Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Simulation of four-body interaction in a nuclear magnetic resonance
  quantum information processor   Four-body interaction plays an important role in many-body systems, and it
can exhibit interesting phase transition behaviors. Historically it was the
need to efficiently simulate quantum systems that lead the idea of a quantum
computer. In this Letter, we report the experimental demonstration of a
four-body interaction in a four- qubit nuclear magnetic resonance quantum
information processor. The strongly modulating pulse is used to implement spin
selective excitation. The results show a good agreement between theory and
experiment.

18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
32
The categories of this paper are: atom-ph
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
7
The categories of this paper are: hep-th