Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Entanglement spectra of coupled S=1/2 spin chains in a ladder geometry   We study the entanglement spectrum of spin-1/2 XXZ ladders both analytically
and numerically. Our analytical approach is based on perturbation theory
starting either from the limit of strong rung coupling, or from the opposite
case of dominant coupling along the legs. In the former case we find to leading
order that the entanglement Hamiltonian is also of nearest-neighbor XXZ form
although with an in general renormalized anisotropy. For the cases of XX and
isotropic Heisenberg ladders no such renormalization takes place. In the
Heisenberg case the second order correction to the entanglement Hamiltonian
consists of a renormalization of the nearest neighbor coupling plus an
unfrustrated next nearest neighbor coupling. In the opposite regime of strong
coupling along the legs, we point out an interesting connection of the
entanglement spectrum to the Lehmann representation of single chain spectral
functions of operators appearing in the physical Hamiltonian coupling the two
chains.

27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph