Localization and Wetting of ⁴He Inside Pre-plated Nanopores

Sutirtha Paul, Taras Lakoba, Paul E. Sokol and Adrian Del Maestro

arXiv:2509.10690

Abstract

Low dimensional quantum fluids, where one can probe the effects of enhanced thermal and quan- tum fluctuations on macroscopic quantum wavefunctions, can be experimentally realized through transverse physical confinement of superfluid helium on scales smaller than the coherence length. Reaching this scale is difficult, requiring confinement in single or multiple pores with nanometer radii. Porous silicates such as MCM-41 have a pore radius larger than the coherence length of 4He, and in this work we systematically explore the possibility of pre-plating pores with different elements to reduce the pore size without localizing the confined superfluid. Through a direct solution of the few-body Schrodinger equation combined with quantum Monte Carlo simulations, we explore the behavior of helium confined inside cylindrical nanopores for a range of pre-plating elements, includ- ing rare gases and alkali metals. For rare gases, we find that helium remains strongly attracted to the pore walls and any atoms in the core form an incompressible liquid. For alkali metals such as Cs, weak interactions between helium and the pre-plating material prevent localization near the walls and enable delocalization in the pore center. Our results extend previous results for helium wetting on flat two dimensional coated substrates to the curved geometry inside nanopores, and demonstrate that alkali pre-plated nanopores may enable a tunable one-dimensional confined quantum liquid of helium.

Description

This repository includes links, code, scripts, and data to generate the figures in a paper.

Requirements

The data in this project was generated via two methods: Relaxation Method and Path Integral Monte Carlo. Processed data is included in the data directory and the full raw quantum Monte Carlo simulation data set is available online at . The full wavefunction files for the 2-body Schrodinger equation are too large for online storage but can be regenerated on the order of 1 day on a single CPU via the code here

1. The two body data was generated using a accelerated relaxation method code given here
2. All many body data was generated with quantum Monte Carlo using our open source path integral software also available on github.

Support

This work was performed with support from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Award Number DE-SC0024333.

Figures

Figure 01: Potential comparisons

Figure 02: Potential accuracy

Figure 03: Waterfall Plots

Figure 04: Radial densities for N=2

Figure 05: Wetting parameter illustration

Figure 06: Wetting parameter evolution

Figure 07: Phase diagram

Figure 08: Many Body densities

Figure 09: Linear density and compressibility

Figure 10: Relaxation and PIMC convergence

This figure is relesed under CC BY-SA 4.0 and can be freely copied, redistributed and remixed.