Quantum Effects in Cold Atom Physics Through Pre-Thermalization Are More Than Expected

On an atom chip (top), clouds of ultracold atoms (red) are created. They are allowed to interfere, creating an ordered matter-wave interference pattern (bottom).
Credit: Vienna University of Technology

Absolute zero is measured at 0 kelvins. The 3rd law of thermodynamics dictate that it is impossible to cool down an object to exactly 0 kelvins. Since cold is the absence of heat, absolute zero would mean that there is no heat left in the object or system. In 2003, MIT Researchers achieved the lowest temperature which is .45 nK (nano kelvin) or 4.5 x 10-10 K or 0.00000000045 K.

Ultracold atoms are atoms that are maintained at temperatures close to absolute zero. The study that uses ultracold atoms in relation to fundamental quantum phenomena is called Cold Atom Physics. Applications for this technology range from quantum computers, and quantum simulators to ultra-high-precision atomic clocks and quantum metrology.

One of the basic underlying phenomenon of cold atom physics is the Boss-Einstein Condensate (BEC). This is a new state of mater that forms in very low temperatures. When atoms are cooled down to very low temperatures, they start to behave in wave like properties, as the temperature keeps going down, they start to merge and behave like one singular wave like particle. This was predicted by Satyendra Nath Bose and Albert Einstein in 1924–25 and was successfully produced and observed in 1995.

Ultracold atoms reveal surprising new quantum effects

Every day we observe systems thermalizing: Ice cubes in a pot of hot water will melt and will never remain stable. The molecules of the ice and the molecules of the water will reach thermal equilibrium, ending up at the same temperature. Well-ordered ice crystals turn into a disordered liquid.

Experiments at the Vienna Center for Quantum Science and Technology (VCQ) at the Vienna University of Technology have shown that in the quantum world the transition to thermal equilibrium is more interesting and more complicated than assumed so far.