Related papers: Exact diagonalization Studies of Two-dimensional F…
We report large-scale quantum Monte Carlo calculations at the T=0 antiferromagnetic to valence-bond-solid (VBS) transition of a two-dimensional S=1/2 XY model with four-spin interactions. Finite-size scaling suggests a discontinuous spin…
We report an analysis of neutron diffraction from single crystals of the spin-liquid pyrochlore Tb2Ti2O7 under the application of magnetic fields along the crystallographic $[110]$ direction. Such a perturbation has been shown to destroy…
We explore both analytically and numerically the properties of doped t-J models on a class of highly frustrated lattices, such as the kagome and the pyrochlore lattice. Focussing on a particular sign of the hopping integral and…
We develop an approach to describe antiferromagnetic magnons on a bipartite lattice supporting the N\'{e}el state using fractionalized degrees of freedom typically inherent to quantum spin liquids. In particular we consider a long-range…
The frustrated spin-$1/2$ $J_1-J_2$ Heisenberg model on the square lattice has been extensively studied since 1988 because of its close relationship to the high-temperature superconductivity in cuprates and more importantly involved novel…
Single-site measurement in a distributed macroscopic antiferromagnet is considered; we show that it can create antiferromagnetic sublattices at macroscopic scale. We demonstrate that the result of measurement depends on the symmetry of the…
We study the ground-state properties of the two-dimensional quantum spin systems having the valence-bond-solid (VBS) type ground states. The ``product-of-tensors'' form of the ground-state wavefunction of the system is utilized to associate…
We perform highly accurate density matrix renormalization group (DMRG) simulations to investigate the ground state properties of the spin-1/2 antiferromagnetic square lattice Heisenberg $J_1$-$J_2$ model. Based on studies of numerous long…
We study the ground state phase diagram of the quantum spin-$1/2$ Heisenberg model on the kagom\'{e} lattice with first- ($J_1 < 0$), second- ($J_2 < 0$), and third-neighbor interactions ($J_d > 0$) by means of analytical low-energy field…
The question of the existence of order in two-dimensional isotropic dipolar Heisenberg antiferromagnets is studied. It is shown that the dipolar interaction leads to a gap in the spin-wave energy and a nonvanishing order parameter. The…
The ground-state properties of the spin-1/2 antiferromagnetic Heisenberg model with spatially anisotropic couplings on a square lattice are investigated by a spin-rotation-invariant Green's-function approach and by Lanczos diagonalizations…
Recent scanning tunnelling microscopy (STM) experiments on underdoped cuprates have displayed modulations in the local electronic density of states which are centered on a Cu-O-Cu bond (Kohsaka et. al., cond-mat/0703309). As a paradigm of…
We study the frustrated and dimerized ferromagnetic-antiferromagnetic $J_1$-$J_1'$-$J_2$ chain using the density-matrix renormalization group (DMRG) method. Based on numerical calculations of the second derivative of energy, spin gap,…
N\'eel ordered antiferromagnets exhibit two-mode squeezing such that their ground state is a nonclassical superposition of magnon Fock states. Here we theoretically demonstrate that antiferromagnets can couple to spin qubits via direct…
We explore the phase diagram and the low-energy physics of three Heisenberg antiferromagnets which, like the kagome lattice, are networks of corner-sharing triangles but contain two sets of inequivalent short-distance resonance loops. We…
New physics can emerge in magnetic materials where quantum fluctuations are enhanced due to reduced dimensionality and strong frustration. One long sought example is the resonating-valence-bond (RVB) state, where atomic magnetic moments are…
We determine where a given concentration of ferromagnetic (FM) bonds doped into a square lattice antiferromagnet must go to minimize the system's total magnetic energy. We find (i) an infinite degeneracy of ground--state arrangements of FM…
We use Quantum Monte-Carlo methods to study the ground state phase diagram of a S=1/2 honeycomb lattice magnet in which a nearest-neighbor antiferromagnetic exchange J (favoring N\'eel order) competes with two different multi-spin…
We explore the spin states in the quantum spin chain compound SrCo$_{2}$V$_{2}$O$_{8}$ up to 14.9 T and down to 50 mK, using single-crystal neutron diffraction. Upon cooling in zero-field, antiferromagnetic (AFM) order of N\'eel type…
We study the zero-temperature phase diagram of a square-lattice $S=1/2$ Heisenberg antiferromagnet with two types of regularly distributed nearest-neighbor exchange constants, $J_1>0$ (antiferromagnetic) and $-\infty < J_2 < \infty $, using…