TY - JOUR
T1 - Superfluidity of4He confined in nanoporous media
AU - Shirahama, Keiya
AU - Yamamoto, Keiichi
AU - Shibayama, Yoshiyuki
PY - 2008/4
Y1 - 2008/4
N2 - We have examined superfluid properties of He confined to a nanoporous Gelsil glass that has nanopores 2.5 nm in diameter. The pressure-temperature phase diagram was determined by torsional oscillator, heat capacity and pressure studies. The superfluid transition temperature Tc approaches zero at 3.4 MPa, indicating a novel quantum superfluid transition. By heat capacity measurements, the nonsuperfluid phase adjacent to the superfluid and solid phases is identified to be a nanometer-scale, localized Bose condensation state, in which global phase coherence is destroyed. At high pressures, the superfluid density has a T-linear term, and Tc is proportional to the zero-temperature superfluid density. These results strongly suggest that phase fluctuations in the superfluid order parameter play a dominant role on the phase diagram, and superfluid properties.
AB - We have examined superfluid properties of He confined to a nanoporous Gelsil glass that has nanopores 2.5 nm in diameter. The pressure-temperature phase diagram was determined by torsional oscillator, heat capacity and pressure studies. The superfluid transition temperature Tc approaches zero at 3.4 MPa, indicating a novel quantum superfluid transition. By heat capacity measurements, the nonsuperfluid phase adjacent to the superfluid and solid phases is identified to be a nanometer-scale, localized Bose condensation state, in which global phase coherence is destroyed. At high pressures, the superfluid density has a T-linear term, and Tc is proportional to the zero-temperature superfluid density. These results strongly suggest that phase fluctuations in the superfluid order parameter play a dominant role on the phase diagram, and superfluid properties.
KW - Nanoporous glass
KW - Superfluid transition
KW - Torsional oscillator
UR - http://www.scopus.com/inward/record.url?scp=41649107886&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=41649107886&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:41649107886
VL - 34
SP - 350
EP - 356
JO - Fizika Nizkikh Temperatur
JF - Fizika Nizkikh Temperatur
SN - 0132-6414
IS - 4-5
ER -