Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Structural and dynamical properties of superfluid helium: a density
  functional approach   We present a novel density functional for liquid 4He, properly accounting for
the static response function and the phonon-roton dispersion in the uniform
liquid. The functional is used to study both structural and dynamical
properties of superfluid helium in various geometries. The equilibrium
properties of the free surface, droplets and films at zero temperature are
calculated. Our predictions agree closely to the results of ab initio Monte
Carlo calculations, when available. The introduction of a phenomenological
velocity dependent interaction, which accounts for backflow effects, is
discussed. The spectrum of the elementary excitations of the free surface and
films is studied.

16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics