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By using the diffusion Monte Carlo method, we obtained the full phase diagram of $^3$He on top of graphite preplated with a solid layer of $^4$He. All the $^4$He atoms of the substrate were explicitly considered and allowed to move during the simulation. We found that the ground state is a liquid of density 0.007 $pm$ 0.001 AA$^{-2}$, in good agreement with available experimental data. This is significantly different from the case of $^3$He on clean graphite, in which both theory and experiment agree on the existence of a gas-liquid transition at low densities. Upon an increase in $^3$He density, we predict a first-order phase transition between a dense liquid and a registered 7/12 phase, the 4/7 phase being found metastable in our calculations. At larger second-layer densities, a final transition is produced to an incommensurate triangular phase.
Surface waves on both superfluid 3He and 4He were examined with the premise, that these inviscid media would represent ideal realizations for this fluid dynamics problem. The work on 3He is one of the first of its kind, but on 4He it was possible to
Using quantum Monte Carlo we have studied the superfluid density of the first layer of $^4$He and H$_2$ adsorbed on graphene and graphite. Our main focus has been on the equilibrium ground state of the system, which corresponds to a registered $sqrt3
A resonance-induced change in the resistivity of the surface state electrons (SSE) exposed to the microwave (MW) radiation is observed. The MW frequency corresponds to the transition energy between two lowest Rydberg energy levels. All measurements a
Spin-spin relaxation time ($T_2$) and magnetic susceptibility ($chi$) of the second layer $^3$He adsorbed on Grafoil, exfoliated graphite, preplated with a monolayer $^4$He are studied by pulsed-NMR in a density range of $0.68 leq rho leq 5.28$ nm$^{
We revisited the phase diagram of the second layer of 4He on top of graphite using quantum Monte Carlo methods. Our aim was to explore the existence of the novel phases suggested recently in experimental works, and determine their properties and stab