Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Solving the quantum many-body problem via correlations measured with a
  momentum microscope   In quantum many-body theory, all physical observables are described in terms
of correlation functions between particle creation/annihilation operators.
Measurement of such correlation functions can therefore be regarded as an
operational solution to the quantum many-body problem. Here we demonstrate this
paradigm by measuring multi-particle momentum correlations up to third order
between ultracold helium atoms in an s-wave scattering halo of colliding
Bose-Einstein condensates, using a quantum many-body momentum microscope. Our
measurements allow us to extract a key building block of all higher-order
correlations in this system|the pairing field amplitude. In addition, we
demonstrate a record violation of the classical Cauchy-Schwarz inequality for
correlated atom pairs and triples. Measuring multi-particle momentum
correlations could provide new insights into effects such as unconventional
superconductivity and many-body localisation.

13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ