Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Anomalous fractional quantization in the kagomelike Heisenberg ladder:
  Emergence of the effective spin-1 chain   We study a Kagome-like spin-$1/2$ Heisenberg ladder with competing
ferromagnetic (FM) and antiferromagnetic (AFM) exchange interactions. Using the
density-matrix renormalization group based calculations, we obtain the ground
state phase diagram as a function of the ratio between the FM and AFM exchange
interactions. Five different phases exist. Three of them are spin polarized
phases; an FM phase and two kinds of ferrimagnetic (FR) phases (referred to as
FR1 and FR2 phases). The spontaneous magnetization per site is $m=1/2$, $1/3$,
and $1/6$ in the FM, FR1, and FR2 phases, respectively. This can be understood
from the fact that an effective spin-1 Heisenberg chain formed by the upper and
lower leg spins has a three-step fractional quantization of the magnetization
per site as $m=1$, $1/2$, and $0$. In particular, an anomalous "intermediate"
state $m=1/2$ of the effective spin-1 chain with the reduced Hilbert space of a
spin from $3$ to $2$ dimensional is highly unexpected in the context of
conventional spin-1 physics. Thus, surprisingly, the effective spin-1 chain
behaves like a spin-1/2 chain with SU(2) symmetry. The remaining two phases are
spin-singlet phases with translational symmetry breaking in the presence of
valence bond formations. One of them is octamer-siglet phase with a spontaneous
octamerization long-range order of the system, and the other is period-4 phase
characterized by the magnetic superstructure with a period of four structural
unit cells. In these spin-singlet phases, we find the coexistence of valence
bond structure and gapless chain. Although this may be emerged through the
order-by-disorder mechanism, there can be few examples of such a coexistence.

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The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
20
The categories of this paper are: acc-phys
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ex
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
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The categories of this paper are: math-ph