Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the existence of a non-relativistic hermitian time operator   The existence of a hermitian time operator is proposed in the framework of
non-relativistic quantum mechanics.The Heisenberg equation of motion is shown
to yield constant rate of flow of time.It is shown to yield results consistent
with classical expectations,when Bohr's correspondence principle is
invoked.Further,it is shown that a massless free particle with non-zero
momentum experiences timelessness in its own frame of reference whereas a
negatively massive particle perceives forwardness of time.Moreover,application
to quantum harmonic oscillators shows instantaneous transition of electrons
from one eigenstate to another.

7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con