Quasi-1D parahydrogen in nanopores

TL;DR

This study uses Quantum Monte Carlo simulations to explore how parahydrogen behaves in nanometer-scale cylindrical pores, revealing tendencies toward crystallization and the absence of superfluid phases, with implications for bulk superfluidity.

Contribution

It provides a detailed theoretical analysis of parahydrogen confined in quasi-1D nanopores, highlighting phase behavior and quantum fluctuations affecting crystallization and superfluidity.

Findings

Quasi-1D parahydrogen tends to crystallize despite quantum fluctuations.

No evidence of topologically protected superfluid phase was found.

The phase behavior depends on pore diameter and wall attraction strength.

Abstract

The low temperature physics of parahydrogen (ph2) confined in cylindrical channels of diameter of the order of 1 nm is studied theoretically by Quantum Monte Carlo simulations. On varying the attractive strength of the wall of the cylindrical pore, as well as its diameter, the equilibrium phase evolves from a single quasi-1D channel along the axis, to a concentric cylindrical shell. It is found that the quasi-1D system retains a strong propensity to crystallization, even though on weakly attractive substrates quantum fluctuations reduce somewhat such a tendency compared to the purely 1D system. No evidence of a topologically protected superfluid phase (in the Luttinger sense) is observed. Implications on the possible existence of a bulk superfluid phase of parahydrogen are discussed