176 research outputs found
Conventional description of Unconventional Coulomb-Crystal phase transitions in three-dimensional classical O(N) spin-ice
We study the phase transition between the high temperature Coulomb phase and
the low temperature staggered crystal phase in three dimensional classical O(N)
spin-ice model. Compared with the previously proposed CP(1) formalism on the
Coulomb-crystal transition of the classical dimer model, our description based
on constrained order parameter is more conventional, due to a fundamental
difference between the O(N) and the dimer model. A systematic epsilon and 1/N
expansion are used to study the universality class of the phase transition, and
a stable fixed point is found based on our calculations for large enough N.Comment: 5 pages, 2 figure
Liquids in multi-orbital SU(N) Magnets with Ultracold Alkaline Earth Atoms
In this work we study one family of liquid states of k-orbital SU(N) spin
systems, focusing on the case of k = 2 which can be realized by ultracold
alkaline earth atoms trapped in optical lattices, with N as large as 10. Five
different algebraic liquid states with selectively coupled charge, spin and
orbital quantum fluctuations are considered. The algebraic liquid states can be
stabilized with large enough N, and the scaling dimension of physical order
parameters is calculated using a systematic 1/N expansion. The phase
transitions between these liquid states are also studied, and all the algebraic
liquid states discussed in this work can be obtained from one "mother" state
with SU(2) x U(1) gauge symmetry.Comment: 5 pages, 1 figur
Quantum Spin Hall, triplet Superconductor, and topological liquid on the honeycomb lattice
We classify the order parameters on the honeycomb lattice using the SO(4)
symmetry of the Hubbard model. We will focus on the topologically nontrivial
quantum spin Hall order and spin triplet superconductor, which together belong
to the (3, 3) representation of the SO(4). Depending on the microscopic
parameters, this (3, 3) order parameter has two types of ground states with
different symmetries: type A, the ground state manifold is [S^2xS^2]/Z_2; and
type B, with ground state manifold SO(3)xZ_2. We demonstrate that phase A is
adjacent to a Z_2xZ_2 topological phase with mutual semion statistics between
spin and charge excitations, while phase B is adjacent to a nonabelian phase
described by SU(2) Chern-Simons theory. Connections of our study to the recent
quantum Monte Carlo simulation on the Hubbard model on the honeycomb lattice
will also be discussed.Comment: 9 pages, 3 figure
Low Energy Effective Field Theories of Sp(4) Spin systems
We study the classical and quantum phase transitions of Sp(4) spin systems on
three dimensional stacked square and triangular lattices. We present general
Ginzburg-Landau field theories for various types of Sp(4) spin orders with
different ground state manifolds such as CP(3), S^7/Z_2, Grassmann manifold
G_{2,5}, G_{2,6} and so on, based on which the nature of the classical phase
transitions are studied, and a global phase diagram is presented. The classical
phase transitions close to quantum phase transitions toward spin liquid states
are also discussed based on renormalization group (RG) flow. Our results can be
directly applied to the simplest Sp(4) and SU(4) Heisenberg models which can be
realized using spin-3/2 atoms and Alkaline earth atoms trapped in optical
lattice.Comment: 8 pages, 4 figure
Emergent Gravity at a Lifshitz Point from a Bose Liquid on the Lattice
We propose a model with quantum bosons on the fcc lattice, which has a stable
algebraic Bose liquid phase at low energy. We show that this phase is described
by emergent quantum gravity at the Gaussian z = 3 Lifshitz fixed point in 3+1
dimensions. The stability of this algebraic Bose liquid phase is guaranteed by
the gauge symmetry of gravitons and self-duality of the low energy field
theory. By tuning one parameter in the lattice boson model we can drive a phase
transition between the z = 3 Lifshitz gravity and another algebraic Bose liquid
phase, described by gravity at the z = 2 Lifshitz point.Comment: 8 pages, 1 figur
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