论文标题
离子陷阱量子计算机的声子模式在Aubry阶段
Properties of phonon modes of ion trap quantum computer in the Aubry phase
论文作者
论文摘要
我们通过分析和数值研究语音模式在离子量子计算机中的特性。离子链被放置在一个谐波陷阱中，具有额外的周期性潜力，无尺度振幅$ k $决定可用于量子计算的三个主要阶段：在零$ k $时，我们有CIRAC-Zoller量子计算机的情况下，低于某个关键的临界幅度$ k <k_c $在kolmogorov-delmogorov-arnold-moser（kam arnold-moser）（kalmogorov-moser）（kalmogorov-moser）（KAM）阶段（k <k_c $高于临界幅度$ k> k_c $离子处于固定阶段，有限频率差距可保护量子门免受温度和其他外部波动的影响。对于Aubry阶段，与CIRAC-Zoller和KAM相相反，声子间隙保持独立于陷阱中的离子数量，保持陷阱中心周围的固定离子密度。我们表明，在Aubry阶段，与CIRAC-Zoller和KAM案例相比，声子模式是更好的局部化。因此，在Aubry阶段，后坐力脉冲导致离子的局部振荡，而在其他两个阶段，它们迅速传播在整个离子链上，使其对外部波动相当明智。我们认为，在Aubry阶段，局部声子模式和声子差距的属性为在此阶段具有大量离子的离子量子计算提供了优势。
We study analytically and numerically the properties of phonon modes in an ion quantum computer. The ion chain is placed in a harmonic trap with an additional periodic potential which dimensionless amplitude $K$ determines three main phases available for quantum computations: at zero $K$ we have the case of Cirac-Zoller quantum computer, below a certain critical amplitude $K<K_c$ the ions are in the Kolmogorov-Arnold-Moser (KAM) phase, with delocalized phonon modes and free chain sliding, and above the critical amplitude $K>K_c$ ions are in the pinned Aubry phase with a finite frequency gap protecting quantum gates from temperature and other external fluctuations. For the Aubry phase, in contrast to the Cirac-Zoller and KAM phases, the phonon gap remains independent of the number of ions placed in the trap keeping a fixed ion density around the trap center. We show that in the Aubry phase the phonon modes are much better localized comparing to the Cirac-Zoller and KAM cases. Thus in the Aubry phase the recoil pulses lead to local oscillations of ions while in other two phases they spread rapidly over the whole ion chains making them rather sensible to external fluctuations. We argue that the properties of localized phonon modes and phonon gap in the Aubry phase provide advantages for the ion quantum computations in this phase with a large number of ions.
