Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Interaction with an obstacle in the 2d focusing nonlinear Schr\"odinger
  equation   We present a numerical study of solutions to the $2d$ cubic and quintic
focusing nonlinear Schr\"odinger equation in the exterior of a smooth, compact
and strictly convex obstacle (a disk) with Dirichlet boundary condition. We
first investigate the effect of the obstacle on the behavior of solutions
traveling toward the obstacle at different angles and with different velocities
directions. We introduce a new concept of weak and strong interactions of the
solutions with the obstacle. Next, we study the existence of blow-up solutions
depending on the type of the interaction and show how the presence of the
obstacle changes the overall behavior of solutions (e.g., from blow-up to
global existence), especially in the strong interaction case, as well as how it
affects the shape of solutions compared to their initial data, (e.g., splitting
into transmitted and reflected parts). We also investigate the influence of the
size of the obstacle on the eventual existence of blow-up solutions in the
strong interaction case in terms of the transmitted and the reflected parts of
the mass. Moreover, we show that the sharp threshold for global existence vs.
finite time blow-up solutions in the mass critical case in the presence of the
obstacle is the same as the one given by Weinstein for {\rm{NLS}} in the whole
Euclidean space $\R^d$. Finally, we construct new Wall-type initial data that
blows up in finite time after a strong interaction with an obstacle and having
a very distinct dynamics compared with all other blow-up scenarios and dynamics
for the {\rm{NLS}} in the whole Euclidean space $\R^d$.

20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio