A bond operator representation of quantum $S=1$ spins is developed along the same line to the bond operator representation of quantum $S=\frac{1}{2}$ spins. The two representations are then applied to investigate the magnetization of the isotropic spin- $1$ antiferromagnetic chains and the spin- $\frac{1}{2}$ and spin- $1$ spin ladders. With the appropriate quantum states projected out, the spin- $1$ chains and the spin- $\frac{1}{2}$ and spin- $1$ spin ladders can be mapped to effective Hamiltonians of the $\mathcal{S}=\frac{1}{2}$ pseudospins in the effective external magnetic fields. The magnetization features of the spin- $1$ chains and the spin- $\frac{1}{2}$ and spin- $1$ spin ladders are then analyzed with the use of the existing rigorous results of the spin- $\frac{1}{2}$ $\mathrm{XXZ}$ spin chains. For spin- $1$ chains, the dependences of the magnetization on the applied magnetic fields are obtained. The $m=\frac{1}{4}$ plateau appearing in the magnetization of the spin- $\frac{1}{2}$ spin ladders and the $m=\frac{1}{4},$ $\frac{1}{2},$ and $\frac{3}{4}$ plateaus in the magnetization of the spin- $1$ spin ladders are studied. The effects of the single-ion anisotropy and the related experiments on spin- $1$ spin ladders are discussed also.A bond operator representation of quantum $S=1$ spins is developed along the same line to the bond operator representation of quantum $S=\frac{1}{2}$ spins. The two representations are then applied to investigate the magnetization of the isotropic spin-$1$ antiferromagnetic chains and the spin-$\frac{1}{2}$ and spin-$1$ spin ladders. With the appropriate quantum states projected out, the spin-$1$ chains and the spin-$\frac{1}{2}$ and spin-$1$ spin ladders can be mapped to effective Hamiltonians of the $\mathcal{S}=\frac{1}{2}$ pseudospins in the effective external magnetic fields. The magnetization features of the spin-$1$ chains and the spin-$\frac{1}{2}$ and spin-$1$ spin ladders are then analyzed with the use of the existing rigorous results of the spin-$\frac{1}{2}$ $\mathrm{XXZ}$ spin chains. For spin-$1$ chains, the dependences of the magnetization on the applied magnetic fields are obtained. The $m=\frac{1}{4}$ plateau appearing in the magnetization of the spin-$\frac{1}{2}$ spin ladders and the $m=\frac{1}{4},$ $\frac{1}{2},$ and $\frac{3}{4}$ plateaus in the magnetization of the spin-$1$ spin ladders are studied. The effects of the single-ion anisotropy and the related experiments on spin-$1$ spin ladders are discussed also.

Physical review. B, Condensed matterFeb 1, 200025 citations

Spin

The MIT Press eBooksMay 28, 20190 citations

Quantum Entanglement in a Spin-Orbit Coupled Bose–Einstein Condensate*

Yixiao Huang, Ning-Ju Hui, Wanfang Liu +2 more

Abstract We study the spin-field and the spin-spin entanglement in the ground state of a spin-orbit coupled Bose–Einstein condensate. It is found that the spin-field and the spin-spin entanglement can be induced by the spin-orbit coupling. By mapping the system to the Dicke-like model, the system exhibits a quantum phase transition from a normal (spin balanced) phase to superradiant (spin polarized) phase. The Dicke-like phase transition can be captured by the spin-field and the spin-spin entanglement arising from the spin-orbit coupling. The spin-field and the spin-spin entanglement increase as the Raman coupling increases in the superradiant phase, while they decrease with the Raman coupling increasing in the normal phase. We also consider the effect of a finite detuning on these entanglement show that the presence of the detuning suppresses the spin-field and the spin-spin entanglement.Abstract We study the spin-field and the spin-spin entanglement in the ground state of a spin-orbit coupled Bose–Einstein condensate. It is found that the spin-field and the spin-spin entanglement can be induced by the spin-orbit coupling. By mapping the system to the Dicke-like model, the system exhibits a quantum phase transition from a normal (spin balanced) phase to superradiant (spin polarized) phase. The Dicke-like phase transition can be captured by the spin-field and the spin-spin entanglement arising from the spin-orbit coupling. The spin-field and the spin-spin entanglement increase as the Raman coupling increases in the superradiant phase, while they decrease with the Raman coupling increasing in the normal phase. We also consider the effect of a finite detuning on these entanglement show that the presence of the detuning suppresses the spin-field and the spin-spin entanglement.

Communications in Theoretical PhysicsDec 1, 20152 citations

Spin

Leonardo Angelini

UNITEXT for physicsJan 1, 20190 citations

Single spin detection with an ensemble of probe spins

Syuhei Uesugi, Yuichiro Matsuzaki, Suguru Endo +2 more

Single spin detection is a key objective in the field of metrology. There have been many experimental and theoretical investigations for the spin detection based on the use of probe spins. A probe spin shows the precession due to dipole-dipole interaction from a target spin, and measurement results of the probe spin allow us to estimate the state of the target spin. Here, we investigate performance of single-spin detection when using an ensemble of probe spins. Even though the ensemble of probe spins inevitably induces projection noise that could hinder the signal from the target spin, optimization of the configuration of the spin ensemble improves the sensitivity such that enhancement of the signal can be much larger than the projection noise. The probe-spin ensemble is especially useful at a large distance from the target spin, where it is difficult for a single spin to read out the target spin within a reasonable repetition time. Our results pave the way for a new strategy to realize efficient single-spin detections.Single spin detection is a key objective in the field of metrology. There have been many experimental and theoretical investigations for the spin detection based on the use of probe spins. A probe spin shows the precession due to dipole-dipole interaction from a target spin, and measurement results of the probe spin allow us to estimate the state of the target spin. Here, we investigate performance of single-spin detection when using an ensemble of probe spins. Even though the ensemble of probe spins inevitably induces projection noise that could hinder the signal from the target spin, optimization of the configuration of the spin ensemble improves the sensitivity such that enhancement of the signal can be much larger than the projection noise. The probe-spin ensemble is especially useful at a large distance from the target spin, where it is difficult for a single spin to read out the target spin within a reasonable repetition time. Our results pave the way for a new strategy to realize efficient single-spin detections.

arXiv:1707.09824Jul 31, 20173 citations

Spin

Ray LaPierre

The Materials Research Society seriesJan 1, 20210 citations

A bond operator representation of quantum

S=1

spins is developed along the same line to the bond operator representation of quantum

S=\frac{1}{2}

spins. The two representations are then applied to investigate the magnetization of the isotropic spin-

1

antiferromagnetic chains and the spin-

\frac{1}{2}

and spin-

1

spin ladders. With the appropriate quantum states projected out, the spin-

1

chains and the spin-

\frac{1}{2}

and spin-

1

spin ladders can be mapped to effective Hamiltonians of the

\mathcal{S}=\frac{1}{2}

pseudospins in the effective external magnetic fields. The magnetization features of the spin-

1

chains and the spin-

\frac{1}{2}

and spin-

1

spin ladders are then analyzed with the use of the existing rigorous results of the spin-

\frac{1}{2}

\mathrm{XXZ}

spin chains. For spin-

1

chains, the dependences of the magnetization on the applied magnetic fields are obtained. The

m=\frac{1}{4}

plateau appearing in the magnetization of the spin-

\frac{1}{2}

spin ladders and the

m=\frac{1}{4},

\frac{1}{2},

and

\frac{3}{4}

plateaus in the magnetization of the spin-

1

spin ladders are studied. The effects of the single-ion anisotropy and the related experiments on spin-

1

spin ladders are discussed also.