论文标题
钻石氮空位中心中自旋动力学的绝热性在时间依赖性磁场中
Adiabaticity of spin dynamics in diamond nitrogen vacancy centers in time-dependent magnetic fields
论文作者
论文摘要
我们研究了横向磁场的存在，研究了沿NV的对称轴振荡磁场中钻石氮空位（NV）中心的自旋动力学。众所周知，否则退化的Zeeman级别$ | m_s = \ pm1 \ rangle $之间的耦合是由于振动磁场的轴向分量发生变化时，由于应变和电场而导致的降低绝热能量水平的Landau-Zener工艺。我们为NV系统得出了有效的两级哈密顿量，其中包括两个级别之间通过虚拟过渡到第三个遥远的级别$ | m_s = 0 \ rangle $，由横向磁场引起的。由于应变和电场，这种耦合增加了耦合，其相位取决于垂直于NV轴的平面中横向场的方向。因此，可以调节Zeeman级别的{\ em总耦合}，以通过完全或部分补偿应变和电场的效果或通过增强它来控制自旋动力学的绝热性。此外，通过改变横向磁场的强度和方向，可以确定NV中心位置的局部应变和电场的强度和方向，甚至可以确定{\ em External}应力和电场。核自旋超精美相互作用显示出引入轴向磁场的核自旋依赖性偏移，而伪磁场会发生伪横断，而绝热性仍然不受核自旋的影响。如果将NV中心耦合到环境中，该环境由带有高斯白噪声光谱的浴室建模，适用于钻石表面附近的NV，则自旋动力学伴随着Zeeman级别种群的放松，并且具有耐腐蚀性，并且具有非单声道型系统纯度。
We study the spin dynamics of diamond nitrogen vacancy (NV) centers in an oscillating magnetic field along the symmetry axis of the NV in the presence of transverse magnetic fields. It is well-known that the coupling between the otherwise degenerate Zeeman levels $|M_S=\pm1\rangle$ due to strain and electric fields is responsible for a Landau-Zener process near the pseudo-crossing of the adiabatic energy levels when the axial component of the oscillating magnetic field changes sign. We derive an effective two-level Hamiltonian for the NV system that includes coupling between the two levels via virtual transitions into the third far-detuned level $|M_S=0\rangle$ induced by transverse magnetic fields. This coupling adds to the coupling due to strain and electric fields, with a phase that depends on the direction of the transverse field in the plane perpendicular to the NV axis. Hence, the {\em total coupling} of the Zeeman levels can be tuned to control the adiabaticity of spin dynamics by fully or partially compensating the effect of the strain and electric fields, or by enhancing it. Moreover, by varying the strength and direction of the transverse magnetic fields, one can determine the strength and direction of the local strain and electric fields at the position of the NV center, and even the {\em external} stress and electric field. The nuclear spin hyperfine interaction is shown to introduce a nuclear spin dependent offset of the axial magnetic field for which the pseudo-crossing occurs, while the adiabaticity remains unaffected by the nuclear spin. If the NV center is coupled to the environment, modeled by a bath with a Gaussian white noise spectrum, as appropriate for NVs near the diamond surface, then the spin dynamics is accompanied by relaxation of the Zeeman level populations and decoherence with a non-monotonic decrease of the purity of the system.
