Bose-Einstein Condensation in SolidHe4

S. O. Diallo, J. V. Pearce, R. T. Azuah, O. Kirichek, J. W. Taylor, H. R. Glyde
2007 Physical Review Letters  
We present neutron scattering measurements of the atomic momentum distribution, n(k), in solid helium under a pressure p = 41 bars and at temperatures between 80 mK and 500 mK. The aim is to determine whether there is Bose-Einstein condensation (BEC) below the critical temperature, T_c = 200 mK where a superfluid density has been observed. Assuming BEC appears as a macroscopic occupation of the k = 0 state below T_c, we find a condensate fraction of n_0 = (-0.10 \pm 1.20)% at T = 80 mK and n_0
more » ... (0.08\pm0.78)% at T = 120 mK, consistent with zero. The shape of n(k) also does not change on crossing T_c within measurement precision.
doi:10.1103/physrevlett.98.205301 pmid:17677706 fatcat:ivuw3tkx7bfulkx5poecbhqrny