Thermodynamic Evidence for Nanoscale Bose-Einstein Condensation in ^4He Confined in Nanoporous Media

Abstract

We report the measurements of the heat capacity of ^4He confined in nanoporous Gelsil glass that has nanopores of 2.5-nm diameter at pressures up to 5.3 MPa. The heat capacity has a broad peak at a temperature much higher than the superfluid transition temperature obtained using the torsional oscillator technique. The peak provides a definite thermodynamic evidence for the formation of localized Bose-Einstein condensates (LBECs) on nanometer length scales. The temperature dependence of heat capacity is well described by the excitations of phonons and rotons, supporting the existence of LBEC.

4 pages, 4 figures, submitted to Phys. Rev. Lett

References in corpus (1)

• Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms

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