Light has intrigued man, (and women alike) from the days of adam. While the greek credited it to the gods... The aryans to the sun and many more cult cultures to many a obtrusive or unobtrusive media... it stands at a visually irrefutable point in man's life(literally and figuratively).
There have been , and if have my way .. will be, many and more theories on light than any other concept in modern physics, but armed with as many theories, principles and few fundamental laws there are, we can but say our knowledge about light is not too much impressive.
Starting from Newton's bold but extremely juvenile assumption that light is made of corpuscles to the Quantum theory of duality of light, which in fact in overtly hard to grasp, Light theories have two basic assumption Light is a wave or a particle.... Now as the light theories developed there came a surprising juncture of duality.....
Like our teacher once said .....
"Maxwell recieved the Nobel prize for stating that light has wave nature........
Planck received the Nobel prize for stating that light has particle nature.......
De brogli received the Nobel prize for stating that light has both wave particle nature.......
Maybe one of u will get the prize for stating that it has neither of the two properties"
The basic problem encountered in studying light is its speed, which causes major anomalies in calculations (or rather MIScalculations). What we have to do then is slow down speed, or even better freeze it.
From now on the discussion is purely theoretical .... and i make a lot of assumption ... not mathematically supported......
Before we Go any further it is necessary to understand BEC.
A Bose–Einstein condensate (BEC) is a state of matter of a dilute gas of weakly interacting bosons confined in an external potential and cooled to temperatures very near to absolute zero (0 K or −273.15 °C). Under such conditions, a large fraction of the bosons occupy the lowest quantum state of the external potential, at which point quantum effects become apparent on a macroscopic scale.
This state of matter was first predicted by Satyendra Nath Bose and Albert Einstein in 1924–25. Bose first sent a paper to Einstein on the quantum statistics of light quanta (now called photons). Einstein was impressed, translated the paper himself from English to German and submitted it for Bose to the Zeitschrift für Physik which published it. Einstein then extended Bose's ideas to material particles (or matter) in two other papers.
Seventy years later, the first gaseous condensate was produced by Eric Cornell and Carl Wieman in 1995 at the University of Colorado at Boulder NIST-JILA lab, using a gas of rubidium atoms cooled to 170 nanokelvin (nK). For their achievements Cornell, Wieman, and Wolfgang Ketterle at MIT received the 2001 Nobel Prize in Physics.
The slowing of atoms by use of cooling apparatus produces a singular quantum state known as a Bose condensate or Bose–Einstein condensate. This phenomenon was predicted in 1925 by generalizing Satyendra Nath Bose's work on the statistical mechanics of (massless) photons to (massive) atoms. (The Einstein manuscript, once believed to be lost, was found in a library at Leiden University in 2005.) The result of the efforts of Bose and Einstein is the concept of a Bose gas, governed by Bose–Einstein statistics, which describes the statistical distribution of identical particles with integer spin, now known as bosons. Bosonic particles, which include the photon as well as atoms such as helium-4, are allowed to share quantum states with each other. Einstein demonstrated that cooling bosonic atoms to a very low temperature would cause them to fall (or "condense") into the lowest accessible quantum state, resulting in a new form of matter.
This transition occurs below a critical temperature, which for a uniform three-dimensional gas consisting of non-interacting particles with no apparent internal degrees of freedom is given by:
where:
 | is | the critical temperature, |
 | is | the particle density, |
 | is | the mass per boson, |
 | is | the reduced Planck constant, |
 | is | the Boltzman constant, and |
 | is | the Riemann zeta function;  |
Gross–Pitaevskii equation
The state of the BEC can be described by the wavefunction of the condensate 
Provided essentially all atoms are in the condensate (that is, have condensed to the ground state), and treating the bosons using mean field theory, the energy (E) associated with the state
![E=\int d\vec{r}\left[\frac{\hbar^2}{2m}|\nabla\psi(\vec{r})|^2+V(\vec{r})|\psi(\vec{r})|^2+\frac{1}{2}U_0|\psi(\vec{r})|^4\right]](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_uNpoXPC1ubAGkmtoWW7XlICFW3bf2sFFOIHsBprUygsPc-STxcXuNmxS8Ng4_uWKBPj56AjS72OQCXN-zTpFPBiRg_3kJaq4rHiYuxw3urX9s-CFX0dIEu6N4NWIxcHPoKTvjvAkect1kOUOYupA=s0-d)
Minimising this energy with respect to infinitesimal variations in
where:
-
is the mass of the bosons, is the external potential, is representative of the inter-particle interactions.
The GPE provides a good description of the behavior of BEC's and is thus often applied for theoretical analysis.
Understanding these concepts we move on to Light behavior in BEC.
The variable speed of light (VSL) concept states that the speed of light in a vacuum, usually denoted by c, may not be constant in some cases. In most situations in condensed matter physics when light is traveling through a medium, it effectively has a slower speed. Virtual photons in some calculations in quantum field theory may also travel at a different speed for short distances; however, this doesn't imply that anything can travel faster than light. While it is usually thought that no meaning can be ascribed to a dimensional quantity such as the speed of light varying in time (as opposed to a dimensionless number such as the fine structure constant), in some controversial theories in cosmology, the speed of light also varies by changing the postulates of special relativity. This though would require a rewrite of much of modern physics, to replace the current system which depends on a constant c.
Certain materials have an exceptionally low group velocity for light waves, a phenomenon called slow light. In 1999, a team of scientists led by Lene Hau were able to slow the speed of a light pulse to about 17 metres per second (61 km/h; 38 mph); in 2001, they were able to momentarily stop a beam. In 2003, scientists at Harvard University and the Lebedev Physical Institute in Moscow, succeeded in completely halting light by directing it into a Bose–Einstein condensate of the element rubidium, the atoms of which, in Lukin's words, behaved "like tiny mirrors" due to an interference pattern in two "control" beams.In doing this we, can effectively understand the actual nature of light ..... The phenomenon of slow light is yet to be experimented upon .. and it has scope for deeper research ... and with hopes that some more revaluations are possible from this research...I conclude my views...
Maybe in the next post i'll discuss the effects of gravity and the concept of black hole as applied to light.
