Vasant Natarajan

Einstein's Miraculous Year

With each passing year, the young Albert Einstein’s achievements in physics in the year 1905 seem to be ever more miraculous. We describe why the centenary of this remarkable year is worthy of celebration.

Einstein as armchair detective: The case of stimulated radiation

Einstein was in many ways like a detective on a mystery trail, though in his case he was on the trail of nature’s mysteries and not some murder mystery! And like all good detectives he had a style. It consisted of taking facts that he knew were correct and forcing nature into a situation that would contradict this established truth. In this process she would be forced to reveal some new truths. Einstein’s 1917 paper on the quantum theory of radiation is a classic example of this style that enabled him to predict the existence of stimulated radiation starting from an analysis of thermodynamic equilibrium between matter and radiation.

The special theory of relativity

The year 2005 has been declared qy the United Nations as the International Year of Physics. This has been done to commemorate Albert Einsteins miraculous year a century ago, during which the young Einstein made a number of remarkable discoveries that changed the course of physics. In that single year, he completed his PhD thesis and published five papers on three different subjects, namely, the photoelectric effect, Brownian motion, and the special theory of relativityl.

The 2001 Nobel Prize in Physics

This year’s Nobel Prize in Physics has been jointly awarded to Eric A Cornell of the National Institute of Standards and Technology, Boulder (USA), Wolfgang Ketterle of the Massachusetts Institute of Technology, Cambridge (USA), and Carl E Wieman of the University of Colorado, Boulder (USA). They have been cited “for the achievement of Bose-Einstein condensation in dilute gases of alkali atoms, and for early fundamental studies of the properties of the condensates”. The scientists have been recognized for their pioneering work in a field that has grown explosively around the world in the past few years. Though the phenomenon of Bose-Einstein condensation (BEC) was predicted by Einstein in 1925 (based on the new statistics of Bose), it was observed only in 1995. In this article, we review the basic physics behind the phenomenon, the experimental techniques involved in achieving it, and high-light some of the potential applications of condensates.

The 2001 Nobel Prize in Physics: Bose-Einstein condensation

This year’s Nobel Prize in Physics has been jointly awarded to Eric A Cornell of the National Institute of Standards and Technology, Boulder (USA), Wolfgang Ketterle of the Massachusetts Institute of Technology, Cambridge (USA), and Carl E Wieman of the University of Colorado, Boulder (USA). They have been cited “for the achievement of Bose-Einstein condensation in dilute gases of alkali atoms, and for early fundamental studies of the properties of the condensates”. The scientists have been recognized for their pioneering work in a field that has grown explosively around the world in the past few years. Though the phenomenon of Bose-Einstein condensation (BEC) was predicted by Einstein in 1925 (based on the new statistics of Bose), it was observed only in 1995. In this article, we review the basic physics behind the phenomenon, the experimental techniques involved in achieving it, and high-light some of the potential applications of condensates.

Standard weights and measures

We trace the evolution of standards for weights and measures from olden days to their modern scientific definitions. Even in the era of modern science, standards till recently used to be defined by artifacts. It is only in the last few decades that we have gone over to definitions based on fundamental constants of nature. This has made the standards universally reproducible. The present standards for time, length, and electrical units are all based on physical constants. The mass standard, represented by the prototype kilogram, is the only remaining artifact, but there are promising proposals to replace that in the near future.

Nobel Prize in physics — 1997

This year’s Nobel Prize in physics recognises the spectacular progress during the last decade in the cooling and trapping of atoms by the use of laser beams. The techniques exploit basic physical principles with great ingenuity and have very interesting applications in precision measurement and the study of new phenomena.