Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the renormalization of contact interactions for the
  configuration-interaction method in two dimensions   The configuration interaction (CI) method for calculating the exact
eigenstates of a quantum-mechanical few-body system is problematic when applied
to particles interacting through contact forces. In dimensions higher than one
the approach fails due to the pathology of the Dirac delta-potential, making it
impossible to reach convergence by gradually increasing the size of the Hilbert
space. However, this problem may be cured in a rather simple manner by
renormalizing the strength of the contact potential when diagonalizing in a
truncated Hilbert space. One hereby relies on the comparison of the CI results
to the two-body ground-state energy obtained by the exact solution of the
Schroedinger equation for a regularized contact interaction. We here discuss a
scheme that provides cutoff-independent few-body physical observables. The
method is applied to a few-body system of ultracold atoms confined by a
two-dimensional harmonic oscillator.

19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an