Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observation of bound state self-interaction in a nano-eV atom collider   Quantum mechanical scattering resonances for colliding particles occur when a
continuum scattering state couples to a discrete bound state between them. The
coupling also causes the bound state to interact with itself via the continuum
and leads to a shift in the bound state energy, but, lacking knowledge of the
bare bound state energy, measuring this self-energy via the resonance position
has remained elusive. Here, we report on the direct observation of
self-interaction by using a nano-eV atom collider to track the position of a
magnetically-tunable Feshbach resonance through a parameter space spanned by
energy and magnetic field. Our system of potassium and rubidium atoms displays
a strongly non-monotonic resonance trajectory with an exceptionally large
self-interaction energy arising from an interplay between the Feshbach bound
state and a different, virtual bound state at a fixed energy near threshold.

17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
6
The categories of this paper are: astro-ph