Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Schr\"odinger equation with piercings   We show that the spectrum of the Schr\"odinger equation in two or higher
dimensions does not change when Dirichlet boundary conditions are enforced on a
number of isolated points inside the original domain (piercings). We have
obtained the analytical solution for spherically symmetric state of the
$d$-dimensional simple harmonic oscillator pierced at the origin. Results for
the case with multiple piercings are obtained numerically and agree with the
theoretical prediction. In the case of a two dimensional parabolic quantum dot
with two electrons and a single piercing in the origin we show that the energy
of the ground state calculated to first order in perturbation theory goes over
to the equivalent result in absence of piercing as the radius of the piercing
becomes infinitesimal. Interestingly, we find that the leading finite size
correction to the interaction energy is negative while the corresponding
correction to the single particle energies is (as expected) positive. For a
finite radius of the piercing and above a critical coupling, the first term
dominates the second and the total energy of the dot with piercing is lower.
Unfortunately the critical coupling found for this example is nonperturbative.
Finally we study configurations allowing bound states in the continuum, showing
that bound states survive to the insertion of piercings and that their energy
is unchanged when the radius of the piercing vanishes.

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The categories of this paper are: quant-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: funct-an
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The categories of this paper are: ao-sci
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The categories of this paper are: acc-phys
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The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: q-bio
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The categories of this paper are: mtrl-th
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The categories of this paper are: econ
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The categories of this paper are: atom-ph
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The categories of this paper are: solv-int
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The categories of this paper are: hep-th
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The categories of this paper are: bayes-an
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The categories of this paper are: cmp-lg