Microscopic molecular superfluid response: theory and simulations
arXiv:1710.02685 · doi:10.1088/0034-4885/77/4/046601
Abstract
Since its discovery in 1938, superfluidity has been the subject of much investigation because it provides a unique example of a macroscopic manifestation of quantum mechanics. About 60 years later, scientists successfully observed this phenomenon in the microscopic world though the spectroscopic Andronikashvili experiment in helium nano-droplets. This reduction of scale suggests that not only helium but also para-H2 (pH2) can be a candidate for superfluidity. This expectation is based on the fact that the smaller number of neighbours and surface effects of a finite-size cluster may hinder solidification and promote a liquid-like phase. The first prediction of superfluidity in pH2 clusters was reported in 1991 based on quantum Monte Carlo simulations. The possible superfluidity of pH2 was later indirectly observed in a spectroscopic Andronikashvili experiment in 2000. Since then, a growing number of studies have appeared, and theoretical simulations have been playing a special role because they help guide and interpret experiments. In this review, we go over the theoretical studies of pH2 superfluid clusters since the experiment of 2000. We provide a historical perspective and introduce the basic theoretical formalism along with key experimental advances. We then present illustrative results of the theoretical studies and comment on the possible future developments in the field. We include sufficient theoretical details such that the review can serve as a guide for newcomers to the field.
85 pages, 20 figures
References in corpus (18)
- Worm Algorithm and Diagrammatic Monte Carlo: A New Approach to Continuous-Space Path Integral Monte Carlo Simulations
- Continuum variational and diffusion quantum Monte Carlo calculations
- Spectroscopy and dynamics in helium nanodroplets
- Disorder and the Supersolid State of Solid He
- Oscillation Frequency Dependence of Non-Classical Rotation Inertia of Solid He
- Ring exchanges and the supersolid phase of 4He
- Observation of non-classical rotational inertia in bulk solid 4He
- Superfluidity and Quantum Melting of para-Hydrogen clusters
- Structure, superfluidity, and quantum melting of hydrogen clusters
- Annealing Effect for Supersolid Fraction in He
- Exact quantum statistics for electronically nonadiabatic systems using continuous path variables
- A molecular superfluid: non-classical rotations in doped para-hydrogen clusters
- Local Superfluidity of Parahydrogen Clusters
- Population size bias in Diffusion Monte Carlo
- Supersolid phases of cold atom assemblies
- Spectroscopy of free radicals and radical containing entrance-channel complexes in superfluid helium nano-droplets
- Path integral formulation for quantum nonadiabatic dynamics and the mixed quantum-classical limit
- Superfluidity of isotopically doped parahydrogen clusters