David Kestenbaum

A Dial-Up Quantum Reality

Physicists have built a tabletop device that allows them to turn the quantum world on and off by pulling electrons through two adjacent corridors atop a tiny microchip. If it doesn9t interact with the device, a single electron will go through both halls, but add something that can detect the route of the electron and it takes one corridor or the other.

Particle Decays Reveal Arrow of Time

PHYSICSThe microscopic level where particles collide and decay has seemed indifferent to the direction of time. But two groups of researchers have now directly detected the forward march of time in the decays of subatomic particles by measuring the rate of a particular decay and showing that it differs from the rate of the same process done in reverse.

A GIANT SNARE FOR MONOPOLES

PHYSICSPhysicists have spent much time searching fruitlessly for magnetic monopoles, the magnetic equivalent of the fundamental bits of electric charge carried by electrons; now they have used the worlds highest energy accelerator and once again come up empty. This nondiscovery, now in press at Physical Review Letters , puts some new limits on the mass of this aspiring particle and has also sparked a bit of a debate about how to look for it.

Under Pressure, Deuterium Gets Into Quite a State

PHYSICSA team of researchers at Lawrence Livermore National Laboratory has used the Nova laser--the worlds most powerful laser--to subject a drop of deuterium to intense pressures and temperatures, mimicking conditions inside giant planets. Their results, published on page [1178][1] indicate that deuterium, and by extension hydrogen, is more compressible and becomes metal-like at lower pressures than expected. The findings may help solve the puzzle of why Saturn appears younger than the rest of the solar system, and they may help explain the intense magnetic fields of planets such as Jupiter. [1]: http://www.sciencemag.org/cgi/content/short/281/5380/1178

Hydrogen Coaxed Into Quantum Condensate

PHYSICSA team of physicists at the Massachusetts Institute of Technology has cooled a cloud of over 100 million hydrogen atoms--10 times more than has been achieved with other atoms--almost to absolute zero, coercing it to form a single quantum blob called a Bose-Einstein condensate. Because hydrogen turns out to be easier than other atoms to probe with lasers, researchers should be able to obtain cleaner pictures of the condensates structure than with other condensates.