Path integral molecular dynamics (PIMD) maps an equilibrium quantum many-body
problem onto a classical system of ring polymers. In this thesis, we apply its
bosonic extension (PIMD-B) to liquid helium-4 at saturated vapour pressure in
the temperature range $T\in[1,3]\,\mathrm{K}$, which includes the superfluid
transition. We simulate $N=64$ atoms and compare the results with PIMC
calculations and experimental measurements.
We show that different observables converge on very different time scales.
The calculated energies reproduce the qualitative behaviour of the reference
data, while the pair correlation function and static structure factor agree
well with the measured spatial structure of the liquid. No pronounced change
in spatial structure is observed at the superfluid transition, whereas
momentum correlations become significantly stronger at low temperatures.
We estimate the superfluid fraction in two ways: from the winding number of
the polymer paths and from the momentum-density correlation function. Both
approaches reproduce the overall temperature dependence of the superfluid
fraction and yield values comparable with PIMC and experiment. These results
show that superfluid properties of bosonic systems can also be studied using
deterministic PIMD-B dynamics.
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