The Bose Einstein Condensate is a group of atoms at the same energy level. The BEC can only be formed at temperatures as low as a few billionths (0.000,000,001) of a degree above Absolute Zero. Atoms will be at different energy levels at normal temperatures, but once the temperature goes down below a certain threshold a large fraction of the atoms will crash down to the lowest energy level. This results on a unique state as an atom in the lowest energy level is spread out a little. As the atom's energy level keeps falling atoms cannot be differentiated from one another and the BEC is formed. All the atoms are in the same place. The atoms are not really spread out, what is really meant is that the possible location of the atom is in that area, the lower the energy level of the atom the bigger the area.
The reason for this is due to the uncertainty principle. The Uncertainty Principle states that the more precisely the momentum is determined, the less precisely the position is known in this instance and vice versa. As the atoms get colder their average speed decreases so the momentum is known more precisely therefore the position of the atom becomes more uncertain, leading to the "spreading out" of the atom.
For the Bose Einstein Condensate to form the temperature must be very low. The temperature might be hard to achieve but the difficulty is in the technique and not the equipment that is quite simple and inexpensive compared to many current physics experiments. It cost $50000 to $100000 only.
To first cool the atoms down lasers are used to slow down the atoms, since the slower the atoms are the cooler they are, the laser light can cool down an atom by...