Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Tensor network simulation of the (1+1)-dimensional $O(3)$ nonlinear
  $\sigma$-model with $\theta=\pi$ term   We perform a tensor network simulation of the (1+1)-dimensional $O(3)$
nonlinear $\sigma$-model with $\theta=\pi$ term. Within the Hamiltonian
formulation, this field theory emerges as the finite-temperature partition
function of a modified quantum rotor model decorated with magnetic monopoles.
Using the monopole harmonics basis, we derive the matrix representation for
this modified quantum rotor model, which enables tensor network simulations. We
employ our recently developed continuous matrix product operator method [Tang
et al., Phys. Rev. Lett. 125, 170604 (2020)] to study the finite-temperature
properties of this model and reveal its massless nature. The central charge as
a function of the coupling constant is directly extracted in our calculations
and compared with field theory predictions.

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The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
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The categories of this paper are: eess
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The categories of this paper are: q-bio
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The categories of this paper are: adap-org
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The categories of this paper are: hep-th
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The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
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The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga