Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: No spin-localization phase transition in the spin-boson model without
  local field   We explore the spin-boson model in a special case, i.e., with zero local
field. In contrast to previous studies, we find no possibility for quantum
phase transition (QPT) happening between the localized and delocalized phases,
and the behavior of the model can be fully characterized by the even or odd
parity as well as the parity breaking, instead of the QPT, owned by the ground
state of the system. Our analytical treatment about the eigensolution of the
ground state of the model presents for the first time a rigorous proof of
no-degeneracy for the ground state of the model, which is independent of the
bath type, the degrees of freedom of the bath and the calculation precision. We
argue that the QPT mentioned previously appears due to unreasonable treatment
of the ground state of the model or of the infrared divergence existing in the
spectral functions for Ohmic and sub-Ohmic dissipations.

15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph