Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Study of hydrogen atom described by a generalized wave equation: what
  can we still learn about space dimensionality   Hydrogen atom is supposed to be described by a generalization of
Schr\"odinger equation, in which the Hamiltonian depends on an iterated
Laplacian and a Coulomb-like potential $r^{-\beta}$. Starting from previously
obtained solutions for this equation using the $1/N$ expansion method, it is
shown that new light can be shed on the problem of understanding the
dimensionality of the world as proposed by Paul Ehrenfest. A surprisingly new
result is obtained. Indeed, for the first time, we can understand that not only
the sign of energy but also the value of the ground state energy of hydrogen
atom is related to the threefold nature of space.

34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th