Hydrogen Bose-Einstein condensate

After years of pioneering efforts atomic hydrogen has now been successfully cooled to a sufficiently low temperature for Bose-Einstein Condensation (BEC) and high precision spectroscopy. 

Abstract. Scientific interest in ultracold hydrogen arises from its properties as a Bose-Einstein condensate, its unique roles as a testing ground for atomic theory and a target for ultra high resolution spectroscopy. We describe major developments since the last hydrogen meeting. 

When Thomas Greytak and Daniel Kleppner atMTT started out 22 years ago to form a Bose-Einstein condensate by cooling and compressing a gas of hydrogen atoms, they did not realize just how arduous the journey would be. 

Kleppner and his students were foiled in their early attempts to realize Bose-Einstein condensation with hydrogen because hy-... 

In all of the excitement generated by the creation of Bose-Einstein condensates, hydrogen offers its own customary charm. Precision spectroscopy awaits. The frequency of the 1S-2S transition measured so precisely by Hansch may be measured with even greater precision. With hydrogen, more atoms can be brought together in a condensate than is the case with other atoms. Hydrogen s simplicity allows theory to be applied to its interactions with exactitude. 

Dale G. Fried, Thomas C. Killian, Lorentz Willmann, David Landhuis, Stephen C. Moss, Daniel Kleppner, and Thomas J. Greytak, Bose-Einstein Condensation of Atomic Hydrogen, Physical Review Letters 81, 3811-3814(1998). 

We recall that Bose-Einstein condensation is the macroscopic occupation of the ground state of a system at finite temperature. For a weakly interacting gas, this phase transition occurs when the inter-particle spacing becomes comparable to the thermal de Broglie wavelength A = /2nh /mkBT, where ks is the Boltzmann constant and T is the temperature. A rigorous treatment for the ideal Bose gas yields n > 2.61221 , where n is the density [35]. At a temperature of 50 yuK, for instance, the critical density for hydrogen is 1.8 x 10 cm. ... 

Ancilotto, F., Calbi, M.M., Gatica, S.M., and Cole, M.W. (2004). Bose-Einstein condensation of helium and hydrogen inside bundles of carbon nanotubes. Phys. Rev. B, 70, 165422 1-11. 

Pried D, Killian TC, Willmann L, Landhuis D, Moss SC, Kleppner D, Greytak TJ. (1998) Bose-Einstein condensation of atomic hydrogen. Phys. Rev. Lett. 81 3811-3814. 

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