisions
(http://www.aip.org/pnu/2004/split/669-2.html); progress in getting fermi
atoms to form superfluids (http://www.aip.org/pnu/2004/split/671-1.html,
http://www.aip.org/pnu/2004/split/681-1.html); evidence, not yet confirmed,
for element 115 (http://www.aip.org/pnu/2004/split/672-1.html); new support
for an accelerating cosmic expansion
(http://www.aip.org/pnu/2004/split/675-1.html); lensing of microwaves using
a flat panel of left-handed material
(www.aip.org/pnu/2004/split/675-2.html); the discovery of a planet-like
object, Sedna, the most distant object observed in the solar system
(http://www.aip.org/pnu/2004/split/677-1.html); the first pure-carbon
magnet, made from carbon nanofoam
(http://www.aip.org/pnu/2004/split/678-1.html); quantum entanglement of an
atom and a photon (http://www.aip.org/pnu/2004/split/680-2.html); parity
violations in electron-electron scattering
(http://www.aip.org/pnu/2004/split/682-2.html); persistent holes appearing
in a shaken fluid (http://www.aip.org/pnu/2004/split/684-3.html); amorphous
steel (http://www.aip.org/pnu/2004/split/689-2.html); one-dimensional water
(http://www.aip.org/pnu/2004/split/689-1.html ); radioac
tive lifetime for an element is altered by enclosure in a buckyball
(http://www.aip.org/pnu/2004/split/700-2.html);
(http://www.aip.org/pnu/2004/split/689-1.html); five-photon entanglement
(http://www.aip.org/pnu/2004/split/690-2.html); Cassini arrives at Saturn
(http://www.aip.org/pnu/2004/split/690-3.html);
optical Hall effect (aip.org/pnu/2004/split/693-1.html); 3D medical imaging
with neutrons (http://www.aip.org/pnu/2004/split/694-1.html); acoustic
electric generator (http://www.aip.org/pnu/2004/split/695-2.html); smallest
atomic clock (http://www.aip.org/pnu/2004/split/698-1.html); CERN's 50th
anniversary (http://www.aip.org/pnu/2004/split/701-3.html; an antenna for
visible light (http://www.aip.org/pnu/2004/split/701-1.html); the 2004
Nobel physics prize going to three of the pioneers of the theory of quantum
chromodynamics (http://www.aip.org/pnu/2004/split/703-1.html); some of the
network physics behind book bestsellers
(http://www.aip.org/pnu/2004/split/709-1.html); spintronic Hall effect
(Science online, Nov 11); a nuclear experiment producing 1400 different
isotopes (http://www.aip.org/pnu/2004/split/710-1.html).

SOFT-METAL WHISKERS, tiny metallic protrusions that grow like hair from
soft metals, are a problem that can cause electronic short circuits
leading, in some cases, to the failure of heart pacemakers, avionic relays,
and satellites.  What to do with the unwanted whiskers---and, in the first
place, understanding how they form---is a problem that's been around for
fifty years.  Now, researchers at Drexel University have arrived at what
they think is an explanation for the cause of whiskers and a potential
method for alleviating them.  Basically, the whiskers form because of
reactions between oxygen and the soft metal such as tin or indium. The
reaction results in a volume increase that pushes the whiskers out.  The
whiskers that form do not have to break off in order to be troublesome;
sometimes they cause mischief merely by bridging two neighboring electronic
pathways that are supposed to be insulated from each other.  The Drexel
scientists believe that an oxygen-barrier coating on pertinent surfaces
should prevent whiskers from developing.
(Barsoum et al. Physical Review Letters, 12 November 2004;
contact Elizabeth Hoffman, enh22{at}drexel.edu)

NON-US FIRST-YEAR PHYSICS GRAD STUDENTS at US universities are fractionally
fewer than they used to be.  Rising pretty steadily over the past 30 years
to a high in 2001 of 53% among first-year physics graduate students, the
foreign fraction dropped to 46% in 2003.  The total number of first year
students (US plus foreign) rose to 3076, the largest number since 1994. 
Who sends the most physics grad students to US departments?  China accounts
for 29% of the first year students in 2003, the
India/Pakistan/SriLanka/Nepal/Bangladesh grouping accounted for 16%,
Western Europe 13%, and Eastern and Central Europe 12%.  (More information
on the reason for the foreign fall-off, on sub-discipline choices, career
expectations, fraction of women, sources of financial support, and so
forth, can be gotten from the AIP report "Graduate Student Report:
First-Year Physics and Astronomy Students in 2002 and 2003."
stats{at}aip.org; contact Patrick Mulvey, 301-209-3070;
www.aip.org/statistics.)

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