Playing with the condensate Einstein-Bose

2001/03/26 Roa Zubia, Guillermo - Elhuyar Zientzia

• Fisika

Anyone would consider three states of matter, solid, liquid, and gas as usual. In general, the difference between the three is the interaction between the molecules of the substance. The strongly bound are usually solid, the bonds in the liquids are weaker and do not occur among all molecules. Any matter will be gas if there is practically no union between its molecules and if they have the same speed as "flying".

For a long time, a fourth opportunity, plasma, has been known. Like gases and liquids, the plasmas are fluid. All its components are ions, that is, species with electric charge. For this reason, its properties opposite the electric fields are very special. An example of this situation are molten salts (but not dissolved in water). By increasing the temperature, the salt is liquid and the strength of the ions is destroyed. This matter is transformed into a fluid of charged particles, the plasma.

Six years ago, physicists found the fifth state of matter, condensed Einstein-Bose. This situation was theoretically proposed by physicists Albert Einstein and Satyendra Nath Bose in 1924. This situation is achieved when the gas cools down to a few kelvin. The gas atoms are united in a particular quantum state. In addition, all atoms join in a point and have very curious properties.

This experiment was first performed in 1995 with helium atoms. At a temperature of 2.17 K (two degrees less than fusion), helium atoms lost their viscosity and joined, as Einstein and Bose announced. Scientists now investigate the condensates made with rubidium atoms.

In recent times, by turning these fluids, physicists have created turbulences. It is a phenomenon obtained through laser cooling. These trailers are one of the characteristics of the superfluids. As published in the journal Science, the greater the torsion generated, the more stable turbulences appear in the condensate, which ensures the behavior of the superfluids.

However, scientists have not sought applications to the Bose-Einstein situation. It is a discovery of the last years that fulfills the formulas of two great physicists. As with superconductivity, the need to have this type of mechanical properties requires very low temperatures, so the field of applications has not yet been treated.