Bose-Einstein Condensate in Solid Helium

Abstract

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 = (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.

4 pages, 5 figures (in press)

References in corpus (4)

• Ring exchanges and the supersolid phase of 4He
• The fate of vacancy-induced supersolidity in 4He
• Supersolid Helium at High Pressure
• Bose Einstein Condensation of incommensurate solid 4He

Cited by in corpus (5)

• Quantum statistics and the momentum distribution of liquid para-hydrogen
• Zero-temperature dynamics of solid 4He from quantum Monte Carlo simulations
• Search for supersolid 4He in neutron scattering experiments at ISIS
• Two-body correlations and the superfluid fraction for nonuniform systems
• Roton-like mode in solid He-4