Anomalous Suppression of Superfluidity in $^4$He Confined in a Nano-porous Glass: Possible Quantum Phase Transition

TL;DR

This study investigates how extreme confinement in nanoporous glass suppresses superfluidity in helium-4, indicating a possible quantum phase transition from superfluid to nonsuperfluid at high pressure and near absolute zero temperature.

Contribution

It provides experimental evidence of a pressure-induced quantum phase transition in helium-4 confined in nanopores, highlighting the effects of nanoscale confinement on superfluidity.

Findings

Superfluidity is suppressed with increasing pressure.

Superfluid transition temperature approaches 0 K at critical pressure.

Evidence suggests a quantum phase transition at 3.5 MPa.

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 $P_c$.