Front Cover
The picture shows a cloud of cold ⁸⁷Rb atoms held in a magneto-optic trap inside a vacuum chamber. The trap uses a combination of laser light and a spherical quadrupole magnetic field to cool the atoms to a temperature of less than one-thousandth of a degree above absolute zero, and simultaneously confine them to a small region of space. The laser light at 780 nm is constantly being absorbed and re-emitted by the trapped atoms. This resonance fluorescence is collected by a lens and captured on a CCD camera to ‘see’ the cloud. In the picture shown, there are more than 10⁸ atoms at a temperature of about 500 mK in a cloud of size 3 mm. Such atom traps are becoming increasingly important for experiments ranging from fundamental research in Bose–Einstein condensation and precision measurements to applications in atomic fountain clocks and nano-lithography.
(The cover picture was taken by Umakant Rapol, Ajay Wasan and Vasant Natarajan, Department of Physics, Indian Institute of Science, Bangalore.)

Back Cover

 

William Donald Hamilton
( 1936 – 2000 )
( Illustration by C Seema )