We have been involved in the development of theories to describe nanoscale superfluid behaviour in doped helium clusters. This work has lead to a very fruitful collaboration with the experimental group of Wolfgang Jäger at the University of Alberta. We were jointly awarded a special Accelerator Grant for Exceptional New Opportunities (AGENO) from NSERC to shed light on the microscopic origins of nanoscale superfluidity.

The helium density around an N2O molecules for a cluster containing 16 helium atoms is illustrated on in the figure on the right.
We have recently been able to show that a molecular dopant can be used as a quantitative probe of the superfluid response of helium at the nanoscale by combining simulation results and spectroscopic measurements [J.Chem.Phys. 124, 081101 (2006); ibid. 125, 144310 (2006)].

These results were obtained using Quantum Monte Carlo approaches based on the Feynman path integral formalism. The figure on the right shows the "paths" for 5 helium atoms solvating an N2O molecule. We plan to use this theoretical treatment in order to bridge the gap between molecular and nano-droplet size regimes. A series of new experimental results pose fascinating questions where our theories can provide further key insights