Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Competition between spin liquids and valence-bond order in the
  frustrated spin-$1/2$ Heisenberg model on the honeycomb lattice   Using variational wave functions and Monte Carlo techniques, we study the
antiferromagnetic Heisenberg model with first-neighbor $J_1$ and
second-neighbor $J_2$ antiferromagnetic couplings on the honeycomb lattice. We
perform a systematic comparison of magnetically ordered and nonmagnetic states
(spin liquids and valence-bond solids) to obtain the ground-state phase
diagram. N\'eel order is stabilized for small values of the frustrating
second-neighbor coupling. Increasing the ratio $J_2/J_1$, we find strong
evidence for a continuous transition to a nonmagnetic phase at $J_2/J_1 \approx
0.23$. Close to the transition point, the Gutzwiller-projected uniform
resonating valence bond state gives an excellent approximation to the exact
ground-state energy. For $0.23 \lesssim J_2/J_1 \lesssim 0.4$, a gapless $Z_2$
spin liquid with Dirac nodes competes with a plaquette valence-bond solid. In
contrast, the gapped spin liquid considered in previous works has significantly
higher variational energy. Although the plaquette valence-bond order is
expected to be present as soon as the N\'eel order melts, this ordered state
becomes clearly favored only for $J_2/J_1 \gtrsim 0.3$. Finally, for $0.36
\lesssim J_2/J_1 \le 0.5$, a valence-bond solid with columnar order takes over
as the ground state, being also lower in energy than the magnetic state with
collinear order. We perform a detailed finite-size scaling and standard data
collapse analysis, and we discuss the possibility of a deconfined quantum
critical point separating the N\'eel antiferromagnet from the plaquette
valence-bond solid.

18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys