BOSE-EINSTEIN CONDENSATE vs EXAM

Read for fun !


A Bose-Einstein condensate(BEC) is like an Exam ! It seems funny, but please keep on reading, I'll prove it. A BEC is created out of atoms or molecules at low temperatures so that all atoms in an ensemble reach the ground state of the potential or a trap. A commonly used trap is a Magneto-Optical Trap (MOT). This is like an exam room with physical walls, exam questions, proctors, professors, and the career in a long term. They bind the test-takers in the exam room tightly.

The most energetic atoms leave an MOT quickly, the same way as a smart test-taker does. The low energy atoms go towards the lower and lower state of the trap and they are bound to form a BEC. Similarly, a less smart test-taker remains in the exam room for the whole time assigned to the exam or even more if the proctors or professors allow to do so ! If the trap is stronger or tighter, the atoms are more firmly trapped than in a weaker trap and the coherence is also maintained for a longer time. Analogously, if the questions in the exam are tougher, it makes a test-taker to remain in the exam room for a longer time; but if the questions are easier, the test takers escape right away ! A good exam will help making a good career of a test taker; it is a similar situation to a good BEC, which can be used for various purposes ranging from the study of its properties to the applications in inertial navigation systems and precision measurements. Oh, most importantly, all atoms in a BEC are in the same quantum state like all the test takers in an exam room; all of them are solving the problems the same way, with a goal of succeeding in the test; they are supposedly in the same state of their minds!

I hope I convinced you that a BOSE-EINSTEIN CONDENSATE is NOT different from an EXAM !

Spin-1/2 system is bizarre object !

Consider a spin-1/2 particle. Rotate it about an axis by a 2 pi angle. You are not getting it back into the same state but with sign flipped. If you rotate it further by another 2 pi angle, you will see the particle in the original state. This is a bizarre object, which is beyond our intuition !

If you ask physicists, why is this? The answer is simple : it is an SU(2) physics, not an SO(3) ! If you want to visualize it, please look at Feynman's description of the rotation of a coffee cup in the following links:

(1) WIKI: http://en.wikipedia.org/wiki/Orientation_entanglement

(2) DEMO: http://www.youtube.com/watch?v=Rzt_byhgujg

Your views on this matter are highly welcome !

Quantum Biology

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.

BEC and spontaneous symmetry breaking

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 !

Optically synthesized magnetic field

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:

(1) http://www.nature.com/nature/journal/v462/n7273/full/nature08609.html

(2) http://prl.aps.org/abstract/PRL/v102/i13/e130401

Note: This post is in progress.

30th CNLS Annual conference at SANTA FE, NM

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 at Houston, Texas

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.