Thursday, December 16, 2010
If there is something very complex and mysterious in nature, that should be the creation of 'life' from 'non-living' atoms and molecules. How is life created out of these atoms and molecules? Keeping the identity from generation to generation with slight modifications in each generation is a real mystery. No two individuals are exactly identical ! 'Thinking ability' or 'intelligence' is a superior quality that humans have; how does this work? Will classical thoughts and laws be enough to solve this mystery or should quantum physics come into play to address this problem ? Erwin Schrodinger, a pioneer of Quantum Physics wrote 'What is life?' in the 1930s and has expressed his thoughts about this in this book. What is BEYOND there than what we think about life?
Let's consider the living beings around us. There are lives of all kinds in nature and they are going this way from millions of years in the past. What forms of life were there in the start of life? It might be an assembly of some materials in a little microscopic pouch which showed some signs - movement, being two or more from the single existing one in the course of time, absorbing some water or air, etc, etc. At first what stimulated the formation of this pouch out of the those non-living atoms? There is another mystery there of atoms and its constituents but for now lets assume that the atoms were already there for some reason. Why did that pouch need to proliferate? Why did it start moving?
Note: This posting is in progress.
Thursday, September 9, 2010
When we consider a non interacting or a weakly interacting dilute thermal gas containing in a vessel, there is a symmetry in the system. That means for an atom, there is not a preferred direction, all directions look the same and it has a random phase. Once the gas is cooled to some low temperature in a trap, it enters in a new phase called a condensate, in which all atoms lie in the same quantum state and have the same macroscopic quantum phase, which is a completely different situation in comparison to the thermal gas. Therefore, the phenomenon of Bose-Einstein condensation is a spontaneous symmetry breaking !
Note: This posting is in progress !
Wednesday, July 21, 2010
When charged particles move in a magnetic field, gauge potentials arise and the effective Hamiltonian has a term containing the vector potential, A. Neutral atoms can also behave like charged particles if the container in rotated in a trapping magnetic fields. But recently, an optically synthesized magnetic field has been created where the neutral atoms experience an effective gauge potential without any rotation, similar to the case of charged particles in an electromagnetic field.
Please look at the following reference for details:
Note: This post is in progress.
Sunday, July 11, 2010
The 30th CNLS Annual Conference, http://cnls.lanl.gov/ultralow/, was organized on 'COMPLEXITY and DISORDER at ULTRA-LOW TEMPERATURES' in La Fonda Hotel, Santa Fe, NM from June 21-25, 2010. A lot of strange and impossible-looking things happen at ultra-low temperatures, including the phenomenon of Bose-Einstein Condensation (BEC). There were a lot of nice oral and poster presentations in the program by the physicists from all around the world. I also presented a poster in the program.
DAMOP2010, http://damop2010.rice.edu/, was organized in Hyatt Regency Hotel, Houston, Texas from May 25-29, 2010. There were a lot of interesting presentations - oral and poster both, several exciting activities, including some activities to celebrate the 50th anniversary of the invention of LASER. In fact, the discovery of LASER has drastically changed the science and technology and the world as a whole. The LASER has found its applications in diverse fields. In fact, one can rarely find a field of science and technology where there is no presence/use of a LASER in one form or another. Atomic, molecular and optical physics is one of the major fields which has gotten a tremendous advantage from the discovery of LASER. In fact, the first observation of a BOSE-Einstein Condensate (BEC) became possible in 1995, after about 70 years of its prediction by Einstein, because of the development of the technique of cooling atoms using a laser.
There were thousands of atomic, molecular and optical physicists, including several Nobel Laureates in the fields.
I also presented by current research in the meeting http://meetings.aps.org/Meeting/DAMOP10/Event/126565.
Tuesday, April 13, 2010
Wednesday, February 24, 2010
A clock is a timekeeping device. In the past, people used the shadow of a building, the position of some fixed stars, the sun, the moon and some other heavenly bodies to keep track of time. As the human civilization progressed, they developed some devices like a water clock and a sand clock to know time. In the early seventeenth century, Galileo discovered that a swinging pendulum can be used as a time keeping device. Inspired by this discovery, Christian Huygens invented a pendulum clock in the mid seventeenth century. These clocks can still be seen used in several places. In the mid twentieth century, it was discovered that atoms can be used to keep time. The 1955 Cesium Atomic Clock with a Cesium beam tube developed at the National Physical Laboratory, UK, kept time to a second in 300 years. To increase the accuracy of the clocks, the interrogation time had to be increased. This could be done by decreasing the speed of the atomic beam or by increasing the length of the the tube. But the problem with the increasing the length of the tube was that the atoms would form a sag in travelling through the tube due to gravitational potential. A new idea was developed where the tube could be rotated so that it would be in a vertical position and the atomic beam could be projected vertically upward. This new configuration along with the development of the laser cooling techniques developed in early nineties made the modern, highly accurate Cesium fountain clocks possible. The modern Cesium clocks developed at NIST, Boulder, Colorado, USA would neither gain nor lose a second in more than 60 million years.
Note: This posting is in progress.