Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Structure of metastable 2D liquid helium   We present diffusion Monte Carlo (DMC) results on a new metastable,
superfluid phase above the crystal ground state in two-dimensional 4He at
densities > 0.065 1/A^2. The state is anisotropic with hexatic orbital order.
This implies that the liquid--solid phase transition has two stages: A second
order phase transition from the isotropic superfluid to the hexatic superfluid,
followed by a first order transition that localizes atoms into the triangular
crystal order. This metastable hexatic phase has finite condensate fraction and
it provides a natural explanation for the superflow in the supersolid grain
boundaries.

22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex