Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Time operator in QFT with Virasoro constraints   Time operator is studied on the basis of field quantization, where the
difficulty stemming from Pauli's theorem is circumvented by borrowing ideas
from the covariant quantization of the bosonic string, i.e., one can remove the
negative energy states by imposing Virasoro constraints. Applying the index
theorem, one can show that in a different subspace of a Fock space, there is a
different self-adjoint time operator. However, the self-adjoint time operator
in the maximal subspace of the Fock space can also represent the self-adjoint
time operator in the other subspaces, such that it can be taken as the single,
universal time operator. Furthermore, a new insight on Pauli's theorem is
presented.

12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph