Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Entanglement spectrum of the degenerative ground state of Heisenberg
  ladders in a time-dependent magnetic field   We investigate of the relationship between the entanglement and subsystem
Hamiltonians in the perturbative regime of strong coupling between subsystems.
One of the two conditions that guarantees the proportionality between these
Hamiltonians obtained by using the nondegenerate perturbation theory within the
first order is that the unperturbed ground state has a trivial entanglement
Hamiltonian. Furthermore, we study the entanglement Hamiltonian of the
Heisenberg ladders in a time-dependent magnetic field using the degenerate
perturbation theory, where couplings between legs are considered as a
perturbation. In this case, when the ground state is two-fold degenerate, and
the entanglement Hamiltonian is proportional to the Hamiltonian of a chain
within first-order perturbation theory, even then also the unperturbed ground
state has a nontrivial entanglement spectrum.

31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
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The categories of this paper are: dg-ga
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The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th