Anomalous Suppression of Superfluidity in 4 He Confined in a Nano-porous Glass: Possible Quantum Phase Transition
Abstract
We explore superfluidity for
4
He confined in a porous glass which has nanopores of 2.5 nm in diameter, at pressures up to 5 MPa. With increasing pressure, the superfluidity is drastically suppressed, and the superfluid transition temperature approaches 0 K at
P
c
=3.5
MPa. The features strongly suggest that the extreme confinement of
4
He into the nanopores induces a quantum phase transition from superfluid to nonsuperfluid at 0 K, and at
P
c
.